Failure Criterion Model Research Articles

Mesostructural Model for the Fatigue Analysis of Open-Cell Metal Foams

Metallic foams exhibit unique properties that make them suitable for diverse engineering applications. Accurate mechanical characterization is essential for assessing their performance under both monotonic and cyclic loading conditions. However, despite the advancements, the understanding of cyclic load responses in metallic foams has been limited. This study aims to propose a mesostructural model to assess the fatigue behavior of open-cell metal foams subjected to cyclic loading conditions. The proposed model considers the previous load history and is based on the analogy of progressive collapse, integrating a finite element model, a fatigue analysis model, an equivalent number of cycles model, and a failure criterion model. Validation against experimental data shows that the proposed model can reliably predict the fatigue life of the metallic foams for specific strain amplitudes.

A three-dimensional failure criterion model considering the effects of fiber misalignment on longitudinal tensile failure

This paper proposes a three-dimensional failure criterion model for unidirectional fiber-reinforced composites. In contrast to previous models that only accounted for the effect of fiber misalignment in the presence of longitudinal compressive stress, the proposed failure criterion model comprehensively considers the effect of localized misaligned regions on the failure under any stress state. Another key contribution of this study is the introduction of the effective misalignment angle. Considering effective misalignment angles, the proposed failure criterion model can reasonably reveal the effect of localized misaligned regions on the failure behavior under different stress states. The agreement between the predicted results and the experimental data proves that the proposed model has good applicability. Furthermore, the influence of initial misalignment angles on failure is analyzed under varying stress conditions. The results indicate that even under longitudinal tensile stress, the initial misalignment angle still plays an important role in the failure behavior of materials.

Shear strength and failure criterion of geopolymer coral aggregate concrete under compression-shear loading

The utilization of geopolymer and coral aggregate in concrete preparation offers cost and time savings associated with the transportation of raw materials, as well as contributes to reducing carbon emissions and resisting the sulfate ions erosion in the marine environment. Concrete structures, including deep beams, corbels, and column joints, are typically subjected to compression-shear loading. For this purpose, a total of 54 cubic specimens are cast to test the compression-shear behavior of geopolymer coral aggregate concrete (GCAC) with different normal stress ratios (k=0,0.1,0.2,0.4,0.6,and0.8) and concrete strength grades (C20, C30, and C40). Subsequently, the failure patterns, load-shear displacement curves, and normal displacement-shear displacement curves of GCAC are obtained. The shear displacement, the shear strength, and its components are also analyzed. The results reveal that coral aggregate with high brittleness and low strength leads to more spalling powder and debris to occur as k increases, and is cut off on the shear surface. With an increase in k (k≥0.6), the descending phase of the load-shear displacement curve becomes steeper due to the higher severity of failure patterns. The shear dilation angle increases with the increase of the concrete strength grade, and first raises and then falls with the increase of k, reaching a maximum value at k=0.4, the same as the percentage of shear dilation strength. Furthermore, the increase in k has a significant negative impact on the percentage of cohesive strength, but not on that contact friction strength. Finally, based on the test results, the J2−I1fc model is determined to be the most suitable for GCAC among the three failure criterion models in this study.

Mechanical properties of multi-recycled aggregate concrete under combined compression-shear loading

The mechanical properties and strength failure criteria of multi-recycled aggregate concrete (multi-RAC) under combined compression and shear loading states are investigated in this paper. The peak shear strength, peak shear displacement, and failure patterns are compared under different regeneration cycles and normal compressive stress ratios. The results reveal that both the peak shear strength and peak shear displacement increase with the increased normal stress ratio. The shear failure pattern with higher severity corresponds to more spalling powder and debris deposited on the shear fracture surface. When the regeneration cycles of coarse aggregate increase, the peak shear strength decreases and the descending trend become more evident with the higher vertical compressive stress ratio. Under the normal compressive stress, contact friction strength is the dominant component of peak shear strength among the cohesive strength, contact friction strength, and shear dilation strength. Based on different stress expressions, three compression-shear failure criterion models considering the regeneration cycles of coarse aggregate under planar stress state were established for RAC. The stress invariance failure criterion model and octahedral stress failure criterion model in quadratic parabolic functional form can provide high prediction accuracies.

