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Steep surrounding rock significantly challenges tunnel stability by affecting the stress distribution and deformation behavior. The angle of dip in surrounding rock greatly influences these factors, heightening the risk of instability along bedding planes, particularly under high ground stress conditions. This paper presents a comprehensive analysis of steep rock strata mechanical properties based on a railway tunnel in Yunnan Province, China. It incorporates long-term field monitoring and various laboratory tests, including point load, triaxial, and loose circle tests. Using experimental data, this study simulated the failure processes of steep surrounding rock and tunnel structures with a custom finite element method (FEM) integrated with the volume of fluid (VOF) approach. The analysis summarized the deformation patterns, investigated the causes of inverted arch deformation and failure, and proposed countermeasures. The findings reveal that increasing the rock dip angle results in greater deformation and accelerated failure rates, with the surrounding rock's loose zone stabilizing at approximately 8 m once deformation stabilizes. At a surface deformation of 8 cm, the failure zone extends to 6 m; however, this extension occurs more rapidly with higher lateral pressure coefficients. Additionally, failure zones develop more quickly in thin, soft rock on steep slopes compared to uniform rock formations. The rise of the tunnel floor is attributed to the steeply inclined, thin surrounding rock. To enhance bottom structure stiffness, this study recommends incorporating an inverted arch structure and increasing both the number and strength of the anchor bolts. [ABSTRACT FROM AUTHOR]

Acoustic Emission (AE) testing is a non-destructive evaluation technique that has gained significant attention in pipeline monitoring. Pencil-lead breaks (PLBs) are commonly used in reproducing and characterising sensors used in AE applications and have emerged as a valuable tool for calibration processes. This technique involves breaking a pencil lead by pressing it on the surface of the test structure and applying a bending moment at a given angle on a surface. The applied force produces a local deformation on the test surface, which is released when the lead breaks. The fracture in these PLBs is assumed to be a step unload; however, this is not the case. In this work, a series of PLB source experiments complemented with parallel numerical simulations were carried out to investigate the actual unload rate by correlating the relationship between AE speed, frequency, and power from PLBs. This was achieved by varying the simulation unload rates recorded over a duration of 2 s on a steel pipe and comparing to the experiment. Analysis of the investigated results from the experimental and numerical models suggests that although the AE line structure of a PLB can be reproduced by simulation for short times only (1 µs), the actual unload rate for PLBs is in the region of 10–8 s. It is concluded that FEA has the potential to help in the recovery of the temporal structure from real AE structures. The establishment of this model will provide a theoretical basis for future studies on the monitoring of non-impulsive AE sources such as impact on pipelines using finite element analysis. [ABSTRACT FROM AUTHOR]

The escalating occurrence of landslides has drawn increasing attention from the scientific community, primarily driven by a combination of natural phenomena such as unpredictable seismic events, intensified precipitation, and rapid snowmelt attributable to climate fluctuations, compounded by inadequacies in engineering practices during site selection. Within the scope of this investigation, contemporary geodetic techniques using the GNSS were employed to monitor structural and surface deformations in and around a hospital edifice situated within an ancient fossil landslide region. Additionally, inclinometer measurements facilitated the determination of slip circle parameters. A subsequent analysis integrated these datasets to scrutinize both the hospital structure and its surrounding slopes. In addition to the finite element method, four different limit equilibrium methods (Bishop, GLE–Morgenstern–Price, Spencer, and Janbu) were used in the evaluation of stability. Since the safety number determined in all analyses was <1, it was determined that the slope containing the hospital building was unstable. The movement has occurred again due to the additional load created by the hospital building built on the currently stable slope, the effect of surface and groundwater, and the improperly designed road route. As a result of geodetic monitoring, it was determined that the sliding speed on the surface was in the N-E direction and was approximately 3 cm, and this situation almost coincided with inclinometer measurements. [ABSTRACT FROM AUTHOR]

The additional deformation of slab track structure subject to arbitrary soil deformation, and subsequently the dynamic deformation coordination between the track and the soil due to a moving vehicle are of significant importance in the analysis of vehicle-track-soil (VTS) interactions. In this work, the finite element modeling and numerical iterative method are presented to compile a simulation program to reveal the deformation coordinated process of slab track-soil interaction reasonably, where the contact-separation relationship at the slab track-soil interface, the interlayered gap between slab track and soil surface, and additional track deformation are derived as additional geometric excitations of VTS interaction system. In numerical studies, different slab track types considering the unit and the longitudinal connected base plates are taken as illustrative and comparative examples, where the deformation coordinated mechanism of slab track-soil interaction and its influence on vehicle-induced vibrations are clarified. [ABSTRACT FROM AUTHOR]

The smelting process of Ferronickel in Indonesia produces a significant amount of waste in the form of Ferronickel Slag (FNS), with an annual accumulation of up to 13 million metric tons. Previous studies have shown promising strength results for concrete utilizing FNS as a fine aggregate. This study aims to analyze the mechanical properties of three reinforced concrete (RC) beams measuring 15 cm × 25 cm × 300 cm, each containing FNS as a 50% substitute for fine aggregate. The RC Beams underwent experimental testing using a four-point loading scheme under semi-cyclic loading conditions. Test results show the beams' capacity had reached up to 8 ton-f and their load–displacement responses show promising results. Digital Image Correlation (DIC) analysis facilitated the observation of surface deformation evolution due to loading, aiding in the identification of concrete crack patterns. Due to semi-cyclic loading, cracks on the beams' surface were experiencing a crack opening and closing phenomenon, where the propagations of cracks ceased or reclosed throughout the unloading process. Moreover, the opening of residual cracks was also captured by DIC analysis. The experimental finding was validated by finite element analysis. The RC beam numerical model was created using the Timoshenko Multi-fiber element in CAST3M software version 2022. Mazars concrete and elastoplastic steel damage model were used as constitutive laws for numerical modeling. The model's load–displacement response demonstrated satisfactory agreement compared to the experimental monotonic loading result. However, the model had limitations regarding the simulation of residual displacements of beams due to semi-cyclic loading. [ABSTRACT FROM AUTHOR]

Dielectric elastomer actuators (DEAs) are increasingly recognized as pivotal components in flexible robotic actuators due to their substantial displacement, high energy density, rapid response times, and adaptable design characteristics. Nonetheless, the widespread adoption of DEAs is impeded by challenges such as elevated manufacturing costs and inherent nonlinear characteristics, which obscure a comprehensive understanding of the interplay between dielectric elastomer (DE) related material properties and voltage stimuli governing DEA operation. This study introduces a sophisticated finite element model that integrates Maxwell stress principles with the hyperelastic behavior inherent in DEs, enabling the numerical elucidation of DEA gripper dynamics. Utilizing this model, the minimum energy structure of DEs and their nonlinear actuation behavior under diverse electric field conditions are analyzed. The model's efficacy is validated through a meticulous comparison of simulated angular deflection and displacement with experimental results obtained from a six-segment DEA gripper across varying electric field intensities. Additionally, the impact of dielectric coefficients on the electro-actuated deformation of the DEA gripper is rigorously assessed, revealing a noteworthy enhancement in electro-actuation efficiency with increasing dielectric constants, particularly under high electric field conditions. Furthermore, the deformation differences of multi-segment DEA grippers under different voltage control strategies were investigated. The causes of these differences are discussed through stress analysis, and a sequential voltage application strategy is designed to optimize the gripping effect. The insights gleaned from this study offer valuable guidance for the design and optimization of DEAs tailored to diverse deformation requirements within the field of flexible robotic actuators. [ABSTRACT FROM AUTHOR]

