Hashin Failure Criteria Research Articles

Numerical simulation of composite grid sandwich structure under low-velocity impact

Abstract The low-velocity impact finite element model of the carbon fiber-reinforced composite grid sandwich structure was established by ABAQUS. Its panels and grid are both carbon fiber-reinforced composite laminates. The constitutive relation of composite laminates is written into the VUMAT user subroutine using the Fortran language. Simulation of intralaminar failure behavior of composite laminates using the three-dimensional Hashin failure criterion. The quadratic stress criterion and the B-K energy criterion were used to simulate the interlaminar failure behavior, and the delamination damage of the composite panel and the interface debonding damage were simulated. The finite element models of four different types of composite grid sandwich structures, including quadrilateral configuration, triangular configuration, mixed configuration, and diamond configuration, were established. The influence of the single grid width and the height of the grid on the impact resistance of each composite grid configuration was studied. Compared with other geometric configurations, triangular grid sandwich structure provides the best energy absorption characteristics, and T-6-10 has the highest fracture absorption energy (15816.46 mJ). The damage propagation law of carbon fiber-reinforced composite grid sandwich structure under impact load is analyzed.

An Experimental and Numerical Study on Impact and Compression after Impact of Stiffened Composite Panels

To develop the full application potential of composite materials, research on the post-buckling behavior of composite stiffened panels is of great significance. In this paper, the impact and compression after impact (CAI) behaviors of four different types of composite stiffened panels were studied by numerical simulation and experimental methods. The low-velocity impact damage simulated dynamically was introduced as the initial state in the compression simulation, and a two-dimensional shell model with Hashin failure criteria and stiffness degradation was adopted to estimate the failure load of composite stiffened panels under impact and CAI. The error between simulation results and test results was less than 10%, showing that the method used in this study achieved considerable accuracy in experimental results. Analysis of the impact test results revealed that the extent of damage is related to many factors, including the cross-sectional size of stiffeners, the spacing of stiffeners, and the material and thickness of the skin. In addition, the influence of fatigue damage on residual strength after impact was also studied experimentally, with results showing that the buckling and failure loads decreased by about 5% under 106 flight fatigue loads. However, there were obvious fluctuations in the load-displacement curves, which may have been caused by debonding between the stiffeners and the skin. Experimental results and the simulation matrix show that the post-buckling ratio increased with the increase of the stiffness ratio, then was stable after 2.0. Furthermore, the thinner the skin, the greater the post-buckling ratio. The experimental and simulation results provide an important reference for the structural design and failure-mechanism analysis of composite stiffened panels.

Progressive failure analysis and burst mode study of type IV composite vessels

ABSTRACT The lightweight high-pressure hydrogen storage vessels composed of polymer liner and composite reinforced layers have attracted more and more attention. In this research, a 2D axisymmetric finite element model was proposed to predict the damage evolution, failure strength and failure mode of the composite overwrapped pressure vessels, in which a user subroutine UMAT based on Hashin failure criteria was introduced to simulate the progressive damage properties of the composite material. The FE models are validated by comparison with the experimental results, and the error between the numerical simulation results and the experimental results was within 10%. It is found that vessels with different lay-up schemes might burst in different locations. Parametric studies are performed to obtain a critical ratio of hoop and helical layers to keep the vessel burst in safe mode.

Modelling of Web-Crippling Behavior of Pultruded GFRP I Sections at Elevated Temperatures.

The concentrated transverse load may lead to the web crippling of pultruded GFRP sections due to the lower transverse mechanical properties. Several investigations have been conducted on the web-crippling behavior of the GFRP sections under room temperature. However, the web-crippling behavior is not yet understood when subjected to elevated temperatures. To address this issue, a finite element model considering the temperature-dependent material properties, Hashin failure criterion and the damage evolution law are successfully developed to simulate the web-crippling behavior of the GFRP I sections under elevated temperatures. The numerical model was validated by the web-crippling experiments at room temperature with the end-two-flange (ETF) and end bearing with ground support (EG) loading configurations. The developed model can accurately predict the ultimate loads and failure modes. Moreover, it was found that the initial damage was triggered by exceeding the shear strength at the web-flange junction near the corner of the bearing plate and independent of the elevated temperatures and loading configurations. The ultimate load and stiffness decreased obviously with the increasing temperature. At 220 °C, the ultimate load of specimens under ETF and EG loading configurations significantly decreased by 57% and 62%, respectively, whereas the elastic stiffness obviously reduced by 87% and 88%, respectively.

Progressive failure analysis of U-notched thin composite plates repaired with a double-sided composite patch

In this study, carbon fiber-reinforced U-notched composite plates were repaired with composite patches made of the same material using adhesive bonding and their mechanical performance was investigated experimentally and numerically. Repairs were made by applying a double-sided composite patch to the notched thin composite plates. The repaired composite plates were tested under tensile load. The effect of the variation in notch width and depth on the repaired plate failure load and type was investigated. At the end of the experiments, load–displacement graphs of each specimen were obtained. The effect of variation in notch depth and width in the repaired specimens was not as dominant as in the non-repaired specimens. While the variation in notch dimensions changed the failure load between 34% and 37% in the non-repaired specimens, this rate was between 18% and 21% in the repaired specimens. In the numerical analysis, progressive failure analysis was performed using the Hashin Failure Criteria. Subroutine codes were written in the program Ansys, which uses the finite element method for numerical analysis. In the results, numerical and experimental load–displacement graphs and failure types of the specimens are presented comparatively. The convergence rate of the experimental and numerical data was between 92% and 99.8%.