An experimental study and failure mechanism analysis on dynamic behaviors of plain concrete under biaxial compression-compression

In order to explore the dynamic mechanical properties of concrete under biaxial compression-compression, a true triaxial instrument was used to conduct an experimental study on the dynamic mechanical properties of plain concrete under biaxial compression-compression. Eight different lateral compressive stresses (0 MPa~14 MPa) and four strain (10−5/s, 10−4/s, 10−3/s and 10−2/s) rate were considered. From this, the effects of lateral compressive stress and loading strain rate on the biaxial compression-compression properties of concrete were compared and analyzed by obtaining the failure modes, principal compressive stress-strain curves and related mechanical characteristic parameters of plain concrete under different loading conditions. The research results show that: with the increase of lateral compressive stress, the failure modes of concrete were developed from columnar failure at low lateral compressive stress to sheet-like failure at high lateral compressive stress. With the increase of lateral stress, the development trend of concrete failure mode decreased gradually under the influence of strain rate. With the increase of lateral compressive stress, the variation range of concrete principal compressive stress decreased first and then tended to be relatively stable under the influence of strain rate. With the increase of strain rate, the increase range of concrete principal compressive stress decreased under the influence of lateral compressive stress. The influence mechanism of lateral compressive stress and strain rate on biaxial compression-compression performance of concrete was analyzed. Meanwhile, based on Kupfer biaxial compression failure criterion, a biaxial compression dynamic failure criterion model considering the effect of loading strain rate on plain concrete was proposed. The research results provided an important theoretical basis for the application and development of concrete engineering.

Experimental investigation of damage evolution and failure criterion on hollow cylindrical rock samples with different bore diameters

The roadway direction is often parallel to the direction of the maximum principal stress for the structure arrangement of underground roadway. To study the instability mechanism of roadway under the maximum principal stress, a series of uniaxial compression acoustic emission (AE) experiments were carried out on hollow red sandstone and granite rock samples with different bore diameters. The test results suggest that the oblique shear or X-shaped shear failure occurs in hollow rock samples, and the failure process is accompanied by a sudden jump in accumulative energy of AE signals, at the same time, the ringing count arrived at peak value. The increase in bore diameter haves contributed to the decline of ringing count and accumulative energy. A statistical damage constitutive model of Weibull distribution was established for hollow rock samples. On the basis of optimizing the damage variable, a damage constitutive model based on AE ringing count was obtained, which can better describe the damage state and stress state of rock samples. The AE accumulative energy was selected as the state variable, and the failure criterion model was finished based on the cusp catastrophe theory to estimate the rock sample failure. The judgment results show that the failure moment of rock sample is accurately included in the judgment time interval. This research can provide reference and technical support for the stability control and monitoring of underground engineering roadways.

Multi-scale finite element modeling of bending behavior of 3D multi-cell spacer weft-knitted composites with different structures

In the present study, a multi-scale finite element model is proposed to predict the linear and nonlinear behavior of the 3D multi-cell spacer weft-knitted composite under bending load. In this study, a unit-cell of the composite which includes plain and biaxial weft-knitted structures was modeled at the meso scale. Periodic boundary conditions were applied to the meso model to calculate the elastic constants of each composite structure. In order to obtain failure parameters of the composites, the Puck failure criterion model was utilized by a VUMAT code for the meso model. Afterward, the elastic constants of the composites based on a Python code were extracted from the meso model. Moreover, failure parameters that include tensile and compressive strength through the fiber and transverse directions were obtained from the meso model. All elastic and failure parameters were used for the macro model which is created with different profiles under bending load. The numerical results at the meso scale showed that the presence of the weft and warp yarns inside the biaxial weft-knitted composite increases the strength of the composite through the course and wale directions. Moreover, the stiffness of the composite would be improved. So, the samples that contained a biaxial composite had more stiffness and bending strength in comparison with plain composite samples because the top and bottom layers were manufactured by the biaxial weft-knitted structure. Besides, the comparison between numerical and experimental force–deflection curves showed that the proposed model could predict the linear and nonlinear behavior of the composites with high accuracy. So, this model can be used for other textile composites with complex shapes to predict the mechanical behavior of them.

