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Beam exit windows are crucial components of any particle accelerator as they provide an interface between the beamline vacuum and target material at atmospheric media. For high beam power machines, special materials and designs are required to withstand high radiation and mechanical loads, while minimizing energy loss during transition and maximizing window lifetime. This research investigates the impact of electron beam exposure to bulk CrMnV and CrMnTiV high entropy alloys (HEAs) with the primary goal of identifying suitable candidate materials for the design of robust and durable exit window settings. The selection criteria include intrinsic characteristics, power dissipation, and mechanical responses. According to the thermodynamic calculations, both equiatomic CrMnV and the addition of 7% of Ti with equiatomic CrMnV yield solid-solutions phases. The structural and mechanical properties of CrMnV and CrMnTiV samples were tested using field emission scanning electron microscopy, atomic force microscopy, scanning electron microcopy with energy dispersive x-ray spectroscopy, x-ray diffraction, and nanoindentation before and after exposure to a dose of ∼66 kGy from a 10 MeV e-beam accelerator. Despite exhibiting beam transmission characteristics comparable to Cr and V, the indentation hardness of HEAs exceeded that of the Cr and V samples by five to six times. The examination of the CrMnTiV irradiated samples revealed organized deformation patterns depicting new features, which we suspect twinning and twin boundaries due to the addition of Ti to CrMnV. Ti, a hexagonal-close-packed crystal structure, is commonly known for deformation twinning behavior. [ABSTRACT FROM AUTHOR]

Using commercially available components, a compact laboratory-type prototype has been developed and assembled to demonstrate single and multicaloric effects arising from single and cyclic applications of magnetic fields and uniaxial mechanical loads. Using the example of the LaFe11.4Mn0.3Si1.3H1.6 alloy with a first-order phase transition near room temperature, the possibility of observing magnetocaloric, elastocaloric, and multicaloric effects is demonstrated. It is shown that by selecting protocols for applying combined external influences: magnetic field and mechanical load, it is possible to observe a synergistic effect for adiabatic temperature change, which amounts to 1.17 K (0.31 T and 19 MPa) at a temperature of 291.5 K for the multicaloric effect, which exceeds the corresponding value of |ΔT| = 0.75 K (0.31 T) at a temperature of 291.65 K for the magnetocaloric effect. The proposed approaches and obtained results can be used for the development of new prototypes of multicaloric cooling systems and the optimization of current ones. [ABSTRACT FROM AUTHOR]

In our previous test model, the abutment teeth and the model base were printed with resin and bonded with a polyether material. Some abutment teeth were fractured during the mechanical load test. Therefore, the aim was to develop and evaluate a new model under mechanical loading until fracture with zirconia FPD frameworks. At a fracture load of up to 1,636 N, neither the artificial abutment teeth nor the base model fractured. Furthermore, the artificial abutment teeth did not detach from the base model. Therefore, the model should be suitable for mechanical testing of most ceramic-based framework materials for three-unit FPDs. [ABSTRACT FROM AUTHOR]

Epoxy insulators in gas-insulated power apparatus are subjected to the combined effects of electrical and mechanical loads. In this work, a simulation model is built based on the energy theory to explore the electrical tree growth of epoxy resin under tensile and compressive stresses. With increasing AC voltage, the electrical tree growth is promoted, exhibiting a morphology with more branches. Tensile stress accelerates the electrical tree growth, while proper compressive stress has the opposite effect. However, when the compressive stress exceeds a certain value, electrical tree growth is promoted again. When the mechanical stress is vertical to the needle electrode, these effects primarily impact the length of the trees. Conversely, in parallel cases, mechanical stress mainly affects the width of the electrical trees. Filler doping play the role of obstacles as well as enhancing the electric field concentration, the electrical tree growth is firstly inhibited and then promoted as the doping content increases. The electrical tree morphologies of simulation and experiment are in good consistency, proving the reasonability of the simulation model. [ABSTRACT FROM AUTHOR]

Due to the importance of safety in the process of structural designing of the modern buildings' ceiling, this study gravitates on a novel topic of analyzing thermoelastic response of the concrete ceiling reinforced with nanoparticles of graphene-platelets (GPL). To this end, the mentioned ceiling is considered as a fully-clamped rectangular plate exposed to simultaneous impact of thermal and mechanical loads. The exact form of the elasticity theory in conjunction with the differential quadrature method is employed for acquiring the behavior of the system. Then, an artificial intelligence-based method is used to accelerate the computational process. Efficiency and accuracy of the employed solution are examined and verified by means of a comparative study. The results of this article would be broadly employed in the structural design of the modern constructions in the near future. [ABSTRACT FROM AUTHOR]

Purpose: The present paper aims to study the influence of the substrate system on the thermomechanical response of various lead-free die attach materials used in power electronics using nonlinear finite element simulations. Design/methodology/approach: Particularly, three ceramic substrate systems, including direct copper bonded (DCB) and aluminum nitride (AlN) – as well as silicon nitride (Si3N4) –based insulated metal substrate (IMS) configurations are examined in this study. Additionally, three die attach systems, namely, silver-tin transient liquid phase (TLP), sintered silver (Ag) and sintered copper (Cu) are included in the analysis. ANSYS software is employed to build the finite element models of the power modules and to conduct the nonlinear thermomechanical investigations. Findings: The simulation results revealed that the IMS, Si3N4 and DCB-based power modules end up with significantly lower interconnect inelastic strains and inelastic strain energies suggesting better fatigue life performance. Additionally, the bonding layer stresses and expected failure mechanism are not influenced by the substrate configuration rather than the bond material. For instance, the silver-tin TLP joints develop high stresses and hence brittle failures are expected. Nonetheless, the sintered Ag and sintered Cu have significantly lower stresses which could lead to fatigue-induced failures. Originality/value: Power electronics use various ceramic-based substrate systems because of their improved thermal conductivity, electrical insulation and heat resistance properties. The proper selection of the substrate structure could highly enhance the thermal fatigue of the power modules. Markedly, the findings of this research are useful for designing highly reliable and effective power modules continuously subjected to thermomechanical loadings. [ABSTRACT FROM AUTHOR]

In challenging operational environments, Lithium‐ion batteries (LIBs) inevitably experience mechanical stresses, including impacts and extrusion, which can lead to battery damage, failure, and even the occurrence of fire and explosion incidents. Consequently, it is imperative to investigate the safety performance of LIBs under mechanical loads. This study is grounded in a more realistic coupling scenario consisting of electrochemical cycling and low‐velocity impact. We systematically and experimentally uncovered the mechanical, electrochemical, and thermal responses, damage behavior, and corresponding mechanisms under various conditions. Our study demonstrates that higher impact energy results in increased structural stiffness, maximum temperature, and maximum voltage drop. Furthermore, heightened impact energy significantly influences the electrical resistance parameters within the internal resistance. We also examined the effects of State of Charge (SOC) and C‐rates. The methodology and experimental findings will offer insights for enhancing the safety design, conducting risk assessments, and enabling the cascading utilization of energy storage systems based on LIBs. [ABSTRACT FROM AUTHOR]

