Hashin Damage Criteria Research Articles

An integrated modeling of barely visible impact damage imaging of CFRP laminates using pre-modulated waves and experimental validation

Nonlinear ultrasonic techniques have been broadly used for detecting barely visible impact damage (BVID) in carbon fiber reinforced plastic (CFRP) from both numerical and experimental approaches. However, the interaction between the BVID and nonlinear ultrasonic is not considered in the currently available numerical models and BVID needs to be more accurately modeled. This work presented an integrated three-dimensional (3D) finite element (FE) model for imaging BVID using pre-modulated wave (PMW) technique, in which the 3D Hashin damage criterion and energy-based damage evolution are introduced to predict intralaminar and interlaminar damage during the impact process. The non-contact PMW tests based on a laser scanning Doppler vibrometer (LSDV) are adopted to experimentally validated the proposed numerical methodology. The results show that the BVID predicted by the FE model agrees well with the experiments. Then, the damage contour images based on frequency spectra of modulation are illustrated to identify the presence of BVID, and damage severity is quantified based on the proposed maximum response amplitude (MRA). It is found that the location of BVID can be identified by the PMW approach numerically and experimentally and the sum of MRA of sidebands exhibits the best sensitivity of the variation of BVID with different energies.

Analysis of multiple impact tests’ damage to three-dimensional four-directional braided composites

Abstract This article was designed with a plurality of impact tests of three-dimensional four-directional braided composites, and the impact response of specimen impacted by a circular punch was studied. Ultrasonic C-scanning was used to detect the internal damage area to study the damage propagation process under multiple impact loads. The finite-element software ABAQUS was used to model the meso-structure of three-dimensional four-directional braided composites. Based on material characteristics, the three-dimensional Hashin damage criterion was used for the fiber bundle, and the maximum stress criterion was used for the matrix to judge the material damage. Combined with test and simulation results, the failure mode and damage evolution process of the specimen under multiple impact loads were studied. The results showed that the impact resistance of the three-dimensional woven composite material is affected by the braided angle. The larger the braided angle of the specimen, the better the impact resistance. The damaged area of the large braided angle material expanded to the periphery, and the damaged area of the small braided angle material was primarily developed in the longitudinal direction. The failure modes of the specimen during the impact process were primarily a longitudinal tensile failure of fiber bundles, transverse tensile failure and transverse compression failure of fiber bundles and matrix.

Numerical analyses of axial tension mechanisms of 3D orthogonal woven E-glass/epoxy composites with drilled holes

As an auspicious composite material, three-dimensional orthogonal woven E-glass/epoxy composites (3DOWC) are associated with drilling processes to assemble the parts for obtaining the desired shape and for the improvement of the component’s quality. This study investigated the axial tensile properties of 3DOWC with 6 mm drilled holes (DH). For comparison, two-dimensional woven E-glass/epoxy laminated composites (2DWC) with the same drilled hole size were also tested. To analyze the effects of holes on the microstructure properties, the finite element (FE) software ABAQUS/Standard was employed to simulate the tensile properties of composites. Hashin damage criteria were used to predict the failure modes of the composite. The stress and strain curves were obtained to compare the numerical and experimental results at the same load condition. The comparisons illustrated the existence of a good agreement between the experimental and finite element method (FEM) results. In addition, scanning electron microscope (SEM) images were used to analyze failure modes and fracture mechanisms. Various degradation phenomena were observed especially fiber fracture, matrix cracking, and tow debonding also less delamination was noticed in 3DOWC than 2DWC.

