Interfacial Damage Evolution Research Articles

Numerical Simulation of Rubber Concrete Considering Fatigue Damage Accumulation of Cohesive Zone Model.

Rubber concrete (RC) has been used in fatigue-resistant components due to its durability, yet the numerical simulation of its fatigue properties remains in its early stages. This study proposes a cohesive zone model (CZM) that accounts for the accumulation of fatigue damage at the mesoscale to investigate the fatigue performance of RC. The model integrates static and fatigue damage in the CZM, effectively capturing damage caused by fatigue loading. Validation was conducted using experimental data from the existing literature. Based on this validation, four concrete beams with varying rubber replacement rates (0%, 5%, 10%, and 15%) were tested. The CZM was employed to describe the mechanical behavior of the interface transition zones (ITZs) and the mortar interior, which were simulated and analyzed under different stress levels. The results demonstrate that the model accurately simulates crack propagation paths, interface damage evolution, and the fatigue life of RC beams under fatigue loading. A functional relationship between fatigue life and stress level was established for various rubber replacement rates. This study provides a reference model for numerical simulations of RC under fatigue loading conditions and introduces new approaches for analyzing the fatigue performance of other materials.

Experimental and numerical validation of high strain rate impact response and progressive damage of 3D orthogonal woven composites

Advanced three-dimensional (3D) woven composites for aerospace and automotive applications are commonly subjected to complex dynamic environments involving vibrations and impacts, resulting in examining their impact properties is extremely important. This paper first experimentally discussed the influences of strain rates, weft yarn densities and loading directions on the impact performances and failure mechanisms of 3D orthogonal woven composites (3DOWCs). Secondly, full-scale finite element models were developed to predict the stress distribution and interfacial damage evolution process. The predictions were well in agreement with the experimental results. This research revealed that the impact characteristics exhibited strain rate sensitivity. With increasing weft yarn densities, the high strain rate impact behaviors also improved. Particularly, the warp impact strength of 3DOWCs with a weft yarn density of 2 yarn/cm (W5-2) at 812 s−1 was 17.4% and 24.0% higher than that of 3DOWCs with a weft yarn density of 1.5 yarn/cm (W5-1) at 822 s−1. Meanwhile, warp impact strength consistently exceeded to that of the weft impact strength. Additionally, strain rates, weft yarn densities, and loading directions dramatically affected the stress distribution and interfacial damage evolution process of 3DOWCs. Significant warp yarns fracture and matrix cracking were the principal failure patterns in the warp impact, whereas the damage in the weft impact was dominated by localized fracture of weft yarns and interfacial debonding.

Model-free chemomechanical interfaces: History-dependent damage under transient mass diffusion

This paper presents a data-driven framework based on distance functional for chemo-mechanical cohesive interfaces to capture transient diffusion and resulting interfacial damage evolution. The framework eliminates reliance on complex constitutive models and phenomenological assumptions, especially avoiding the coupling tangent terms with a given material database. The interfacial chemical potential and its jumps are used to expand the phase space for describing the chemical states of interfaces. Subsequently, a novel chemo-mechanical distance norm, including traction-separation pair, interfacial chemical potential-concentration pair and corresponding chemical potential jump-flux pair, is presented. Momentum conservation law for interfacial tractions and mass conservation law for interfacial concentration are enforced via Lagrange multipliers. For tracking the history-dependent state of the interface damage, an internal variable, termed interface integrity, is introduced to condition the interfacial database and manage the subsets mapping strategies, following physically motivated evolution constraints. Numerical examples are conducted to investigate the efficiency and capability of the present framework. A monotonic loading test validates a good numerical convergence relative to the number of data points. Subsequent cyclic loading simulations, compared with the reference solutions, show that the algorithm is well suitable to predict the history-dependent interface damage evolution under complex loading paths. Finally, the chemo-mechanically coupled examples capture phenomena such as interfacial swelling and interface degradation induced by transient diffusion and stress-driven diffusion. The current work provides a promising tool for understanding chemo-mechanical behaviors of interfaces within heterogeneous composites.

