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The stress analysis of structures subjected to cyclic loading requires stress—strain relations simple enough to be usable efficiently in computer program and yet adequate to describe the essential features of the plastic behaviour of the material reasonably well. The constitutive equation for cyclic plasticity incorporating the motion of the centre of the loading surface is proposed. Using the modified plastic work, the dependency of the loading history of materials is taken into account. The Ramberg—Osgood law which is applied to each stress—strain loop from the current centre of the loading surface plays an important role. This computer simulation for stress—strain relation of cyclic loading is justified from the point of view of several kinds of experiments on type 304 austenitic stainless steel.

This study aims to propose a semiempirical and semitheoretical cyclic compaction constitutive model of coarse-grained soil filler for the high-speed railway (HSR) subgrade under cyclic load.

According to the basic framework of critical state soil mechanics and in view of the characteristics of the coarse-grained soil filler for the HSR subgrade to bear the train vibration load repeatedly for a long time, the hyperbolic empirical relationship between particle breakage and plastic work was derived. Considering the influence of cyclic vibration time and stress ratio, the particle breakage correction function of coarse-grained soil filler for the HSR subgrade under cyclic load was proposed. According to the classical theory of plastic mechanics, the shearing dilatation equation of the coarse-grained soil filler for the HSR subgrade considering particle breakage was modified and obtained. A semiempirical and semitheoretical cyclic compaction constitutive model of coarse-grained soil filler for the HSR subgrade under cyclic load was further established. The backward Euler method was used to discretize the constitutive equation, build a numerical algorithm of “elastic prediction and plastic modification” and make a secondary development of the program to solve the cyclic compaction model.

Through the comparison with the result of laboratory triaxial test under the cyclic loading of coarse-grained soil filler for the HSR subgrade, the accuracy and applicability of the cyclic compaction model were verified. Results show that the model can accurately predict the cumulative deformation characteristics of coarse-grained soil filler for the HSR subgrade under the train vibration loading repeatedly for a long time. It considers the effects of particle breakage and stress ratio, which can be used to calculate and analyze the stress and deformation evolution law of the subgrade structure for HSR.

The research can provide a simple and practical method for calculating deformation of railway under cyclic loading.

The purpose of this paper is to deal with the FE analysis of strain constraint around the crack tip under cyclic loading and its utilization using crack growth prediction strip yield model (SYM). During cycling, the constraint develops based on the load history. The monotonic loading is analyzed mostly, but during cyclic loading the conditions are different. The constraint is analyzed after several loading cycles applied in upwards part of the cycle and the formula for its development is proposed.

The study is based on the 3D FE analysis of middle-cracked tension specimen M(T). The strain constraint is described by Newman’s factor α. The variability of constraint factor α was analyzed for several load levels and specimen thicknesses. The crack is considered as non-propagating with straight crack front. The material is modelled as elastic-perfectly plastic. The SYM is modified by implementing variable constraint and the experimental results are compared with the simulation.

In major part of the loading cycle, it was found by FE analysis, that the constraint factor α_g is lower after overloads than when creating monotonic plastic deformation on the same load level. The value of α_g is governed by the ratio of thickness B over the plastic zone size r_p. By implementing the variable constraint factor into the SYM, the improvement of the predicted specimens lives under variable amplitude loading was shown.

The new phenomenon on the variability of strain constraint during cyclic loading is presented. The development of constraint factor α_g during cyclic loading is different from the monotonic loading and should be accordingly implemented into prediction models.

The purpose of this study is to develop two empirical models that predict the shear strength of exterior beam-column joints exposed to monotonic and cyclic loading using Gene expression programming (GEP).

The GEP model developed for the monotonic loading case is trained and validated using 81 data test points and that for cyclic loading case is trained and validated using 159 data test points that collected from different 9 and 39 experimental programs, respectively. The parameters that are selected to develop the cyclic GEP model are concrete compressive strength, joint aspect ratio, column axial load and joint transverse reinforcement. The monotonic GEP model is developed using concrete compressive strength, column depth, joint width and column axial load.

GEP models are proposed in this paper to predict the joint shear strength of beam-column joints under cyclic and monotonic loading. The predicted results obtained using the GEP models are compared to those calculated using the ACI-352 code formulations. A sensitivity analysis is also performed to further validate the GEP models.

The proposed GEP models provide an accurate prediction for joint shear strength of beam-column joints under cyclic and monotonic loading that is more fitting to the experimental database than the ACI-352 predictions where the GEP models have higher R² value than the code formulations.