Dynamic fracture behaviour of additively manufactured polymers and composites under ballistic impact

Recent technological advancements led to active research in the field of additive manufacturing (AM) thanks to its ability to fabricate complex structures with reduced material waste. While many studies focused on quasi-static performance of AM materials and structures, investigations on the dynamic performance of these materials are still limited, especially for polymers and composites. The aim of this research is to investigate the dynamic fracture behaviour of AM polymer composites under ballistic impact. Nylon reinforced with short carbon fibres was selected, and fused deposition modelling was used to fabricate solid quasi-isotropic structures. Quasi-static tensile and compression tests were carried out based on ASTM standards to characterise the elastic-plastic properties of the manufactured material. Based on these tests, the material’s deformation and fracture behaviour can be considered elastic-brittle. Further, dynamic mechanical analysis was conducted under a frequency sweep at room temperature to examine the viscoelastic properties; the material exhibited high elastic behaviour. Then, ballistic impact tests were performed on solid plates using a gas gun with 9 mm spherical steel projectiles at velocities ranging from 95 m s-1 to 120 m s-1. Post-experimental observation revealed the complete target perforation, with a circular hole at the front of the plates and delamination at the back. The dynamic experimental conditions were reproduced within the finite-element simulations, employing Hashin damage criteria via a user subroutine. A similar perforation was achieved at the front of the plate.

Simulation Study on Tensile Strength of Carbon Fiber Twisted Sewing Thread

The twist of the suture is an important parameter that affects the suture effect. If the suture is not twisted, the suture is easy to wear and fluff during the sewing process, resulting in thread breakage. At the same time, that will affect the suture effect and the strength of the suture itself. The article uses experiments and simulations to compare the mechanical properties of carbon fiber twisted threads. Refer to GB/T 3362—"Test Method for Tensile Properties of Carbon Fiber Multifilament" to test the tensile strength of T700-12K carbon fiber tow. And in ABAQUS, the three-dimensional Hashin damage criterion is used for 20 twists/m, 50 The carbon fiber sewing thread with twists/m and 80 twists/m is subjected to finite element prediction. The results show that the carbon fiber sewing thread with 80 twists/m has higher tensile strength than the carbon fiber sewing thread with 20 twists/m and 50 twists/m.

Multi-objective optimization of adhesively bonded single-lap joints of carbon fiber reinforced polymer laminates based on genetic algorithm

To improve its structural performance, the multi-objective optimization of adhesively bonded single-lap joints of carbon fiber reinforced polymer (CFRP) laminates was carried out based on genetic algorithm. Firstly, finite element (FE) models were constructed using 3D Hashin damage criteria and triangle cohesive zone model (CZM), those well capture the intra-laminar, inter-laminar and adhesive damages during the tensile loads, respectively. And its effectiveness was verified through experiments. Secondly, using the Latin hypercube sampling (LHS) method and polynomial response surface method (RSM), a multi-objective optimization agent model with tensile strength and shear strength as the objective function was established based on lap the length, the adhesive thickness and the width of the bonded parts. Finally, the tensile strength and shear strength agent model was optimized to obtain Pareto solution set based on genetic algorithm (GA), and the Pareto solution set was sequenced by technique for order preference by similarity to ideal solution (TOPSIS) method to obtain the optimized single-bonded joint structure design scheme. The result shows that the experimental measurements of tensile load tests concur with the numerical predictions and validate the FE models. The tensile strength and shear strength of the adhesively bonded single-lap joints of CFRP laminates have a significant correlation with the lap length, the thickness of the adhesive layer and the width of the bonded parts. Compared with the numerical simulation results, the error of the quadratic response surface proxy model results is less than 2.3%. Compared with the conventional single lap bonding structure, the tensile strength and shear strength are increased by 2.65% and 17.24%, respectively.

The role of ply angle in interlaminar delamination properties of CFRP laminates

The paper describes the fracture toughness of biomimetic architected carbon fiber reinforced polymer (CFRP) laminates via experimental and numerical methods. High-fidelity Finite Element (FE) models in conjunction with modified Mises criteria have been developed to evaluate the effect of the interlaminar architectures on the fracture toughness of bio-inspired helicoidal composites. A bi-linear cohesive zone model (CZM) with Hashin damage criterion has been used here to simulate the interlaminar and intralaminar damage behaviors during quasi-static three-point bending (3 PB) tests of biomimetic architected CFRP laminates, and 3 PB test results extracted from open literature and obtained in this work have been used to validate the load-displacement response of the specimens predicted from the proposed FE model. Mode I and mode II interlaminar fracture toughness of these layered composites have also been identified as semi-analytical functions of the stacking angle of two adjacent layers, and the predictions show a good agreement with the corresponding experimental data. This work provides guidelines about the use of the bionic design CFRP composite in applications where toughness is critical.

