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Most viscous‐plastic sea ice models use the elliptical yield curve. This yield curve has a fundamental flaw: it excludes acute angles between deformation features at high resolution. Conceptually, the teardrop (TD) and parabolic lens (PL) yield curves offer an attractive alternative. These yield curves feature a non‐symmetrical shape, a Coulombic behavior for the low‐medium compressive stress, and a continuous transition to the ridging‐dominant mode, but their published formulation leads to negative or zero bulk and shear viscosities and, consequently, poor numerical convergence with stress states at times outside the yield curve. These issues are a consequence of the original assumption that the constitutive equations of the commonly used elliptical yield curve are also applicable to non‐symmetrical yield curves and yield curves with tensile strength. We derive a corrected formulation for the constitutive relations of the TD and PL yield curves. Results from simple uni‐axial loading experiments show that with the new formulation the numerical convergence of the solver improves and much smaller nonlinear residuals after a smaller number of total solver iterations can be reached, resulting in significant improvements in numerical efficiency and representation of the stress and deformation fields. The TD and PL yield curves lead to smaller angles of failure that better agree with observations. They are promising candidates to replace the elliptical yield curve in high‐resolution pan‐Arctic sea ice simulations. Plain Language Summary: Sea ice is a complicated dynamical system. It consists of many individual floes that interact in many ways. A sea‐ice model must contain many simplifying assumptions, sacrificing some observed properties. It is common to treat sea ice as an unusual fluid that behaves like an ideal plastic material and deforms permanently under high external loading (e.g., strong winds). The law that describes how the material yields to high loading contains a yield curve. This curve is usually an ellipse, a mathematically simple and acceptable approximation to the real yield curve. However, this yield curve cannot reproduce the orientation of conjugate failure lines when sea ice breaks. This paper discusses alternative yield curve shapes, the teardrop and parabolic lens yield curves, to reflect the sea ice's granular nature more accurately. We present improved constitutive equations that solve three issues in the original formulation that led to poor numerical and nonphysical behavior. Simple numerical experiments show that the improved formulation leads to a reduction of the computing time and large improvements in the representation of stresses and deformation within the sea‐ice model. The new formulation creates pairs of failure lines with smaller and more realistic angles than with the elliptical yield curve. Key Points: The constitutive equation of the elliptical yield curve is not applicable to yield curves such as the teardrop (TD) or parabolic lens (PL)We present new constitutive equations for the TD and PL that solve this problem and improve numerical convergenceThe TD and PL yield curves lead to failure angles that better agree with observations [ABSTRACT FROM AUTHOR]

The inverse analysis of the deformation moduli of high arch dams based on displacement monitoring data is essential for structural safety assessment. In traditional inverse analysis methods, the deformation moduli are identified based on the single‐objective optimization and the hydrostatic component derived from the statistical model. This type of method has two main shortcomings: First, it treats the essential multi‐objective optimization problem as a single‐objective problem; second, the extracted hydrostatic component may be biased due to the multicollinearity of variables in the statistical model. This paper presents a methodology for the inverse analysis of the deformation moduli of high arch dams under a multi‐objective optimization strategy. The methodology employs empirical mode decomposition to extract the aging component from displacement monitoring data. Then, thermomechanical analysis is used to reconstruct the remaining hydrostatic and temperature components, thereby avoiding the biases encountered in solving the statistical model. The adaptive polynomial chaos expansion method is embedded in the NSGA‐III algorithm to establish and solve multi‐objective functions in the inverse analysis. Additionally, a composite decision index considering errors and test information is proposed to determine acceptable deformation moduli from the Pareto solution set. A high arch dam is selected to illustrate this methodology with static and dynamic monitoring data. The results show that the identified deformation moduli have errors of 3.8% and 7.2% in displacement and acceleration, respectively. The proposed methodology can yield deformation modulus values that are more consistent with the physical implications than those of the single‐objective optimization method. [ABSTRACT FROM AUTHOR]

Axial Seamount is a seafloor volcano with frequent eruptions and periodic cycles of inflation and deflation. Seafloor pressure gauges monitor vertical deformation with time, but inherent instrumental drift complicates and biases geodetic interpretation. A drift corrected pressure recorder was deployed on Axial Seamount on 6 July 2018, at coordinates 45° 57.29′ North latitude, −130° 0.56′ East longitude, depth 1,535 m. This system includes two independent quartz‐resonant pressure gauges, which nearly continuously observe the seafloor pressure. At regular intervals, the gauges are calibrated in situ with a modified deadweight tester at a pressure within 98% of the nominal seafloor pressure. Using the calibration data, the drift of each gauge has been modeled as a simple linear plus decaying exponential function of time. The two estimated linear sensor drift rates are 0.45 ± 0.12 and 0.36 ± 0.08 kPa/year; the modeled sensor drift represents a significant error if uncorrected. The standard deviations of the drift model residuals are of order 0.06 kPa or 6 mm depth equivalent. Once calibrated, the difference between the two seafloor pressure timeseries exhibits a RMS deviation of ±6 mm at the 90% confidence limit and a linear trend less than 1 mm/year. A time series from July 2018 to December 2021 tracks the inflation of Axial Seamount with differing inflation rates over different time intervals. Plain Language Summary: The seafloor undergoes movements due to earthquakes and volcanoes, but seafloor motions are difficult to measure with conventional methods. One approach is to use pressure gauges to monitor changes in seafloor depth, but unavoidable gauge drift complicates the interpretation. This paper describes an instrument that can measure and remove gauge drift, providing a precise and unbiased measurement. This instrument also uses the power and data infrastructure of a seafloor instrumentation network, which allows for longer measurements and continuous monitoring. Axial Seamount is west of Oregon and undergoes repeated cycles of uplift due to magma injection, followed by submarine volcanic eruptions and deflation; a new cycle of magma injection and uplift begins anew. This instrument can be used, along with other sensors, to monitor the pattern and rates of deformation. Key Points: A pressure logging instrument with in situ sensor drift correction was deployed on Axial SeamountA 42‐month pressure gauge time series, converted to equivalent vertical displacement, demonstrates internal consistency at the sub‐cm levelThe drift corrected uplift time series is measuring uplift of the Axial volcanic system [ABSTRACT FROM AUTHOR]

In adsorption processes of the liquid or gas phase, a particular dynamic adsorption behavior caused by the reversible mechanical deformation (expansion or contraction) of absorption materials driven by the host–guest interaction is called "flexible adsorption," and the materials with this particular behavior can be called "flexible adsorption materials." Flexible absorption materials, such as crosslinked polymers, have received much attention from researchers due to their flexible framework structure and specific adsorption kinetics. They have shown great potential in gas storage and other energy applications. This paper reviews recent advances in the definition, theoretical development, and classification of flexible absorption materials. Potential application examples of flexible absorption materials in gas/liquid absorption and separation, functional devices, and energy catalysis are analyzed to guide their development. [ABSTRACT FROM AUTHOR]