Structural batteries offer multiple advantages, providing viable solutions for electric mobility. By playing a dual role as both an energy storage device and structural component, they can achieve a larger transportation range and greater safety. However, they are exposed to external mechanical loads that can exacerbate the mechanical stresses induced by the electrochemical cycling. It should be noted that batteries undergo stress due to the intercalation and deintercalation of Li+. In fact, when lithium ions are inserted into the active materials, mechanical tension occurs, which can cause cracks and pulverization of the particles. Consequently, the individual particles lose their electrical connectivity. Another aging process is caused by the expansion of the active materials due to mechanical strain during the insertion of lithium ions, resulting in changes in particle volume. In addition to this electrochemical stress, there is added mechanical stress due to their role as a structural component. This paper explores the superposition of these two phenomena and tries to understand the fatigue and failure mechanisms induced by mechanical strain and electrochemical cycling (Li+ intercalation/deintercalation) in structural batteries. To achieve this, we plan to use the fiber bundle model as a theoretical approach to study the damage and fracture of fiber-reinforced composite materials. [ABSTRACT FROM AUTHOR]

Magneto-electro-elastic (MEE) materials are a specific class of advanced smart materials that simultaneously manifest the coupling behavior under electric, magnetic, and mechanical loads. This unique combination of properties allows MEE materials to respond to mechanical, electric, and magnetic stimuli, making them versatile for various applications. This paper investigates the static and time-harmonic field solutions induced by the surface load in a three-dimensional (3D) multilayered transversally isotropic (TI) linear MEE layered solid. Green's functions corresponding to the applied uniform load (in both horizontal and vertical directions) are derived using the Fourier-Bessel series (FBS) system of vector functions. By virtue of this FBS method, two sets of first-order ordinary differential equations (i.e., N-type and LM-type) are obtained, with the expansion coefficients being Love numbers. It is noted that the LM-type system corresponds to the MEE-coupled P-, SV-, and Rayleigh waves, while the N-type corresponds to the purely elastic SH- and Love waves. By applying the continuity conditions across interfaces, the solutions for each layer of the structure (from the bottom to the top) are derived using the dual-variable and position (DVP) method. This method (i.e., DVP) is unconditionally stable when propagating solutions through different layers. Numerical examples illustrate the impact of load types, layering, and frequency on the response of the structure, as well as the accuracy and convergence of the proposed approach. The numerical results are useful in designing smart devices made of MEE solids, which are applicable to engineering fields like renewable energy. [ABSTRACT FROM AUTHOR]

Detrended fluctuation analysis (DFA) and sample entropy (SE) measure the long-term correlations and regularity of gait patterns, respectively, having previously been used to identify participants at risk of falling, previous history of injury, or patients with motor diseases. Since these measures are more sensitive to gait impairment than linear measures (e.g., the standard deviation [SD] of stride time), they can be potentially used in military medicine to identify soldiers at risk of injury. However, clinometric properties are yet to be established. What is the repeatability of DFA, SE, and traditional linear measures of stride time variability (SD and coefficient of variation [CV]) under various load and speed constraints? Fourteen Australian Army trainee soldiers (age: 25.6 ± 5.9 y, height: 1.74 ± 0.08 m, body mass: 77.2 ± 15.1 kg, service: 1.5 ± 1.8 y) attended three sessions over two weeks, completing four 12-minute walking trials on an instrumented treadmill in each session. Participants walked with a combination of 0 kg or 23 kg loads at a self-selected or 5.5 km/h speed. Heel contacts from the right foot were identified using treadmill-embedded force plates. From 512 stride time intervals, linear (SD and CV), and non-linear (DFA and SE) measures were obtained. To assess the between-session repeatability, intraclass correlations (ICC 2,1) were employed. There was poor-to-moderate repeatability for the SD (ICC: 0.357–0.545) and CV (ICC: 0.371–0.529). DFA showed poor-to-moderate repeatability (ICC: 0.013–0.504), while SE had poor repeatability (ICC: 0.133–0.226). Previous studies have shown that differences of > 0.19 in DFA and > 0.66 in SE can differentiate between healthy and pathological gait. These values are greater than this study's reported standard error of measurement, indicating that clinically meaningful changes may still be detectable despite low repeatability. • The repeatability of stride time measures during loaded marching were established • Linear and non-linear measures demonstrated poor-to-moderate repeatability • Non-linear measures had a variation of less than 10 % between sessions • Meaningful changes in stride time measures can be detected during marching [ABSTRACT FROM AUTHOR]

The operation of iontronic capacitive sensors typically requires an external alternating current (AC) power source, resulting in additional energy consumption and AC‐frequency‐related sensing performance. Here, a class of self‐powered iontronic capacitive sensing units (SICSUs) is proposed based on a dynamic electric double layer (EDL), with a significant charge sensitivity of up to 24270 pC N−1, surpassing most piezoelectric materials by nearly 10 times. The effects of various design parameters and loading conditions on the sensing performance of the SICSUs are systematically investigated. The EDL at the hydrogel‐electrode interface is characterized in situ, revealing the underlying mechanism for high sensitivity and linearity. The capability of SICSUs in detecting diverse human‐related mechanical loads is demonstrated. Furthermore, a robotic hand equipped with a SICSU‐based artificial algesia sensor is fabricated to mimic the withdrawal reflex behavior of a human hand when its skin detects noxious stimuli caused by sharp objects. [ABSTRACT FROM AUTHOR]

Large or repeated mechanical loads degrade polymeric materials by accelerating chain fragmentation. This mechanochemical backbone fracture usually occurs by homolysis of otherwise inert C–C, C–O and C–S bonds, generating highly reactive macroradicals. Because backbone fracture is detrimental on its own and the resulting macroradicals can initiate damaging reaction cascades, a major thrust in contemporary polymer mechanochemistry is to suppress it, usually by mechanochemical release of "hidden length" that dissipates local molecular strain. Here we summarize an emerging complementary strategy of channelling mechanochemically generated macroradicals in reaction cascades to form new load-bearing chemical bonds, which enables local self-healing or self-strengthening, and/or to generate mechanofluorescence, which could yield detailed quantitative molecular understanding of how material-failure-inducing macroscopic mechanical loads distribute across the network. We aim to identify generalizable lessons derivable from the reported implementations of this strategy and outline the key challenges in adapting it to diverse polymeric materials and loading scenarios. [ABSTRACT FROM AUTHOR]

In this article, the behavior of the truncated conical shell subjected to thermomechanical loading in their inner and outer layers with internal heat generation source is investigated. The displacement field obeys kinematic of the first order shear deformation theory and the first-order temperature theory is used. Two-dimensional temperature analysis has been performed along the thickness and axis of the shell, which can be defined under various loading and thermomechanical boundary conditions. The set of governing equations is a system of differential equations with variable coefficients which are solved by using the analytical matched asymptotic expansion of the perturbations technique. The mentioned solution has little computational cost, therefore can be used well in parametric studies for optimization. It was shown, axial displacement is somehow independent of the radial axis and its maximum value occurs near the upper boundary. The conical shell has expanded in the radial direction. Also the maximum temperature happens approximately in the middle of the length of the conical shell. The parametric study showed, with the increase heat flux in the outer layer thereby expanding the area of heat application which would let more heat in than out. Also it was found, controlling the lifetime of the structure is the result of directing the cone angle. The results obtained from the analytical solution were compared with the Finite Element Method (FEM) analysis and the results of similar related articles, only to show a good agreement. [ABSTRACT FROM AUTHOR]

This study presents a thermo-mechanical fracture analysis of porous functionally graded cracked plates using the extended finite element method. Three types of functionally graded cracked plates with two different types of porosity distributions, namely homogeneous and nonhomogeneous, are considered in this investigation. Specifically, edge and center-cracked porous functionally graded material plates are analyzed to determine the stress intensity factors. Thermo-mechanical loading conditions are considered to simulate the effects of temperature gradients and mechanical stresses on cracked plates. The analysis aims to investigate the influence of the crack length, crack location, porosity distribution, porosity volume fraction, crack angle, and material gradient on the SIF values. The results of the study provide valuable insights into the behavior of functionally graded cracked plates with different porosity distributions. The findings contribute to the understanding of the mechanical response of such plates under thermo-mechanical loading conditions and can aid in the design and optimization of structures made from functionally graded porous materials. [ABSTRACT FROM AUTHOR]

