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Based on a review of literature and a few case studies, this paper summarizes the state of the art on the dating of folds and thrusts, then presents and discusses how recent advances in K–Ar illite and U–Pb calcite geochronology applied to brittle structures in fold-and-thrust belts have helped better constrain the timing, sequence, duration and rates of deformation.

The deformation behaviors of Co0.96Cr0.76Fe0.85Ni1.01Hf0.40 eutectic high-entropy alloy (EHEA) under high strain rates have been investigated at both room temperature (RT, 298 K) and liquid nitrogen temperature (LNT, 77 K). The current Co0.96Cr0.76Fe0.85Ni1.01Hf0.40 EHEA exhibits a high yield strength of 740 MPa along with a high fracture strain of 35% under quasi-static loading. A remarkable positive strain rate effect can be observed, and its yield strength increased to 1060 MPa when the strain rate increased to 3000/s. Decreasing temperature will further enhance the yield strength significantly. The yield strength of this alloy at a strain rate of 3000/s increases to 1240 MPa under the LNT condition. Moreover, the current EHEA exhibits a notable increased strain-hardening ability with either an increasing strain rate or a decreasing temperature. Transmission electron microscopy (TEM) characterization uncovered that the dynamic plastic deformation of this EHEA at RT is dominated by dislocation slip. However, under severe conditions of high strain rate in conjunction with LNT, dislocation dissociation is promoted, resulting in a higher density of nanoscale deformation twins, stacking faults (SFs) as well as immobile Lomer–Cottrell (L-C) dislocation locks. These deformation twins, SFs and immobile dislocation locks function effectively as dislocation barriers, contributing notably to the elevated strain-hardening rate observed during dynamic deformation at LNT.

In this work, models of the deformation behavior of polymer films of polyethylene and polyvinyl chloride are developed and analyzed, taking into account the influence of thickness, mechanical stress, temperature, time and dose of electron and ion irradiation. Experimental studies included tensile tests of polyethylene films of different thicknesses irradiated with krypton ions and electrons, as well as measuring the return deformation and its rate. It is shown that the quadratic and exponential models best describe the dependences of deformation on stress. Analytical formulas for the rate and acceleration of deformation are obtained, taking into account the influence of temperature and radiation dose. The results demonstrate a significant increase in the elastic properties and return deformation of irradiated samples, which is explained by the cross-linking of macromolecules and changes in the molecular structure under the influence of radiation. The proposed models and formulas can be effectively used in the development of devices and systems for monitoring the deformation of polymeric materials under radiation exposure in the aerospace, nuclear and electronic industries. Using the statistical analysis method, it was shown that the exponential model describes the dynamics of polyethylene deformation with a determination coefficient R2 = 0.985, which significantly exceeds the accuracy of the linear model (R2 = 0.85).

Solid–solid phase transformations can affect energy transduction and change material properties (e.g., superelasticity in shape memory alloys and soft elasticity in liquid crystal elastomers). Traditionally, phase-transforming materials are based on atomic- or molecular-level thermodynamic and kinetic mechanisms. Here, we develop elasto-magnetic metamaterials that display phase transformation behaviors due to nonlinear interactions between internal elastic structures and embedded, macroscale magnetic domains. These phase transitions, similar to those in shape memory alloys and liquid crystal elastomers, have beneficial changes in strain state and mechanical properties that can drive actuations and manage overall energy transduction. The constitutive response of the elasto-magnetic metamaterial changes as the phase transitions occur, resulting in a nonmonotonic stress–strain relation that can be harnessed to enhance or mitigate energy storage and release under high–strain-rate events, such as impulsive recoil and impact. Using a Landau free energy–based predictive model, we develop a quantitative phase map that relates the geometry and magnetic interactions to the phase transformation. Our work demonstrates how controllable phase transitions in metamaterials offer performance capabilities in energy management and programmable material properties for high-rate applications.

The effect of strain rate on the microstructure and deformation mechanism of a Mg–Y–Nd–Zr alloy was studied. The microstructure and texture were examined by optical microscopy and electron backscatter diffraction, and the dislocation structures were observed by transmission electron microscopy. The results showed that the Mg–Y–Nd–Zr alloy exhibited positive strain rate sensitivity under high-strain-rate compression. At a strain rate of 830 s −1 , many grains were re-oriented owing to the formation of a large number of tensile twins in the specimen. With increasing strain rate, the number of extension twins decreased, but those of contraction twins, double twins, and < c + a > dislocations increased. The dominant deformation mechanism of the material changed from extension twin-dominated deformation to extension twin- and < c + a > slip-dominated deformation.

Carbon-fiber composites are considered to be one of the suitable materials for the fabrication of prosthetic feet. However, commercially available composites-based prosthetic foot designs present several problems for lower limb amputees, such as low tensile strength, reduced impact resistance, high cost, and weight structure. Modulating the mechanical properties of carbon-fiber composites using a simplified method can help reduce these issues. Therefore, our present research aims to identify the impact of increasing the concentration of carbon fiber in the fabrication of carbon-fiber composites by using the hand layup method without the vacuum bagging technique. To improve the mechanical strength of carbon-fiber laminates, an increasing number of carbon-fiber layers are used in sample preparation. This study aims to determine the tensile strength of the laminates with a different number of carbon-fiber laminations. For the preparation of the sample specimen, black 100% 3 K 200 gsm carbon fiber with a cloth thickness of 0.2 mm and tensile strength of 4380 Mpa was laminated with two parts of epoxy resin Araldite® LY556 and Aradur hardener at a ratio of 100:30 to make the test specimen. The results indicated an overall improvement in the tensile strength of carbon-fiber laminates owing to the increase in the number of carbon-fiber layers in successive samples. The maximum achieved tensile strength through the present experimental protocol is 576.079 N/mm2, depicted by a prepared specimen of 10 layers of carbon fiber. Secondly, an increase in the deformation rate has also been observed by increasing the loading rate from 2 mm/min to 5 mm/min during the tensile testing of fabricated samples. These sample carbon-fiber composites can be used in the fabrication of prosthetic feet by controlling the experimental conditions. The fabricated prosthetic foot will assist in rehabilitating lower-limb amputees.