The fluid–solid coupling effect is more pronounced in the process of deep coal seam development compared to shallow coalbed methane, exerting a greater influence on production, and cannot be disregarded. Throughout the extraction process, the interaction between effective stress and gas desorption triggers deformation within the coal seam, leading to dynamic changes in both porosity and permeability. This paper has developed a fully coupled gas flow and deformation model that contains the coal matrix and discrete fractures to describe the dynamic gas seepage behavior and deformation of deep coal seams within a coupled wellbore–hydraulic fractures–matrix system. The model's validity is corroborated through the examination of fracture aperture, employing the finite element numerical simulation capabilities of COMSOL Multiphysics. Subsequent to the model's validation, an in-depth investigation into the permeability and production variations under diverse parametric conditions is conducted. This analysis also encompasses the assessment of hydraulic fracture geometry's impact. The simulation outcomes reveal that the permeability alterations during coal seam development are subject to the counteracting influences of gas desorption and effective stress. Moreover, it is observed that an increase in the Langmuir volume strain constant and initial porosity correlates with enhanced production, whereas a diminution in the hydraulic fracture compression coefficient leads to increased cumulative production. Notably, the optimal production is attained when hydraulic fractures are oriented vertically yet asymmetrically relative to the horizontal well. [ABSTRACT FROM AUTHOR]

Plastoelastohydrodynamic lubrication of rough surfaces (R-PEHL) is a cutting-edge area of research in interface fluid-structure coupling analysis. The existing R-PEHL model calculates the elastic-plastic deformation of rough surface by the Love equation in a semi-infinite space smooth surface, which deviates from the actual surface. Therefore, it is an innovative work to study the exact solution of elastic-plastic deformation of rough surface and its influence on the solution results of R-PEHL model. In this paper, a new contact calculation model of plastoelastohydrodynamic lubrication (PEHL) with three-dimensional (3D) rough surface is proposed by integrating numerical method of EHL and finite element method. The new model eliminates an original error introduced by the assumption of semi-infinite space in contact calculation, providing wide applicability and high accuracy. Under the given rough surfaces and working conditions, the study reveals that: (1) the oil film pressure calculated by the new model is lower than that of the smooth surface in semi-infinite space by 200–800 MPa; (2) the Mises stress of the new model is 2.5%–26.6% higher than that of the smooth surface in semi-infinite space; (3) compared with the semi-infinite space assumption, the rough surface plastic deformation of the new model is increased by 71%–173%, and the local plastic deformation singularity may appear under the semi-infinite space assumption; (4) the plastic deformation caused by the first contact cycle on the rough surface of the new model accounts for 66.7%–92.9% of the total plastic deformation, and the plastic deformation of the semi-infinite space accounts for 50%–83.3%. This study resolves the contradiction between the smooth surface assumption and the rough surface in the existing R-PEHL model, establishing a solid logic foundation for the accurate solution of R-PEHL model. [ABSTRACT FROM AUTHOR]

Precision polishing of aeroengine blades involves a complex material removal process, primarily due to the presence of numerous abrasive grains bonded on the polishing tool. Therefore, understanding the surface formation mechanism at the microscale, as a result of a single abrasive grain's interaction with the workpiece, is pivotal for deciphering the collective effect of numerous abrasive actions. Since conducting single-grain cutting experiments at the microscale presents significant challenges, the finite element method (FEM) is considered an effective method for revealing microscopic physical phenomena and conducting in-depth research on cutting mechanisms. In this research, the simplified single-grain scratch experiment was conducted first, and then, the adaptive remeshing technique in Abaqus was utilized to simulate the elastic and plastic deformation of the workpiece surface during the polishing process, supplementing the physical measurement results that are difficult to achieve in the scratch experiment. The single-grain scratch experiment results show that elastic deformation of the workpiece material persists throughout the grain cutting process, and the elastic deformation FEM simulation results show that the pure rubbing phase is confined to an extremely short length after the interference occurs between the grain and the workpiece. To delve into the plastic deformation of workpiece surface in FEM simulation, the material pile-up ratio was used, and the effect of polishing variables such as cutting speed, cutting depth, and grain size on microscopic surface creation was focused on. Among them, cutting depth and grain size significantly affect the surface creation of workpiece material. In addition, the microscopic plastic deformation when the abrasive grain cut-in and cut-out phases during the polishing process is different. The outcomes of these simulations are anticipated to inform future experimental strategies and foster advancements in the development of more efficient and precise aeroengine blade polishing techniques. [ABSTRACT FROM AUTHOR]

The excellent shape stability of thermally expanded metamaterials and the good bandgap properties of acoustic metamaterials have a wide range of promising applications in aerospace and sensors. Here, a bi-material-directional honeycomb metamaterial (BHM) with tunable coefficient of thermal expansion (CTE) and bandgap properties is proposed. The theoretical analysis and numerical simulations are employed to reveal the thermal deformation mechanism of the BHM. In addition, the analytical expression of the effective Young's modulus is established by considering both tensile and bending deformation. Based on the Bloch theorem, the band structures of the BHM are calculated by the finite element method. Parameter analysis confirms that the CTE and bandgap of the BHM can be simultaneously regulated and drastically adjusted by changing the geometric parameters and material combinations. Meanwhile, the coupling relationship of the effective CTE, Young's modulus, and total effective bandgap width are investigated. The results show that the BHM can have tunable CTE function and large total effective bandgap width by selecting suitable parameters while satisfying stiffness requirements. This study achieves a dual objective of specific CTE properties and bandgap design through rational material selection and shape design, which makes the metamaterials have better tunability and multifunctionality. [ABSTRACT FROM AUTHOR]

Axial Seamount is a submarine volcano on the Juan de Fuca Ridge with enhanced magma supply from the Cobb hotspot. We compare several deformation model configurations to explore how the spatial component of Axial's deformation time series relates to magma reservoir geometry imaged by multi‐channel seismic (MCS) surveys. To constrain the models, we use vertical displacements from seafloor pressure sensors and repeat autonomous underwater vehicle (AUV) bathymetric surveys between 2016 and 2020. We show that implementing the MCS‐derived 3D main magma reservoir (MMR) geometry with uniform pressure in a finite element model with uniform elastic host rock properties poorly fits the geodetic data. To test the hypothesis that there is compartmentalization within the MMR that results in heterogeneous pressure distribution, we compare analytical models using various horizontal sill configurations constrained by the MMR geometry. Using distributed pressure sources significantly improves the Root Mean Square Error (RMSE) between the inflation data and the models by an order of magnitude. The RMSE between the AUV data and the models is not improved as much, likely due to larger uncertainty of the AUV data. The models estimate the volume change for the 2016–2020 inter‐eruptive inflation period to be between 0.054 and 0.060 km3 and suggest that the MMR is compartmentalized, with most magma accumulating in sill‐like bodies embedded in crystal mush along the western‐central edge of the MMR. The results reveal the complexity of Axial's plumbing system and demonstrate the utility of integrating geodetic data and seismic imagery to gain insights into magma storage at active volcanoes. Plain Language Summary: Axial Seamount is a submarine volcano on the Juan de Fuca Ridge (NE Pacific Ocean) with enhanced magma supply from the Cobb hotspot. Its frequent activity and long‐term deformation time series covering eruptions in 1998, 2011, and 2015 make it an ideal place to study volcanic processes. Improved magma reservoir modeling at Axial will aid in understanding how magma transport and storage are related to surface deformation, seismicity, and eruption timing. Here we compare several models of Axial's magma reservoir to explore how the spatial component of the observed deformation at Axial compares to seismically imaged magma reservoir geometry. To constrain the models, we use vertical displacements covering an inflation period between 2016 and 2020, derived from pressure measurements collected at seafloor benchmarks and repeated bathymetric surveys. The models estimate the volume change for the 2016–2020 inflation period to be between 0.054 and 0.060 km3. Our results suggest that Axial's magma reservoir is compartmentalized, with most magma accumulating in sill‐like bodies embedded in crystal mush. The results reveal the spatial complexity of Axial's plumbing system and demonstrate how deformation data and seismic imagery can be used together to gain deeper insights into magma storage at active volcanoes. Key Points: Uniform pressurization of Axial Seamount's seismically imaged magma reservoir does not adequately fit the observed geodetic dataOur models estimate that Axial's magma reservoir inflated by 0.054–0.060 km3 during the inter‐eruptive recharge period between 2016 and 2020Axial's magma reservoir is likely compartmentalized, with magma accumulating in sills along the western‐central edge of the magma reservoir [ABSTRACT FROM AUTHOR]