The atomic‐level fundamental understanding of the rolling contact fatigue (RCF) mechanism using molecular dynamics (MD) simulation is yet to be understood more clearly. In this paper, the atomistic behavior of the single‐crystal Ni is studied under dynamic rolling contact loading with the help of MD simulations at varying temperatures of the specimen. The deformed material is investigated using atomic strain analyses to evaluate the shear, volumetric strain distribution, and von Mises stress. Furthermore, dislocation and stacking–fault analyses are done to determine the deformation mechanism of the material with the oscillation cycles. Simulation studies infer that dislocation defects tend to increase with the temperature of the specimen logarithmically. The deformation majorly results in partial dislocations, indicating low stacking fault (SF) energy. The present work opens up a new field of study to understand the RCF mechanisms, which can provide the foundational work to understand other face‐centered cubic (FCC) materials. Highlights: The degree of straining and defect generation depends on cycles and ambient temperature.Specimen undergoes relaxation as von Mises stress decrease with increasing cycles.Partial dislocations are more dominant, indicating low stacking fault energy. [ABSTRACT FROM AUTHOR]

The ion‐sensitive field effect transistors (ISFETs), proposed little over 50 years ago, today make the most promising devices for lab‐on‐a‐chip, implantable, and point‐of‐care (POC) diagnostics. Their compatibility with CMOS (Complementary Metal Oxide Semiconductor) technology and the low cost through mass production have been the driving factors so far. Nowadays, they are also being developed in flexible form factors for new applications such as wearables and to improve the effective usage in existing applications such as implantable systems. In this regard, the CMOS ultra‐thin chip (UTC) technology and the bonding by printing are the noteworthy advances. This paper comprehensively reviews such new developments in the CMOS‐compatible ISFETs, along with their theory, readout circuitries, circuit‐based techniques for compensation of the ISFET's instabilities, such as the offset, flicker noise, and drift. The sensing mechanisms and the properties of interface between the electrolyte under test and the metal‐oxide based ion‐sensitive electrodes have been discussed along with a brief overview of the metal‐oxide based pH sensors. An overview of the reported mechanically flexible pH sensors, including ISFETs, is provided and the history of ISFET applications are also covered. Finally, established models that can be used to design flexible circuits are presented, and possible opportunities to use circuit techniques to compensate for mechanical deformation are discussed. [ABSTRACT FROM AUTHOR]

The operating ambient of flexible electronics interconnects is a complex environment that includes mechanical deformation, electric current, and temperature. It is a potential threat to the long‐term service reliability of flexible electronic devices. This paper aims to develop a multiphysics fatigue model for flexible metal films. The effect of multiphysics fields is considered in the Coffin–Manson relationship based on reasonable simplification. The fatigue behavior of copper films of various thicknesses on a flexible substrate was investigated when electrical current and mechanical displacement loads were applied simultaneously. The developed model is validated to compare with experimental results. The numerical results show that it can analyze the effect of multiphysics fields and predict the fatigue life of copper films. Therefore, it could be a means to assess the fatigue performance of metal films on flexible substrates in multiphysics fields. Highlights: A FEM fatigue model for flexible metal films was developed in multiphysics fields.The electrothermal effect has little effect on the fatigue life of the thinner film.The electrothermal effect will change the initial position of the fatigue damage.As temperature rises exponentially, the fatigue life of thicker film decreases rapidly. [ABSTRACT FROM AUTHOR]

In large‐span grid structures with thousands of members involved, bending deformation of members is one of the most commonly observed damages affecting the normal service, even the safety of structures. Traditional testing and monitoring methods show weakness in the accurate judgment of crooked members and precision of deformation measurements. In this paper, a new deformation inspection and monitoring method of grid structures using image‐based 3D reconstruction is proposed, wherein a new method is put forward to automatically recognize and extract the shape deformation of the structural member for the first time. First, the key area with multiple members is modeled as a three‐dimensional mesh model using image‐based 3D reconstruction. Then, a new automated recognition and extraction algorithm of shape deformation (AREAS) is carried out, and crooked members, together with their deformed shapes, are extracted from the mesh model through AREAS. In this study, a load experiment of a quadrangular pyramid grid structure containing artificial crooked members and speckled members is designed to compare the deformation measurements using image‐based 3D reconstruction with those using laser scanning. The comparison of deformation and deformation increment shows an average error within 1 mm for image‐based 3D reconstruction, which validates the proposed method in on‐site inspection and monitoring. [ABSTRACT FROM AUTHOR]

The use of hard X-ray transmission nano- and microdiffraction to perform in situ stress and strain measurements during deformation has recently been demonstrated and used to investigate many thin film systems. Here a newly commissioned sample environment based on a commercially available nanoindenter is presented, which is available at the NanoMAX beamline at the MAX IV synchrotron. Using X-ray nanoprobes of around 60-70 nm at 14-16 keV and a scanning step size of 100 nm, we map the strains, stresses, plastic deformation and fracture during nanoindentation of industrial coatings with thicknesses in the range of several micrometres, relatively strong texture and large grains. The successful measurements of such challenging samples illustrate broad applicability. The sample environment is openly accessible for NanoMAX beamline users through the MAX IV sample environment pool, and its capability can be further extended for specific purposes through additional available modules. [ABSTRACT FROM AUTHOR]

The Eulerian two‐phase boiling model of the subcooled boiling of coolant in a 3 × 3 fuel assembly is established and compared with the experimental data to verify its accuracy. The effects of four shapes of bow deformation on subcooled boiling flow and heat transfer characteristics are obtained by comparing and analyzing the distributions of thermal–hydraulic parameters, including the axial wall superheat, liquid phase temperature, axial void fraction, various heat fluxes, heat transfer coefficient, and turbulent kinetic energy. All shapes of bow deformation will lead to the redistribution of coolant among different subchannels, and the distributions of thermal–hydraulic parameters would be greatly affected. The bow deformation of fuel rod easily causes local boiling, which results in local high temperature of liquid phase and bubble accumulation, and a decrease in the area of high liquid phase heat transfer coefficient on the surface of bowing fuel rod. Additionally, the non‐uniform distribution of turbulent kinetic energy caused by bow deformation in different axial sections not only affects the heat transfer performance of coolant, but also causes the increment in pressure drop, which has negative effects on the safe operation of the nuclear reactor. This paper can provide data and theoretical support for engineering design. [ABSTRACT FROM AUTHOR]

The auxetic structures attract much attention because of their good properties, such as enhanced energy absorption capacity and buckling resistance. It is an important topic to combine the auxetic structures with other materials or structures to improve their mechanical properties. In this paper, a composite auxetic structure was proposed, in which the embedded structure and re‐entrant structure can deform independently to adjust the mechanical properties. Under uniaxial compression, the effects of changes in the embedded structure and re‐entrant structure on Poisson's ratio, relative Young's modulus, and energy absorption of the composite auxetic structure were studied. By introducing the rate of change of mechanical properties, the effects of the embedded structure and re‐entrant structure on the composite auxetic structure were studied. The results show that changing the embedded structure for Poisson's ratio and relative Young's modulus and changing the re‐entrant structure for energy absorption can maximize the material utilization. And changing the re‐entrant structure can make the mechanical properties of the composite auxetic structure reach a larger adjustable range. This study can provide a new way for the combination of future auxetic structures to meet the needs of different applications in civil engineering. [ABSTRACT FROM AUTHOR]