Conglomerate rock interface debonding characteristics and damage evolution based on cohesive phase-field method

Rock failure often occurs due to uneven mechanical strength and discontinuous strain at the interface. However, due to the complex interaction mechanism between different phases of conglomerate, it is necessary to improve the crack growth model at the conglomerates' interface. In view of the physical structure and mechanical properties of conglomerate materials, this paper innovatively adopts the cohesive phase field model to study the material deformation and crack growth of conglomerate materials. Different from the traditional phase field model, this model characterises the real structure of the interface by adding an interface phase field, which is used to simulate the debonding of the interface during crack propagation and damage evolution. The regularization of the phase field is carried out to ensure the smoothness of the interface. The transition state of the interface region is determined by the element and the additional phase field. The energy equation is coupled with the crack propagation process using the crack surface density function. The evolution of the damaged phase field and displacement field is driven by the principle of energy minimization. The innovative assumption is that there is a virtual crack at the crack tip, and the interface related elements show a certain cohesive softening form during the damage evolution, which is the main way to realize the particularity of interface mechanics. By controlling the crack dispersion state and stiffness degradation of the material, several ideal softening models are innovatively assumed according to the cohesive force change law to satisfy the mechanical properties and stress function constraints. When cutting blocks n=2.5×104, the errors of the linear model, exponential model, and compound inverse model are 1.76%, 7.48%, and 5.19%, respectively. The results of the exponential model agree well with the stress strength (the error is 2%) and interface crack kinking angle (68.89°). The simulation results indicate that the deformation process of the conglomerate can be divided into three stages: elastic deformation stage, crack propagation stage, and stable load stage. The tensile strength of conglomerate is positively correlated with interface's fracture toughness and proportion of gravel area, respectively.

Influence of interphase type and thickness on the interface properties and tensile damage evolution of C/SiC composites

In this paper, the influence of interphase type (i.e. single-phase (PyC) and co-deposited (PyC+SiC)) and thickness (i.e. 300, 600, 1000, and 2000 nm) on the interface properties and damage evolution of mini-C/SiC composites under cyclic loading/unloading tension was investigated. The micromechanical constitutive model was adopted to derive the damage parameter of inverse tangent modulus (ITM) and perform the hysteresis analysis to estimate the interface properties of the mini-C/SiC composites with large debonding energy. Experimental damage evolution of the ITMs with unloading or reloading stress was analyzed for different interphase types and thickness. The interface properties (e.g. the interface debonding stress and interface debonding energy) were obtained through the hysteresis analysis. Relationships between the loading/unloading ITMs, interface properties, and interphase type and thickness were established.

Cohesive Properties of Bimaterial Interfaces in Semiconductors: Experimental Study and Numerical Simulation Using an Inverse Cohesive Contact Approach.

Examining crack propagation at the interface of bimaterial components under various conditions is essential for improving the reliability of semiconductor designs. However, the fracture behavior of bimaterial interfaces has been relatively underexplored in the literature, particularly in terms of numerical predictions. Numerical simulations offer vital insights into the evolution of interfacial damage and stress distribution in wafers, showcasing their dependence on material properties. The lack of knowledge about specific interfaces poses a significant obstacle to the development of new products and necessitates active remediation for further progress. The objective of this paper is twofold: firstly, to experimentally investigate the behavior of bimaterial interfaces commonly found in semiconductors under quasi-static loading conditions, and secondly, to determine their respective interfacial cohesive properties using an inverse cohesive zone modeling approach. For this purpose, double cantilever beam specimens were manufactured that allow Mode I static fracture analysis of the interfaces. A compliance-based method was used to obtain the crack size during the tests and the Mode I energy release rate (GIc). Experimental results were utilized to simulate the behavior of different interfaces under specific test conditions in Abaqus. The simulation aimed to extract the interfacial cohesive contact properties of the studied bimaterial interfaces. These properties enable designers to predict the strength of the interfaces, particularly under Mode I loading conditions. To this extent, the cohesive zone modeling (CZM) assisted in defining the behavior of the damage propagation through the bimaterial interfaces. As a result, for the silicon-epoxy molding compound (EMC) interface, the results for maximum strength and GIc are, respectively, 26 MPa and 0.05 N/mm. The second interface tested consisted of polyimide and silicon oxide between the silicon and EMC layers, and the results obtained are 21.5 MPa for the maximum tensile strength and 0.02 N/mm for GIc. This study's findings aid in predicting and mitigating failure modes in the studied chip packaging. The insights offer directions for future research, focusing on enhancing material properties and exploring the impact of manufacturing parameters and temperature conditions on delamination in multilayer semiconductors.