This study introduces extended isogeometric analysis method (XIGA) as a tool to investigate fracture behavior in isotropic and orthotropic materials under uniaxial and biaxial mechanical loads. Utilizing isogeometric analysis knot spans to discretize the problem domain and second order perturbation technique within XIGA framework derives mean and coefficient of variance values for mixed-mode stress intensity factors (MMSIFs) by considering variations in input parameters, including crack length, crack angle and material elastic properties. Mixed-mode SIF is evaluated using the proper interaction integral method subjected to different loading conditions showcases versatility of the proposed approach. The alignment between the existing literature and Monte Carlo simulations demonstrates a robust correspondence, validating the accuracy and reliability of the stochastic XIGA technique. This research establishes the efficacy of the approach in comprehensively addressing fracture analysis across different mechanical loading scenarios. [ABSTRACT FROM AUTHOR]

This paper examines the shaft resistance mobilisation ratio as a predictor of cumulative displacement of small-scale floating and end-bearing energy pile foundations subjected to vertical compressive loads embedded in dry sandy soils. A reduced friction model pile was subjected to different mechanical loads and two long-duration, cyclic heating/recovery temperature changes. The pile, soil and container temperatures, pile strains, and vertical displacements are monitored, analysed, and discussed. The results further validate numerical analyses that propose the shaft resistance mobilisation ratio as a variable to identify thresholds above which permanent cyclic thermo-induced deformations may occur. Overall, the experimentally observed responses indicate incremental deformations as the shaft resistance mobilisation ratio increased. The results also suggest that a mobilisation ratio of 66% could be a potential conservative lower-bound limit that could control the increment of thermal-induced vertical displacements in the long term under free pile head conditions. This suggests that a performance-based design would be a reasonable approach for energy piles, and monitoring programs should be set in the field before loading and thermo-activation. [ABSTRACT FROM AUTHOR]

Embedded fiber Bragg gratings are increasingly applied for in-situ strain measurement in fiber-reinforced plastics, integral to high-end aerospace equipment. Existing research primarily focuses on in-plane strain measurement, limited by the fact that fiber Bragg gratings are mainly sensitive to axial strain. However, out-of-plane strain measurement is equally important for comprehending structural deformation. The birefringence of fiber Bragg gratings shows promise for addressing this problem; yet, the strain transfer relationship between composites and optical fibers, along with the decoupling method for multi-directional strains, remains inadequately explored. This study introduces an innovative method for multi-directional strain measurement in fiber-reinforced plastics using the birefringence of a single-fiber Bragg grating. The strain transfer relationship between composites and embedded optical fibers was derived based on Kollar's analytical model, leading to the development of a multi-directional strain decoupling methodology. This method was experimentally validated on carbon fiber/polyetherimide laminates under thermo-mechanical loading. Its reliability was confirmed by comparing experimental results and finite element simulations. These findings significantly broaden the application scenarios of fiber Bragg gratings, advancing the in-situ measurement technology crucial for the next generation of high-end aerospace equipment. [ABSTRACT FROM AUTHOR]

The mechanical behaviors of the clamped laminated arch with temperature-dependent material properties under the thermal and mechanical loadings are studied in this paper. An analytical method based on the theory of thermoelasticity is proposed for predicting the exact solutions of stresses and displacements in the arch with arbitrary thickness and layer numbers. The clamped support is equivalent to a simply support with a support reaction with the unit pulse function and the Dirac function. The space state method is utilized to establish the state equation by employing the displacements and stresses as the state variables. A slice model is introduced to simplify the coefficient matrix. Based on the continuities at the interfaces, the displacement and stress relationships between the internal and external surfaces of the laminated arch are derived with the transfer matrix method. Exact solutions for the displacements and stresses can be obtained according to the stress boundary conditions on the surfaces of the laminated arch. Finally, convergence and comparison studies demonstrate the excellent efficiency and accuracy of the present method. The influences of material dependency with temperature, thermal load, and thickness-to-radius ratio on the distributions of displacements and stresses are discussed in detail. [ABSTRACT FROM AUTHOR]

This paper presents a root cause analysis case study of defective Hall effect sensor devices. The study identified a complex failure mode caused by chip–package interaction, which has a similar signature to discharging defects such as ESDFOS (electrostatic discharge from outside to surface). However, the study revealed that the defect was induced by local mechanical force applied to IC structures due to the presence of large irregular shaped filler particles within the mold compound. Extensive failure analysis work was conducted to identify the failure mode, including the development of a new backside analysis strategy to preserve the mold compound during IC defect localization and screening. A combination of different failure analysis techniques was used, including CMP delayering, PFIB trenching, SEM PVC imaging and large area FIB cross-sectioning. The study found that the mold compound of the package caused thermo-mechanical strain onto the silica filler particle due to epoxy shrinkage during the molding process. Additionally, extra-large, irregularly shaped filler particles (called twin particles), located on top of the chip surface, can cause locally high compression stresses onto the IC layers, initiating cracks in the isolation layers under certain conditions forming a leakage path over the time. Thermo-mechanical finite element analysis was applied to verify the mechanical load condition for these large irregular shaped filler particles. As a result, an additional polyimide layer was introduced onto the IC to mitigate the mechanical stress of mold compound particles to avoid this failure mode. [ABSTRACT FROM AUTHOR]

The objective of this manuscript is to examine the thermodynamical disturbances in a rotating nonlocal transversely isotropic thermoelastic solid half-space. The enunciation is applied to Lord–Shulman model of generalized thermoelasticity with Eringen's nonlocal elasticity theory. The formulation is subjected to a mechanical load. The expressions for the displacement components, stresses and temperature field are obtained by using normal mode technique and the numerical computations have been carried out with the help of MATLAB software for zinc crystal-like material. The comparisons are made among the results obtained by taking into account the different values of rotation parameter $ (\Omega =0.0, 0.1, 0.3) $ (Ω = 0.0 , 0.1 , 0.3) , nonlocal parameter $ (\varepsilon =0.195\times 10^{-9}, 0.195\times 10^{-4}, $ (ε = 0.195 × 10 − 9 , 0.195 × 10 − 4 , $ 0.195\times 10^{-1}) $ 0.195 × 10 − 1) and time $ (t=0.1, 0.3, 0.5) $ (t = 0.1 , 0.3 , 0.5). The outcomes point out a strong impact of the rotation, nonlocality and time on the physical quantities and agree with the boundary conditions. Although various studies exist in the literature for local and isotropic thermoelastic medium, but the current results are presented in an anisotropic and nonlocal thermoelastic rotating medium, which have not been studied so far. [ABSTRACT FROM AUTHOR]