Self‐healing soft electronic material composition is crucial to sustain the device long‐term durability. The fabrication of self‐healing soft electronics exposed to high moisture environment is a significant challenge that has yet to be fully achieved. This paper presents the novel concept of a water‐assisted room‐temperature autonomous self‐healing mechanism based on synergistically dynamic covalent Schiff‐based imine bonds with hydrogen bonds. The supramolecular water‐assisted self‐healing polymer (WASHP) films possess rapid self‐healing kinetic behavior and high stretchability due to a reversible dissociation–association process. In comparison with the pristine room‐temperature self‐healing polymer, the WASHP demonstrates favorable mechanical performance at room temperature and a short self‐healing time of 1 h; furthermore, it achieves a tensile strain of 9050%, self‐healing efficiency of 95%, and toughness of 144.2 MJ m−3. As a proof of concept, a versatile WASHP‐based light‐emitting touch‐responsive device (WASHP‐LETD) and perovskite quantum dot (PeQD)‐based white LED backlight are designed. The WASHP‐LETD has favorable mechanical deformation performance under pressure, bending, and strain, whereas the WASHP‐PeQDs exhibit outstanding long‐term stability even over a period exceeding one year in a boiling water environment. This paper provides a mechanically robust approach for producing eco‐friendly, economical, and waterproof e‐skin device components. [ABSTRACT FROM AUTHOR]

High-pressure (>1 GPa) torsion apparatus can be coupled with in situ X-ray tomography (XRT) to study microstructures in materials associated with large shear strains. Here, deformation experiments were carried out on multi-phase aggregates at ∼3-5 GPa and ∼300-500°C, using a rotational tomography Paris-Edinburgh press (RoToPEc) with in situ absorption contrast XRT on the PSICHE beamline at Synchrotron SOLEIL. The actual shear strain reached in the samples was quantified with respect to the anvil twisting angles, which is γ ≤ 1 at 90° anvil twist and reaches γ ≃ 5 at 225° anvil twist. 2D and 3D quantifications based on XRT that can be used to study in situ the deformation microfabrics of two-phase aggregates at high shear strain are explored. The current limitations for investigation in real time of deformation microstructures using coupled synchrotron XRT with the RoToPEc are outlined. [ABSTRACT FROM AUTHOR]

As the understanding of disease grows, so does the opportunity for personalization of therapies targeted to the needs of the individual. To bring about a step change in the personalization of medical devices it is shown that multi‐material inkjet‐based 3D printing can meet this demand by combining functional materials, voxelated manufacturing, and algorithmic design. In this paper composite structures designed with both controlled deformation and reduced biofilm formation are manufactured using two formulations that are deposited selectively and separately. The bacterial biofilm coverage of the resulting composites is reduced by up to 75% compared to commonly used silicone rubbers, without the need for incorporating bioactives. Meanwhile, the composites can be tuned to meet user defined mechanical performance with ±10% deviation. Device manufacture is coupled to finite element modelling and a genetic algorithm that takes the user‐specified mechanical deformation and computes the distribution of materials needed to meet this under given load constraints through a generative design process. Manufactured products are assessed against the mechanical and bacterial cell‐instructive specifications and illustrate how multifunctional personalization can be achieved using generative design driven multi‐material inkjet based 3D printing. [ABSTRACT FROM AUTHOR]

Piezoelectric composites will cause different degrees of deformation when ambient temperature changes during transportation, storage and use, affecting the performance and reliability seriously. The deformation measurement of cylindrical piezoelectric composites based on fiber Bragg grating (FBG) measurement is presented in this paper. The deformation and electromechanical properties of cylindrical piezoelectric composites over a wide range of temperature, from 233 K to 373 K, are investigated in detail. The deformation of piezoelectric composites in different directions is calculated. Adding deformation information, the frequency constant and dielectric constant data are modified. The results show that, at 233 K, the relative change of curvature of the cylindrical composite material in the arc direction is 0.024% and the relative change of deformation in the width and thickness direction are 0.018% and 0.026%, respectively. When the environment's temperature is increased to 100℃, the relative change of curvature in the arc direction is 0.019% and the relative changes of deformation in the width and thickness direction are 0.019% and 0.008%, respectively. After adding the deformation information, the most evident changes of frequency constant and dielectric constant are between 303 K and 333 K, the rate of change (slope) of frequency constant and the dielectric constant are −1.82983 kHz·mm/K(decreasing) and 3.85591 kHz·mm/K(increasing), respectively. [ABSTRACT FROM AUTHOR]

Electro-chemo-mechanical (ECM) coupling refers to mechanical deformation due to electrochemically driven compositional change in a solid. An ECM actuator producing micrometre-size displacements and long-term stability at room temperature was recently reported, comprising a 20 mol% Gd-doped ceria (20GDC), a solid electrolyte membrane, placed between two working bodies made of TiOx/20GDC (Ti-GDC) nanocomposites with Ti concentration of 38 mol%. The volumetric changes originating from oxidation or reduction in the local TiOx units are hypothesized to be the origin of mechanical deformation in the ECM actuator. Studying the Ti concentration-dependent structural changes in the Ti-GDC nanocomposites is therefore required for (i) understanding the mechanism of dimensional changes in the ECM actuator and (ii) maximizing the ECM response. Here, the systematic investigation of the local structure of the Ti and Ce ions in Ti-GDC over a broad range of Ti concentrations using synchrotron X-ray absorption spectroscopy and X-ray diffraction is reported. The main finding is that, depending on the Ti concentration, Ti atoms either form a cerium titanate or segregate into a TiO2 anatase-like phase. The transition region between these two regimes with Ti(IV) concentration between 19% and 57% contained strongly disordered TiOx units dispersed in 20GDC containing Ce(III) and Ce(IV) and hence rich with oxygen vacancies. As a result, this transition region is proposed to be the most advantageous for developing ECM-active materials. [ABSTRACT FROM AUTHOR]

The deformation and fracture of surrounding rock in deep underground engineering have the characteristics of time mutation and space continuity. In order to monitor and provide early warning of the dynamic deformation and fracture characteristics of deep surrounding rock, a real‐time digital displacement measuring instrument was developed in this paper. The proposed device represented a kind of surrounding rock deformation and fracture monitoring method, which had the continuous and real‐time advantages. Based upon the simulation experiments, the dynamic deformation and fracture of deep roadway surrounding rock were measured synchronously using the digital displacement measuring instrument testing system (DDMITS) and the V‐STARS measurement system. Comparative measurement results indicated that the DDMITS had a higher reliability. The deformation of roadway surrounding rock gradually increased with the increase of loading. The roof deformation and caving changing patterns in coal seam mining were studied using similar simulation experiments based on the DDMITS. The vertical displacement response of rock strata was more obvious than the horizontal displacement. There was a sharp increase in the vertical displacement during the collapse of the rock strata. Additionally, the vertical displacement velocity showed fluctuations. Meanwhile, the fluctuations in the vertical displacement acceleration increased significantly. The DDMITS could achieve full‐field measurement and the noncontact measurement of three‐dimensional deformation. [ABSTRACT FROM AUTHOR]

This paper examines the fracture of AA6061‐T6 specimens with ductile behavior having notches with keyhole geometry under combined loading of tension/torsion. The investigation is performed by theoretical and experimental methods. New fracture tests are performed using a loading fixture on the samples made of AA6061‐T6 weakened by keyhole notches with different notch tip radii. For theoretically estimating the onset of fracture in the tested notched specimens, a concept called "Fictitious Material Concept (FMC)" is used to equate the ductile material with a fictitious brittle material. Therefore, use of this concept allows use of the linear elastic brittle fracture criteria for ductile materials. The brittle fracture criteria utilized are the "mean stress (MS)" and "maximum tangential stress (MTS)" criteria. The small difference between the theoretical and experimental results confirms that use of the combination of FMC with the two criteria is successful in predicting failure of the keyhole notched AA6061‐T6 samples. [ABSTRACT FROM AUTHOR]