Interface behaviour analysis of China railway track system Ⅱ slab ballastless track under temperature action and initial gap damage

The interface damage is considered to be one of the main diseases of China Railway Track System (CRTS) Ⅱ slab ballastless track, which will affect the long-term performance of the track structure and safety operation of high-speed trains. This study aims to reveal the interface damage mechanism between the track slab and the cement asphalt (CA) mortar layer of CRTS Ⅱ slab ballastless track, under different combinations of temperature actions and initial gap damage. A three-dimensional finite element model of CRTS Ⅱ slab ballastless track was established, in which a cohesive constitutive model was incorporated to simulate the interaction behavior of the interface. The interface damage evolution under different temperature actions and initial gap damage was analyzed. The analysis results show that: (1) Overall temperature has a more obvious effect on interface damage compared with temperature gradient, and the greater the overall temperature drops, the lower the decrease of interface damage will be; (2) When initial gap damage occur at the slab end, the growth rate of interface damage under temperature gradient is greater than that under overall temperature; The interface will begin to delaminate when the overall temperature drop reaches −50°C and the gap length becomes greater than one fastener spacing; and (3) When initial gap damage occur at the slab edge, the influence of overall temperature on interface damage is greater than that of temperature gradient; The interface gap damage reaches level II (according to TG/GW 115-2012) at the slab edge under the combination of −50°C and −50°C/m, while the slab center interface is unlikely to be damaged under negative temperature.

Mechanics, damage and energy degradation of rock-concrete interfaces exposed to high temperature during cyclic shear

Shear properties of the rock-concrete interface are critical to the stability of deep underground engineering projects, particularly in high-temperature environments caused by geothermal activity, fire or nuclear waste radiation. A series of cyclic shear tests were performed on the pre-heated sandstone-concrete interface under both CNL and CNS conditions. The study carefully examined the degradation characteristics of shear mechanics, as well as the evolution of interfacial damage and energy, during cyclic shear of rock-concrete interface. The experimental results show that the pre-heating temperature and the number of shear cycles have considerable effects on the adhesion, shear strength, normal deformation, shear stiffness and friction coefficient of the sandstone-concrete interface, especially under CNS conditions. Furthermore, the nonlinear evolution of interfacial damage and energy release during cyclic shear is highly dependent on the pre-heating temperature. These test results provide valuable insights for revealing the mechanical degradation and evaluating the shear performance of rock-concrete interfaces in deep underground engineering projects subjected to high-temperature environments.

The influence of geometric characteristic on the pullout behavior of basalt FRP minibar embedded in concrete

AbstractWith the increasing demand on structural toughness and energy absorption capacity, the addition of fiber to concrete has become an issue of significance. This paper studies the bond behavior of Basalt FRP (BFRP) minibar with straight, twisted and crimped geometric characteristics. The failure modes, pullout curves and bond strength were compared, and their interface degradation, damage evolution and failure mechanism between single fiber and concrete matrix were analyzed. Additionally, commercial steel fibers and polypropylene fibers were compared with the BFRP minibars to clarify the effect of fiber type on failure morphology, bond strength and interface properties. The results showed that the pulling out process for straight BFRP minibars, twisted BFRP minibars and crimped BFRP minibars was constituted by the elastic bonding stage, the partial de‐bonding stage, the complete de‐bonding stage and the pullout of fiber. The bond strength was composed of chemical adhesion and mechanical bond, where the mechanical bond play important role after the initial failure of chemical adhesion. The bond strength of crimped BFRP minibar, the hooked steel fiber, the indented polypropylene fibers and the twisted BFRP minibar were enhanced by 358%, 324%, 115%, and 54.5% compared to straight BFRP minibars. The interface bonding strengths improve with the increase of matrix strength. Dense microstructures of matrix improve the bond strength. The bond‐slip constitutive model was proposed for crimped, twisted and straight BFRP minibars with regression coefficient of 0.978, 0.891, and 0.992, respectively.Highlights Influence of fiber geometry and concrete strength on the pullout behavior Interface degradation, damage evolution and failure mechanism between minibar and concrete Bond‐slip constitutive model of straight, twisted and crimped BFRP minibars