Effect of the fiber cut angle on the shearing strength of unidirectional and cross-ply carbon-fiber-reinforced thermoplastic laminates

This paper quantitatively clarifies the effect of the fiber cut angle on the shearing strength of carbon-fiber-reinforced thermoplastic laminates. First, the shearing strength of the unidirectional and cross-ply laminates was measured at various cut angles. Next, two mechanics models, a rule-of-mixture-based model and a failure criterion model, were established to predict the shearing strength of the unidirectional and cross-ply laminates. The rule-of-mixture model explains the effect of the cut angle on the shearing strength of the unidirectional laminate. The failure criterion model predicts the dependence of the cut angle on the shearing strength for both laminates. Finally, finite element analysis was performed to semi-quantitatively evaluate the assistance effect of bending stress. It was revealed that the effective bending stress is almost equivalent to the stress averaged over approximately the one-layer thickness from the surface.

Mechanical performance and failure criterion of coral concrete under combined compression-shear stresses

The mechanical performance of coral concrete under combined compression-shear stresses was investigated using the multifunctional true triaxial testing machine. The shear load–displacement curves, normal displacement-shear displacement curves, and shear failure modes were obtained. Based on the test results, the shear failure modes, deformation proprieties, peak shear strength, and shear strength components were analyzed. The results show that almost all coral aggregates on the shear failure surface are broken. With the normal stress ratio increasing, the fiction traces and tiny concrete debris on the shear failure surface increase, and the peak shear strength and corresponding shear displacement also increase. The shear strength components include cohesion strength, contact friction strength, and shear dilation strength, where the contact friction strength dominates the shear strength with the existence of normal stress. Based on different stress expressions, five failure criterion models are proposed, where the one based on stress invariant achieves the highest prediction accuracy.

Experimental study and failure criterion analysis on combined compression-shear performance of rubber concrete (RC) with different rubber replacement ratio

In order to study the combined compression-shear mechanical properties of rubber concrete (RC), the compression-shear tests of RC under varying axial compression ratios and rubber content were carried out using compression-shear hydraulic servo machine. The shear failure modes and shear load–displacement curves of RC were generated. The characteristics points of load–displacement curves, peak shear strength, residual strength, shear failure displacement, for instance, were also extracted under different loading conditions. The effect of the axial compression ratios and replacement level of rubber particles on the shear mechanical properties of concrete was evaluated. It was reported that shear failure of RC developed slowly while shear failure plane was relatively flat by an increase in axial compression ratio. The friction traces on shear failure plane got more evident when the law of change was not associated to the replacement ratio of rubber particles. Research results also indicated that with successive increase in replacement ratio, the shear strength of concrete gradually decreases while the shear displacement gradually increases. Simultaneously, the increase coefficient of shear load of RC shows a decreasing trend, influenced by the axial compression ratio. The shear strength, residual load and shear displacement were enhanced as the axial compression ratio increased. While the reduction degree of shear load is larger due to the rubber replacement ratio. The cohesion and internal friction angle of concrete decrease by an increase in the rubber replacement ratio while the friction coefficient of the shear failure plane is relatively stable. The failure criterion models of concrete associated with the rubber replacement ratio under combined compression-shear stress are derived from the theory of plane stress space and octahedral stress space. Model results show favorable consistence with experimental data. The manuscript discussed and analyzed the mechanism of concrete under combined compression-shear. The research of this paper is of great significance for scientific research and engineering applications of RC.