This paper recounts the atmosphere in the Cavendish Laboratory during Lawrence Bragg's triumphant final years there through the eyes and the work of a young research student, and hence reflects some measure of Bragg's personality. The opportunity is taken to deal in detail with Bragg's contribution to our understanding of crystal plasticity, which is seldom described, being overshadowed by his many superb contributions to the determination of crystal structure. Bragg produced in 1940-1942, through his development of the bubble model of a crystal structure, the first demonstration of how crystal dislocations move. His suggestion of the use of microbeams led rather directly to the development of modern thin-film transmission electron microscopy. [ABSTRACT FROM AUTHOR]

ABSTRACT This paper deals with the rectangular tensile sheet with symmetric double edge notch cracks. Such a crack problem is called an edge notch crack problem for short. By using a hybrid displacement discontinuity method (a boundary element method), two edge notch models are analyzed in detail. By changing the geometrical forms and parameters of the edge notch, and by comparing the stress intensity factors (SIFs) of the edge notch crack problem with those of the double edge cracked plate tension specimen (DECT), which is a model frequently used in fracture mechanics, the effect of the geometrical forms and parameters of the edge notch on the SIFs of the DECT specimen, is revealed. Some geometric characterestic parameters are introduced here, which are used to formulate the notch length and the branch crack length, which are to be determined in mechanical machining of the DECT specimen So we can say that the geometric characterestic parameters and the formulae used to determine the notch length and the branch crack length presented in this paper perhaps have some guidance role for mechanical machining of the DECT specimen. [ABSTRACT FROM AUTHOR]

This paper presents an approach to the prediction of multi-directional crack growth in braided composite T-piece specimens using cohesive zone models. Failure predictions given by the cohesive model together with experimental results are presented. The effects of single and multi-directional crack model on failure prediction are investigated. Results show that both models agree with experimental data, single-crack model agrees with the maximum value of experimental data, and multi-directional crack model agrees with the mean value. The simulation of multi-directional crack growth of T-piece specimens is important in the study of their failure mechanism. Investigation reported in this paper indicates that prediction of failure loads by the multi-directional crack model is necessary in the design of some particular composite components which have similar features to the T-piece specimens. [ABSTRACT FROM AUTHOR]

Flow patterns of liquid‐liquid two‐phase fluids in a new helical microchannel device were presented in this paper. Three conventional systems were considered: kerosene‐water, n‐butyl acetate‐water, and butanol‐water. Six different flow patterns, slug flow, continuous parallel flow, discontinuous deformation parallel flow, discontinuous deformation parallel‐droplet flow, droplet‐slug flow, and filiform‐droplet flow, were observed. The influence of interfacial tension, microchannel structure, and rotation rate on two‐phase flow patterns were studied, and a universal flow pattern map was presented and discussed. The systems without mass transfer (0.1 g/g (10 %) tri‐n‐butyl phosphate (TBP)‐water, 0.2 g/g (20 %) TBP‐water, and 0.8 g/g (80 %) TBP‐water) and the system with mass transfer (0.8 g/g (80 %) TBP‐0.62 g/g (62 %) H3PO4) were used to verify the validity of the proposed universal flow pattern map in predicting flow patterns. The results showed that the former compared with the latter can be predicted more accurately by the universal flow pattern map. [ABSTRACT FROM AUTHOR]

The interplay between compaction‐driven fluid flow and plastic yielding within porous media is investigated through numerical modeling. We establish a framework for understanding the dynamics of fluid flow in deforming porous materials that corresponds to the equations describing solitary porosity wave propagation. A concise derivation of the coupled fluid flow and poro‐viscoelastoplastic matrix behavior is presented, revealing a connection to Biot's equations of poroelasticity and Gassmann's theory in the elastic limit. Our findings demonstrate that fluid overpressure resulting from channelized fluid flow initiates the formation of new shear zones. Through three‐dimensional simulations, we observe that the newly formed shear zones exhibit a parabolic shape. Furthermore, plasticity exerts a significant influence on both the velocity of fluid flow and the shape of fluid channels. Importantly, our study highlights the potential of spontaneous channeling of porous fluids to trigger seismic events by activating both new and pre‐existing faults. Plain Language Summary: In this study, we looked at how fluids move through porous rocks and how they interact with the solid frame of the rocks. The physics was explored in two‐ and three‐dimensions by leveraging the power of high‐performance computing (HPC) based on graphical processing units (GPU). We found that two key processes occur at the same time: fluid flow gets concentrated into channels due to the changing pressure and interaction with the solid material, and it also forms dike‐like structures as it pushes into newly formed shear zones. Importantly, our study highlights the potential of spontaneous channeling of porous fluids to trigger seismic events by activating both new and pre‐existing faults. This research underscores the complex relationship between fluid flow dynamics and geomechanical processes, offering insights into the mechanisms underlying earthquake initiation. Key Points: We present the numerical modeling of fully coupled fluid flow and poro‐viscoelastoplastic matrix flow with decompaction weakeningWe show that fluid overpressure at the tip of the fluid flow channel triggers the development of non‐symmetric shear bandsWe discover that plastic yielding accelerates the fluid flow and modifies the fluid flow pattern [ABSTRACT FROM AUTHOR]

Batteries made of charge carriers from Earth‐crust abundant materials (e.g., Na, K, and Mg) have received extensive attention as an alternative to Li‐ion batteries for grid storage. However, a lack of understanding of the behavior of these larger ions in the electrode materials hinders the development of electrode structures suitable for these large ions. In this study, we investigate the impact of alkali ions (Li, Na, and K) on the redox chemistry and mechanical deformations of iron phosphate composite cathodes by using electrochemical techniques and in situ digital image correlation. Na‐ion and Li‐ion intercalation demonstrate a nearly linear correlation between electrochemical strains and the state of charge and discharge. The strain development shows nonlinear dependance on the state of charge and discharge for K ions. Strain rate calculations show that K ion intercalation results in a progressive increase in the strain rate for all cycles. Li and Na intercalation induce nearly constant strain rates with the exception of the first discharge cycle of Na intercalation. When the same amount of ions are inserted into the electrode, the electrode shows the lowest strain generation upon Li intercalation compared to larger alkali ions. Na and K ions induce similar volumetric changes in the electrode when the state of charge and discharge is around 30%. Although the electrode experiences larger absolute strain generation at the end of the discharge cycles upon Na intercalation, strain rates were found to be greater for K ions. Potential‐dependent behaviors also demonstrate more sluggish redox reactions during K intercalation, compared to Li and Na. Our quantitative analysis suggests that the strain rate, rather than the absolute value of strain, is the critical factor in amorphization of the crystalline electrode. [ABSTRACT FROM AUTHOR]

The paper deals with the study of structural response of partially cracked nuclear containment model structure in over pressurized condition with the simulated experiments conducted under severe accidents analysis program for Indian nuclear containment structures. In this research, the fracture characterization of concrete containment structure is also investigated through the over pressure experiments on the BARC Containment (BARCOM) test model structure, which represents 1:4 scale of the prototype 540 MWe Tarapur pre‐stressed nuclear containment structure. In addition to the surface‐type electrical resistance, strain gauges conventionally and commonly deployed for containment proof‐test and ultimate load capacity evaluation of containment models, embedded vibratory wire strain gauges (VWSGs), the digital image correlation (DIC) technique, and soap bubble tests are employed in this study. For fracture characterization, an optical crack profile (OCP) technique is developed through DIC full‐field experiment conducted at the identified critical locations with conventional strain gauges to evaluate the fracture energy and the characteristics of the fracture process zone of concrete containment model structure subjected to the over‐pressure condition for its performance assessment in the case of the beyond design basis accidents. The combination of conventional sensors and full‐field DIC deployed for the first time on the largest scale containment model along with the associated analysis is shown to be effective in fracture characterization and improved structural integrity assessment of the containment model. [ABSTRACT FROM AUTHOR]