Aging of bolted joints prepared from electron‐beam‐cured multiwalled carbon nanotube‐based nanocomposites with variable torques

AbstractWe evaluate the behavior of a bolted joint prepared from electron beam (EB)‐cured carbon/epoxy nanocomposites under accelerated weathering environment at varying bolt tightening torques. For strength improvement, different weight percentages (wt%) of multiwalled carbon nanotubes (MWCNTs) in the range 0.1–0.5 wt% were incorporated into the composite laminates; 0.3 wt% of MWCNT had the maximum tensile strength. The properties of EB‐cured composites were compared with those of thermally cured ones. For accelerated weathering, cyclic exposure of ultraviolet (UV) radiation as well as condensation at elevated temperatures was conducted for 1000 h on the nanocomposite specimens. The chemical, physical, thermal, and mechanical properties of the nanocomposites were studied under accelerated aging conditions. To determine the failure loads in the bolted joints, specimens were prepared as per ASTM D5961. It was found that after 1000 h of aging, there was only 5% reduction in the ultimate failure load for joints prepared with the addition of MWCNTs. It was also found that the bolt torque had a positive effect on the performance of the joints. The experimental results were validated with progressive damage analysis using the characteristic curve method along with the Hashin damage criteria.

Cylindro-Conical Mild Steel Projectile Impact on E-Glass Fiber Reinforced Laminated Composite Plate Including Delamination Analysis

Computational impact analysis of an E-glass fiber reinforced laminated composite structure with a conical nose shaped projectile is performed including delamination analysis. In addition to intralaminar damage analysis, interlaminar damage analysis is considered due to the laminated configuration of the protective structure. Threat is made of mild steel projectile and it is modeled using Johnson-Cook material model with ductile damage criterion. Intralaminar and interlaminar damage modeling of target material is realized in the frame of Hashin damage criteria and quadratic nominal stress criterion with Benzeggagh-Kenane fracture criterion, respectively. Stress and damage distribution both in target and threat materials are obtained by mesh gradation analysis via Abaqus/Explicit v6.19. Effect of delamination analysis in computational impact modeling is evaluated by considering the computational cost regarding CPU time and wall clock time. Larger von Mises stresses obtained when excluding interlaminar debonding in the analysis. It is found that delamination analysis significantly improved the damage evaluation of composite laminates owing to impact loading with small computational effort.

Numerical studies of the low velocity impact behaviour on hybrid fiber metal laminates

Abstract The Fiber metal laminates (FML) are the advanced composites that comprise the property of metal and FRP layers. FMLs are used for the manufacturing of fuselage skins, Cargo floors and the leading edge of aircraft etc. In this paper, Explicit Finite element method used for the simulation of low velocity impact behaviour on the fiber metal laminates. The FML with glass fiber (GFML) and FML with hybrid (Carbon + Glass) fiber (HFML) have been considered for the simulation. The Johnson-Cook material model is used to model the plasticity and damage of the Aluminium layer. Hashin Damage criteria were used for the FRP layers. Comparison of Force-Time and Force- Displacement histories are carried out. From the studies it is found that Carbon and Glass fiber based HFML are superior compared to the GFML.

Shear Response of Glass Fibre Reinforced Polymer (GFRP) Built-Up Hollow and Lightweight Concrete Filled Beams: An Experimental and Numerical Study.

This paper investigated the static behaviour of glass fibre reinforced polymer (GFRP) built-up hollow and concrete filled built-up beams tested under four-point bending with a span-to-depth ratio of 1.67, therefore focusing their shear performance. Two parameters considered for hollow sections were longitudinal web stiffener and strengthening at the web–flange junction. The experimental results indicated that the GFRP hollow beams failed by web crushing at supports; therefore, the longitudinal web stiffener has an insignificant effect on improving the maximum load. Strengthening web–flange junctions using rectangular hollow sections increased the maximum load by 47%. Concrete infill could effectively prevent the web crushing, and it demonstrated the highest load increment of 162%. The concrete filled GFRP composite beam failed by diagonal tension in the lightweight concrete core. The finite element models adopting Hashin damage criteria yielded are in good agreement with the experimental results in terms of maximum load and failure mode. Based on the numerical study, the longitudinal web stiffener could prevent the web buckling of the slender GFRP beam and improved the maximum load by 136%. The maximum load may be further improved by increasing the thickness of the GFRP section and the size of rectangular hollow sections used for strengthening. It was found that the bond–slip at the concrete–GFRP interface affected the shear resistance of concrete–GFRP composite beam.

