Failure Mechanisms Of Structures Research Articles

Theoretical study on progressive collapse of truss string structures under cable rupture

Cables are critical components of truss string structures and cable failure can cause serious damage to the structure or even progressive collapse. However, little theoretical research work deals with this phenomenon. In this study, a rapid analysis method for the progressive collapse of truss string structures based on the nonlinear buckling material model was proposed. The results showed that the rapid analysis method could reduce the computational time by at least 30% and effectively improve computational efficiency. Based on the validated rapid analysis method, the progressive collapse failure mechanism of truss string structures under cable rupture was analyzed. The results showed that progressive collapse failure mechanisms could be divided into two categories. In one category, compression buckling of the upper chord member leads to a loss of load capacity and a rapid increase in deflection without convergence, resulting in progressive collapse of the structure. In the other category, tensile yielding of the lower chord member results in a gradual loss of stiffness and a slow increase in deflection without convergence, leading to progressive collapse of the structure. Moreover, a series of assumptions and simplifications were made, followed by the establishment of calculation equations for the progressive collapse load capacity and deflection of truss string structures under cable rupture. By comparing the theoretical values with the finite element values as well as test values, the accuracy of the equations proposed in this study for calculating the progressive collapse load capacity and deflection of truss string structures was verified.

In-plane flexural behavior of hollow brick masonry walls with horizontal holes

Recent seismic events proved that buildings built with hollow brick masonry walls performed quite poorly when subjected to horizontal actions. To provide insights, an experimental study was conducted to evaluate the flexural behavior of existing slender masonry walls built with clay hollow bricks with horizontal holes and cement-based mortar. Two full-scale specimens were designed and built to exhibit an in-plane rocking behavior when subjected to cyclic horizontal loads such as those induced by an earthquake; the pivotal aim of the experimental test is to assess the actual ductility of such a mechanism for this specific wall typology. The test results show that, unlike other masonry wall typologies exhibiting ductility in the case of in-plane flexural mechanism, this construction typology performs quite poorly under horizontal loads also in the case of rocking, with very little deformation capacity, which reduces by increasing the compressive strength of the mortar. A sudden failure was observed for quite reduced drifts in the experimental tests; failure was associated with the brittle crushing of the pier toe, in which compressive stresses were concentrated. The brittle collapse mechanism also entails the inability of the wall to further sustain the vertical loads, once the ultimate in-plane flexural capacity is reached. A numerical study was carried out; the finite element model was validated against the experimental results. The comparative assessment showed that the finite element model accurately predicts the structural behavior, lateral strength, and failure mechanism of the specimens. Parametric analyses on the validated finite element model (FEM) were carried out to further investigate the structural behavior of different wall layouts or mechanical properties. Finally, a simplified bilinear behavior-curve is proposed to model the flexural response of slender walls, which can be specifically implemented when addressing an equivalent frame approach in the seismic vulnerability assessment of existing buildings built with the analyzed construction typology.

The effect of rock hardness and integrity on the failure mechanism of mortar bolt composite structure in a jointed rock mass

The appearance of joints in the rock tunnels makes the rock mass show obvious anisotropy and discontinuity in physical and mechanical properties, which has a significant influence on the rock mass stability. As one of the normally used support structures in tunnel construction, Mortar bolts will inevitably pass through the joints during the process. Both rock hardness and rock mass integrity will directly affect the anchorage performance of mortar bolts in joint rock. Considering this, this paper designs a mortar bolt pull-out experiment to investigate the joint rock failure modes and bolt-grout composite structure failure modes under different conditions of rock hardness and rock mass integrity. By taking the two influencing factors of rock hardness and integrity into account, the calculation formulas of ultimate pull-out load and ultimate displacement of mortar bolts in joint rock are established and proposed.

A Review on Structural Failure of Composite Pressure Hulls in Deep Sea

With the increasing application and study of lightweight and high strength fiber reinforced polymer composites in ocean industry, the structural failure problem of composite pressure hulls has attracted great attention from many researchers in China and globally. Analysis of the structural failure mechanisms is foundational to the design of deep-sea composite pressure hulls, since nowadays the design rules of pressurized vessels is mostly formulated according to their failure modes. Hence, this paper aims to review the research on the structural failure of composite pressure hulls in deep sea settings. First of all, the applied research status on composite material in marine equipment is analyzed, including inspection modalities for composite pressure hulls. The review then focuses on the three main failure modes, namely overall buckling, material failure and snap buckling of the deep-sea composite pressure hulls. The study identifies further problems of composite pressure hulls to be solved through the application of the deep sea equipment research, aiming to provide a reference for the study of mechanical behavior, ultimate strength computation, and design of thick composite pressure hulls for deep sea equipment.