Underwater pelletizing of thermoplastic materials has gained high importance within the chemical and the compounding industry. It is known for producing comparatively spherical pellets with good bulk characteristics. Pellet shapes are determined by the viscous and elastic properties of the melt as well as various process conditions. Therefore, deformation of the melt strands because of the water flow at the die-hole opening may result in undesired shapes. This is particularly the case when processing polymers of low viscosity. This paper defines an analytical framework describing the pellet formation at the die-hole opening. Furthermore, a nondimensional DS number is developed as a measure for the deformation sensitivity of different polymer materials. In order to validate this approach, a new camera system and video recording method has been developed, which allows for a visual analysis of the cutting process in underwater pelletizing systems. Examining different materials at various process parameters, this paper identifies the main parameters responsible for pellet deformation and demonstrates how the DS number can be used to anticipate these effects. POLYM. ENG. SCI., 55:1170-1176, 2015. © 2014 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

This paper presents a 3D thermomechanical constitutive model for polycarbonate (PC) polymers, aiming to predict the material characteristics of PC under complex thermomechanical boundary and strong impact loading conditions. The model is applied to simulate the high‐velocity ballistic impact tests. Quasi‐static tension, Split‐Hopkinson Tension Bar (SHTB), and ballistic impact tests are carried out to experimentally investigate the thermomechanical behavior of PC. Fundamental characteristics of PC, such as the transient yield peak, the post‐yield softening and the subsequent hardening, are characterized by introducing two scalar and one tensorial internal variables. Constitutive equations, specifically, (i) the plastic flow rule; (ii) the evolution equations associated with the internal variables; (iii) the temperature evolution; (iv) the strain rate, temperature and pressure‐dependent yield limit are derived within a thermodynamically consistent framework. The model is then implemented into the finite element software ABAQUS/Explicit by means of a user‐defined material subroutine VUMAT. Finally, numerical simulations are carried out and validated against experimental data. Finite element simulations of the ballistic tests well demonstrate the capabilities of the proposed model to accurately predict thermomechanical behavior of PC undergoing high‐velocity impact loadings. POLYM. ENG. SCI., 58:2237–2248, 2018. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: Micromechanical fracture modelling is an effective method to predict ductile fracture in steel structures. This paper aims to establish a simplified and general fracture model for various loading conditions, which is convenient to calculate the instantaneous damage index. With the concept of the ductile damage factor, a unified ductile damage factor model considering the difference of rates between void growth and shrinkage has been proposed. Based on experiment results and finite element analysis, the model parameters for Q235B Chinese structural steel were calibrated. The ductile damage factor and equivalent plastic strain at fracture initiation were investigated. Comparison among the proposed model, experimental results, and the cyclic void growth model demonstrated the effectiveness and accuracy of the proposed model. A parametric study was conducted to investigate the influence of cyclic constitutive parameters on the accuracy of fracture prediction. The predicted results are acceptable while reducing those calibrated cyclic constitutive parameters by 20%. [ABSTRACT FROM AUTHOR]

Thermally activated shape memory polymers (SMP) are typically programmed by initially heating the material above the glass transition temperature (Tg), deforming to the desired shape, cooling below Tg and unloading to fix the temporary shape. Though this approach is employed in small‐scale applications, the process of deforming at high temperatures becomes a time, labor, and energy expensive process while applying to large structures (e.g. deployable space structures). The reversible plasticity shape memory (RPSM) property provides an alternate programming approach wherein the material is plastically deformed to a temporary shape at temperatures well below the transition temperature, preferably at room temperature. This paper aims to study the advantages of RPSM programming under bending and torsional deformations in multi‐walled carbon‐nanotube (MWCNT) reinforced epoxy nanocomposites. The samples are characterized for their thermal, morphological, and mechanical properties. The shape recovery behavior under various deformation modes is studied in detail. The effect of deformation level, relaxation time, and thermo‐mechanical cycles are also studied. All samples show excellent shape memory properties under all deformation modes and programming conditions. As a result, it is demonstrated that the RPSM programming can be used as an effective and a simplified alternative to conventional shape memory programming. POLYM. ENG. SCI., 58:E189–E198, 2018. © 2018 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Abstract: Highly deformable materials, such as elastomers and gels, can withstand very large deformation without failure, and this response is usually insensitive to the presence of macroscopic defects. These polymer‐based materials, different from the traditional ones which are usually characterized by an enthalpic elasticity, show a mechanical response which is governed by the state of internal entropy of their molecular network. If fracture energy is large, the noticeable ability of soft materials to rearrange their network at the microscale, to display large deformation and to dissipate energy thanks to their viscoelasticity, allows the minimization of the local detrimental effect of existing flaws. In the present paper, the mechanical behavior of silicone‐based edge cracked plates with different crack sizes and severity of the intrinsic flaws embedded in the material is examined by taking into account the time‐dependent effects. Experimental and theoretical aspects are discussed to explain the defect tolerance of such materials. The detrimental effect of intrinsic voids is quantified, and the beneficial effect due to strain at low rates is analysed. The critical distance is related to the ultimate stretch value, the quality of the material, and the crack size. [ABSTRACT FROM AUTHOR]

The paper describes the effect of different manipulations (addition of fiber, nanoclay, nucleating agents and chain extender, blending, annealing, use of a higher mold temperature and stereocomplexation) on the heat resistance of poly(lactic acid) (PLA) and poly(hydroxybutyrate) (PHB). Therefore, the differential scanning calorimetry profiles, the vicat softening temperatures and the degradation temperatures were measured and compared to standard PLA, PHB, and polypropylene (PP) as reference materials. Furthermore, a comparison between VST and HDT as parameters for heat resistance was made by examining the deformation during contact with hot water. Stereocomplexation and the use of a higher mold temperature seemed the best techniques to obtain PLA‐based materials with good heat resistance, while other manipulations had little to no effect on the processed biopolymer. The addition of chain extender to PLA and PHB had no effect on processed polymers, but it did improve the thermal degradation of PLA during processing. Furthermore, hot fill tests showed that higher VST values were more reliable as a heat resistant parameter than HDT values for these kinds of application. The VST values of PHB were similar to PP, suggesting that PHB also provides opportunities as a packaging material for food products that undergo a heat treatment. POLYM. ENG. SCI., 58:513–520, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]