The existing jacking force estimation formula considers the jacking pipe as a rigid body, which is inconsistent with the actual working state of a thin-walled slender jacking pipe. This study established a finite element displacement control model to estimate the jacking force of a slender thin-walled pipe, and obtained a jacking force fitting formula considering the deformation of the jacking pipe, the contact range, the friction coefficient of the contact surface, and the normal stress of the contact surface. The relationship between the jacking force and the jacking distance was established under certain conditions. One-quarter contact can better reflect the actual force state of a slender and thin-walled jacking pipe. From the viewpoint of accurately predicting the jacking force, the displacement control finite element method outperforms the theoretical formula, and the calculation time is controllable. [ABSTRACT FROM AUTHOR]

Triply periodic minimal surfaces (TPMS) and honeycomb structures are typical representatives of porous structures. In this paper, multi‐layer structures based on the combination of P‐surfaces and honeycomb structures are fabricated and the compression deformation characteristics are investigated based on quasi‐static compression tests and finite element simulation. The results show that the established finite element model can better simulate the deformation and damage modes of the multi‐layer structure, and the multi‐layer structure exhibits layer‐by‐layer deformation and sequential compression collapse in the deformation process. The tensile stress is crucial in the deformation and damage process of the P‐structure layer. The honeycomb structure layers show two different deformation modes: the inverted bell‐shaped "upward extrusion" and the bell‐shaped "downward extrusion." [ABSTRACT FROM AUTHOR]

Integrated heating and mechanical rolling forming (IHMRF) has recently been introduced for manufacturing complex curvature hull plates. It fabricates the target curved plate by sequential loading along the multipath. Accurate and efficient prediction of the deformation of the plate is the basis for developing the process planning and ensuring the quality of the forming. The inherent-strain method is ideal for this purpose, but its prediction accuracy needs to be improved. This paper proposes a multipath process-based inherent-strain method (MPISM), which considers the effect of the sequential loading process of the multipath on plate deformation. First, the effect of loading paths near the plate edge was investigated, which in turn clarified the rationale for obtaining the inherent strain only in the plate center. Secondly, a strain correction strategy was established by analyzing the variation pattern of the inherent strain caused by the crossing or proximity of the previous path and the subsequent path. This allowed the effects of the loading process to be taken into account in the elastic analysis. Based on the plate-and-shell theory, the idea of an equivalent inherent strain distribution is also presented. This makes the loading of inherent strains more accurate in the elastic finite-element model. MPISM predictions and experimental results show good agreement. Compared with the thermo-elastic–plastic finite element method, the MPISM substantially improves efficiency while maintaining accuracy. Compared with the original inherent-strain method, the MPISM is more accurate in terms of deformation magnitude prediction. [ABSTRACT FROM AUTHOR]

With the improvement of the planning level of underground space, the location of the planned under-crossing tunnel can be known in advance when constructing the upper-span tunnel. Therefore, pre-protection measures can be taken in advance during the construction of the upper-span tunnel. A new pre-protection method of a pipe-jacking channel was proposed to reduce the adverse effects of under-crossing shield tunnels. Numerical simulations of different pre-protection schemes were carried out using the finite element method to analyze its deformation control effect. The simulation results show that the deformation control effect of the gantry reinforcement scheme is the most significant. It is shown that the displacement of the pipe-jacking channel is more significantly suppressed with pre-protection measures than without preventive protection measures. The vertical displacement curve of the pipe-jacking channel exhibits a "W" shape after the construction of the double-lane shield underpass. By comparing the three different working conditions, it is found that the maximum vertical displacement and surface settlement of the pipe-jacking channel greatly reduced the gantry reinforcement pre-protection. Compared with Case 3, the effect of the pre-protection measures adopted in Case 2 was less obvious, which indicated that the form of the pre-protection had an important influence on controlling the deformation of the pipe-jacking channel. [ABSTRACT FROM AUTHOR]

Switching operations in a power system network can lead to transient overvoltage in the high voltage (HV) winding of distribution transformers that causes high-stress build-up. This paper presents the relationship between electromagnetic force due to a standard switching impulse (SSI) and mechanical deformation/displacement behaviours for a disc-type transformer. The analysis was carried out based on a three-dimensional (3D) modelling of a continuous HV disc winding configuration whereby it is subjected to the switching transient voltage and force excitations through the finite element method (FEM). The electric transient solver analysed the static and dynamic aspects of the electromagnetic forces associated with the variation of forces versus time. The transient structural solver evaluated the structural behaviours of the disc winding related to the axial height and radial width of the winding under electromagnetic forces. It is found that the positively dominant axial force generated in the winding with a magnitude of 8.7 N causes the top and bottom layers of disc winding to tilt and displace. In addition, the positive average radial force of 1.4 N causes the circumference of the winding to experience hoop tension and outwardly stretch. [ABSTRACT FROM AUTHOR]

Hydrogen storage is a crucial factor that limits the development of hydrogen energy. This paper proposes using a split liner for the inner structure of a hydrogen storage cylinder. A self-tightening seal is employed to address the sealing problem between the head and the barrel. The feasibility of this structure is demonstrated through hydraulic pressure experiments. The influence laws of the O-ring compression rate, the distance from the straight edge section of the head to the sealing groove, and the thickness of the head on the sealing performance of gas cylinders in this sealing structure are revealed using finite elements analysis. The results show that when the gas cylinder is subjected to medium internal pressure, the maximum contact stress on the O-ring extrusion deformation sealing surface is greater than the medium pressure. There is sufficient contact width, that is, the arc length of the part where the stress on the O-ring contact surface is greater than the medium pressure, so that it can form a good sealing condition. At the same time, increasing the compression ratio of the O-ring and the head's thickness will help improve the sealing performance, and reducing the distance from the straight edge section of the head to the sealing groove will also improve the sealing performance. [ABSTRACT FROM AUTHOR]

Double ridges are sprawling features observed globally across the icy surface of Europa. They consist of two topographic highs flanking a trough. The topographic relief of the ridges is approximately 100 m, and the ridges extend up to hundreds of kilometers in length. The interior structure and dynamics of Europa's ice shell are currently poorly constrained. Therefore, accurate models for the formation of these prominent surface features can be useful for determining how the ice shell operates. We hypothesize that double ridges form as a result of incremental ice wedging. We use both analytical and numerical finite element models to quantify the deformation that occurs as an ice wedge grows incrementally within the ice shell. We show that incremental growth of the ice wedge results in surface deformation that matches the size and shape of typical Europan double ridges, including their topographic relief and surrounding troughs. We find that as the depth of the ice wedge increases, double ridges become broader and shorter. We explore the possibility of local and non‐local sources for the liquid water that freezes to produce the wedge and ultimately argue in favor of local sources of liquid water within the ice shell. Plain Language Summary: Europa, the second Galilean satellite, is hypothesized to have a global salt‐water ocean underneath its outer icy shell. Double ridges are a common feature on Europa's icy surface. They consist of a long trough bordered on either side by uplifted hills of ice. The height of the ridges above the surface is approximately 100 m, and the ridges may extend for hundreds of kilometers over the surface of the moon. Models that show how surface features, like double ridges, may form can tell us about characteristics of the ice shell and underlying ocean that are otherwise hard to measure. We use two different techniques to model a process for how double ridges might form. In this process, water, possibly from the subsurface ocean, enters a long vertical crack in the ice shell and freezes along the sides of the crack. Over time as water continues to enter and freeze in the same place, a new wedge of ice grows inside the ice shell and pushes on material around it. The ice wedge forces ice at the surface of the shell to deform into the same size and shape of double ridges that have been observed on Europa. Key Points: Numerical modeling suggests that double ridges are produced by wedges of ice that grow within Europa's ice shellAnalytical and numerical models show that an ice wedge within Europa's ice shell elastically deforms the surface into double ridgesIce wedge material may be sourced from the ocean or locally from cryovolcanic dikes or water reservoirs within the shell [ABSTRACT FROM AUTHOR]