Simulation of CFRP/aluminum foam sandwich structure under high velocity impact

To profoundly reveal the protective performance of CFRP/aluminum foam sandwich structure, the high-speed impact simulation models of CFRP, aluminum foam and their sandwich structures are built by ABAQUS/Explicit module. The VUMAT user material subroutine is written for CFRP panel, and Hashin damage criterion is introduced. The elastic constitutive model and macro modeling method for the aluminum foam are chosen. The impact process under different working conditions is numerically simulated and the reliability of the model is verified by one-stage light gas gun loading experiment at the corresponding simulation conditions. At the same time, the protective performance of CFRP/ aluminum foam sandwich structure under different steel projectile shapes, impact velocities and impact angles (the angle between the ballistic and the target normal line) are simulated. The results show that the Mises stress nephogram of CFRP panel is peanut-like with obvious directivity. The stress wave propagates fastest in the direction perpendicular to the fiber. In the impact velocity range of 172−450 m/s, with the increase of impact velocities, the loss of kinetic energy will increase, but the increase of kinetic energy loss will decrease with the increase of impact velocities, and the contact force between the projectile and the sandwich structure will also increase. Thus the sandwich structure will have more serious delamination and fiber breakage, which will consume more kinetic energy. When the velocity of the projectile is greater than 300 m/s, the impact capability of the sandwich structure tends to the upper limit of impact capacity. In the impact velocity range of 170∼300m/s, the sandwich structure has stronger protective performance than ball-nosed projectile when the flat-nosed projectile impact, and the difference of the residual velocity between the two kinds of projectiles is larger. The shape of the projectile has a great influence on the protective performance of the CFRP/ aluminum foam sandwich structure. When the impact velocity is greater than 300m/s, the residual velocities of the two kinds of projectiles are almost the same, and the shapes of the projectile have a gradual effect on the performances of the CFRP/ aluminum foam sandwich structure. The anti-shock performance of sandwich structure under oblique impact is stronger than that of vertical impact. With the increase of impact angles, the transverse deformation of sandwich structure increases, and the anti-shock performance of sandwich structure also increases.

Investigations on the strength of mechanical joints prepared from carbon fiber laminates with addition of carbon nanotubes

The present work is to examine the failure modes and failure loads in pin joints prepared from carbon/epoxy composite laminates with addition of multiwalled carbon nanotubes (MWCNT) as nanofillers. The effect of MWCNT in the carbon/epoxy composites was studied by adding 0.1 to 0.5 wt.% content in the epoxy resin. The maximum tensile strength was observed upto 0.3 wt.%, which is due to the enhanced interfacial bond strength and the efficient stress transfer between the stiff MWCNT and soft polymer matrix through refined polymer/MWCNT interface. The nanocomposite laminates for pin joints were prepared using optimised 0.3 wt.% of MWCNT. The different geometric combinations of width to diameter (W/D) and edge to diameter (E/D) ratios were varied from 2 to 5, respectively. The numerical analysis was performed using Hashin damage criteria along with progressive damage analysis to compare the predicted failure loads with the experimental results.

Analysis of Industrial Safety Helmet Under Low-Velocity Impact

The study focuses on developing a computational model on low-velocity impact which includes the study of different composite materials, and the materials selected include thermosets such as carbon–epoxy, glass–epoxy and thermoplastic such as Twintex material. The above materials were selected because of their high impact resistance properties as well as energy absorption capacity. Furthermore, the damage tolerance of these materials is higher when compared to the polycarbonate material which is presently used. The analysis was carried out using ABAQUS–CAE software where the study was extended to two different types of impact, i.e., linear and oblique, with their damage evolution and analytical validation. The study further focuses on energy absorption capacity, depth of penetration and strain energy absorption by the material under linear and oblique impacts. The analysis revealed the fact that the material Twintex is superior to carbon–epoxy and glass–epoxy with regard to the stress developed. The analysis was carried out by incorporating the Hashin damage criteria also. It was observed that the Twintex material offered more resistance to the depth of penetration in both types of impact. The computational results were compared with analytical results, and they were found to be very close with a minimum deviation.