Landslide susceptibility mapping (LSM) can accurately estimate the location and probability of landslides. An effective approach for precise LSM is crucial for minimizing casualties and damage. The existing LSM methods primarily rely on static indicators, such as geomorphology and hydrology, which are closely associated with geo-environmental conditions. However, landslide hazards are often characterized by significant surface deformation. The Small Baseline Subset-Interferometric Synthetic Aperture Radar (SBAS-InSAR) technology plays a pivotal role in detecting and characterizing surface deformation. This work endeavors to assess the accuracy of SBAS-InSAR coupled with ensemble learning for LSM. Within this research, the study area was Shiyan City, and 12 static evaluation factors were selected as input variables for the ensemble learning models to compute landslide susceptibility. The Random Forest (RF) model demonstrates superior accuracy compared to other ensemble learning models, including eXtreme Gradient Boosting, Logistic Regression, Gradient Boosting Decision Tree, and K-Nearest Neighbor. Furthermore, SBAS-InSAR was utilized to obtain surface deformation rates both in the vertical direction and along the line of sight of the satellite. The former is used as a dynamic characteristic factor, while the latter is combined with the evaluation results of the RF model to create a landslide susceptibility optimization matrix. Comparing the precision of two methods for refining LSM results, it was found that the method integrating static and dynamic factors produced a more rational and accurate landslide susceptibility map.

In this paper, to study the development of load-carrying capacity and long-term creep performance of reinforced concrete beams under different corrosion patterns, the rate-dependent model of concrete is used as the basis to consider the creep development process from the meso-scale level. The porosity mechanics method is used to simulate the generation and penetration process of corrosion products. Three corrosion conditions are set: bottom longitudinal reinforcement corrosion, top longitudinal reinforcement corrosion and all reinforcement corrosion. The corrosion rate is used as the variable in each corrosion condition. The results show that: (1) the greater the corrosion rate in all conditions, the lower the bearing capacity. In addition, the corrosion of top longitudinal reinforcement causes the damage form of the beam to change to brittle damage; (2) the creep coefficient decreases with the increase in corrosion rate in all working conditions, but the main factor for this phenomenon is the obvious increase in initial deformation. Consequently, it is not suitable to follow the conventional creep concept (deformation development/initial deformation) for the development of plastic deformation of damaged members. It is more reasonable to use the global deflection to describe the long-term deformation of corrosion-damaged members.

It is challenging to precisely measure the slow interseismic crustal-deformation rate from Synthetic Aperture Radar (SAR) data. The long-wavelength orbital errors, owing to the uncertainties in satellite orbit vectors, commonly exist in SAR interferograms, which degrade the precision of the Interferometric SAR (InSAR) products and become the main barrier to extracting interseismic tectonic deformation. In this study, we propose a novel temporal-network orbital correction method that is able to isolate the far-fault tectonic deformation from the mixed long-wavelength signals based on its spatio–temporal characteristic. The proposed approach is straightforward in methodology but could effectively separate the subtle tectonic deformation from glaring orbital errors without ancillary data. Both synthetic data and real Sentinel-1 SAR images are used to validate the reliability and effectiveness of this method. The derived InSAR velocity fields clearly present the predominant left-lateral strike-slip motions of the Tuosuo Lake segment of the Kunlun fault in western China. The fault-parallel velocity differences of 5–6 mm/yr across the fault between areas ~50 km away from the fault trace are addressed. The proposed method presents a significantly different performance from the traditional quadratic approximate method in the far field. Through the implementation of the proposed method, the root mean square error (RMSE) between the LOSGPS and our derived descending InSAR LOS (line of sight) measurements is reduced to less than one-third of the previous study, suggesting its potential to enhance the availability of InSAR technology for interseismic crustal-deformation measurement.

Current research and technical standards primarily rely on observational methods to evaluate the printability of 3D printing materials. There is a lack of quantitative assessment metrics for extrudability and supportability, and experimental data cannot be used to characterize extrudability and buildability. Further research is needed. Based on traditional workability parameters (such as flowability), this study explored the influence of printability characteristics and adopted two quantitative indicators—extrusion uniformity and cumulative deformation rate—to comprehensively evaluate material performance from two aspects, while observing the trend of changes in traditional workability indicators and print quality under experimental conditions. The experimental results showed that the extrusion uniformity of 3D-printed mortar initially improved and then gradually deteriorated as flowability increased, and was inversely proportional to dynamic yield stress. The cumulative deformation rate decreases with the improvement of height retention capability and the increase in static yield stress. Through parameter analysis, the optimal printing performance conditions were determined: when the extrusion uniformity is below 3.3% and the cumulative deformation rate is ≤6%, the corresponding dynamic yield stress range is 200 Pa to 800 Pa, and the static yield stress range is 1800 Pa to 3300 Pa. Under these parameters, the mortar exhibits excellent printing performance, including high-layer stacking capability (≥30 layers) and enhanced structural stability. This experiment demonstrates that using these two quantitative indicators can simply and efficiently evaluate the performance metrics of 3D-printed materials, while also revealing the relationship between the workability and printing quality of 3D-printed recycled micro-powder geopolymer materials.