In view of the none ground grouting reinforcement and well point dewatering conditions for shield receiving of conventional mine tunnel under building and to avoid excessive deformation of ground surface and building and ensure the shield receiving of anhydrous conditions, the shield receiving scheme of advanced large pipe shed+two end walls+backfill mortar in the tunnel+dewatering in the caisson in the tunnel is proposed. The shield receiving project of mine-method tunnel under buildings in the section of Keyuan-Jiuxing Avenue of Chengdu Metro Line 5 is taken as the background, the finite element method is used to analyze and study the settlement and deformation law of the ground surface and buildings, which is verified by field measurement. The research results show that: based on the shield receiving scheme of backfilling mortar body in the tunnel and sinking well dewatering, the extreme value of surface settlement is 3.81 mm, which is less than the control value of surface vertical deformation. In addition, the shield tunneling within the range of about 35 m from the end wall of the mine method tunnel has a significant impact on the surface settlement, and monitoring and measurement shall be strengthened during the construction. The settlement extreme value of the building directly above the shield receiving section is 8.52 mm, which is also less than the control value of the building settlement. The extreme values of ground surface and building settlement are located directly above the axis of the shield tunnel, and the field measured values are basically consistent with the calculated values. Therefore, the shield receiving technical scheme is reasonable, feasible, safe and reliable. [ABSTRACT FROM AUTHOR]

Coseismic deformation of large earthquakes causes significant property damages and fatalities, which requires quantitative research of multiple disciplines such as geodesy, geological investigation, seismic tomography, and seismic dislocation theory. The finite element method accounts for material heterogeneity and geometric complexity, making it suitable for studying the coseismic deformation of large earthquakes. This paper develops a parallel elastic finite element program that utilizes split nodes and high-performance parallel computing technology on the FELAC software platform to study the coseismic deformation of large earthquakes. We verify the accuracy of the parallel elastic finite element program by comparing its results with the analytical solutions from seismic dislocation theory for four ideal earthquake cases. Finally, we established parallel elastic finite element models to study the coseismic deformation of the 2008 Wenchuan earthquake. The simulation results are consistent with the GPS and InSAR data. Coseismic surface deformation results are significantly influenced by medium regional heterogeneity with different layered structures besides the Longmenshan fault. The finite element program lay the foundation for the inversion of the coseismic fault rupture process based on the heterogeneous medium model and complex geometric model. [ABSTRACT FROM AUTHOR]

Postseismic deformation at convergent margins is controlled mainly by continuous slip on the fault (afterslip) and relaxation of the earthquake‐induced stress in the viscoelastic upper mantle (viscoelastic relaxation). Study of these deformation processes provides insight into the rheological properties of upper mantle and slip behavior of the fault. We have constructed a three‐dimensional finite element model to investigate the postseismic deformation of the 2018 Mw 7.9 Kodiak earthquake. We derived the first 2‐year postseismic Global Positioning System observations to constrain afterslip and upper mantle rheology in the south‐central Alaska. The upper mantle is separated into the mantle wedge and oceanic upper mantle topped by an 80‐km thick asthenosphere layer by the subducting slab. Results show that afterslip generally occurred in areas adjacent to the rupture zone and has a small magnitude of a few tens of millimeters. The viscosities of the asthenosphere and mantle wedge are determined to be in a range of 1–4 × 1018 and 0.5–5 × 1019 Pa s with an optimal value of 2 × 1018 and 2 × 1019 Pa s, respectively. Model results reveal a localized weak mantle wedge of ∼1018 Pa s beneath Lower Cook Inlet that may be due to the fluids dehydrated from the slab. Coulomb stress changes show that the earthquake enhanced coseismic and postseismic stress loading of up to 0.9 and 0.1 bar, respectively, on the shallow subduction interface near Kodiak Island, but there is no obvious triggered seismicity, probably due to the low stress status already released by the 1964 Mw 9.2 Alaska earthquake. Plain Language Summary: Large earthquakes cause prolonged postseismic surface deformation in areas hundreds of kilometers from the rupture zone that can be recorded by geodetic methods. The postseismic deformation is mainly due to continuous aseismic slip on the fault (afterslip) and viscoelastic relaxation of the earthquake‐induced stresses in the upper mantle. On 23 January 2018, an Mw 7.8 strike‐slip earthquake ruptured multiple faults in the Pacific plate southwest of the Alaska subduction zone. Global Positioning System (GPS) stations west and northwest of the Gulf of Alaska have continuously recorded the postseismic surface deformation that is up to 16 mm near Kodiak Island within the first 2 years. We have constructed a three‐dimensional finite element model to study the stress‐driven afterslip and viscoelastic relaxation of upper mantle following this event. The rheological properties of the upper mantle in the Alaska subduction zone are well constrained by GPS observations. Model results reveal a localized weak mantle wedge near Lower Cook Inlet that is consistent with a low velocity zone at depths of ∼60–250 km from tomography studies. We also estimate coseismic and postseismic stress change over the subduction interface due to the 2018 Kodiak earthquake. Key Points: Postseismic deformation of the 2018 Kodiak earthquake is controlled by afterslip and viscoelastic relaxation of the upper mantleUnderestimation of the observations near Lower Cook Inlet may indicate locally weakened mantle wedgeThe event promotes strain accumulation on the shallow megathrust near Kodiak Island where has no obvious triggered seismicity [ABSTRACT FROM AUTHOR]

Steel tubes find widespread applications in various structural elements, including load-bearing columns, stair guardrails, and security bollards, due to their high strength and durability. However, these structures are susceptible to damage under impact loading conditions. While prior studies have focused on drop hammer shapes like rectangles, wedges, cylinders, and hemispheres, research on the impact of a conical-shaped hammer on square and rectangular steel tubes remains limited. Therefore, this study aims to analyse the damage resulting from the impact of a conical-shaped hammer on square steel tubes using nonlinear Finite Element Analysis (FEA) software ABAQUS/Explicit. The investigation explores the effects of various parameters, including tube geometry, impact location, impactor mass, and impact height, on tube deformation and fracture behaviour of tube. Through comprehensive analysis, it was observed that the impacted site exhibited punching failure accompanied by inward bending of the tube, while outward buckling occurred at the support. The energy absorption process was examined, and the effect of the aforementioned parameters on the energy absorption capacity (EAC) was assessed. The findings indicate that the thickness of the steel tube has the most significant impact on the impact force and EAC. Additionally, the deflection of the tube was primarily influenced by the length of the hollow section. [ABSTRACT FROM AUTHOR]