In this paper, we propose a plate model, within the framework of finite-strain elasticity, to study the magneto-mechanical behaviors of hard-magnetic soft material plates. The 2D vector plate equation is derived from the 3D governing equations through a series expansion and truncation approach. The displacement and traction boundary conditions on the edges of plate samples are also proposed. Compared with the other plate or shell theories, the current plate model naturally incorporates the elastic incompressibility and the magneto-mechanical coupling effect of the material, which doesn't involve any a priori hypotheses on the geometry and deformation of the plates. Thus, it is applicable for modeling the large deformations of hard-magnetic soft material plates. To show the efficiency of the plate model, we study a benchmark problem, i.e., the plane-strain bending deformations of plate samples induced by magnetic and mechanical loads. Some analytical solutions of the plate equation system are derived, which provide accurate predictions on the magneto-mechanical response of the plate samples with different thickness-length ratios and magnetization directions. To promote applications of the plate model, we further derive a simplified plate equation system and write out its weak form, which is then implemented into the finite element software COMSOL Multiphysics. The efficiency of the simplified plate equation system is also verified through some typical examples. It is found that the numerical results obtained from the 2D plate model show good consistency with those of the 3D volume model, while the plate model exhibits obvious advantages in the aspects of numerical efficiency. • The magneto-mechanical response of hard-magnetic soft material plates is studied. • A plate model is proposed through the series-expansion and truncation approach. • Field-induced bending deformations of plate samples are studied analytically. • A simplified plate equation system is derived and its weak form is established. • Numerical simulations based on the plate model show good accuracy and efficiency. [ABSTRACT FROM AUTHOR]

Structural strengthening solutions typically employ externally bonded reinforcement (EBR) systems with carbon fiber (CF) sheets because of these materials' lightweight, corrosion resistance, and electromagnetic immunity. However, elevated ambient temperatures can negatively impact the mechanical performance of EBR, as documented in the literature. Therefore, American bridge design specifications assume a concrete surface temperature of 60 °C (140 °F), which reflects the extreme conditions that bridge structures may experience, particularly in regions with intense sunlight and high ambient temperatures. Therefore, sustainable design solutions require a reliable quantification of the effects of temperature. This study extends a recently developed bending test layout and builds the analytical modeling procedure to quantify the stiffness degradation under repeated temperature and mechanical loads. The explicitly obtained equivalent stresses in the tensile concrete determine the stiffness measure independent of the loading condition and sequence. This test program used 12 laboratory samples. All beam samples faced the mechanical load repetitions and entire unloading. Three selected beams were additionally treated at 60 °C for 10 hours in a heating chamber between the loading repetitions. These tests identified a substantial (three times) decrease in the bonding performance of the CF sheets after eight heating rounds. Scanning electron microscopy (SEM) identified the corresponding microstructure changes. • This work proposes an efficient measure to quantify flexural stiffness. • It is suitable for repeated combinations of temperature and mechanical loads. • The wet-layup CF EBR system tends to lose its reinforcement performance at 60 °C. • This effect appears after three mechanical load and heating repetitions. • The epoxy bond deterioration can explain the reinforcement efficiency decrease. [ABSTRACT FROM AUTHOR]

[Objective] The hydraulic coupling behavior of rocks is closely related to the safety and stability of various rock engineering projects, including tunnel excavation, dam construction, oil and gas extraction, and rock slope stability analysis. The failure of rock masses and the evolution of permeability are part of a gradual dynamic process that is interrelated. On the one hand, the external load applied to the rock mass alters its microphysical, macrophysical, and mechanical properties, thereby affecting its permeability. On the other hand, changes in permeability can alter the distribution of permeability pressure, affect the effective stress within the rock mass, and consequently influence its stability. Additionally, the rock mass contains numerous fractures and fissures resulting from diagenetic processes, tectonic movements, and excavation disturbances, which complicates the assessment of the stability and reliability of the rock mass. Therefore, fully quantifying the mechanical properties and permeability evolution of prefabricated fractured rocks under hydraulic coupling is essential for minimizing damage in rock engineering projects. Despite recent advances in rock mechanics testing technology, measuring the microstructural changes in rocks under hydraulic mechanical loads during laboratory tests remains a challenge. [Methods] The rock failure process is closely associated with acoustic emission (AE), which is defined as transient elastic waves generated by the rapid release of energy within a material. Owing to its high sensitivity to crack initiation, propagation, and coalescence in loaded rocks, AE monitoring is a powerful tool for studying brittle rock failure. This technology has been widely applied in rock mechanics research and engineering applications. This article employs AE technology to conduct triaxial hydraulic coupling tests on intact sandstone and prefabricated fractured sandstone samples. The primary objective is to explore the micro-mechanisms of permeability evolution under hydraulic coupling loads through a series of laboratory tests. The strength and deformation characteristics, macroscopic failure modes, and permeability evolution patterns of prefabricated fractured sandstone under hydraulic coupling were examined. Additionally, the spatiotemporal evolution of AE events and the statistical distribution of fracture types during the failure process of prefabricated fractured sandstone were analyzed using AE technology. [Results] The experimental results indicate the following: 1) Antiwing cracks occur when the inclination angles of prefabricated cracks are 45°, 75°, and 90°, whereas specimens with other prefabricated crack inclination angles predominantly exhibit wing crack failures. 2) During the spatiotemporal evolution of AE events, the compression events resulting from the closure of cracks and pores during the initial compression stage represent the primary microscopic mechanism for the decrease in permeability. 3) The increase in permeability is mainly attributed to tensile and shear microcracks associated with volume expansion, whereas the decrease in permeability is caused by shear microcracks associated with volume compression and compression microcracks. [Conclusions] Under triaxial hydraulic coupling, the strength and deformation characteristics, macroscopic failure modes, and permeability of prefabricated fractured sandstone specimens are influenced by the inclination angle of the prefabricated fractures. The decrease in permeability mainly results from compression events that lead to fracture closure and pore collapse, whereas the increase in permeability is attributed to the continuous accumulation of tensile and shear events, which is also influenced by the inclination angle of pre-existing fractures. [ABSTRACT FROM AUTHOR]

This article analyzes the effect of electrolytic plasma nitriding on the performance of medium-carbon steel 45 under increased mechanical loads and in aggressive environments. Nitrided samples in carbamide electrolytes, both with and without the addition of ammonium nitrate, were compared to the initial material. SEM with EDX and XRD analysis was used to examine the microstructure and phase composition of nitrided samples. Wear resistance was studied using the 'ball-on-disk' method and Vickers microhardness testing, while corrosion resistance was studied using potentiodynamic polarization curves. The study results show that the sample without ammonium nitrate demonstrated better mechanical and corrosion properties due to a more homogeneous and denser nitride layer, approximately 10 µm thick, containing phases FeN and Fe4N. Its wear resistance doubled compared to that of the initial sample. The sample treated in an electrolyte with the addition of ammonium nitrate demonstrated a higher current density (2.8672 × 10−5 A/cm2) and a lower corrosion potential (−0.565 V) compared to the initial sample (i_corr = 1.8971 × 10⁻5 A/cm2, E_corr = −0.480 V) and the sample without ammonium nitrate (i_corr = 1.7315 × 10−5 A/cm2, E_corr = −0.376 V). This is due to the formation of an uneven nitride layer and the presence of microcracks on the surface. [ABSTRACT FROM AUTHOR]

The development of modern reusable launchers, such as the Themis project with its LOX/LCH4 Prometheus engine, CALLISTO—a reusable VTVL-launcher first-stage demonstrator with a LOX/LH2 RSR2 engine, and SpaceX's Falcon 9 with its Merlin 1D engine, underscores the need for advanced control algorithms to ensure reliable engine operation. The multi-restart capability of these engines imposes additional requirements for throttling, necessitating an extended controller-validity domain to safely achieve low thrust levels across various operating regimes. This capability also increases the risk of component failure, especially as engine parameters evolve with mission profiles. To address this, our study evaluates the dynamic reliability of reusable rocket engines (RREs) and their subcomponents under different failure modes using multi-physics system-level modelling and simulation, with a particular focus on turbopump components. Transient condition modelling and performance analysis, conducted using EcosimPro-ESPSS software (version 6.4.34), revealed that turbopump components maintain high reliability under nominal conditions, with turbine blades demonstrating significant fatigue life even under varying thermal and mechanical loads. Additionally, the proposed predictive model estimates the remaining useful life of critical components, offering valuable insights for improving the longevity and reliability of turbopumps in reusable rocket engines. This study employs deterministic, thermally dependent structural simulations, with key control objectives including end-state tracking of combustion chamber pressure and mixture ratios and the verification of operational constraints, exemplified by the LUMEN demonstrator engine and the LE-5B-2 engine class. [ABSTRACT FROM AUTHOR]