Fluid-structure interaction studies on marine propeller

Composite propellers offer high damping characteristics and corrosion resistance when compared with metal propellers. But the design of a hybrid composite propeller with the same strength of metal propeller is the critical task. For this purpose, the present paper focusses on fluid-structure interaction analysis of hybrid composite propeller with Carbon/Epoxy, R-Glass/Epoxy and S2-Glass/Epoxy to find its strength at the same operating conditions of the baseline aluminium propeller. The surface and solid models of the hybrid composite propeller are modelled using modelling software (CATIA) and these models are imported into mesh generation software (Hypermesh) to generate the surface mesh and solid mesh respectively. This surface model of the hybrid composite propeller is imported into computational fluid dynamics software (Fluent) to estimate the pressure loads on propeller blades. These pressure loads from Fluent are imported into FEA software (Abaqus) and applied on the propeller to find the deformation and strength of hybrid composite propeller due to fluid-structure interaction loads. Optimization study is carried out on hybrid composite propeller with different layup sequences of Carbon/R-Glass/S2-Glass to find the optimum strength. From the optimization study, it is found that the hybrid composite propeller with layup-3 of 55/55/90/0/0/90/450/90/ 0/90/45/90/45/90/0/90/0 degrees generates the least stress compared with other layups for the same pressure load obtained from fluid flow simulations. Damage initiation analysis is also carried out on hybrid composite propeller with optimized layup-3 based on Hashin damage criteria and found that the design is safe.

Evaluasi Frame Sepeda saat Tabrakan Dengan Metode Ekplisit Elemen Hingga

In this paper, numerical method of crash impact by using explicit dynamic model was used to evaluate the bike frame design. Frontal impact simulation model was carried out to understand the characteristics of energy absorption, stress distribution and deformation of the bike frame. Carbon fiber T300 composite with elasticity modulus 129,79 GPa and overall frame weight is 1,8 kg was used in this simulation as material properties. Hashin damage criteria was used in this numerical analysis since this criteria was widely used to assess composite material damage simulation. In this study Head Tube angle (HTA) and Top Tube Angle (TTA) was modified. The modified HTA was varied from 69O to 76O and TTA was 70O to 86O. This modification was based on the original frame design which the HTA and TTA are 71.5O and 74O respectively. This modification was aimed to find the effect of HTA and TTA modification to energy absorption and stress distribution in the bike frame design. Simulation result shows that TTA and HTA modification affect the energy absorption of the bike frame. The smaller the energy absorption of the bike frame shows that the frame has poor quality of stress distribution.

Crashworthiness analysis of polymer composites under axial and oblique impact loading

A study was made to evaluate the design variables that affect the crashworthiness parameters of an energy absorber while dissipating the crash forces during road vehicle accidents. In order to find out causes, nonlinear crushing analysis is performed with the finite element code of ABAQUS/Explicit software. An investigation was conducted on homogeneous and heterogeneous ply orientation modeled structure of composite materials under axial and oblique impact loadings to find out the suitable model or structure for lightweight vehicle applications according to the crashworthiness. Crashworthiness parameters such as peak force and deformation length were considered, to investigate acomposite tube under axial and oblique loading conditions with materials such as carbon fiber reinforced plastic (CFRP), glass fiber reinforced plastic (GFRP). Continuum Damage Mechanics (CDM) approach is used to observe the changes and investigation on the dynamic response of composite material under sudden crashes in a different arrangement. A progressive damage model is adapted to determine the status of damage of elements in each failure with references to predefined energy absorption value. Hashin damage criteria are used, to estimate the reduction of stiffness of the material while crack initiation and its propagation during impacts. Different tube arrangement of fiber orientations (0°, ±45°, 90°) of ply and axial and oblique types of impact loading were mostly affecting results a lot in a crushing analysis. Non homogenous composite tube showed the better crashworthiness parameters than the homogenous structure. In oblique loading analysis, in both cases (CFRP and GFRP), the peak force and the deformation values decrease with increases in oblique angle due to the change of fiber properties, inclination as well as the contact area between the tube and impactor.