Deposition path patterns play an important role in controlling residual stresses and deformation in direct energy deposition-arc (DED-arc) process. In this paper, the effects of various path patterns on the evolution of the temperature history, residual stress distribution, and substrate deformations are investigated through experiments and finite element analysis. The predicted results of temperature fields and substrate deformations are verified experimentally by the infrared thermal imager and the laser profile scanner, respectively. It is found that the path patterns have significant effects on the stress distribution in the first few layers, and the minimum substrate deformation is obtained by the zigzag path along the short edge of the block. The proposed finite element method and measuring method are confirmed to be effective and feasible, providing valuable insight into the residual stresses and deformations control in the DED-arc process. [ABSTRACT FROM AUTHOR]

In response to the problem of significant post-construction settlement that may occur in a motor racing circuit (MRC), two representative composite foundation testing areas, PHC pile (pre-tensioned spun high-strength concrete pile) and CFG pile (cement fly ash gravel pile), were selected for field tests to obtain the deformation law of pile–soil. Then, finite element numerical simulation was used to carry out back analysis on the geological mechanical parameters of the testing areas. The results showed that the error of soil settlement between the piles in the PHC pile and CFG pile testing areas were 8.2% and 9.6%, respectively, with good inversion precision. The obtained geological mechanical parameters can be used to predict the settlement of the rest of the MRC. On this basis, a finite element numerical model was constructed to analyze the bearing and deformation characteristics of the foundation of the MRC under five types of working conditions that may cause significant post-construction settlement. It showed that the settlement of the embankment was large in the middle and small on both sides after the consolidation of the embankment. The maximum settlement was about 27.0 mm, and the maximum longitudinal uneven settlement ratio of the embankment was 1.3/4000. The axial force of piles in the PHC pile and CFG pile composite foundations increased first and then decreased with depth. The maximum bending moment was located at the foot of slopes or at the boundary of strata, which was relatively small in the middle of the embankment. The deformation of the embankment and the bearing capacity of the piles could meet engineering requirements. This study has certain guiding significance for the design and construction of similar pile-net composite foundations. [ABSTRACT FROM AUTHOR]

This paper proposes a scale model test to simulate shield tunnel excavation over long distances. The test simulates the whole process of shield tunneling through the Weihe River on Xi'an Metro Line 1, where the tunneling length and diameter reach 100 m and 6 m, respectively. The dimensions of the test setup were 6.0 m × 1.0 m × 1.0 m, the diameter of the tunnel model was 160 mm, and the geometric similarity ratio was 1:40. Finite element analysis and field measurements were performed to complement the test results. By comparing the finite element simulation and field measurement, the scale model test was validated and verified to be reliable. The results show that the test effectively predicts riverbed deformation caused by shield construction. In addition, it can be applied to soil stability analysis and the impact evaluation of surface deformation in other shield-crossing rivers, complex strata, and superstructure groups, providing auxiliary guidance for shield constructions. [ABSTRACT FROM AUTHOR]

In recent years, additive-subtractive hybrid manufacturing (ASHM) technology has become a research hotspot. To realize high-precision manufacturing of complex parts and avoid machining interference, alternating additive manufacturing (AM) and subtractive manufacturing (SM) are valuable to be adopted. In this paper, a finite element numerical model was established to simulate the temperature history, stress distribution, and deformation trend of the thin-walled parts alternately fabricated by AM and milling process. Then, 316L stainless steel thin-walled samples were built by the alternating ASHM process. The molten pool temperature, the surface residual stress, and the surface contour of samples were measured and analyzed. The results show that high tensile stress is exhibited at the junction of the AM segment with the substrate or the previous SM segment. With the increase of deposition height, the tensile stress decreases first and then increases. After the subsequent milling, the surface residual stress level shows a decreasing trend, which is because the milling-induced compressive stress offsets the initial residual tensile stress. Moreover, the deformation of the two ends and the top of the AM segments is more significant than that of the bottom. After SM, the deformation in the top area of the SM segments is still slightly more extensive than the bottom area. The subsequent AM process results in a small increase in the residual stress of the milled segment, but had little effect on its surface deformation. Finally, the repeated cutting height between two segments was studied. Compared with the previous work, this strategy considers the effect of the alternating ASHM process on the residual stress and deformation of thin-walled parts. This study has certain guiding significance for the manufacture of thin-walled parts such as turbine blades and parts with internal structure by alternating ASHM process. [ABSTRACT FROM AUTHOR]

The development of gear toward lightweight means that the gear body flexibility grows, which will lead to a series of dynamic problems for the thin-rimmed gear transmission and increase the vibration and noise of gear transmission. Therefore, a novel dynamic model is proposed that can reflect the structural flexibility of the thin-rimmed gear. In this model, the gear teeth are first sliced along the tooth width direction, and the time-varying mesh stiffness of the gear pair for each slice of all the gear teeth is calculated. Then, the dedendum circle surfaces of each tooth on the gear body are divided, and remote points are established on the divided surfaces and gear shaft; the condensed finite element models (FEMs) of the gear body are established considering the centrifugal and inertia forces, and the housing FEMs are established as well. Subsequently, the flexible deformations of the divided surfaces on the gear body are extracted and converted to the actual meshing point to obtain the system meshing force and meshing moment by multiplying by the meshing stiffness. These results are then returned to the FEMs, and a thin-rimmed gear transmission dynamics model is established finally. By comparing simulation and experimental results, the model is validated. The effects of gear body flexible deformation, centrifugal force, gear parameters, and manufacturing errors on the system dynamics are studied. The proposed model provides constructive guidance for high-speed thin-rimmed gear high performance design and manufacturing. [ABSTRACT FROM AUTHOR]

Aiming for sensing balloon catheters which are able to provide intraoperative information of the vessel stiffness and shape, the present study uses finite element analysis (FEA) to evaluate the interaction between high-compliant elastomer balloon catheters with the inner wall of a non-cylindrical-shaped lumen structure. The contact simulations are based on 3D models with varying balloon thicknesses and varying tissue geometries to analyse the resulting balloon and tissue deformation as well as the inflation pressure dependent contact area. The wrinkled tissue structure is modelled by utilizing a two-layer fibre-based Holzapfel-Gasser-Ogden constitutive model and the model parameters are adapted based on available biomechanical data for human urethral vessel samples. The balloon catheter structure is implemented as a high-compliant hyper-elastic silicone material (based on polydimethylsiloxane (PDMS)) with a varying catheter wall thickness between 0.5 and 2.5 µm. Two control parameters are introduced to describe the balloon shape adaption in reaction to a wrinkled vessel wall during the inflation process. Basic semi-quantitative relations are revealed depending on the evolving balloon deformation and contact surface. Based on these relations some general design guidelines for balloon-based sensor catheters are presented. The results of the conducted in-silico study reveal some general interdependencies with respect to the compliance ratio between balloon and tissue and also in respect of the tissue aspect ratio. Further they support the proposed concept of high-compliant balloon catheters equipped for tactile sensing as diagnosis approach in urology and angioplasty. [ABSTRACT FROM AUTHOR]

According to the World Health Organization (WHO), approximately 1.3 billion people experience visual impairments. Daily exposure to various levels of luminous beams directly impacts the front layer of the visible structure, leading to corneal injuries. To comprehensively understand this, we reconstructed a three-dimensional model utilizing the PENTACAM® system. This enabled us to accurately determine the 50th percentile dimensions of the fibrous layer of the eyeball. Using the Ogden mathematical model, we developed a 3D cornea model, treating it as a soft tissue with predictable behavior, considering mechanical properties such as viscoelasticity, anisotropy, and nonlinearity. Employing the Finite Element Method (FEM), we analyzed five distinct test scenarios to explore the structural response of the cornea. Luminous beam properties were instrumental in establishing varying mechanical loads, leading to structural deformations on the corneal surface. Our findings reveal that when a smartphone's screen emits light at a frequency of 651.72 THz from 200 mm, displacements in the corneal layer can reach up to 9.07 µm. The total load, computed by the number of photons, amounts to 7172.637 Pa. [ABSTRACT FROM AUTHOR]