A comprehensive review is presented on the main analytical methods used in the specialized literature to evaluate the buckling loads of thin-walled cylindrical shells (TWCS) subjected to different mechanical loads or load combinations. The analytical formulations are first presented for unstiffened TWCS, followed by stiffened TWCS in different configurations (stiffeners in the axial direction, circumferential direction or both axial and circumferential directions, placed on the external or internal surface of the shell). This research can serve as a helpful resource for researchers investigating this field, allowing the analytical methods to be used as a reference basis for numerical and experimental results regarding the behavior of structures in the category of TWCS. [ABSTRACT FROM AUTHOR]

Integrated heat and roll forming (IHMRF) is a process that uses thermal and mechanical loads to produce localized plastic strains in plates to form complex curvature hull plates. The magnitude of the resulting plastic strain depends mainly on the following forming parameters: the machining parameters (power of the heat source, speed of the heat source, and the forming depth of the rollers), the thickness of the plate, and the thermo-physical and mechanical properties of the plate. Finding the correspondence between the plastic strain and forming parameters is the key to selecting the appropriate machining parameters for forming. A data-driven approach is ideal for this purpose. However, due to the characteristics of the IHMRF process, the forming process involves a large number of variables, and different materials have different temperature-dependent yield strengths. These high-dimensional input characteristics create a conflict between the required number of samples and the model training requirements. This paper presents a physically informed data-driven (PIDD) approach for modeling the relationship between forming parameters and plastic strains in IHMRF. Based on dimensional analysis and domain knowledge, the proposed method derives the basic thermal and mechanical relationships between the forming parameters, obtaining a much smaller number of physical parameters. These physical parameters are expressions of the physical knowledge of forming in low-dimensional space. Using the physical parameters yields higher accuracy on fewer sample data points than directly using the forming parameters as input features. Furthermore, the models trained on a variety of commonly used materials and plate thicknesses achieved comparable accuracy to the numerical simulation with unseen materials and plate thicknesses. Experimental and numerical simulations further verify the effectiveness of the proposed method by machining plates of various materials to the same shape. [ABSTRACT FROM AUTHOR]

Active repair systems employing piezoelectric (PZT) patches have emerged as promising solutions for mitigating crack propagation and enhancing structural integrity in various engineering applications. However, the existing literature predominantly focuses on the application of PZT patches for repairing structures under mechanical loading. In this study, a finite element analysis (FEA) is employed to investigate the repair of a centre-cracked aluminium plate under both mechanical and thermo-mechanical loading conditions. This study explores the influence of key parameters, including temperature, PZT patch thickness, type of PZT material, adhesive material, and adhesive thickness, on the structural integrity and crack propagation behaviour. The results reveal significant differences in stress distribution and crack propagation tendencies under varying loading conditions and parameter settings. These findings emphasize the necessity of considering thermo-mechanical loading conditions and parameter variations when designing effective active repair systems. In conclusion, this study provides valuable insights into optimizing PZT patch-based repair strategies for improved structural integrity and crack mitigation in aerospace and other engineering applications under diverse loading scenarios. [ABSTRACT FROM AUTHOR]

Bolted joints, with their advantages of simple structure and convenient disassembly and assembly, are widely used in complex equipment fields such as aerospace systems and weaponry. Subject to complex mechanical loads, the contact surfaces may undergo nonlinear behaviors such as contact–separation and viscous slip, leading to the nonlinear degradation of the connection stiffness, which severely threatens the safety and reliability. These have driven research on bolted joints to span multiple disciplines, from interfacial micro-friction to macro-structural dynamics. Therefore, from the field of micro-friction to macro-dynamics, this review summarizes and analyzes three major degradation models, outlines the experimental development in connected structures, and provides an overview of the numerical analysis methods for degradation simulation. This paper also looks forward to the development directions for future research on the degradation of connected structures. [ABSTRACT FROM AUTHOR]

Purpose: To assess the fracture resistance and failure mode of endodontically treated premolars reconstructed by different preparation approaches: cervical margin relocation (CMR) and crown lengthening (CL) with complete ferrule (CLF) and partial ferrule (CLPF) with three different post and core systems. Materials and Methods: In this in vitro study, 100 maxillary premolars were assigned to the following 10 groups according to their preparation approach and type of post and core system (n = 10): (I) control (intact teeth), (II) prefabricated fiber post (PFP) and composite core with CMR (PFP‐CMR), (III) polyethylene fiber‐reinforced composite (PEFRC) with CMR (PEFRC‐CMR), (IV) casting post (CP) and core with CMR (CP‐CMR), (V) PFP‐CLPF, (VI) PEFRC‐CLPF, (VII) CP‐CLPF, (VIII) PFP‐CLF, (IX) PEFRC‐CLF, and (X) CP‐CLF. After thermomechanical loading, the fracture resistance and failure mode were assessed. Data were analyzed statistically (α = 0.05). Results: In all post and core systems, the CLPF approach had lower fracture resistance than CMR (p < 0.05); CLF showed higher fracture resistance than CLPF only in the PFP system (p = 0.038). In PEFRC and CP systems, the difference between CLF and CLPF was not significant (p > 0.05). No significant difference was found in fracture resistance of different post and core systems with the same preparation approach (p > 0.05). CLPF showed the highest frequency of favorable, and CLF showed the highest frequency of unfavorable fractures. Conclusion: CLPF yielded lower fracture resistance than CMR. The difference in fracture resistance was not significant between CLF and CMR but the frequency of unfavorable fractures was higher in CLF than in other groups. [ABSTRACT FROM AUTHOR]

This work develops a Hermitian C differential reproducing kernel interpolation meshless (DRKIM) method within the consistent couple stress theory (CCST) framework to study the three-dimensional (3D) microstructure-dependent static flexural behavior of a functionally graded (FG) microplate subjected to mechanical loads and placed under full simple supports. In the formulation, we select the transverse stress and displacement components and their first- and second-order derivatives as primary variables. Then, we set up the differential reproducing conditions (DRCs) to obtain the shape functions of the Hermitian C differential reproducing kernel (DRK) interpolant's derivatives without using direct differentiation. The interpolant's shape function is combined with a primitive function that possesses Kronecker delta properties and an enrichment function that constituents DRCs. As a result, the primary variables and their first- and second-order derivatives satisfy the nodal interpolation properties. Subsequently, incorporating our Hermitian C DRK interpolant into the strong form of the 3D CCST, we develop a DRKIM method to analyze the FG microplate's 3D microstructure-dependent static flexural behavior. The Hermitian C DRKIM method is confirmed to be accurate and fast in its convergence rate by comparing the solutions it produces with the relevant 3D solutions available in the literature. Finally, the impact of essential factors on the transverse stresses, in-plane stresses, displacements, and couple stresses that are induced in the loaded microplate is examined. These factors include the length-to-thickness ratio, the material length-scale parameter, and the inhomogeneity index, which appear to be significant. [ABSTRACT FROM AUTHOR]