Numerical Studies on Failure Mechanisms of All-Composite Sandwich Structure with Honeycomb Core under Compression and Impact Loading Conditions.

The all-composite sandwich structure with the honeycomb core is a lightweight and high-strength structure with broad application scenarios. The face sheet and honeycomb core of the proposed all-composite sandwich structure in this work are composed of carbon-fiber-reinforced polymer (CFRP) composites. The mechanical response and damage mechanism of the all-composite sandwich structure under out-of-plane quasi-static compression and out-of-plane impact are studied by numerical methods. The refined finite element models of the sandwich structures are built on the ABAQUS/Explicit platform. The micromechanics of failure (MMF) theory based on physical component failure is used to describe the intralaminar damage mechanism of the face sheet and honeycomb core, and the mixed-mode exponential cohesive zone model (ECZM) is utilized to simulate the initiation and evolution of interlayer damage. In addition, the cohesive contact approach is adopted to capture the debonding failure at the face-sheet/core. The numerical results show that the all-composite sandwich structure has the characteristics of large structural stiffness and strong energy absorption ability. The failure mechanism of the all-composite sandwich structure under compression is mainly matrix damage and delamination of the honeycomb core, with buckling and folding in appearance. Under out-of-plane impact, matrix damage and delamination arise on the upper sheet, little damage is observed on the lower sheet, and the delamination damage morphology tends to be circular with increasing impact energy. In addition, the interface failure of the upper-sheet/core is more than that of the lower-sheet/core. In addition, the matrix damage near the impact center of the honeycomb core tends to be consistent with the delamination contour, and a small amount of fiber failure is also observed, which manifests as a collapse morphology of the impact area. The research results enrich the understanding of the mechanical behavior of all-composite sandwich structures with honeycomb cores and provide theoretical support for their potential applications.

Experimental research on performance degradation of TSV microstructure under thermal cycling, vibration and electrical stress

Through‑silicon-via (TSV) microstructure is the key structure of 3D integrated packaging, and its reliability during service plays a very important role in the long-term reliable operation of the chip. However, the failure mechanism and reliability evaluation of the TSV structure in the service process of the chip have not been fully elucidated. Chips inevitably bear various stresses during the service process, such as thermal stress, vibration stress, electrical stress, etc. In this paper, a TSV reliability test chip that can be easily loaded with various stresses was designed first, and the resistivity of the TSV microstructure was tested. It is found that the resistivity of TSV has a significant scale effect. Then, thermal cycling, vibration and electromigration tests were carried out, and the failure mode, performance degradation trend and failure distribution of TSV microstructure under thermal cycling, vibration and electrical stress were analyzed. Finally, the failure analysis of the tested chip was carried out by scanning electron microscope (SEM) and high-resolution industrial micro-CT, and the potential failure mechanism were analyzed and discussed.

A Finite Element Analysis of Tunnel Lining Demolition by Blasting for Subway Tunnel Expansion

In this paper, a practical project of subway tunnel lining demolition via blasting for the construction of a subway station under the action of the blasting load and the weight of collapsed rock mass was proposed. The tunnel overbreak and underbreak quality, the failure mechanism of the tunnel lining structure, the particle peak velocity (PPV), and the stress evolution law of the surrounding rock caused by tunnel blasting were researched using LS-DYNA. Firstly, the results show that the blasting parameters presented in this paper can maintain the cross-section of a smooth outline of tunnel excavation and the overbreak or underbreak quality in control. Secondly, the tensile stress in the existing tunnel lining caused by blasting exceeded the concrete tensile strength, and the radius of the burst fracture was 0.86 m, which is greater than the thickness of the tunnel lining (0.7 m). Thirdly, the blasting stress in the surrounding rock peaked within 0.1 × 10−3 s after the blasting, and failure of the surrounding rock occurred. Moreover, the relationship between the PPV and the distance from the blasting center shows that the blasting parameters used in this paper can effectively control the PPV. Therefore, this study reveals that the expansion of existing tunnels into subway stations using this method can improve the efficiency of construction.