Design and fabrication of carbon-fiber-wound composite pressure vessel with HDPE liner

This work focuses on the fiber winding design and fabrication method of a carbon fiber wound composite pressure vessel with HDPE liner. The design parameters of the fiber winding layers, the fiber winding tensions, and the pre-charge pressures of the liner were studied. The hoop and helical winding layers were designed, and a finite element analysis model was established by combining the cubic spline thickness prediction method. A progressive damage analysis based on the Hashin failure criterion and the Camanho degradation criterion was conducted. The failure mode and the burst pressure of the vessel were obtained. By analysis of the critical buckling load of the liner and the design of the winding tensions, the pre-charge pressure was obtained by combining with the equivalent temperature method. A composite pressure vessel was fabricated and a burst test was carried out to verify the effectiveness of the design method and the fabrication process.

Numerical Study on the Rebound of Low-Velocity Impact-Induced Indentation in Composite Laminate

Indentation is an effective indication of LVI damage in PMCs. However, indentation can rebound partly with time. Thus, a good understanding of the rebound behavior of the impacted pit is helpful in damage assessment for composites. In this paper, a transverse isotropic viscoelastic model and a viscoelastic cohesive interface model are proposed to represent the viscoelastic properties of ply and the interface between adjacent plies, respectively. In these models, we implement the in-plane 3D Hashin failure criterion to simulate ply level failures and the stress-based quadratic failure criterion and linear softening mixed-mode BK law to simulate cohesive interface failure initiation and propagation, respectively. LVI testing was performed on specimens at different impact energies (30 J, 40 J, and 50 J). Dents induced by impact will eventually rebound due to the viscoelastic behavior of plies and cohesive interfaces. This results in a decrease in depth with time. This indentation and its rebound phenomenon were simulated in ABAQUS by considering viscoelasticity with user-defined material subroutines. The simulation results show good agreement with the experimental observations and are validated accurately in terms of the indentation’s initial depth upon impact and its final rebound with time. From experiments, it was observed that the decrease in the original depth of indentation initially becomes faster with time after impact; then, it slows down with time and eventually stops due to viscoelasticity. While this decrease in the original depth of indentation remains invariable with time in simulation, it has a different rebound path.

Explicit multi-scale modelling of intrinsic self-healing after low-velocity impact in GFRP composites

In this work, a multi-scale framework is used for modelling of Low Velocity Impact (LVI) and post-impact healing of woven intrinsically self-healing FRP composite structures. The matrix constituent is modelled using the elastic–plastic micro-damage healing model. Furthermore, the reinforcing fibres are modelled as linear elastic with Hashin failure criterion and progressive damage model. The employed micromechanical model is the Rule of Mixtures (ROM). The developed model is implemented into Abaqus/Explicit user material subroutine VUMAT and validated using the LVI experimental results available in the literature. Tested specimens consisted of a self-healing epoxy resin and woven E-glass fabric as the matrix constituent and reinforcement, respectively. Validation results by comparing contact forces have shown that the model accurately predicts damaging mechanisms in the specimen. Additionally, prediction of fibre damage is in satisfactory agreement with experimental results. Finally, prediction of damaged and healed areas corresponds to experimental ultrasonic measurements.

Progressive Failure Analysis of Laminated CFRP Composites under Three-Point Bending Load

In this paper, the mechanical behavior and damage evolution of CFRP laminates under three-point bending loads were investigated. Based on the three-dimensional Hashin failure criterion and cohesive zone method, a progressive damage analysis model was constructed to predict seven different failure modes, and an improved stiffness matrix degradation law was proposed. Numerical simulations were performed using ABAQUS finite element software and UMAT user subroutines and verified by three-point bending tests. The experimental results show that the relative errors of the flexural strength and flexural modulus of the current model simulation results and the experimental data were −3.10% and −2.70%, respectively, and the damage evolution process after the ultimate load was accurately predicted. Meanwhile, the predicted final failure and damage modes were consistent with the micrographs of the failed specimens.

Computational model for predicting the low-velocity impact resistance and tolerance of composite laminates

We present a numerical model for predicting the low velocity impact resistance and tolerance of multidirectional carbon fiber-reinforced composite laminates made of non-crimp fabric. A finite element model is developed wherein the heterogeneous plies are replaced by equivalent homogeneous orthotropic plies. The low-velocity impact of a carbon–epoxy laminate is investigated using an explicit finite element model. Intralaminar failure and damage is evaluated using the 3D Hashin failure criteria and a surface-based cohesive behavior is implemented to capture the delamination between the plies. Following the low velocity impact, the finite element model is subjected to axial compression to investigate the compressive residual strength after impact, which is a measure of damage tolerance. The computational model is used to investigate the impact resistance and tolerance of a 24-ply multidirectional symmetric laminate reinforced with carbon fiber non-crimp fabric. The low velocity impact response and the compressive residual strength after impact are validated with experimental data for different levels of impact energy. It is found that the computational model can predict the impact resistance and damage tolerance for impact energies up to 50 J.