Micromechanism-based chemo-mechanical cohesive model for polymer interface under transient chemical mass diffusion

This paper presents a fully coupled thermodynamically consistent chemo-mechanical cohesive zone model for polymer interfaces subjected to a chemo-mechanical environment. A bond-chain-interface method is exploited to describe the macroscopically interfacial performances controlled by the chemical reaction extent and the microscopic properties of interface. The energetics of bond stretching and the coupling between reactive-diffusive mechanisms and mechanics at the polymer interface are taken into account. The cohesive zone model is implemented using finite element method software ABAQUS through UEL subroutines. The numerical simulation with the cohesive element is directly compared to a single lap shear experiment for chemo-mechanical fracture of a bio-inspired polymer interface. Besides, a particularly numerical example including the chemical diffusion and compression case is conducted, it clearly shows the proposed model can capture the features of shear flux and stress-driven diffusion, which verifies the completeness of the chemo-mechanical interface theory. Finally, a parametric analysis is conducted to assess the influences of critical bond stretch, areal chain density and chemical reaction rate on the evolution of interfacial damage and rate of chemical diffusion. The model also accounts for the phenomenon where a strong polymer interface effectively restricts chemical diffusion across an interface. This research provides a novel investigative tool to study chemo-mechanical fracture of polymer interfaces, with potential applications in materials science and engineering.

Study on the interface damage of CRTS II track slab under high- and low-temperature cycles based on acoustic emission

China Railway Track System (CRTS) II slab tracks have been widely used in high-speed railway construction. Interface debonding between the track slab and cement-emulsified asphalt (CA) mortar is one of the typical diseases of the CRTS II slab tracks. Properly evaluating the interfacial strength of the track slab and CA mortar under high- and low-temperature cycles is crucial for optimizing the repair in engineering practices. In this study, the track slab and CA mortar (TSCAM) composite specimens were prepared for high-low temperature cycle (HLTC) tests. Then, the shear and tensile tests were carried out to study the interlayer bonding properties of TSCAM under different HLTCs. In addition, the acoustic emission (AE) technique was employed to monitor the signals generated in the specimen during the tests. Furthermore, the AE parameters were analyzed, including ringing counts, energy, b-value and amplitude-frequency. The results show that the number of HLTCs significantly contributed to the deterioration of the interface bond strength between the track slab and the CA mortar. The interface normal bond strength showed a higher decrease than the tangential bond strength with the increase of HLTCs. In addition, the relationships of the shear and tensile bond strength of the TSCAM composite specimen with HLTC were deduced. The tangential and normal bond strength degradation properties of the composite were well fitted by the function of quadratic polynomial and power exponents, respectively. The AE activities of the composite specimens in the shear and tensile tests were gradually reduced with increased HLTC. The AE signals were the strongest when the specimen failed along the interface. Furthermore, the intensity of AE events during the shear test was higher than that during the tensile test under the same HLTC. The overall b-values of the shear and tensile specimens without HLTC were the largest and did not change significantly with the increase of HLTC. The amplitude range of the peak frequency gradually decreased as the HLTC increased. The amplitude and peak frequency of the tensile test was smaller than that of the shear test under the same HLTC. This indicates that the AE technique can monitor the interface damage evolution pattern of the TSCAM composite specimen throughout the tests.

Interfacial thermal damage and fatigue between auxetic honeycomb sandwich and underneath substrate

A general model to evaluate the interfacial thermal damage and predict the fatigue life of the auxetic honeycomb-substrate structure (H-SS) is built. To improve the accuracy, all material parameters in the model are temperature-dependent. The transient temperature field and the associated thermal stresses associated with the temperature changes in the structure are determined by the finite difference method. The interfacial thermal stress intensity factor is employed to characterize the stress concentration behavior. Based on the stress field and the stress concentrations at the interface, interfacial thermal damage evolution and fatigue life prediction of the structure are made. The results show that the auxetic property can significantly enhance the fatigue life of the structure. The fatigue life will be undervalued when the effect of temperature-dependent material properties (TDMPs) is neglected. Furthermore, the influence of TDMPs on the fatigue life of the structure will increase as the absolute value of the internal cell angle increases. This paper provides a comprehensive assessment of the thermal damage and fatigue life of auxetic H-SSs and can serve as a solid theoretical foundation for future applications of related structures in extreme temperature environments.