Polymer nanocomposites have found ubiquitous use across diverse industries, attributable to their distinctive properties and enhanced mechanical performance compared to conventional materials. Elucidating the elastic‐to‐plastic transition in polymer nanocomposites under diverse mechanical loads is paramount for the bespoke design of materials with desired mechanical attributes. In the current work, the elastic‐to‐plastic transition is probed in model systems of polyethylene oxide (PEO) and silica, SiO2, nanoparticles, through detailed atomistic molecular dynamics simulations. This comprehensive, multi‐scale analysis unveils pivotal markers of the elastic‐to‐plastic transition, highlighting the quintessential role of microstructural and regional heterogeneities in density, strain, and stress fields, featuring the polymer‐nanoparticle interphase region. At the atomic level, the behavior of polymer chains interacting with nanoparticle surfaces is traced, differentiating between free and adsorbed chains, and identifying the microscopic origins of the linear‐to‐plastic transition. The mechanical behavior of subregions are characterized within the PEO/SiO2 nanocomposites, focusing on the interphase and bulk‐like polymer areas, probing stress heterogeneities and their decomposition into various force contributions. At the inception of plasticity, a disruption is discerned in isotropy of the polymeric density field, the emergence of low‐density regions, and microscopic voids/cavities within the polymer matrix concomitant with a transition of adsorbed chains to free. The yield strain also emerges as an inflection point in the local versus global strain diagram, demarcating the elastic limit, and the plastic regime shows pronounced strain heterogeneities. The decomposition of the atomic Virial stress into bonded and non‐bonded interactions indicates that the rigidity of the material is primarily governed by non‐bonded interactions, significantly influenced by the volume fraction of the nanoparticle. These findings emphasize the importance of the microstructural and micromechanical environment at the polymer‐nanoparticle interface on the linear‐to‐plastic transition, which is of great importance in the design of nanocomposite materials with advanced mechanical properties. [ABSTRACT FROM AUTHOR]

Erectile dysfunction (ED) is a prevalent type of sexual dysfunction, and continuous monitoring of penile tumescence and rigidity during spontaneous nocturnal erections is crucial for its diagnosis and classification. However, the current clinical standard device, limited by its active mechanical load, is bulky and nonwearable and strongly interferes with erections, which compromises both monitoring reliability and patient compliance. Here, we report a wearable adaptive rigidity monitoring (WARM) system that employs a measurement principle without active loads, allowing for the assessment of penile tumescence and rigidity through a specifically designed elastic dual-ring sensor. The dual-ring sensor, comprising two strain-sensing rings with distinct elastic moduli, provides high resolution (0.1%), robust mechanical and electrical stability (sustaining over 1000 cycles), and strong interference resistance. An integrated flexible printed circuit (FPC) collects and processes sensing signals, which are then transmitted to the host computer via Bluetooth for ED assessment. Additionally, we validated the WARM system against the clinical standard device using both a penile model and healthy volunteers, achieving high consistency. Furthermore, the system facilitates the continuous evaluation of penile erections during nocturnal tumescence tests with concurrent sleep monitoring, demonstrating its ability to minimize interference with nocturnal erections. In conclusion, the WARM system offers a fully integrated, wearable solution for continuous, precise, and patient-friendly measurement of penile tumescence and rigidity, potentially providing more reliable and accessible outcomes than existing technologies. [ABSTRACT FROM AUTHOR]

Ratcheting analysis for cantilever beams subjected to the thermomechanical loads is presented using the finite element method. The cantilever beam is constrained along the vertical direction, and plane stress conditions are assumed according to the bilinear isotropic hardening model. Two points are considered to obtain areas of ratcheting by using linear extrapolation. The results and output diagrams for ratcheting with elastic-perfect plastic behavior are illustrated. It was revealed that the beam behaves elastically after the first considerable plastic strain, which is seen in two shakedown regimes. The numerical results are verified with known and analytical results in the literature. The results indicate a strong correlation between the outcomes from the cyclic ANSYS Parametric Design Language (APDL) model and Bree's analytical predictions. This consistency between the finite element analysis and the analytical solutions underscores the potential of finite element analysis as a powerful tool for addressing complex engineering challenges, offering a reliable and robust alternative to traditional analytical methods. [ABSTRACT FROM AUTHOR]

Silicon nitride (Si3N4) is widely used in structural ceramics and advanced manufacturing due to its excellent mechanical properties and high-temperature stability. These applications always involve deformation under mechanical loads, necessitating a thorough understanding of their mechanical behavior and performance under load. However, the mechanical properties of Si3N4, particularly at the micro- and nanoscale, are not well understood. This study systematically investigated the mechanical properties of bulk Si3N4 and Si3N4 whiskers using in situ SEM indentation and uniaxial tensile strategies. First, nanoindentation tests on bulk Si3N4 at different contact depths ranging from 125 to 450 nm showed significant indentation size effect on modulus and hardness, presumably attributed to the strain gradient plasticity theory. Subsequently, in situ uniaxial tensile tests were performed on Si3N4 whiskers synthesized with two different sintering aids, MgSiN2 and Y2O3. The results indicated that whiskers sintered with Y2O3 exhibited higher modulus and strength compared to those sintered with MgSiN2. This work provides a deeper understanding of the mechanical behavior of Si3N4 at the micro- and nanoscale and offers guidance for the design of high-performance Si3N4 ceramic whiskers. [ABSTRACT FROM AUTHOR]

A thermo-mechanical progressive analysis model is proposed for predicting fatigue-driven delamination in composite laminated plates. The delamination is simulated based on extended layerwise method (XLWM). The traction-separation law is employed to the heat flux transfer and mechanical load transfer across the delamination front. A thermo-mechanical cohesive zone model (TM-CZM) is developed by Peerlings damage law to simulate the fatigue characteristic of delamination front. In the numerical examples, the effects of mesh lengths, acceleration multipliers, interface strengths, and cyclic temperature load magnitudes on the delamination expansion process are investigated, and the temperature-life curves of composite laminates are determined as well. [ABSTRACT FROM AUTHOR]

This research focuses on enhancing the preventive maintenance strategies currently employed for induction motors within ship propulsion systems, advocating for a shift towards a predictive maintenance model. It introduces a real-time monitoring framework that continuously observes the induction motor, providing essential support to maintenance personnel. The motor operates under a range of environmental and operational conditions, including temperature fluctuations, rotational speeds, and mechanical loads. These variations can obscure the current time series data, potentially masking signs of actual damage and hindering effective damage detection. To tackle this issue, the proposed framework utilizes artificial intelligence (AI) technology, specifically the well-established autoencoder, in conjunction with the Mahalanobis statistical distance. This approach accounts for the diverse operating conditions during the training phase, allowing it to model complex, non-linear relationships and effectively differentiate between normal and anomalous states. The framework is integrated into a decision support platform designed for real-time operations in maritime settings, offering a sophisticated system architecture that aims to align advanced damage detection methodologies with the maritime industry's need for real-time, user-friendly solutions. [ABSTRACT FROM AUTHOR]

This paper explores the adaptation of pseudo-rigid-body models (PRBMs) for simulating large geometric nonlinear deflections in passive exoskeletons, expanding upon their traditional application in small compliant systems. Utilizing the AnyBody modeling system, this study employs force-dependent kinematics to reverse the conventional simulation process, enabling the calculation of forces from the deformation of PRBMs. A novel approach, termed "Constraint Force", is introduced to facilitate this computation. The approach is thoroughly validated through comparative analysis with laboratory trials involving a beam under bending loads. To demonstrate the functionality, the final segment of this study conducts a biomechanical simulation incorporating motion capture data from a lifting test, employing a novel passive exoskeleton equipped with flexible spring elements. The approach is meticulously described to enable easy adaptation, with an example code for practical application. The findings present a user-friendly and visually appealing simulation solution capable of effectively modeling complex mechanical load cases. However, the validation process highlights significant systematic errors in the direction and amplitude of the calculated forces (20% and 35%, respectively, in the worst loading case) compared to the laboratory results. These discrepancies emphasize the inherent accuracy challenges of the "Constraint Force" approach, pointing to areas for ongoing research and enhancement of PRBM methods. [ABSTRACT FROM AUTHOR]