Low-velocity impact behaviors of repaired CFRP laminates: Effect of impact location and external patch configurations

Experimental and numerical approaches are used to investigate the effect of impact location and different external patch configurations on the low-velocity impact behaviors of repaired CFRP laminates. Various external patches with different thicknesses (number of layers) and stacking sequences are considered and those patches are used to repair single side of the damaged laminate plates to improve the impact-resistance. To predict the damage initiation and progression of the repaired CFRP laminates under impact loading, a continuum damage mechanics (CDM) model that combines 3D Hashin damage criteria and cohesive zone model (CZM) is proposed. The corresponding drop-weight impact tests are conducted to experimentally obtain the impact response such as impact force and energy. Numerical impact simulations have been performed to study the effect of impact location during the low-velocity impact behaviors of repaired structures. Parametric studies of patch thickness and stacking sequence are also carried out using the low-velocity impact simulation to analyze their effect on the impact-resistance. Finally, this study provides an optimization cafeteria to identify the important design parameter to perform external patch repair based on the simulation results.

Study of Composite Fiber Reinforcement of Cracked Thin-Walled Pressure Vessels Utilizing Multi-Scaling Technique Based on Extended Finite Element Method

One of the most important challenges of storing fluids in thin walled pressure vessels under internal pressure is preventing crack propagation. At low temperatures, steel shows brittle crack propagation characteristic, which is highly dangerous. In this paper, a new numerical model is presented, in order to investigate the reinforcement of a cracked thin walled pressure vessel by composite patch. The extended finite element method (XFEM) technique is used to model brittle crack propagation through the thickness of a thin-walled pressure vessel utilizing the multi-scaling technique. Crack propagation in the thickness of a pressure vessel was studied utilizing the combination of XFEM approach in fracture mechanics and multi-scaling technique. Then, the critical energy, which is the maximum strain energy that the pressure vessel can absorb before the brittle crack starts to propagate, was calculated using the numerical techniques of XFEM. In order to increase the critical energy, cohesive elements and composite patches with different stacking sequence, which were extracted from previous experimental and analytical studies, were used, and the best stacking sequence was identified using the current XFEM code. Moreover, the optimization was carried out using the traditional optimization technique for reinforcing with composite patches, which was based on the optimum ratio of the increased critical energy to the thickness of the reinforcement. Results obtained show that, keeping constant the reinforcing thickness and changing the stacking angle, the maximum energy capacity is increased by 7–11%. Also, by increasing the thickness of the reinforcement, a significant growth in strain energy capacity (up to 40%) is observed. The Hashin damage criterion was used to ensure that none of the laminas’ damage during the crack propagation is critical.

Bending behavior of single hat-shaped composite T-joints under out-of-plane loading for lightweight automobile structures

This paper presents an analytical, numerical, and experimental study on the failure behavior of single hat-shaped T-joints made of plain woven carbon fiber polymer (T300/epoxy 618) and subjected to out-of-plane bending. The T-joint is manufactured by vacuum bag molding process at room temperature. An analytical model is developed to analyze the experimental results and to establish the associated failure criteria. Two failure modes: (a) laminate buckling and (b) laminate crushing are considered, and the theoretical relationships for predicting the failure load associated with each of the two modes were developed. The experimental data correlate closely with the analytically predicted behavior, including failure mode and bending stiffness. In particular, both laminate buckling and laminate crushing are observed during the experiment with laminate crushing being the final failure mode, which can be considered to be the most important failure mode of the fabricated T-joint. In addition, numerical simulations based on the finite element method and the Hashin damage criteria also accurately predict the flexural modulus, the peak load, and failure locations of the T-joint obtained in the test.