Thermal arching and interfacial damage evolution of CRTS-II slab track under solar radiation in alpine and plateau regions

Arch deformation and interface failure of CRTS-II slab track have become crucial issues for the operation safety of high-speed railways. However, few researchers investigated the mechanics and deformation behaviour on CRTS-II slab track exposed to high-altitude plateau climatic environments. This study proposes an analysis approach for thermal arching and interface damage evolution of the slab track structure under solar radiation in alpine and plateau environments. The time-dependent solar temperature distribution is loaded on the refined finite element model (FEM) of the slab track structure’s thermal deformation in high-altitude plateau climatic environments. The analysis approach is validated by comparing the calculated and experimental data. The track slab's maximum and minimum vertical temperature gradient (VTG) are 94.49 °C/m and −45.02 °C/m, respectively. The narrow joint damage is an incentive for the inverted V-shaped thermal arching and interface separation of the slab track structure under solar radiation. The interfacial gap of slab track structure in alpine and plateau regions reaches more than 14 mm during summer. The proposed analysis approach is a valuable reference to the construction temperature, maintenance, and damage monitoring of slab track structure in alpine and plateau regions.

On accurate characterization of interfacial morphology and damage evolution of thermoplastic composite welded joints: A microscale study via in-situ micro-CT

Thermoplastic composites are regarded as a potential alternative to their thermoset counterparts in aircraft industries owing to their cost-effective manufacturing process and weldability. However, one of the most significant limitations of the currently used evaluation methods for the welded joints is that they are mostly destructive, which makes the loss of information on the initial features of the welding interface. In this study, the interfacial morphology and damage evolution of ultrasonic welded GF/PPS thermoplastic composite joints were accurately characterized by using in-situ micro-CT technique. The morphology of the weldline was demonstrated by the evolution of void defects, fibre architecture and resin contents of specimens created using different sonotrode travels. Based on that, the damage evolution scenario of the specimens welded at 40% and 100% travels was successively analysed via in-situ micro-CT analysis. In the final part, the newly proposed technique was comparatively discussed with the traditional characterization methods.

Numerical simulation on damage behaviors of tile-mortar interface induced by mortar shrinkage and temperature cycles

In this study, the initiation and evolution of interfacial damage between tile and mortar induced by mortar shrinkage, temperature cycles and their coupling actions were investigated and compared based on a novel fatigue cohesive zone model for the first time. Firstly, the fatigue cohesive zone model was established by coupling a bi-linear cohesive zone model with a fatigue damage evolution model and verified by comparing with experimental values. Then, the deformations and stresses at tile-mortar interface under various scenarios of mortar shrinkage and temperature cycles were calculated. Finally, the interfacial damage characteristics were systematically studied in terms of three indices including damage degree, damage area and debonding area. Results showed that a larger shrinkage of mortar brought about a higher relative movement and stronger interfacial stress, thereby accelerating the propagation of interfacial damage from the rim to the center. In the case of considerably low mortar shrinkage, the interfacial relative deformations were too low to provoke any interfacial damage. The increases of temperature amplitudes promoted the accumulation and propagation of interfacial damage, causing an earlier appearance of debonding. The effects of cooling cycles were much greater than those of heating cycles. The damage degrees induced by cooling cycles were equivalent to those by mortar shrinkage in certain cases. Although considerably low shrinkage failed to initiate interfacial damage, its coupling with temperature cycles significantly aggravated interfacial damage, in particular for debonding area remarkably increased after 1000 cooling cycles.