Seismic anisotropy is a powerful tool to map deformation processes in the deep Earth. Below 660 km, however, observations are scarce and conflicting. In addition, the underlying crystal scale mechanisms, leading to microstructures and crystal orientations, remain poorly constrained. Here, we use multigrain X‐ray diffraction in the laser‐heated diamond anvil cell to investigate the orientations of hundreds of grains in pyrolite, a model composition of the Earth's mantle, at in situ pressure and temperature. Bridgmanite in pyrolite exhibits three regimes of microstructures, due to transformation and deformation at low and high pressure. These microstructures result in predictions of 1.5%–2% shear wave splitting between 660 and 2,000 km with reversals in fast S‐wave polarization direction at about 1,300 km depth. Anisotropy can develop in pyrolite at lower mantle conditions, but pressure has a significant impact on the plastic behavior of bridgmanite, and hence seismic observations, which may explain conflicting anisotropy observations. Plain Language Summary: Seismologists rely on observable data to construct models that describe the dynamic state of the Earth's lower mantle. These models, however, require constraints such as mantle composition and material behavior at high pressures and temperatures, which can be provided through experimental mineral physics. In this study, we use a high pressure devices and X‐rays to impose deformation and image the state of our sample with increasing pressure and temperature. We are able to extract information of individual mineral grains within our assemblage, such as the number of grains per phase and their orientations. Using this experimental data, we identify three regimes of grain orientations in bridgmanite in the lower mantle, corresponding to transformation from lower pressure phases, and deformation at low and high pressure. With this information, we are able to make predictions about how seismic waves travel and behave based on the deformation state of the lower mantle. Key Points: Three microstructure/anisotopy regimes in bridgmanite in the Earth's lower mantle: transformation, low‐P deformation, high‐P deformationEffect of pressure on the active slip systems of bridgmanite with a shift at approximately 50 GPa or 1,300 km depth in the Earth's mantleUp to 2% shear wave splitting predicted at all depth with changes in fast polarization direction for each microstructural regime [ABSTRACT FROM AUTHOR]

Although magma migration is a necessary condition for the occurrence of a volcanic eruption, static analytical models for ground deformations consider stationary sources that undergo a change only in forces acting in the Earth's interior, such as changes in pressure or volume in a geometrically defined body. The variations in pressure or volume are mostly linked to the fluid dynamics or the superficializing of magma batches. Detection and tracking of magma motion in volcanic areas represent fundamental capabilities in predicting possible eruptions and therefore in reducing their associated risks. In the 3‐dimensional space, a magma migration defines a starting volume in depression and an arrival volume in overpressure. These end members can be modeled with two bonded point sources. Such a double‐point source can be considered the equivalent of a physical dipole. Here, the analytical solutions to predict ground deformations caused by a dipole source are presented and analyzed. The dipole analytical source allows modeling the effects on ground deformation of magma migration and vice versa. Estimating the magma migration from the measured ground deformation through data inversion. The dipole solution is compared with the basic volumetric source to discern its distinctive peculiarities and range of applicability. In addition, a discrepancy analysis with the equivalent numerical model was conducted to evaluate the approximation errors of the analytical model. To evaluate the practical value of the proposed model, two case studies on Sinabung volcano and Mt. Etna are presented. The analysis of continuous deformation data from GNSS (Global Navigation Satellite System) stations on Mt. Etna shows that a dipole source activates days before the December 2018 eruption, thus allowing the identification of the final magma rise. Plain Language Summary: Traditional analytical models for ground deformations focus on fixed sources and do not consider the possibility that magma may move, which is important for predicting volcanic eruptions. To better understand and predict eruptions, it is crucial to track magma migration. The dipole analytical source is a tool that helps model how magma movement affects ground deformation. It estimates magma migration by analyzing measured ground deformation data. This method provides information on the source's strength, location, and migration direction. Two case studies on Sinabung volcano and Mt. Etna show the practical value of the dipole source. In the Mt. Etna case, a dipole source was identified days before the December 2018 eruption, demonstrating its potential for early detection. Key Points: Analytical solutions for ground deformations caused by a dipole source are presented and analyzedThe differential dipole model can describe a movement of magma within the plumbing systemThe dipole model can be useful in identifying the magmatic rising phase that potentially anticipate an eruption [ABSTRACT FROM AUTHOR]

To improve the extraction of coal resources, gob‐side entry driving is gradually being promoted and applied. However, as the thickness of the coal seam increases, the deformation control of the roadway becomes more difficult. Aiming at this problem, a combination of theoretical calculation, numerical simulation, and field test was used to analyze the aspects of the stress environment, surrounding rock properties, and support forms. The phenomenon and mechanization of intensified deformation and failure of roadway with increasing coal seam thickness were revealed. The specific results include: (1) The ratio of principal stress at the excavation position controls the maximum failure depth of roadway, and the direction of principal stress determines the location of the maximum failure depth; (2) As the thickness of the coal seam increases, the properties of the surrounding rock at the excavation position decrease, the principal stress ratio increases, and the deflection angle of the principal stress increases, which lead to an intensification of the deformation and failure of the roadway. Based on the deformation and failure characteristics of the roadway and the shortcomings of the original support form, a control strategy and support scheme based on a new support structure called "Anchor Cable with C‐shaped Tube" is proposed, which has achieved better deformation control effect in on‐site application. [ABSTRACT FROM AUTHOR]

The effect of water diffusion on the strength of silica glass is discussed. When silica glass is immersed in hot water and held there for an extended period, its strength increases over that of freshly damaged glass. We propose that this increase in strength is due to water diffusion into exposed surfaces of the test specimen, resulting in swelling of the glass and a fracture mechanics shielding of cracks present in the glass surface. In the present paper, we show that the shielding may be broken down into two parts, that associated with the crack itself and that associated with the free surface of the specimen. The explanation proposed here has been neglected in earlier studies. The approach allows us to obtain a reasonable quantitative explanation for the strengthening of silica glass by soaking in hot water. [ABSTRACT FROM AUTHOR]

ABSTRACT In this paper, a series of advanced searching algorithms have been examined and implemented for accelerating multi-axial fatigue cycle counting efforts when dealing with large time histories. In a computerized calculation of the path-length dependent cycle counting method, most of the central processor unit's (CPU) time is spent on searching for the maximum range or distance in a stress or strain space. A brute-force search is the simplest to implement, and will always find a solution if it exists. However, its cost, in many practical problems, tends to grow exponentially as the size of the loading spectrum increases with a search time measured in the order of O( n2), where n is the number of spectrum data points. In contrast, a form of Andrew's monotone chain algorithm, as demonstrated in this paper, can remarkably reduce the solution time to the order of O( n log n). The effectiveness of the new path-length searching procedure is demonstrated by a series of worked examples with a varying degree of non-proportionality in multi-axial loading history. [ABSTRACT FROM AUTHOR]

This paper offers a methodology for coping with information loss following consolidation of data on fatigue crack propagation rates derived from different experiments. It is customary, both in the literature and in standardization, to consolidate results of several experiments conducted under similar conditions, using identical materials. This reduces the ability to implement a probabilistic fracture mechanics approach in order to reliably calculate the distribution of the number of cycles needed to reach a critical value (CV; onset of instability or failure). Such reliable calculation requires, among other things, an estimation of the distribution characteristics of the crack progression curves coefficients represented by models such as Paris or NASGRO, and an estimation of joint distributions of equation coefficients representing such models. Consolidated data reduce the ability to estimate these required distribution characteristics. This work suggests an analytical approach that uses consolidated data, but enables the information to be treated as if it were possible to attribute the data to the various experimental specimens from which they were obtained. Consequently, information required for the evaluation of the distribution of the number of cycles needed to reach a CV can be obtained. The proposed approach is generic and can be applied in additional scientific fields that can benefit from separation of data obtained from different experiments. [ABSTRACT FROM AUTHOR]