Investigation on three-dimensional failure criterion of asphalt mixture considering the effect of stiffness

In order to reveal the effect of complex stress state on the characteristics of strength and stiffness of asphalt mixture, the self-developed double confining pressure triaxial test method was used in this study. The one-time failure and resilient modulus tests in complex stress state were carried out on the SMA-13 and AC-13 asphalt mixtures widely used in China's asphalt pavement, especially in the combined tensile-compressive stress state. The failure principal stress of material and its stress-strain data under the step loading condition were obtained. The calculation model of resilient modulus in complex stress state and the failure criterion I1-J2 in the principal stress space were established. On this basis, based on the generalized Hooke's law, a three-dimensional strain failure criterion model for asphalt mixture considering the effect of stiffness was also established by the conversion method. The research results can provide experimental and theoretical support for the reasonable selection and resistance calculation of material parameters of asphalt mixture in complex stress state.

Uncertainty Quantification of Simplified Viscoelastic Continuum Damage Fatigue Model using the Bayesian Inference-Based Markov Chain Monte Carlo Method

The simplified viscoelastic continuum damage model (S-VECD) has been widely accepted as a computationally efficient and a rigorous mechanistic model to predict the fatigue resistance of asphalt concrete. It operates in a deterministic framework, but in actual practice, there are multiple sources of uncertainty such as specimen preparation errors and measurement errors which need to be probabilistically characterized. In this study, a Bayesian inference-based Markov Chain Monte Carlo method is used to quantify the uncertainty in the S-VECD model. The dynamic modulus and cyclic fatigue test data from 32 specimens are used for parameter estimation and predictive envelope calculation of the dynamic modulus, damage characterization and failure criterion model. These parameter distributions are then propagated to quantify the uncertainty in fatigue prediction. The predictive envelope for each model is further used to analyze the decrease in variance with the increase in the number of replicates. Finally, the proposed methodology is implemented to compare three asphalt concrete mixtures from standard testing. The major findings of this study are: (1) the parameters in the dynamic modulus and damage characterization model have relatively strong correlation which indicates the necessity of Bayesian techniques; (2) the uncertainty of the damage characteristic curve for a single specimen propagated from parameter uncertainties of the dynamic modulus model is negligible compared to the difference in the replicates; (3) four replicates of the cyclic fatigue test are recommended considering the balance between the uncertainty of fatigue prediction and the testing efficiency; and (4) more replicates are needed to confidently detect the difference between different mixtures if their fatigue performance is close.

Strength and deformation properties of structural lightweight concrete under true tri-axial compression

In this paper, the strength and deformation of structural all lightweight concrete (ALWC), structural semi-lightweight concrete (SLWC) and normal weight concrete (NWC) subjected to uniaxial, equibiaxial and truly tri-axial compression was experimentally studied and compared. The stress-strain curves in three principal directions were recorded, and the failure modes of different specimens under various stress states were observed. Test results showed that the failure modes were mainly dependent on the stress ratio, but independent of concrete types. For all types of concrete, the peak strength under biaxial and triaxial compression is substantially higher than uniaxial compressive strength. At the lower compression stress ratio, i.e. σ1/σ3 = 0.1, all the concrete exhibited relatively brittle behavior, the relative tri-axial compressive strength of ALWC and SLWC was in a range of 1.61–2.05 and 1.93–2.63 respectively, compared to 2.25–3.21 for NWC. The peak deformation in three principal directions for ALWC and SLWC was far greater than that of NWC. At the higher compression stress ratio, i.e. σ1/σ3 = 0.25, all concretes showed pseudo-ductile behavior, the relative tri-axial compressive strength and peak deformation in three principal directions of ALWC and SLWC became close to those of NWC. Considering the role of the intermediate principal stress for concrete under true triaxial compression, a 4-parameter failure criterion model with different material constants was developed. The proposed failure surface was verified against experimental data of NWC, ALWC, and SLWC under multiaxial loads in this paper, as well as low strength LWC under truly tri-axial compression in the literature. It provided the experimental and theoretical foundations for strength analysis of LWC structures subject to complex loads.