Numerical analysis of deformation and failure mechanism of metal truss structure of spacecraft under re-entry aerothermodynamic environment

A coupled aerodynamic-thermoelastic analysis framework is presented to simulate the deformation and failure mechanism of metal truss structure for spacecraft under re-entry aerothermodynamic environment. The three-dimensional dynamic thermo-mechanical coupling finite element algorithm is developed by computable modeling of thermoelasticity and heat conduction equations to solve the thermo-mechanical coupling response of spacecraft structure. The aerodynamic boundary conditions such as temperature, heat flux and pressure distribution are computed and provided by the gas-kinetic unified algorithm (GKUA) based on the Boltzmann model equation. The linear interpolation method is designed and employed to couple the boundary conditions between the external aerodynamic flow field and the solid structure interface. The present thermo-mechanical coupling algorithm is verified on one-dimensional and two-dimensional transient heat flow problems with analytical solutions, and good consistency is achieved. The reliability of the GKUA for solving the boundary conditions of the external flow field and the dynamic thermo-mechanical coupling algorithm for the thermal response behavior of the internal structure material is verified by the consistency calculation of the internal and external temperature distribution. Then, the aerodynamic-thermoelastic analysis framework is further applied to study the deformation behavior of structural thermo-mechanical responses and failure mechanism of a hollow sphere under re-entry aerothermodynamic environment with emphasis placed on the influence of flight speeds, rarefied effects, algorithm schemes and damping effects. The numerical results obtained by the presented algorithm including the internal temperature, thermal stress and deformation distribution law are compared and analyzed. Finally, the deformation and failure mechanism of spacecraft structure during re-entry process are solved and analyzed by the present algorithm framework. The displacement, temperature and stress distribution contours of the structure are presented to make a preliminary understanding and evaluation on the process of spacecraft deformation and failure disintegration. It is indicated that the present coupled aerodynamic-thermoelastic analysis framework can provide a reliable, applicable and efficient platform for the thermo-mechanical coupling responses and failure mechanism of re-entry spacecraft in the end of life.

Effect of biochemical attack on the mechanical performance of used concrete sewer pipes

The structural response and failure mechanisms of 35 used concrete sewer pipes are investigated by means of a combined experimental–numerical approach, whereby specific attention focuses on determining the effect by biochemical attack. Accordingly, the degree of degradation of the inner and outer surfaces of the pipes is carefully analysed by visual inspection, and subsequently categorized in 6 different surface condition classes. The type and degree of biochemical attack are determined by respectively performing X-ray diffraction analyses and phenolphthalein tests. The sewer pipes, which vary in age, size and geometry, are subjected to biaxial loading conditions in a full-scale test set-up. The experiments show that the material degradation of relatively old sewer pipes can be considerable, and for a large part may be attributed to the process of biogenic sulphide corrosion. This process typically induces a weak, corroded layer at the inside of the pipe, which is characterized by the appearance of exposed granulates and porous mortar between the granulates. The experimental failure responses of the used sewer pipes are compared against numerical results obtained from detailed Finite Element Method (FEM) simulations. The failure response of each sewer pipe type is well predicted by the FEM model if the negligible mechanical properties of the biogenic sulphide corrosion layer at the inside of the pipe are accounted for in the simulations. The relatively low concrete tensile strength of old sewer pipes and the reduced effective wall thickness due to biogenic sulphide corrosion cause that the ultimate bearing strength and structural stiffness of these pipes may be more than a factor of two lower than those of completely new sewer pipes. The results of the present work provide a scientific basis for the decision-making process on sewer rehabilitation and replacement, in particular by revealing and quantifying the influence on the structural bearing strength by biogenic sulphide corrosion. • Structural response and failure mechanisms of 35 used concrete sewer pipes are investigated via a combined experimental–numerical approach. • Effect of biochemical attack on bearing strength is quantified. • Mechanical collapse of sewer pipes is characterized by the development of 4 failure cracks. • Results provide a scientific basis for decision-making process on sewer rehabilitation and replacement.