Cold drawing steel wires lead to an increase of their mechanical strength and to a drop of their ductility. The increase of their mechanical strength has long been related to the reduction of the various material scales by plastic deformation, but the mechanisms controlling their elongation to failure have received relatively little attention. It is usually found that heavily deformed materials show a tendency to plastic strain localization and necking. However, in this paper it is shown that, though the steel wires are plastically deformed up to strain levels as high as 3.5, a significant capability of plastic deformation is preserved in as-drawn wires. This apparent contradiction is resolved by the existence of residual stresses inside the wire. Finite element analyses have been conducted in order to show that residual stresses, inherited from the drawing process, are sufficient to produce a significant hardening effect during a post-drawing tensile test, without introducing any hardening in the local material behaviour. The main conclusion of this paper is that once the material has lost its hardening capabilities, residual stresses, inherited from the process, control the elongation of cold drawn wires. The finite element method allowed also the determination of the residual stress field that would lead to the best agreement between the simulated and the experimental stress strain curve of as-drawn wires. [ABSTRACT FROM AUTHOR]

Cold drawing of steel wires leads to an increase of their mechanical strength and to a drop in their ductility. The increase of their mechanical strength has long been related to the reduction of the various material scales by an intense plastic deformation. Besides, it was discussed in the companion paper that large plastic deformation leads to the loss of the material hardening capabilities and that, in such a case, residual stresses preserve the elongation to failure of wires. Experimental measurements of residual stresses inside the wire have therefore been undertaken. In this paper, lattice parameters as measured using synchrotron diffraction are compared with those calculated using the residual stress fields as determined by the finite-element method. There is a major disagreement between experimental and numerical results that is too large to be attributed to the errors of the finite-element analyses. Therefore, neutron diffraction experiments have also been performed. These measurements show that there is a significant variation of the lattice parameter with the drawing level, which is not inherited from residual stresses, and that variation is very sensitive to the cooling rate after processing. It is therefore proposed that cold drawing would induce a phase transformation of the steel, possibly a martensitic transformation. [ABSTRACT FROM AUTHOR]

A new multiaxial fatigue damage model named characteristic plane approach is proposed in this paper, in which the strain components are used to correlate with the fatigue damage. The characteristic plane is defined as a material plane on which the complex three-dimensional (3D) fatigue problem can be approximated using the plane strain components. Compared with most available critical plane-based models for multiaxial fatigue problem, the physical basis of the characteristic plane does not rely on the observations of the fatigue crack in the proposed model. The cracking information is not required for multiaxial fatigue analysis, and the proposed model can automatically adapt for different failure modes, such as shear or tensile-dominated failure. Mean stress effect is also included in the proposed model by a correction factor. The life predictions of the proposed fatigue damage model under constant amplitude loading are compared with a wide range of metal fatigue results in the literature. [ABSTRACT FROM AUTHOR]

This paper describes the effects of a single overload event, within otherwise constant amplitude cycles, on the plasticity-induced closure process for mode I fatigue crack growth in the small-scale yielding (SSY) regime. The 3-D finite element (FE) analyses extend the initially straight, through-thickness crack front by a fixed amount in each load cycle, using a node release procedure. Crack closure during reversed loading occurs when nodes behind the growing crack impinge on a frictionless, rigid plane. A bilinear, purely kinematic hardening model describes the constitutive response of the elastic–plastic material. Extensive crack growth in the analyses, both before and after the overload, allows the crack to grow out of the initial and the post-overload transient phases, respectively. The work presented here shows that the large plastic deformation in the overload cycle reduces the crack driving force through enhanced closure. Further, the residual plastic deformations due to the overload cause a disconnected pattern of closure in the wake long after the crack front passes through the overload plastic zone. The computational studies demonstrate that the 3-D scaling relationship for crack opening loads established in our earlier work for constant amplitude cycling (with and without a T-stress) also holds before, during and after the overload event. For a specified ratio of overload-to-constant amplitude loading , the normalized opening load at each location along the crack front remains unchanged when the constant amplitude peak load , thickness ( B) and material flow stress all vary to maintain a fixed value of . The paper concludes with a comparison of the post-overload response predicted by the 3-D analyses and by the conventional Wheeler model. [ABSTRACT FROM AUTHOR]

The fluid containment in vessels, pipes, containers, etc. often requires the use of seals in order to assure the absence of leak in the junction zones. Sealing mechanism is typically achieved through the use of elastomeric elements that form contact with the surrounding rigid materials the containers are made of. A proper design and safety evaluation of the containment capacity of seals requires the careful evaluation of the contact pressure distribution between the soft (seal) and hard (vessel) elements. In the present paper such a problem is considered and solved through contact stress and strain evaluation based on fracture mechanics; numerical and experimental analyses on elastomeric elements are considered in order to verify the proposed modeling procedure. It is shown that the desired safety level against leakage can be ensured on the basis of the classical fracture mechanics parameters when the seal crack tip exists, or through contact strain assessment when the stress singularity vanishes. Such results can be useful in the design of seal shapes and for estimating the pressure to be applied to the sealed bodies in order to guarantee no leaks. Finally, some final relevant conclusions on the present study on leak containment are drawn. [ABSTRACT FROM AUTHOR]

This paper presents experimental data for a 0.2%C steel/artificial seawater system showing the influence of shear loading on corrosion response, via measurements of electrochemical variables, e.g. anodic/cathodic Tafel slopes and polarization resistance. Based on the results of these tests, several corrosion fatigue tests were conducted at different stress levels under potentiostatic control. Analysis of the results shows there to be a dependence of corrosion rate on the ratio of applied/yield strain and test frequency. In addition, the corrosion current associated with corrosion fatigue (CF) damage appears to be dependent upon the crack size, which in turn shows a relationship with fatigue crack growth rate. This paper sets out to determine the influence of stress on electrochemical parameters, i.e. free corrosion potential, Ecorr , polarization resistance, Rp , anodic, τa and cathodic, τc Tafel constants. Based upon these results, it is found that a simple linear relationship between stress and corrosion damage does not exist. Furthermore, analysis of the corrosion current fluctuations during corrosion fatigue crack growth shows a minimum current coincident with the point at which a crack is growing at its slowest rate. [ABSTRACT FROM AUTHOR]

The objective of this paper is to develop a micromechanics model for the onset and subsequent multiplication of transverse cracks in the 90° layers of a cross-ply laminate under uniaxial tension. The micromechanics study of transverse matrix cracking is performed by a combination of finite element and analytical analyses. Based on the Griffith fracture criterion, the evolution of transverse matrix crack density is predicted. The prediction compares well with existing experimental data in the literature. Analytical expressions of the non-linear effective stress–strain curves are also obtained for a wide range of material systems. In addition, an analytical expression of the effective stiffness is derived based on the differential self-consistent method. The analytical results agree very well with the finite element calculations. [ABSTRACT FROM AUTHOR]