We introduce a surface finite element method for the numerical solution of Navier–Stokes equations on evolving surfaces with a prescribed deformation of the surface in the normal direction. The method is based on approaches for the full surface Navier–Stokes equations in the context of fluid‐deformable surfaces and adds a penalization of the normal component of the velocity. Numerical results demonstrate the same optimal order of convergence as proposed for surface (Navier–)Stokes equations on stationary surfaces. The approach is applied to high‐resolution three‐dimensional scans of clothed bodies in motion to provide interactive virtual fluid‐like clothing. [ABSTRACT FROM AUTHOR]

The temperature gradient rolling (GTR) method effectively addresses the issue of uneven deformation of surface and core in the rolling of extra-thick plate. Different from the traditional near uniform temperature rolling (UTR) process, GTR involves a significant temperature gradient along the thickness direction of the rolled piece. As a result, the rolling force prediction model used in uniform temperature rolling cannot be directly applied in GTR. Rolling force prediction model is crucial for process control models of plate mill and serves as the foundation for plate thickness control. However, there has been limited research on rolling force prediction methods specifically for GTR. In order to predict the change of rolling force in GTR process and enhance the control of the rolling process, the current paper proposed a simplified method based on the deformation resistance model, temperature distribution fitting, differential method, and loop iteration. The precision of the method was examined by using a finite element model and plane strain experiment, demonstrating a mean error between the method and FEM was less than 5%. [ABSTRACT FROM AUTHOR]

The increasing frequency of extreme rainfall is leading to a rise in groundwater levels in coastal areas, significantly affecting high-speed railway operations. To address this concern, this study developed a 2.5-dimensional finite element model of a coupled track-embankment-ground system based on Biot's porous media theory to analyze the effect of groundwater level rise on the critical velocity of high-speed railways and vibration responses. The findings reveal a consistent decrease in the critical velocity of high-speed railways with rising groundwater levels. Particularly, the increase in groundwater levels within the embankment significantly influences the critical velocity compared to a similar rise in the foundation's groundwater level. Furthermore, deformations induced by passing trains significantly increase as groundwater levels rise. Specifically, when the groundwater level rises from the foundation bottom to the subgrade surface, subgrade surface deformation increases by approximately 55%. As trains approach the critical velocity, significant vibration phenomena, known as the "Mach effect," occur at the foundation surface. Importantly, as groundwater levels rise, the "Mach effect" intensifies. Analyzing the vibrating frequency spectrum of the displacement response demonstrates a substantial increase in vibration amplitude, particularly in the high-frequency region, as groundwater levels rise. This study highlights that the rise in groundwater level not only amplifies vibrations but also extends the propagation of high-frequency vibrations, underscoring the importance of effective embankment waterproofing in controlling track vibrations. [ABSTRACT FROM AUTHOR]

The purpose of the study was to conduct an experimental-numerical analysis of the critical state (buckling) of thin-walled composite structures with a square cross-section. The subject of the study was thin-walled composite structures, which were made of CFRP - carbon epoxy composite. The structures were characterized by a closed square cross-sectional shape. In the research paper, stability tests of axially compressed thin-walled struts were performed in order to determine the critical state of the structures. Experimental tests were carried out on a universal testing machine, using a system for optical measurement of deformation of structures. Numerical simulations were carried out using the finite element method (FEM). The research made it possible to evaluate the work of the structure in the buckling state from a qualitative as well as quantitative point of view. During the study, the buckling form and the corresponding critical load were determined - which quantitatively and qualitatively showed high agreement for both experimental testing and numerical simulation. The novelty of the present paper was the use of several interdisciplinary research methods (testing machine, optical deformation measurement system and numerical simulations) in order to determine the critical state of thin-walled composite structures with closed sections. [ABSTRACT FROM AUTHOR]

Three-dimensional spacer fabric is a type of one-piece sandwich structure consisting of two outer layers and vertical and inclined spacer monofilaments. It behaves like a cushioning material, having linear, plateau, and densification stages under compression. This article elucidates the compression mechanism of a typical spacer fabric in terms of global deformation, local deformation, and internal contact behavior of spacer monofilaments through finite element simulation. While the linear stage is post-buckling of spacer monofilaments with tight constraints, the plateau stage is a combination of post-buckling, torsion, rotation, and contact of spacer monofilaments. The densification stage is attributed to the contact between spacer monofilaments and outer layers, which decreases the effective length to bear the load and enhances the constraints on the spacer monofilaments. The vertical spacer monofilaments with almost triple the normal strains of the inclined ones contribute more to compression resistance. [ABSTRACT FROM AUTHOR]

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The stability of reservoir bank slope during impoundment is significant for the safe operation of hydropower stations. The deformation evolution of a slope adjacent to dam is analyzed based on the field monitoring data. The main influencing factors and spatial distribution of the slope deformation during impoundment are identified based on the multiple regression model and K-means cluster analysis, respectively. Subsequently, the deformation mechanism of the slope is analyzed by three-dimensional nonlinear finite element method. Then, an inversion analysis method based on improved adaptive genetic algorithm and back propagation neural network is proposed. The measured deformations of 44 monitoring points are used to inverse a total of 27 mechanical parameters, including deformation parameters, strength parameters and Biot coefficients of 9 materials. Finally, the influence of sample numbers on the prediction accuracy and the robustness of the neural network are discussed. The results indicate that the deformation rate of the slope is substantially associated with the impounding process. The water pressure component and aging component of the deformation account for a relatively high proportion while the temperature component is negligible. The deformation is mainly affected by material softening and effective stress of shallow-buried fractured rock mass, in which the latter dominates. The water load on the dam surface is the deformation inducement of the deep rock mass. The proposed inversion method can reasonably obtain the weakening rate of materials and make the numerical model accurately fit in with the actual state of the slope. [ABSTRACT FROM AUTHOR]

Understanding the mechanical evolution of magmatic systems requires careful assessment of their rheological characteristics, particularly in light of the growing evidence that magma reservoirs are dominated by magma‐mush surrounded by thermally‐altered host‐rock. To address this complexity, we develop models for volcano deformation based on a poroviscoelastic source within a thermo‐viscoelastic host. We use Finite Element modeling to investigate the rheological and mechanical response to melt injection in a Maxwell poroviscoelastic reservoir hosted in a temperature‐dependent standard linear solid viscoelastic ("thermo‐viscoelastic") crust. Our models consider the competing roles of poroelastic diffusion, and viscoelastic creep and relaxation. All cause time‐dependent post‐injection deformation. Post‐injection deformation of a poroviscoelastic reservoir in an elastic crust is dominated by poroelastic diffusion, a consequence of the short relaxation timescale of a hot and relatively low viscosity mush. For cooler, more viscous mush, the magnitude of viscoelastic deformation increases, supplementing the deformation caused by post‐injection poroelastic diffusion. Thermo‐viscoelasticity of the crust amplifies the poroelastic deformation response of the magma‐mush, leading to increased time‐dependent deformation both during and after melt injection. The rate of post‐injection surface deformation decreases at a rate proportional to the reservoir temperature. Crucially, our model sensitivity analysis demonstrates that the wall rock thermo‐viscoelastic response contributes more to surface deformation than the viscous effect of the magma‐mush. For this reason, neglecting the viscoelastic properties of the host rock and the poroelastic properties of the reservoir in interpretations of surface deformation data could produce errors in inferred processes (e.g., injection duration) and subsurface characteristics (e.g., reservoir compressibility, shape and depth). Plain Language Summary: Measurements of volcano deformation can provide crucial insights into the mechanical behavior of magmatic systems if the physical properties of the systems are known. Past assumptions of magma chambers as molten bodies surrounded by elastic rock are not sufficient, however, to model the behavior of more realistic reservoirs comprising a mixture of melt plus crystal—"magma‐mush"—in thermally‐altered wall rock. More appropriate are models that treat the magma‐mush as poroviscoelastic and the wall rock as viscoelastic. In this study, we develop new numerical models that simulate volcano deformation caused by melt injection into a shallow poroviscoelastic magma reservoir that is surrounded by viscoelastic wall rock. Under these conditions, surface deformation continues after the injection has stopped. Our model further shows that for high temperature reservoirs, poroelastic diffusion, that is, the movement of melt through the mush, dominates surface deformation. Our results emphasize the importance of considering both the host rock and magma‐mush viscoelastic properties to understand the processes that cause surface deformation during and after melt intrusion. Key Points: The rheology of a magma‐mush and its host affect the mechanical evolution of a sub‐volcanic system and the associated surface deformationWall rock thermo‐viscoelastic characteristics have a greater control than magma‐mush viscoelasticity on volcano surface deformationNeglecting the viscoelastic properties of the host rock and the magma‐mush reservoir can lead to misestimating subsurface characteristics [ABSTRACT FROM AUTHOR]