Mohr-Coulomb failure criterion from unidirectional mechanical testing of sand cores after thermal exposure

Sand core samples were subjected to thermal pre-conditioning profiles between 200 and 500 °C both in ambient air and under sealed conditions. These were customised similar to an industrial cast aluminium cylinder head. The samples were investigated via unconfined compression, splitting tensile, shear, and bending tests. The suitability of the data to parametrise a Mohr–Coulomb failure criterion model was evaluated.Four core types were examined more closely. The relative retained strength evolution was largely independent of the test type. Structural changes such as hardening or degradation were indicated by changes of the elastic bending modulus. In particular, polyurethane-coldbox-bonded sand cores after 400 °C pre-conditioning without air exchange retained 40% of the initial strength compared to 20% after treatment in air. Less atmospheric influence was revealed by furan warmbox-bonded cores, showing a decrease to 30% of the initial strength up to a 300 °C pre-conditioning temperature. Inorganic silicate-bonded cores using quartz sand exhibited a decrease in strength to 10% up to a 400 °C pre-conditioning temperature. In contrast using a silicate-bonded sintered mullite granulate, more than 50% of the initial strength was retained up to a 500 °C pre-conditioning temperature.Based on position-dependent temperature profiles, evolving during casting within the insulating sand cores, the mechanical behaviour until failure can be predicted and assigned, further allowing the evaluation of the mechanical core removal.

Experimental and Numerical Investigation of Charpy Impact Test of Spin Arc Welded C1018 plates

AISI 1018 low carbon steels are widely used in dynamic environment where material undergo sudden loads. In this study the Finite element simulation of impact test of Spin arc welded 1018 steel plates was analysed using Abaqus Explicit 6.14. Damage evaluation of spin arc weld and base metal are proposed by Johnson-Cook failure criterion model. The geometry, material and contact properties of base and weld metal are obtained from tensile test results. The specimen and striker are controlled by linear surface to surface interface. The numerical results are compared with experimental Charpy impact test for validation.

State of the art in fatigue modelling of composite wind turbine blades

This paper provides a literature review of the most notable models relevant to the evaluation of the fatigue response of composite wind turbine blades. As wind turbines spread worldwide, ongoing research to maximize their lifetime – and particularly that of wind turbine blades – has increasingly popularized the use of composite materials, which boast attractive mechanical properties. The review first presents the wind turbine blade environment, before distributing fatigue models broadly between three categories: life-based failure criterion models, which are based on S-N curve formulations and constant-life diagrams to introduce failure criteria; residual property calculation models, which evaluate the gradual degradation of material properties; and progressive damage models, which model fatigue via the cycle-by-cycle growth of one or more damage parameters. These are then linked to current testing standards, databases, and experimental campaigns. Among the fatigue modelling approaches covered, progressive damage models appear to be the most promising tool, as they both quantify and qualify physical damage growth to a reasonable extent during fatigue. The lack of consensus and shortcomings of literature are also discussed, with abundant referencing.

The multi-axial strength performance of composited structural B-C-W members subjected to shear forces

This paper presents a new method to compute the shear strength of composited structural B-C-W members. These B-C-W members, defined as concrete-filled steel box beams, columns and shear walls, consist of a slender rectangular steel plate box filled with concrete and inserted steel plates connecting the two long-side steel plates. These structural elements are intended to be used in structural members of super-tall buildings and nuclear safety-related structures. The concrete confined by the steel plate acts to be in a multi-axial stressed state: therefore, its shear strength was calculated on the basis of a concrete\'s failure criterion model. The shear strength of the steel plates on the long sides of the structural element was computed using the von Mises plastic strength theory without taking into account the buckling of the steel plate. The spacing and strength of the inserted plates to induce plate yielding before buckling was determined using elastic plate theory. Therefore, a predictive method to compute the shear strength of composited structural B-C-W members without considering the shear span ratio was obtained. A coefficient considering the influence of the shear span ratio was introduced into the formula to compute the anti-lateral bearing capacity of composited structural B-C-W members. Comparisons were made between the numerical results and the test results along with this method to predict the anti-lateral bearing capacity of concrete-filled steel box walls. Nonlinear static analysis of concrete-filled steel box walls was also conducted by using ABAQUS and the results agreed well with the experimental data.