We developed an open source, extensible Python‐based framework, that we call the Versatile Modeling Of Deformation (VMOD), for forward and inverse modeling of crustal deformation sources. VMOD abstracts from specific source model implementations, data types and inversion methods. We implement the most common geodetic source models which can be combined to model and analyze multi‐source deformation. VMOD supports Global Navigation Satellite System (GNSS), InSAR, electronic distance measurement, Leveling and tilt data. To infer source characteristics from observations, VMOD implements non‐linear least squares and Markov Chain Monte‐Carlo Bayesian inversions, including joint inversions using different sources of data. VMOD's structure allows for easy integration of new geodetic models, data types, and inversion strategies. We benchmark the forward models against other published results and the inversion approaches against other implementations. We apply VMOD to analyze deformation at Unimak Island, Alaska, observed with continuous and campaign GNSS, and ascending and descending InSAR time series generated from Sentinel‐1 satellite radar acquisitions. These data show an inflation pattern at Westdahl volcano and subsidence at Fisher Caldera. We use VMOD to test a range of source models by jointly inverting the GNSS and InSAR data sets. Our final model simultaneously constrains the parameters of two sources. Our results reveal a depressurizing spheroid under Fisher Caldera ∼4–6 km deep, contracting at a rate of ∼2–3 Mm3/yr, and a pressurizing spherical source underneath Westdahl volcano ∼6–8 km deep, inflating at ∼5 Mm3/yr. This and past applications of VMOD to volcanic unrest benefit from an extensible framework which supports jointly inversions of data sets for parameters of easily composable multi‐source models. Plain Language Summary: We developed a computational framework called the Versatile Modeling Of Deformation (VMOD) to calculate surface deformation created by buried pressure, tensile and shear sources, or find parameter values for a model that fits observed surface deformation. The framework has three main components. One component handles the model, one component handles the data, and the remaining component handles the algorithm that finds the most probable values for the parameters of a given model. Deformation can be observed using different techniques such as Global Navigation Satellite System (GNSS) or satellite images. The framework supports most of these techniques and allows users to add new techniques or deformation models. We validate our framework with literature results and contrast it with similar software used in the volcano deformation community. We apply the framework to analyze a deformation episode at Westdahl volcano and Fisher Caldera on Unimak Island, Alaska. The deformation is captured by GNSS and satellite radar images. Our results suggest a deflating spheroid ∼4–6 km deep with a rate of ∼2–3 Mm3/yr for Fisher Caldera and a inflating spherical source underneath Westdahl volcano ∼6–8 km deep, at a rate of ∼5 Mm3/yr. This and previous experiences highlight the advantages of multi‐source model deformation observations from different techniques. Key Points: We introduce a Python‐based object‐oriented modeling and inversion framework for geodetic data (Versatile Modeling Of Deformation (VMOD))VMOD's expandable framework design enables easy integration of new observation types, new deformation models, or inversion strategiesWe validate VMOD against literature and a community exercise, and use it to infer deformation sources at Fisher Caldera and Westdahl volcano [ABSTRACT FROM AUTHOR]

With the engineering background of the gob‐side entry of panel SA1104 in Heiyanquan Coal Mine, the deformation characteristics and control technology of the surrounding rock for gob‐side entry with small pillar in gently inclined coal seam have been studied by field observation, numerical simulation, and theoretical analysis. The study show that: (1) The surrounding rock has obvious asymmetric deformation characteristics, the roof subsidence on the solid coal side is larger than that on the small coal pillar side; the deformation of small coal pillar side rib is more significant than that of the solid coal side rib, which is concentrated in the middle and upper part, and slip deformation occurs at the upper sharp corner; the middle part of solid coal side rib exhibits prominent deformation; and floor heave is shifted to the small coal pillar side. (2) The stress concentration zone on the small coal pillar side is located 1.9 m from the high rib, while the stress concentration zone on the solid coal side is located 4.1 m from the low rib. The difference in the rib‐to‐rib peak stress is 4.2 MPa, and the stress concentration on the solid coal side is larger than that on the small coal pillar side. (3) Poor physical and mechanical properties of the surrounding rock, high in‐situ stress, and high deterioration degree of the surrounding rock structure are the main internal causes of the entry deformation; strong mining disturbance, arbitrary support parameters, and large section sizes are the main external causes of the entry deformation. (4) The asymmetric combined support program is proposed, featuring "non‐equidistant cable + inclined bolt on the roof, bolt extension + cable supplement on the small coal pillar side rib, and bolt encryption on the solid coal side rib", and it had a positive on‐site application effect. [ABSTRACT FROM AUTHOR]

In recent decades, polymer semiconductors, extensively employed as charge transport layers in devices like organic field‐effect transistors (OFETs), have undergone thorough investigation due to their capacity for large‐area solution processing, making them promising for mass production. Research efforts have been twofold: enhancing the charge mobilities of polymer semiconductors and augmenting their mechanical properties to meet the demands of flexible devices. Significant progress has been made in both realms, propelling the practical application of polymer semiconductors in flexible electronics. However, integrating excellent semiconducting and mechanical properties into a single polymer still remains a significant challenge. This review intends to introduce the design strategies and discuss the properties of high‐charge mobility stretchable conjugated polymers. In addition, another key challenge faced in this cutting‐edge field is maintaining stable semiconducting performance during long‐term mechanical deformations. Therefore, this review also discusses the development of healable polymer semiconductors as a promising avenue to improve the lifetime of stretchable device. In conclusion, challenges and outline future research perspectives in this interdisciplinary field are highlighted. [ABSTRACT FROM AUTHOR]

This paper focuses on the deformation origin of PbZr0.52Ti0.48O3 ( PZT) fiber mats obtained by electrospinning. The main cause of deformation of the green mats during heating was found to be a nonuniform relaxation of the stretched PVP polymer, due to nonuniform thermal decomposition of the Pb-hexanoate in the fibers. This relaxation starts under 100°C, well below the polymer decomposition temperature. The shrinkage was found to accelerate above the polymer glass transition point, giving rise to an overall linear change of almost 50%. The 'green' PZT mats were easily separated from the collector by first depositing a pure PVP sublayer on the collector. An optimal fabrication and slow multistep thermal treatment process that provides fiber mats with desired PZT phase and overcomes the nonuniform deformation is described. [ABSTRACT FROM AUTHOR]

In this paper, a low-temperature densification process of Al-Si alloy infiltration was developed to fabricate C/SiC-Ti3Si(Al)C2, and then the microstructure, mechanical, and electromagnetic interference ( EMI) shielding properties were studied compared with those of C/SiC-Ti3SiC2 and C/SiC-Si. The interbundle matrix of C/SiC-Ti3Si(Al)C2 is mainly composed of Ti3Si(Al)C2, which can bring various microdeformation mechanisms, high damage tolerance, and electrical conductivity, leading to the high effective volume fraction of loading fibers and electrical conductivity of C/SiC-Ti3Si(Al)C2. Therefore, C/SiC-Ti3Si(Al)C2 shows excellent bending strength of 556 MPa, fracture toughness 21.6 MPa·m1/2, and EMI shielding effectiveness of 43.9 dB over the frequency of 8.2-12.4 GHz. Compared with C/SiC-Si and C/SiC-Ti3SiC2, both the improvement of mechanical properties and EMI shielding effectiveness can be obtained by the introduction of Ti3Si(Al)C2 into C/SiC, revealing great potential as structural and functional materials. [ABSTRACT FROM AUTHOR]

ABSTRACT Polymer composites are suitable alternatives to metals in some applications as they are cost effective, lightweight and corrosion resistant. Short fibre reinforced polymer composites (SFRPCs) are typically subjected to complex loadings in applications, including static, cyclic, thermal and their combinations. These applications may also involve harsh environmental conditions such as elevated temperature and moisture which can dramatically affect mechanical properties. In this paper, a broad survey of the literature on mechanical behaviour of SFRPCs at elevated temperatures is presented. The mechanical behaviours included consist of tensile, creep, isothermal fatigue, thermo-mechanical fatigue and creep-fatigue interaction. Environmental effects such as moisture and ageing at elevated temperatures are also included. The studies reviewed include experimental works, modelling works and failure mechanisms studies. A critical assessment of the information from the literature presented for each type of behaviour is also provided. [ABSTRACT FROM AUTHOR]