Warm deformation is a plastic-forming process that differs from traditional cold and hot forming techniques. At the macro level, it can effectively reduce the problem of high deformation resistance in cold deformation and improve the surface decarburization issues during the hot deformation process. Microscopically, it has significant advantages in controlling product structure, refining grain size, and enhancing product mechanical properties. The Gleeble-1500D thermal–mechanical physical simulation system was used to conduct isothermal compression tests on GCr15 bearing steel. The tests were conducted at temperatures of 600–1050 °C and strain rates of 0.01–5 s−1. Based on the experimental data, the critical strain model and dynamic recrystallization model for the warm–hot forming of GCr15 bearing steel were established in this paper. The model accuracy is evaluated using statistical indicators such as the correlation coefficient (R). The dynamic recrystallization model exhibits high predictive accuracy, as indicated by an R-value of 0.986. The established dynamic recrystallization model for GCr15 bearing steel was integrated into the Forge® 3.2 numerical simulation software through secondary program development to simulate the compression process of GCr15 warm–hot forming. The dynamic recrystallization fraction was analyzed in various deformation regions. The grain size of the severe deformation zone, small deformation zone, and difficult deformation zone was compared based on simulated compression specimens under the conditions of 1050 °C and 0.1 s−1 with the corresponding grain size obtained with measurement based on metallographic photos; the relative error between the two is 5.75%. This verifies the accuracy of the established dynamic recrystallization and critical strain models for warm–hot deformation of GCr15 bearing steel. These models provide a theoretical basis for the finite element method analysis and microstructure control of the warm–hot forming process in bearing races. [ABSTRACT FROM AUTHOR]

We conducted two three-dimensional numerical models to investigate the effects of the surrounding surface surcharge on the deformation of the retaining structure. The results obtained by the finite element model are in good agreement with the field measurements. The deflection of the diaphragm wall increased by 2-3 times owing to the surrounding surface surcharge, which implies that the surrounding surface surcharge magnifies the excavation-space effect. The maximum wall deflections were approximately 0.03-0.05 H (H is the excavation depth) in the case without surface surcharge. However, the maximum wall deflections increased up to 0.05-0.19 H when surrounding surface surcharges were applied on the surface ground around excavation. The surrounding surface surcharge leads to the increase of the maximum wall deflection. [ABSTRACT FROM AUTHOR]

Under weak geological conditions, soil deformation and surface settlement are the key factors affecting the success of shallow-buried rectangular excavation. To investigate this issue, an underpass of Zhongxiao East Road in Taipei City was used as a case study. The surface settlement and lateral deformation of an underground diaphragm wall caused by the excavation of a rectangular pedestrian underpass using the pipe-roof preconstruction method (PPM) were investigated by 3D finite element analysis. The numerical analysis results showed that the constructed numerical analysis model had considerable accuracy. The use of PPM combined with a box culvert structure to form a pedestrian underpass could effectively control the surface displacement above the box culvert. Under the condition of the same sectional area, the smaller the width of the pipe-roof structure, the more the impact on the ground surface was reduced. The maximum positive bending moment and maximum negative bending moment on the pipe roof produced by excavation at each stage were roughly inversely related to the height per the width of the cross-section of the pipe diaphragm structure. The results showed that the pipe-roof structure was suitable for underground excavation with shallow-buried depth in the soft soil of the Taipei Basin. Moreover, the shallow-buried box culvert was more sensitive to the subsidence caused by construction than the deep-buried box culvert. [ABSTRACT FROM AUTHOR]

To improve the processibility of high-volume fraction SiC p /Al composites and reduce the surface defects after machining, a machining method of laser-ultrasonic vibration assisted machining (L-UVAM) were presented in this paper. Aiming to study the mechanism of material deformation and surface formation in L-UVAM, a finite element model (FEM) of L-UVAM was developed and the corresponding experiments were conducted. The results combined simulation and experiments revealed that particle fracture, interface failure and crack propagation were the main forms of material deformation, and the support of the matrix for particles was weakened because of the softening effect caused by laser heating, which makes it easier for the tool to push particles distribution along the shear plane. In addition, the failure of the particles depended on its relative position to the tool. Compared with traditional machining, the surface quality of L-UVAM was better, and there were fewer broken particles and defects in the processed surface. The results obtained by simulation are in close agreement with cutting experiments. Therefore, L-UVAM can be applied in efficient machining of SiC p /Al composites. [ABSTRACT FROM AUTHOR]

In this paper, the roller bearings partial wear due to extreme inclined load caused by poor installation is investigated. First, based on non-Hertz contact theory, a quasi-static model of roller bearing with inclined load is established by the influence coefficient method. The influence of deflection angle between the inner ring and outer ring on the non-uniform contact characteristics is discussed. The finite element model of roller bearing housing is established and optimized by the theoretical results. The double-loading zones characteristic of roller bearings caused by the inclined installation of the housing is analyzed. The influence of the extreme position of the rollers on the deformation of the bearing is also considered. The partial wear experiment of the bearing is carried out. The contact surface roughness and deformation of the outer ring are measured. Fusing the analytical analysis, finite element analysis, and experiment, the effects of external inclined loads, rollers extreme positions, and wear on the deformation of the contact surface of the outer ring are systematically studied to reveal the mechanism of partial wear. [ABSTRACT FROM AUTHOR]

The pile–beam–arch method (PBA) method is increasingly being used in the construction of metro stations with complex traffic conditions. The rise–span ratio of the arch not only affects the height of the station, but also affects the rationality of the design of subway stations and the safety of construction. The mechanical response of steel pipe piles with different rise–span ratios and the effect of controlled surface settlement have been investigated in the interactions involved in pile–soil system. In this paper, the finite element model of each rise–span ratio was established, and the rationality of the model was demonstrated by comparing the numerical simulation calculation with the field surface settlement monitoring data. The mechanical characteristics and influence analysis of the surface deformation during the excavation of the cave pile method were investigated. The results show that the maximum axial force of the central pile first decreases and then increases with the increase in the rise–span ratio. The maximum bending moment of the arch decreases as the rise–span ratio increases, and the maximum axial force of the arch is negatively correlated with the rise–span ratio. The maximum axial force of the central pile is located at the bottom plate. Due to the symmetry of the structure, the bending moment of the centre pile is small, but the maximum bending moment of the whole station is located at the side wall of the bottom plate. As the rise–span ratio increases, the surface settlement first decreases and then increases. The construction of the pilot tunnel and the upper arch is the most important factor leading to the surface settlement, so it is necessary to strengthen the soil layer. [ABSTRACT FROM AUTHOR]