New failure criterion models for concrete under multiaxial stress in compression

Biaxial and triaxial compression tests were performed on 100 × 100 ×100 mm cubic specimens of concrete under different stress loading rates. All the tests were performed using a true triaxial testing machine. The analysis of the data revealed that the intermediate principal stress, hydrostatic stress and shear stress are the main factors influencing the failure criterion for concrete under multiaxial stress. Based on the twin shear strength theory, three failure criterion models were developed. The five-parameter model A considers the shear strength as the main factor, the five-parameter model B considers hydrostatic strength as the main factor, and the six-parameter model considers both the shear strength and hydrostatic strength. The parameters for these failure criterion models have clear physical significance and form the failure criterion in a theoretical analysis. Models A and B apply to different stress states and show similar results. The six-parameter model can apply to most stress states, but the computed results depend on the boundary conditions. This convenient model can also be extended for nonlinear analyses of concrete under multiaxial stress in compression.

Composite laminate oriented reliability analysis for fatigue life under non-probabilistic time-dependent method

The problem of composite laminate fatigue assessment under small samples and less probability information is always concentrated, and the mechanical properties of composite structure are deteriorated due to damage accumulation effect of fatigue issue. On the basis of analyzing the current reliability modeling method, this paper developed the reliability evaluation strategy based on the non-probability theory, and considering composite structure response to the external cycle load influence, time-varying reliability analysis model is established, which is different from the quasi-static analysis method, and finally the application for composite structure fatigue problem based on the non-probability of the time-varying reliability analysis is put forward. In the proposed method, every single layer reliability is analyzed combining the non-probabilistic theory with Tsai–Wu failure criterion model, comparing with the traditional probabilistic reliability theory, the method of non-probability is not constrained by probability distribution information, in view of that, the approach has stronger practicability; Introducing for the first-passage conceptions, the crossing rate is evaluated through the non-probabilistic reliability method, finally the time-varying reliability index of composite material structure is established. After analysis steps are given in detail, laminated plate structure is presented to demonstrate the validity and reasonability of the developed methodology.

A comprehensive evaluation of the fatigue behaviour of plant-produced RAP mixtures

In this study, the fatigue performance of 12 plant-produced mixtures from New Hampshire and Vermont that contain reclaimed asphalt pavement (RAP) contents of 0–40% by total weight of mixture was evaluated. The mixture tests included dynamic modulus, uniaxial fatigue, beam fatigue, and overlay tests. Also, the simplified viscoelastic continuum damage (S-VECD) model failure criterion, called the GR method, was applied and input to the linear viscoelastic pavement analysis for critical distresses (LVECD) programme to predict the fatigue behaviour of the tested mixtures on thin and thick asphalt pavement structures. In order to explain the observed fatigue behaviour, the performance grades (PGs) of the binders that were extracted and recovered from the mixtures were determined. In general, the addition of RAP resulted in an increase in the stiffness of the materials. The magnitude of the impact of higher RAP percentages varied with each set of mixtures. The S-VECD model and beam fatigue test data showed a loss of fatigue resistance for high-percentage RAP mixtures in most of the cases. The overlay tester results showed clear drops in performance at higher RAP contents. The impact of lowering the PG of the virgin binder to compensate for higher levels of RAP also was studied. Lowering the PG led to improvement in the fatigue properties and was found to be a convenient practice. The changes in the measured properties also appeared to be a function of mix design variables that included the stiffness of the RAP, asphalt content, and production parameters such as silo storage times. In some cases, the effects of these factors outweighed the impact of the RAP level or PG of the virgin binder in the mixtures.