Experimental and numerical study on the ballistic impact resistance of the CFRP sandwich panel with the X-frame cores

Fiber reinforced composite sandwich structures have wide applications in reducing the weight of high-speed aircrafts due to their processibility and high specific performance. It is of great significance for the safety to study the failure mechanism of composite sandwich structures under the ballistic impact and improve the structural impact resistance. However, the previous researches mainly focus on the performance of the hybrid sandwich structures with foam cores or metal grid cores. The main novelty of this study is to investigate the ballistic impact resistance of a composite composite sandwich panel with the fiber reinforced X-frame cores by using the projectile impact tests and numerical simulations. The impact resistance of this integrally molded fiber reinforced cores is less reported and is expected to be superior than that of the common aluminum, polymer and foam cores. For comparison, the carbon fiber composite cross-ply laminates with the identical areal density and the foam reinforced sandwich panels with the X-frame are tested. The experimental results indicate that the ballistic limit of the X-frame sandwich panel is similar to that of its equivalent laminate under the normal projectile penetration. Filling foams increase the structural ballistic limit velocity and energy absorbing amount by 18.2% and 33.9%, respectively. The widest range of fiber breakage and delamination on the sandwich panel observed appear at impact velocities approaching the ballistic limit, while the local damage is found under the high-speed perforation. The numerical results indicate that the projectile kinetic energy dissipated by the X-frame core accounts for over 50% of the total under the normal impact and the core has the better specific energy absorption capacity than the skins. The impact oblique angle and impact position are found to have a significant effect on the impact resistance of the X-frame sandwich panel through the numerical calculations.

Strength analysis of composite envelope structures considering the tension–shear coupling and cutting pattern effect

Various strength criteria have been extensively used in the structural design of stratospheric airships. However, it is still a critical challenge to accurately predict the failure strength for ensuring structural safety due to the complex mechanical behaviors of multi-layer composite envelope materials under various loading environments. This article thus aims to establish refined numerical models for the strength prediction of envelope structures. Firstly, the mechanical properties of envelope materials were tested and investigated comprehensively. The creative concept of tension–shear​ coupling is demonstrated by the shear constitutive relation and failure criterion. Secondly, with consideration of the cutting pattern effect originating from the manufacturing procedure, a new equal-diameter flattening method for cutting gores is proposed. Finally, inflation-bursting tests of spherical and ellipsoidal envelopes were conducted to validate the proposed refined numerical models. The maximum deviation of strengths predicted by the novel criterion is less than 8% for both envelope structures, indicating that the tension–shear effect plays a significant role in the failure mechanism of flexible thin-walled envelope structures.

Fabrication method and dynamic responses of composite sandwich structure with reentrant honeycomb cores

Composite sandwich structure with reentrant honeycomb cores was fabricated using a novel manufacturing method. The dynamic responses and failure mechanism of composite sandwich structure with reentrant honeycomb cores subjected to impulsive loading were experimentally and numerically investigated. Foam aluminum projectile impact experiments of sandwich structures with different relative densities were carried out under different impulsive loads. The effects of the relative density and impulsive loading on the dynamic response, failure mechanism and the deformation response of rear face sheets were analyzed and discussed. The experimental results demonstrated that the sandwich structure with higher relative density has better impact resistance. The finite element model for composite sandwich structure with reentrant honeycomb cores was constructed, the numerical simulation results were in good agreement with the experimental results. Both experimental and numerical results showed that the reentrant honeycomb cores underwent obvious negative Poisson's ratio deformation under impacting.

3D numerical investigation on response of shield tunnel under combined effects of fire and structural loading

As a significant infrastructure hazard, fires in tunnels have brought about a great deal of economic and social losses each year. From a holistic tunneling design perspective, it is essential to predict accurately the displacements and internal forces of the lining under coupled effects of elevated temperatures and various loading conditions. To this end, an elaborate three-dimensional (3D) numerical model, which incorporated the concrete segments, reinforcing rebars and connecting bolts, was established to investigate the deformation and failure mechanism of the segmental ring in shield tunnels under coupled effects of fire and structural loading. The validation based on the experimental results of segment lining and joints shows that the established model can be employed to analyze the entire tunnel ring structures. Two types of numerical models, i.e., single-ring and three-ring models, were established and the thermo-mechanical coupled performance were examined. Based on the verified model, the general temperature field and deformation distribution were described and elaborated. With respect to the significant insights on mechanical behaviors of shield tunnel rings in fire, the results of inner force redistribution, the joint opening elaboration and the failure mechanism of the shield tunnel structure under fire effects and initial loadings were further discussed. The results of this study can provide valuable guidance for the fire resistance design in the tunnel.