Background: Surgeons often encounter patients with intestinal failure due to inadequate intestinal length ("short bowel syndrome"/SBS). Treatment in these patients remains challenging and the process of physiologic adaptation may take years to complete, which frequently requires parenteral nutrition. We propose a proof-of-concept mechanical bowel elongation approach using a self-expanding prototype of an intestinal expansion sleeve (IES) for use in SBS to accelerate the adaptation process. Methods: IESs were deployed in the small intestines of Sprague Dawley rats. Mechanical characterization of these prototypes was performed. IES length–tension relationships and post-implant bowel expansion were measured ex vivo. Bowel histology before and after implantation was evaluated. Results: IES mechanical studies demonstrated decreasing expansive force with elongation. The deployment of IES devices produced an immediate 21 ± 8% increase in bowel length (p < 0.001, n = 11). Mechanical load testing data showed that the IESs expressed maximum expansive forces at 50% compression of the initial pre-contracted length. The small-intestine failure load in the rats was 1.88 ± 21 N. Intestinal histology post deployment of the IES showed significant expansive changes compared to unstretched bowel tissue. Conclusions: IES devices were scalable to the rat intestinal model in our study. The failure load of the rat small intestine was many times higher than the force exerted by the contraction of the IES. Histology demonstrated preservation of intestinal structure with some mucosal erosion. Future in vivo rat studies on distraction enterogenesis with this IES should help to define this organogenesis phenomenon. [ABSTRACT FROM AUTHOR]

A continuum theory of pantographic lattices, based on second-grade elasticity, is presented. The proposed model is able to describe the mechanical behavior of a type of material structure made up of multiple layers of pantographic sheets connected with a third family of fibers. Thus, these materials are characterized by an orthogonal pattern of fibers that can bend, stretch and twist. Numerical experiments illustrate the predictive potential of the model when the material is subjected to different types of mechanical loads, including compression, torsion and two kinds of bending. Analyzing the material responses for these various tests makes it possible to reveal unusual deformation patterns characteristic of such "pantographic blocks." Numerical simulations using the finite element method are intended to assist in designing an experimental program using 3D-printed specimens made of different materials. [ABSTRACT FROM AUTHOR]

The aim of the present study is to elucidate the non-linear stability characteristics of randomly distributed carbon nanotube-reinforced fiber composite (RD-CNTRFC) beams subjected to thermo-mechanical loading. Effective material properties of RD-CNTRFC are estimated using the Eshelby-Mori-Tanaka approach and Halpin–Tsai micromechanical techniques. The material properties are considered to be temperature-dependent, and the influence of carbon nanotube (CNT) agglomeration is also incorporated in material properties estimation of hybrid matrix. The strain-displacement relations are assumed by incorporating the higher-order shear deformation theory and geometrical nonlinearity (von Kármán). The governing partial differential equations are obtained by minimizing the total potential energy of the beam. Buckling loads of beam subjected to in-plane compressive loads are estimated using Eigen value approach. Similarly, buckling temperatures are also determined by solving Eigenvalue problem iteratively due to temperature-dependent material properties. The non-linear equilibrium paths under thermal and mechanical loadings are traced through iterative Eigenvalue approach. Numerical results are presented to elucidate the influence of various parameters like CNT agglomeration, ply sequences, span-to-depth ratio, boundary conditions, and mass fraction of CNTs. [ABSTRACT FROM AUTHOR]

In this paper large deformation of the skew microplate made of laminated composite enhanced with graphene nanosheets is investigated using first shear deformation theory (FSDT) when the plate undergoes combination of mechanical and thermal loads. Halpin-Tsai model is utilised to model mechanical properties while for thermal properties Schapery model is considered. First, shear deformation of the plate was obtained while using Green-Lagrange tensor the non-linear strain of the microplate is extracted using the von-Karman assumptions. Then, by Modified Coupled Stress Theory (MCSD), the components of Cauchy and Couple stress tensors are specified. Finally, using Hamilton Principle the governing equation of the microplate and boundary conditions are computed. After deriving analytical governmental equation results are presented for the simple support boundary condition and the proposed model is validated by previously reported data and it proves to be promising. Primary results showed that with raising skew angle deflection and bending moment decreases which means microplate becomes more rigid in higher skew angles. Higher mechanical loads lead to higher deflections and bending moments. Four different configurations of the layers were analysed from which angle-ply configuration possessed highest deflection and bending while UD configuration revealed the lowest values of deflection and bending moment. [ABSTRACT FROM AUTHOR]

To date, the traffic-induced dynamic behavior of geosynthetic-encased stone column-supported embankments (GESC) under traffic cyclic loads accompanied by embankment consolidation has not been well studied. Three-dimensional (3D) coupled mechanical and hydraulic modeling is performed using FLAC3D, which considers the fluid flow during the lifespan of three stages: (1) embankment construction (EC): (2) consolidation (C) under embankment surcharge; and (3) cyclic loading (CYC). During the simulation, excess pore pressure, stress concentration, settlement, and lateral displacement are monitored, and the total settlement and lateral displacement could be easily obtained by accumulating the components of the three stages. Parametric analyses are conducted on the reinforcement forms and cyclic loading characteristics that include the dynamic stress amplitude and loading frequency. The ordinary stone (OSC) and GESCs could reduce the settlement and lateral displacement during each stage by improving the strength of the foundation and accelerating drainage consolidation; however, GESCs outperform the columns without geoencasement. In addition, the stress concentration ratio under embankment filling decreased with the increase in the dynamic stress amplitude and loading frequency, which led to the increase in the percentage of the cyclic loading-induced settlement to total settlement. [ABSTRACT FROM AUTHOR]

High-speed milling (HSM) of Ti-6Al-4V is subjected to complex thermo-mechanical loads, leading to alteration in metallurgical conditions within the cutting deformation zones, adversely impacting the mechanical performances of manufactured products. Hence, inclusive insight into microstructural alterations within the Adiabatic Shear Band (ASB) and the milled surface becomes essential for better service performance. This study first developed a Finite Element (FE) milling model to simulate the machining process of Ti-6Al-4V. The proposed FE model is validated through experimental results regarding cutting forces (CFs), cutting temperature (CT), and chip geometry, where the absolute relative error between simulations and experiments was less than 15 %. Secondly, Zenner-Holloman (Z-H) and Hall-Petch (H-P) equations were incorporated into a user-defined subroutine to simulate dynamic recrystallization (DRX) for grain size and microhardness prediction. Simulation results revealed that the grains became finer in the ASB than on the milled surface. In particular, when the cutting speed and feed rate were increased to 350 m/min and 0.30 mm/tooth, the grain size in the ASB decreased from 14 to 0.68 and 0.44 µm, while in the topmost milled surface, it reduced to 7.06 and 6.75 µm, respectively. Conversely, microhardness exhibited an inverse correlation with grain size and increased with cutting speed and feed rate. Furthermore, the impact of increased plastic strain and temperature on the grains during chip segmentation was also examined. Finally, the proposed FE model validity was established by comparing simulated results with experimental data using advanced characterization techniques. This research significantly contributes to a comprehensive understanding of microstructural evolution and its implications for the mechanical performance of machined titanium components. [ABSTRACT FROM AUTHOR]