Accurate simulation on the forming and failure processes of fiber metal laminates: A review

Fiber metal laminates (FMLs) are a kind of composite material prepared by alternately arranging fiber layers and metal sheets at a certain temperature and pressure. It has been widely used in aerospace and automobile transportation for its excellent combined mechanical properties. For the forming and failure processes of FMLs, the interfacial behavior and damage evolution of components are hard to be observed experimentally. Therefore, it is of great importance to simulate them accurately. In this article, the development and application of FMLs were first introduced. Then the comparison of constitutive models in FMLs simulation was given, especially the dynamic constitutive model applied to the metal layer. After that, the important aspects of damage evolution, interface behavior, and model optimization in the simulation on the forming and failure process of FMLs were analyzed, and the emphasis is on the nonlinear progressive damage model of different materials, the construction of cohesive zone model and superior meshing methods. Furthermore, the experimental verifications of FMLs simulation were given. It is shown that the deformation behavior and damage characteristics of various kinds of FMLs during forming and failure processing can be accurately predicted by reasonable numerical simulation. Eventually, the future outlooks for numerical simulation of FMLs was proposed. Through this review, scholars and engineers who are interested in FMLs can systematically understand the numerical simulation work of FMLs, which is helpful in improving the quality of research in this field.

EMI-based interfacial damage evolution of CFRP plates-strengthened RC beams under low-cycle fatigue loading and wetting/drying cycles

EMI-based interfacial damage evolution of CFRP plates-strengthened RC beams under low-cycle fatigue loading and wetting/drying cycles

A multiscale model integrating artificial neural networks for failure prediction in turbine blade coatings

The failure prediction of turbine blade coatings remains a significant challenge due to complex microstructure and multiphysics failure mechanisms. A multiscale life prediction model integrating artificial neural networks was developed, which considers the failure mechanism of oxidation, creep and thermal mismatch in microscale, and the combined effect of gas and coolant conditions, film cooling and TBCs in macroscale. The model exhibits better prediction accuracy on interface oxidation, damage evolution and failure region of TBCs on turbine vane. Based on the model, the coupled effect of thermal, oxide growth and thermal mismatch on TBCs failure of turbine vane is discovered.

Terahertz data analytics-based bonding interface damage characterization in a multilayer structural composites under cyclic loading

Adhesively-bonded composite structures are under various environmental loads during their service life. Therefore, it is imperative to monitor the evolution of the bonding interfaces under loading to evaluate the bonding properties of the composite structures. A terahertz (THz) quantitative characterization method is proposed based on the scale invariant feature transform (SIFT) image matching algorithm. The terahertz data for the bonding interface before and after loading were obtained using a terahertz time-domain spectroscopy system along with the flight time imaging of the bonding interface. The imaging results of the bonding interface before and after loading were matched by SIFT image processing technology, and the THz flight time difference was obtained using differential calculations to characterize the thickness change of the bonding interface. Furthermore, the initiation and development of interface damage were studied, and the changes in the bonding interface thickness and debonding damage state under the cyclic loading tests were analyzed, providing information on the growth of the damaged area and damage severity. The results show that the proposed method can ultimately realize the characterization of the thickness changes and the evolution of the debonding damages at the interface of the bonded composite structures under cyclic stress, thus circumventing the shortcomings of the conventional damage-evolution characterization methods. The findings can also provide helpful insights into the effect of stress load on the bonding interface damage evolution for the studied system.

Mushroom-Shaped Micropillar With a Maximum Pull-Off Force

Abstract The bioinspired structure of the mushroom-shaped micropillar has been considered a blueprint of functionalized adhesives due to its prominent dry adhesive performance. Among the design strategies, the geometrical parameters of the stalk and tip are of significance for improving their adhesion performance. In this study, mushroom-shaped micropillars in different diameters of the stalk and tip are fabricated by a new fabrication approach, and the adhesion measurements are performed to study the influences of loading conditions and geometrical parameters on the pull-off force. The experimental and numerical results suggest that the stalk and tip diameters strongly affect the interfacial detachment behavior and the pull-off force. Two detachment modes are distinguished by the positions of the crack initiation. Finite elemental analyses reveal the detachment mechanisms by the interfacial stress distribution and damage evolution. According to the detachment mechanisms, a structure design strategy for mushroom-shaped micropillar with maximum pull-off force is proposed. The present studies provide a fresh insight into the adhesion behaviors of mushroom-shaped micropillars and contribute to the future adhesive design.