Energy Absorption Characteristics and Failure Mechanism of Fabric Composite Channel Section Structure under Axial Crushing Loading

A nonlinear progressive damage model was adopted to study the energy absorption mechanism of fabric composite channel section structures under axial quasi-static crushing loading. Based on continuous damage mechanics (CDM), intralayer and interlayer failure were initiated by the maximum stress and quadratic nominal stress criteria, respectively. The damage process of the material is described using the progressive damage evolution law based on the stiffness degradation method. The different failure modes exhibited by the composite channel section structure under different crushing displacements are analyzed in detail. The effects of geometric sizes and stacking sequences on the initial peak value, specific energy absorption (SEA), mean load, and failure mode are analyzed and discussed. The results show that thickness has a positive effect on the specific energy absorption and induces progressive failure of the structure. The initial peak force is a positive correlation function with respect to thickness and flange length. The flange length and stacking sequence have a significant effect on the crushing load response of the structure, and a reasonable stacking sequence can improve the crushing behavior of the structure.

Corrosion reaction kinetics and high‐temperature corrosion testing of contact element strips in ultra‐high voltage bushing based on the phase‐field method

For the structural characteristics of power transmission equipment such as bushings, the plug-in structure is mostly used for current-carrying connections owing to the large size and long distance at high voltage levels. The contact element strip is the key component of the current-carrying structure, carrying the combined electrical–thermal effect. Its electrical current-carrying performance is important. In recent years, discharge failures caused by the overheating failure of electrical connections have occurred from time to time. However, there have been relatively few studies on the failure mechanism of the electrical connection structures of high-voltage power transmission equipment, such as bushings. In this study, from the perspective of corrosion reaction kinetics, a two-dimensional phase-field model of high-temperature corrosion is established to obtain the carrier concentration distribution in the film. The effects of temperature, gas partial pressure, film thickness, and applied electric field on the growth rate of corrosion reaction film were calculated using the finite element method. At the same time, with the contact element strips used in the bushing as the test object, a corrosion test was carried out in SF6 atmosphere to simulate the high-temperature corrosion caused by the uneven current carrying of the contacts in actual operating conditions. Combined with the effect of temperature on the film growth rate, the contact area was the most severely corroded location. The simulation can provide a qualitative analysis for the contact degradation test and a new method for studying the factors affecting the corrosion mechanism of contact element strips.

High-speed multi-camera 3D DIC measurement of the deformation of cassette structure with large shaking table

Vision-based deformation measurement methods have been proposed to overcome the disadvantages of laborious, time-consuming measurement data that are difficult to accurately obtain using contact sensors in three directions. However, such methods remain a challenge for large-scale applications owing to difficulties in full-field imaging, stereo calibration, and measurement resolution, among other factors. To the best of our knowledge, there are no reports on the three-dimensional (3D) full-field measurement of a large shaking table structure with multiple cameras. In this paper, a multi-camera 3D DIC method using four high-speed cameras to measure the multi-layer structure model in a shaking table is proposed. To calibrate the stereo cameras with a large field of view, a speckle-based calibration method and a coordinate system unification method are proposed. The implementation of the proposed method is illustrated with a shaking table test for a 1/8 scaled 15-story high-rise cassette concrete structure with several different intensity levels of ground motions. The results of displacement, velocity, and acceleration of the structure measured using the proposed method correspond well with those of a laser displacement meter and accelerometer. The experiment results show that this method can guarantee full-field measurements in the range of tens of square meters and realize a sub-millimeter displacement measurement accuracy. They also indicate that the proposed multi-camera 3D DIC method has high potential for understanding the failure mechanism of structures and improving the structural design.

Thermo-mechanical performance of 3D-printed TC4 hierarchical lattice-truss-core sandwich structures in high temperature conditions