This paper describes the self-heating effects resulting from mechanical deformation in the additively manufactured aluminium alloy AlSi7Mg0.6. The material's self-heating effect results from irreversible changes in the material's microstructure that are directly coupled with the inelastic deformations. These processes are highly dissipative, which is reflected in the heat generation of the material. To describe such effects, a numerical framework that combines an elasto-viscoplastic Chaboche model with the Gurson Tvergaard Needleman damage approach is analysed and thermomechanically extended. This paper characterises the sample preparation, the experimental set-up, the development of the thermomechanical approach, and the material model. A user material subroutine applies the complete material model for the finite element software Abaqus 2022. To validate the material model and the parameters, a complex tensile test is performed. In order to check the finite element model, the energy transformation ratio is included in the evaluation. The numerical analyses of the mechanical stress evolution and the self-heating behaviour demonstrate good agreement with the experimental test. In addition, the calculation shows the expected behaviour of the void volume fraction that rises from the initial value of 0.0373 % to a higher value under a complex mechanical load. [ABSTRACT FROM AUTHOR]

This study investigates five cases of municipal solid waste (MSW) landfill slope failures in the USA, China, Sri Lanka, and Greece, with the aim of assessing the safety margins and reliability of these slopes. The stability and reliability of the landfill slopes were evaluated under both static and seismic loading conditions, using pre-failure geometries and geotechnical data, with analyses conducted in accordance with Eurocode 7, employing all three design approaches. Under static loading, the factors of safety were close to unity, and reliability indexes ranged from 1.0 to 2.8, both falling below the recommended values set by Eurocode. The landfill slopes failed to meet the stability criteria in Design Approaches 2 and 3, while in Design Approach 1, four out of five landfills met the criteria. Under seismic conditions, safety factors and reliability indexes were significantly lower than the prescribed criteria in all analyses. Sensitivity analyses revealed that in two cases, unit weight and friction angle were the dominant parameters, while cohesion was the dominant parameter in one case. The findings of this study underscore the importance of establishing minimum design requirements for MSW landfill slope stability to mitigate potential risks to public health and the environment. [ABSTRACT FROM AUTHOR]

The global transition to renewables in response to climate change has largely been supported by the expansion of wind power capacity and improvements in turbine technology. This is being made possible mainly due to improvements in the design of highly efficient turbines exceeding a 10 MW rated power. Apart from power efficiency, wind turbines must withstand the mechanical stress caused by wind–hydro conditions. Such comprehensive structural analysis has rarely been performed previously, especially for large-scale wind turbines under real environmental conditions. The present work analyzes the energy production and structural performance of an NREL-IEA 15 MW wind turbine using measured wind and hydro data. First of all, an optimum operating range is determined in terms of the wind speed and blade pitch angle to maximize the power coefficient. Then, at this optimum range, a detailed breakdown of the forces and moments acting on different components of the wind turbine is presented. It was found that wind speeds of 9 to 12 m/s are best suited for this wind turbine, as the power coefficient is at its maximum and the mechanical loads on all components are at a minimum. The loads are at a minimum due to the optimized blade pitch angle. The bending force on a monopile foundation (fixed on the seabed) is found to be at a maximum and corresponds to nearly 2000 kN. The maximum blade force is nearly 700 kN, whereas on the tower it is almost 250 kN. The maximum force on the tower occurs at a point which is found to be undersea, whereas above-sea, the maximum force on the tower is nearly 20% less than the undersea maximum force. Finally, seasonal and annual energy production is also estimated using locally measured wind conditions. [ABSTRACT FROM AUTHOR]

To construct resilient structures, systems and sustainable buildings, capable of enduring fatigue, inclement weather, and seismic activity, researchers are actively seeking effective solutions to minimize vibrations and cyclic loading. Although these factors may not have immediate effects, they contribute to residual deformation in structures that gradually grows over time. For this reason, shape memory alloy (SMA) can be used as a perfect damper to dissipate the mechanical load in structures construction and buildings. The SMA actuators characterized by several thermo-mechanical functions, they are generally used in different applications as Mechatronics, Biomedical, Mechanical engineering and building systems. This study aims to adapt SMA actuator with structures for construction and buildings, in order to ensure a high displacement and vigilance taking into account fatigue phenomena to repulse mechanical fatigue and fretting. Accordingly, a thermomechanical analysis has been developed using finite element techniques to describe shape memory alloys' behavior and can integrate these material as a thermomechanical actuator dampers in building engineering systems. Furthermore, the suggested model elucidates the actuator's thermomechanical response, showcasing its adaptable behavior to both superelasticity and the shape memory effect within the desired structure in the building. Thus, the numerical findings affirm the efficacy of the proposed design that based on shape memory materials in addressing thermomechanical fatigue within buildings, concurrently enhancing structural resilience against mechanical fatigue. The primary outcome of this study is the successful preservation of the Ni-Ti superelastic response within the proposed system. This preservation is validated through cycling variations of up to 7.6% strain, significantly surpassing the requirements typically mandated for applications in earthquake engineering. [ABSTRACT FROM AUTHOR]

Interior permanent magnet synchronous motors (IPMSMs) which are driven by matrix converters have many advantages, including one‐stage power conversion, high efficiency, bidirectional power transfer, near unity input power factor, and low input current harmonics. However, the virtual DC‐link voltages of matrix‐converters vary from 0.866Vdc${V}_{dc}$ to Vdc${V}_{dc}$ and the current commutations of matrix‐converters create serious three‐phase stator harmonic currents as well. Moreover, matrix‐converter‐based IPMSM drive systems, in general, have very large external loads, which require advanced control methods. To solve these problems, two adaptive controllers, including a model reference adaptive controller and a self‐tuning controller, are investigated in this article for matrix‐converter PMSM drive systems. From the experimental results, the proposed two adaptive speed controllers provide excellent dynamic responses, which are superior to PI speed controllers, including faster transient responses, better tracking abilities, and greater robustness. As a result, this proposed matrix‐converter‐based IPMSM drive system is very suitable in industrial applications. [ABSTRACT FROM AUTHOR]

This scoping review presents an overview of physical fitness parameters in rhythmic gymnastics as well as the association of fitness with gymnasts' performance, competitive level, and age. PubMed, Scopus, and Sport Discus databases were searched. Of the 586 records retrieved, 41 studies met the inclusion criteria (n = 1915 participants). The included studies examined flexibility, aerobic capacity, muscle power, muscle endurance, muscle strength, sprint speed, agility, balance, and coordination. Performance was associated with flexibility, aerobic capacity, lower-limb muscle power, agility, muscular endurance, balance, and coordination from a young age. Flexibility, aerobic capacity, and muscle power were, in general, higher in high-level gymnasts than in low-level gymnasts or controls. Older rhythmic gymnasts demonstrated higher scores than the younger ones in flexibility, aerobic capacity, balance, and sport-specific coordination but not in muscle endurance, while some studies reported a decline in muscle power with age. Supplementary physical fitness training improved all physical abilities irrespective of the gymnasts' level. Rhythmic gymnastics training alone improved muscle power, agility, speed, muscular endurance, and balance to a lesser extent than targeted fitness training. Muscular strength, speed, and agility are largely under-researched in rhythmic gymnastics. Emphasis should be given to targeted strength and power training due to the high mechanical loads placed on skeletally immature athletes. [ABSTRACT FROM AUTHOR]