The purpose of this paper is to study the phenomenology of Al₂O₃-DBC substrate thermal-cracking under different high temperature cyclic loadings. The extremely low cycle fatigue (ELCF) life prediction model for ductile materials was used to describe the thermal fatigue life of Al₂O₃-DBC substrates.

Four groups of thermal cycling tests using Al₂O₃-DBC substrates with 0.65 mm thick copper were conducted using different peak temperatures. The failure samples were observed by optical microscope. The thermal plastic strain distribution in the Al₂O₃-DBC substrates was analyzed using a finite element method with the Chaboche model for describing plastic deformation of copper. The ELCF life prediction model was used to predict the life of Al₂O₃-DBC substrates under high temperature cyclic loadings.

Interface cracking was observed to initiate at the short edge of the bonded copper and deviated into the ceramic layer when the crack grew beyond the critical length of 0.1-0.8 mm. The interface crack deviated into the ceramic layer at different thickness and grew parallel to the interface layer between the ceramic layer and copper layer. The crack propagation stopped after certain cycles. The copper layer with 10-20 μm thick alumina inside was not split away totally from the ceramic layer. The ELCF life prediction model could predict the life of Al₂O₃-DBC substrates well under high temperature cyclic loading. The material constants in the extremely low fatigue life prediction model were obtained using thermal fatigue tests results.

The influence of copper layer thickness and ceramic layer thickness on thermal cracking characteristics of DBC substrate should be studied in the future. Failure models should also be further investigated.

The failure model of Al₂O₃-DBC substrates under high temperature cyclic loading was studied. A method for predicting the life of the substrate samples under high temperature cyclic loading was proposed.

While additive manufacturing via melt-extrusion of plastics has been around for more than several decades, its application to complex geometries has been hampered by the discretization of parts into planar layers. This requires wasted support material and introduces anisotropic weaknesses due to poor layer-to-layer adhesion. Curved-layer manufacturing has been gaining attention recently, with increasing potential to fabricate complex, low-weight structures, such as mechanical metamaterials. This paper aims to study the fabrication and mechanical characterization of non-planar lattice structures under cyclic loading.

A mathematical approach to parametrize lattices onto Bèzier surfaces is validated and applied here to fabricate non-planar lattice samples via curved-layer fused deposition modeling. The lattice chirality, amplitude and unit cell size were varied, and the properties of the samples under cyclic-loading were studied experimentally.

Overall, lattices with higher auxeticity showed less energy dissipation, attributed to their bending-deformation mechanism. Additionally, bistability was eliminated with increasing auxeticity, reinforcing the conclusion of bending-dominated behavior. The analysis presented here demonstrates that mechanical metamaterial lattices such as auxetics can be explored experimentally for complex geometries where traditional methods of comparing simple geometry to end-use designs are not applicable.

The mechanics of non-planar lattice structures fabricated using curved-layer additive manufacturing have not been studied thoroughly. Furthermore, traditional approaches do not apply due to parameterization deformations, requiring novel approaches to their study. Here the properties of such structures under cyclic-loading are studied experimentally for the first time. Applications for this type of structures can be found in areas like biomedical scaffolds and stents, sandwich-panel packaging, aerospace structures and architecture of lattice domes.

This work presents an experimental approach to study the mechanical properties of non-planar lattice structures via quasi-static cyclic loading, comparing variations across several lattice patterns including auxetic sinusoids, disrupted sinusoids and their equivalent-density quadratic patterns.

Steel fibers reinforced concrete (SFRC) is now widely accepted as a construction material for its added benefits. The proven increases in high shear capacity, toughness, bridging action of fibers and bond improvement from addition of steel fibers into mix design is a field yet to be explored, Therefore, Reinforced Cement Concrete (RCC) beam-column joint with steel fibers was modeled and analyzed for cyclic loading.

Beam-column joint is the most critical section of a structure under mixed loading such as that during a seismic episode. Therefore, in this research a reinforced SFRC beam column joint is modeled and analyzed for cyclic earthquake loading with the help of finite element analysis (FEA) software ABAQUS to compare the results with the experimental study.

Nonlinear static and nonlinear dynamic analysis are carried out on the SFRC joint for the comparison of simulated results with the experimental analysis.

In this paper, Initially, modeling of SFRC joint was done. Then, the finite element analysis of beam-column joint with steel fibers was carried out. After number of simulations, obtained FEA results were compared with the experimental work on the based on the load vs deflection curve, shear stresses, plastic strain region and plastic strain pattern. After the comparison, it was found that the performance of the numeric model for cyclic loading verified the experimental study, and the results obtained were quite promising.