Hierarchical lattice-truss-core sandwich structures have attracted increasing attention by virtue of superior performance in both mechanical properties and lightweight hierarchy topology. However, little work has been reported about the thermo-mechanical responses of such emerging structures. In this research, the effects of high temperature on the out-of-plane compressive properties and failure mechanisms of 3D-printed hierarchical lattice structures are experimentally and numerically investigated. Based on a single-stage pyramidal sandwich structure (P), two kinds of sandwich structures consisting of hierarchical pyramidal truss cores are designed: pyramidal-hollow (PH) and pyramidal-cylinder (PC), all kinds of the structures are integrally fabricated by 3D printing technique of titanium alloy (TC4). The thermo-mechanical coupling and responses during compression are experimentally evaluated from 25 °C to a high temperature of 350 °C. The relevant numerical simulations are carried out by finite element analysis (FEA), which are in well agreement with experimental measurements. It is evident that, compared with the single-stage lattice plate with a same weight, the 3D printed PC-1 type hierarchical configuration has a 131.93% increment in the internal heat-transfer area. Meanwhile, it has a 19.31% and a 26.58% increment in bearing capacity at room and high temperature, respectively. The superior integrated load-bearing and heat shielding efficiency are elucidated through the systematical analysis of the influence of hierarchical design on detrimental failure modes under high temperature: buckling and mixed buckling-plastic fracture of the basic and secondary hierarchy. This work could provide a fundamental knowledge for the future design of lightweight structures with thermo-mechanical superiority in high temperature conditions, such as hypersonic flight vehicles scenarios.

Predicting the failure mechanism of RC slabs under combined blast and impact loading

The dynamic structural behaviour and failure mechanisms of the reinforced concrete (RC) slabs under the combined blast and impact loading is numerically evaluated using the software LS-DYNA. The developed material model for concrete includes the plasticity behaviour under dynamic loading. The developed model includes the modified equation of state (EOS) which accounts for the loss of cohesive property and increase in compaction strength of the concrete material. The failure surface includes the effect of strain rate along with the lode angle and damage variable. The behaviour of concrete at low and high hydrostatic pressure is predicted with the developed model. The model has been formulated using a user-defined material model (UMAT). The predictions of the developed UMAT and in-built Winfrith concrete model (WCM) is compared with experimental results available in the literature. The developed concrete model can predict the failure mechanisms and the dynamic response of the slab accurately when compared with the results of WCM. Only limited experiments are available on the behaviour of RC slabs under combined blast and impact loading. Hence, the validation for analysis of the impact and blast loading scenario is carried out separately with the experimental results. The performance under the combined loading scenario is analysed by varying the sequence of applying the impact and blast loads. The slab subjected to impact-blast loading showed an increased dynamic response. The slab shows severe spallation, scabbing because of the flexural shear mode of failure caused by impact loading before the initiation of subsequent blast loading. The RC slabs subjected to longer impact duration before the initiation of subsequent blast loading under impact-blast loading scenario exhibited a more dynamic response. The failure of RC slabs under combined blast and impact loads shows increased localized damage and the stress concentration at the support caused by impact mass. The effect of slab thickness and reinforcement percentage is also studied by varying the velocity of the impact mass. The statistical analysis is carried out to study the uncertainty in the stress response of the developed model using the random variation of the input material parameters. The analysis is carried out to find the most influential input material parameter and the parametric study considered to study the combined impact and blast loading response of the slab.

Study on the seismic control measure of the underground large-scale frame structure

The seismic control measures with isolation bearings (SMIB) on top column joints are widely employed in underground frame structures with small cross-sections. This paper reveals the seismic control mechanism of the SMIB, and verifies the applicability of the SMIB for the underground large-scale frame structure (ULSFS). It is found that: the stresses of middle columns in the ULSFS would be controlled to some extent, but the seismic responses of floor slabs and outside walls would increase due to the smaller lateral horizontal resistance after the SMIB. The SMIB can not aim at the failure mechanism of the ULSFS, and it has been demonstrated to be ineffective for the ULSFS. Therefore, an innovative separation seismic control measure (SSCM) is proposed for the ULSFS based on the structural seismic characteristics and failure mechanisms. The fixed beam-column joints in the frame structure are released to be hinged, and the energy dissipation devices are added between the internal frame structure with outside walls. The analysis results show that the SSCM would cut down the adverse effects of the considerable soil structure interaction and decrease the seismic responses of the whole ULSLS efficiently. The seismic reduction ratio also demonstrates the SSCM has highly reliable seismic control effects on both the entire structure and vulnerable positions.

Dynamic responses and failure mechanism of composite double-arrow auxetic structure under impact loading

Composite double-arrow auxetic structures were designed and fabricated. The local impact experiments were carried out on the auxetic structures to explore the dynamic responses and failure modes. The effects of relative density and impulse level on the impact properties were analyzed and discussed. As the relative density increased, the local deformation of the auxetic structures and the damage of the core layer decreased, and the overall response of the auxetic structure increased. The finite element model was used to simulate the impact responses of the auxetic structures, and the numerical simulation results were in good agreement with the experimental results.