Switchable adhesives have attracted widespread attention due to their strong reusability and adaptability to operate stably in complex environments. However, the simple fabrication of adhesive structures and reliable control of adhesion remain challenging. Here, we developed a neodymium iron boron/polydimethylsiloxane (NdFeB/PDMS) magnetic composite with optimal mechanical and magnetic performance. Then we fabricated lamellar structures and setal arrays using a molding and magnetic field-induced process, imitating the multi-level adhesion system of gecko feet. The lamellar can be deformed under the action of a magnetic field to control the adhesion, and the setal array is used to enhance adhesion and provide self-cleanability to the adhering surface. Switchable adhesion was realized by applying an external magnetic field, where the maximum adhesion strength was 5.1 kPa, and the switchable range was within 40%. Through finite element analysis simulations and experimental verification, it was proved that the adhesion force variation was ascribed to the magnetic field-induced surface deformation. Finally, we installed the adhesive on the end of the robotic arm, realizing the transfer of the target object. This work provides a simple method to fabricate a gecko-like surface and a practical strategy to realize switchable adhesion, which sheds light on broad application potential in production lines, medical products, and more. [ABSTRACT FROM AUTHOR]

Permanent ground deformation induced by surface faulting can seriously threaten the structural integrity of buried pipelines. The failure mode of fracturing in pipe wall is somewhat difficult to be simulated by the classical finite element method. In this work, brittle damage of buried pipelines subjected to different dip-slip faults is investigated by using peridynamics, where the pipes are characterized as peridynamics shell structures and the surrounding soil is simulated as Winkler springs. Three sets of experiments are simulated using the proposed modeling strategy, and good agreements between experimental and numerical results are achieved, in terms of progressive brittle damage features (deformation and crack patterns). The first crack initiates under a certain fault displacement, and then it propagates inwardly to penetrate through the cross section on the footwall side. A new crack then occurs on the other side in a later stage. Pipeline failure is more prone to occur within the zone of three times the pipe diameter from the fault plane, showing three broken segments by the two dominant cracks eventually. Parametric study suggests that reverse faulting is more harmful to the pipeline than normal faulting. The most unfavorable dip angles for pipelines under normal and reverse faulting are 65° and 75°, respectively. The pipeline with a thicker pipe wall or a higher critical energy release rate, being buried in a smaller burial depth or a looser sand condition, shows a higher capacity to resist the dip-slip fault. [ABSTRACT FROM AUTHOR]

Constraints on the amount and pattern of ground deformation induced by dike emplacement are important for assessing potential eruptions. The vast majority of ground deformation inversions made for volcano monitoring during volcanic unrest assume that dikes are emplaced in either an elastic half-space (a homogeneous crust) or a crust made of horizontal layers with different mechanical properties. We extend these models by designing a novel set of two-dimensional finite-element method numerical simulations that consider dike-induced surface deformation related to a mechanically heterogeneous crust with inclined layers, thus modeling a common geometry in stratovolcanoes and crustal segments that have been folded by tectonic forces. Our results confirm that layer inclination can produce localized ground deformation that may be as much as 40× higher in terms of deformation magnitude than would be expected in a non-layered model, depending on the angle of inclination and the stiffness of the rock units that host and are adjacent to the dike. Generated asymmetrical deformation patterns produce deformation peaks located as much as 1.4 km away from those expected in non-layered models. These results highlight the necessity of accurately quantifying both the mechanical properties and attitude of the geology underlying active volcanoes. [ABSTRACT FROM AUTHOR]

The 1884 Andalusia Earthquake, with an estimated magnitude between 6.2 and 6.7, is one of the most destructive events that shook the Iberian Peninsula, causing around 1200 casualties. According to paleoseismology studies and intensity maps, the earthquake source relates to the normal Ventas de Zafarraya Fault (Granada, Spain). Diverse studies registered and later analyzed hydrological effects, such as landslides, rockfalls, soil liquefaction, all-around surge and loss of springs, alterations in the phreatic level, discharge in springs and brooks and well levels, along with changes in physical and chemical parameters of groundwater. Further insight into these phenomena found an interplay between hydromechanical processes and crust surface deformations, conditions, and properties. This study focuses on analyzing and simulating the features involved in the major 1884 event and aims at elucidating the mechanisms concerning the mentioned effects. This ex-post analysis builds on the qualitative effects and visible alterations registered by historical studies. It encompasses conceptual geological and kinematic models and a 2D finite element simulation to account for the processes undergone by the Zafarraya Fault. The study focuses on the variability of hydromechanical features and the time evolution of the ground pore–pressure distribution in both the preseismic and coseismic stages, matching some of the shreds of evidence found by field studies. This procedure has helped to shed light on the causal mechanisms and better understand some parameters of this historical earthquake, such as its hypocenter and magnitude. This methodology can be applied to other events registered in the National Catalogues of Earthquakes to achieve a deeper insight, further knowledge, and a better understanding of past earthquakes. [ABSTRACT FROM AUTHOR]

• The novel Zebra-EVA layer is used as encapsulant for Tilling Ribbon (TR) module. • Cracking performance of TR module is investigated during the lamination and mechanical load cycles. • Finite element modelling (FEM) of the lamination and mechanical load process is used to predict the thermo-mechanical stresses of each layer inside PV module. • The correlation analysis between the stress and induced cracks on cells throughout the mechanical load cycles is implemented. Photovoltaic (PV) module failures due to silicon cell cracking are gaining more and more attention. It is found that Ethylene Vinyl Acetate (EVA) is one of the most significant contributions to reduce failures resulting from the fracture of silicon solar cells. In this work a full understanding of the impact of lamination and external mechanical loads on the cracking of newly developed tilling ribbon (TR) mono-crystalline modules (encapsulated with a Zebra-EVA), and the direct impact of micro-cracks on the module power after mechanical load test, has been developed. Finite element modelling (FEM) is used to predict the temperature and stress distribution inside each layer and the surface deformation of the PV assembly in the encapsulation, as well as the accumulated stresses of the PV module under mechanical loads. Comparing to the conventional PV module, a TR module was found to have significantly enhanced efficiency by 1.5% with an increased power of more than 20 W. Compared to the conventional EVA layer, Zebra-EVA could reduce the probability of micro-cracks by 3.6% during lamination and effectively decrease the mechanical stress imposed on silicon cells when the module is exposed to external mechanical conditions, offering a lower cracking risks and less power losses, which agreed with the simulation results. It is shown that conversion efficiency of a PV module is improved through TR technique, while its lamination-induced cracking and the failure probability induced from mechanical loading can be efficiently reduced by utilizing Zebra-EVA encapsulate. [ABSTRACT FROM AUTHOR]

The rim of a post-exploitation basin is a particularly dangerous zone for buildings. This is due to the impact of mining on the nearby buildings, which persists even after exploitation activities are finished. The rim of the basin remains constantly deformed. This paper presents numerical analyses of buildings located in Marklowice (Silesian Voivodeship, Poland). They are located in an area that was exploited for mining, above the initial exploitation edge on the rim of the basin. The area of the analysed buildings was geodetically monitored during mining works. The results of the measurements allowed the observation of changes in terrain deformation indicators, together with the determination of the settlement's final values after the operation was completed. Knowledge of the results enabled the preparation of numerical analyses of buildings with the use of the finite element method (FEM), the purpose of which was to determine the residual stresses in the structures after the end of the exploitation. The results are presented in the form of stress maps, which show changes in the internal forces in buildings left by mining operations. Specific examples are used. Two residential two-storey buildings were analysed; they were built using traditional brick methods, with a single-storey outbuilding. All of the analysed buildings are located in the mining commencement zone, in which the deformation of the surface has not faded away. [ABSTRACT FROM AUTHOR]