The research aims to investigate the impact of thermo-mechanical aging on SBR under cyclic-loading. By conducting experimental analyses and developing a 3D finite element analysis (FEA) model, it seeks to understand chemical and physical changes during aging processes. This research provides insights into nonlinear mechanical behavior, stress softening and microstructural alterations in SBR compounds, improving material performance and guiding future strategies.

This study combines experimental analyses, including cyclic tensile loading, attenuated total reflection (ATR), spectroscopy and energy-dispersive X-ray spectroscopy (EDS) line scans, to investigate the effects of thermo-mechanical aging (TMA) on carbon-black (CB) reinforced styrene-butadiene rubber (SBR). It employs a 3D FEA model using the Abaqus/Implicit code to comprehend the nonlinear behavior and stress softening response, offering a holistic understanding of aging processes and mechanical behavior under cyclic-loading.

This study reveals significant insights into SBR behavior during thermo-mechanical aging. Findings include surface roughness variations, chemical alterations and microstructural changes. Notably, a partial recovery of stiffness was observed as a function of CB volume fraction. The developed 3D FEA model accurately depicts nonlinear behavior, stress softening and strain fields around CB particles in unstressed states, predicting hysteresis and energy dissipation in aged SBRs.

This research offers novel insights by comprehensively investigating the impact of thermo-mechanical aging on CB-reinforced-SBR. The fusion of experimental techniques with FEA simulations reveals time-dependent mechanical behavior and microstructural changes in SBR materials. The model serves as a valuable tool for predicting material responses under various conditions, advancing the design and engineering of SBR-based products across industries.

This study aims to evaluate the failure behavior of glass fiber-reinforced epoxy (GFRE) laminate subjected to cyclic loading conditions. It involves experimental investigation and statistical analysis using Weibull distribution to characterize the failure behavior of the GFRE composite laminate.

Fatigue tests were conducted using a tension–tension loading scheme at a frequency of 2 Hz and a loading ratio (R) of 0.1. The tests were performed at five different stress levels, corresponding to 50%–90% of the ultimate tensile strength (UTS). Failure behavior was assessed through cyclic stress-strain hysteresis plots, dynamic modulus behavior and scanning electron microscopy (SEM) analysis of fracture surfaces.

The study identified common modes of failure, including fiber pullouts, fiber breakage and matrix cracking. At low stress levels, fiber breakage, matrix cracking and fiber pullouts occurred due to high shear stresses at the fiber–matrix interface. Conversely, at high stress levels, fiber breakage and matrix cracking predominated. Higher stress levels led to larger stress-strain hysteresis loops, indicating increased energy dissipation during cyclic loading. High stress levels were associated with a more significant decrease in stiffness over time, implying a shorter fatigue life, while lower stress levels resulted in a gradual decline in stiffness, leading to extended fatigue life.

This study makes a valuable contribution to understanding fatigue behavior under tension–tension loading conditions, coupled with an in-depth analysis of the failure mechanism in GFRE composite laminate at different stress levels. The fatigue behavior is scrutinized through stress-strain hysteresis plots and dynamic modulus versus normalized cycles plots. Furthermore, the characterization of the failure mechanism is enhanced by using SEM imaging of fractured specimens. The Weibull distribution approach is used to obtain a reliable estimate of fatigue life.

This paper aims to predict fatigue life and fatigue limit of fiber-reinforced ceramic-matrix composites (CMCs) with different fiber preforms, i.e. unidirectional, cross-ply, 2D-, 2.5D- and 3D-woven, at room and elevated temperatures.

Under cyclic loading, matrix multicracking and interface debonding occur upon first loading to fatigue peak stress, and the interface wear appears with increasing cycle number, leading to degradation of the interface shear stress and fibers strength. The relationships between fibers fracture, cycle number, fatigue peak stress and interface wear damage mechanism have been established based on the global load sharing (GLS) criterion. The evolution of fibers broken fraction versus cycle number curves of fiber-reinforced CMCs at room and elevated temperatures have been obtained.

The predicted fatigue life S–N curve can be divided into two regions, i.e. the Region I controlled by the degradation of interface shear stress and fibers strength and the Region II controlled by the degradation of fibers strength.

The proposed approach can be used to predict the fatigue life and fatigue limit of unidirectional, cross-ply, 2D-, 2.5D- and 3D-woven CMCs under cyclic loading.

The fatigue damage mechanisms and fibers failure model were combined together to predict the fatigue life and fatigue limit of fiber-reinforced CMCs with different fiber preforms.