Computational analysis of bidirectional carbon fibre/epoxy nanocomposites using different failure criteria

Numerical analysis provides an opportunity to solve complex problems using mathematical models. The increasing trend of numerical simulations supports many industries and research organisations to reduce the experimental work. In the present study, considering the positive aspects of numerical analysis, investigations have been done using different failure criteria on the carbon fibre/epoxy composites. Various failure criteria have been discussed that can be used for unidirectional and bidirectional fibre reinforced polymer composites. In this study, the best-suited failure criteria, i.e. Maximum stress, Tsai-Wu and Hashin criteria were combined with the progressive damage analysis to investigate the failure of bidirectional woven carbon fiber/epoxy polymer composites. The experimental validations were also done for numerical predictions. It was found that the Hashin failure criterion gave the results closest to the experimental failure analysis of pin joints. In pin joints prepared from carbon fiber/epoxy composite laminates, Hashin failure criteria predicted the increment in ultimate failure loads in the range of 12–16% for higher values of width to diameter (W/D) and edge to diameter (E/D) ratios. For pin joints prepared from multiwalled carbon nanotubes (MWCNTs) added carbon fiber/epoxy composite laminates, the prediction given by Hashin failure criteria was in the range of 15–19%.

Progressive failure analysis of open-hole composite laminates using FLWT-SCB prediction model

This paper presents the original incorporation of the smeared crack band (SCB) damage model within the full layerwise theory (FLWT) framework, to contribute to the increase of the computational efficiency of the progressive failure analysis of open-hole laminar composites loaded in tension, simultaneously preserving the accuracy of the conventional 3D finite element models. The developed FLWT-SCB prediction model was implemented into an original FLWTFEM framework allowing for the accurate 3D stress fields and excellent visualisation capacity. The response of damaged lamina, in both fiber and matrix directions, was described by distinct bilinear strain-softening curves. The mesh dependency problem was minimized by scaling the fracture energy using a characteristic element length.Both the failure initiation and failure modes were determined using the Hashin failure criterion. To verify the model effectiveness, the obtained results were compared against the experimental and benchmark data from the literature. Mesh dependency was analysed to confirm the benefits of suggested model, as well. The obtained results agreed with the experimental ones and those from the literature.According to the numerical results, FLWT-SCB allows for coarser meshes than those used in the standard finite element models, leading to improved computational efficiency without compromising the accuracy. The model also demonstrated the weak dependency between the size of the structure and the mesh. The advantages of using FLWT-SCB damage model in achieving significant improvements in computational efficiency are highlighted.

Research on the mechanical and water-repellent properties of bionic carbon fiber reinforced plastic composites inspired by coelacanth scale and lotus leaf

Carbon fiber reinforced plastic (CFRP) laminates are widely used in vessel side plate, underwater propeller, and submarine oil pipeline because they possess superior specific strength and hydrophobicity compared with metal materials. However, conventional CFRP laminates are limited by insufficient mechanical properties and incompetent water-repellent performance. Herein, a biomimetic double-helicoidal superhydrophobic laminate (BDHSL) was designed and manufactured through a method combining hot press forming and two-step spraying. The BDHSL was composed of double-helicoidal (inspired by coelacanth scale) carbon fiber prepreg and SiO2-based coating with multiscale hierarchical structures (inspired by lotus leaf), which displayed excellent mechanical properties and water-repellency. Besides, mechanical tests were carried out systematically. Remarkably, the peak impact force of the BDHSL at the impact energy of 20 J was 2865.25 N, which increased by 136.88% compared with traditional unidirectional laminate (UL 1209.56 N). Meanwhile, the finite element simulation was conducted using 3D Hashin's failure criteria. The simulation results showed that the predicted stress-deflection curve for four types of laminates correlated well with experimental results. Moreover, the water contact angle of BDHSL reached approximately 156.5°, which indicated its superhydrophobicity. What is more, the durability and water-repellency of the SiO2-based coatings were investigated, which further confirmed its potential underwater applicability. The investigations in this work offer a promising way to effectively design and fabricate exquisitely structured CFRP laminates with hierarchically textured coatings that are more suitable for various marine applications under practical conditions, such as offshore oil drilling platform, autonomous underwater vehicle, high-speed ship, and so forth.

Elastic-plastic progressive damage model and low-velocity impact failure mechanism of composite materials

An elastic-plastic progressive damage model (PDM-3DEP) was proposed to study the mechanical response and damage development of composite laminates under low-velocity impact. The 3D Hashin failure criterion and an improved three-dimensional damage evolution model that considers strain component of ε33 and shear stain are implemented to describe the initiation and evolution of damage modes. The zero-thickness cohesive elements which follow bilinear traction-separation law are applied to simulate delamination. The numerical and experimental mechanical curves and damage distribution of composite laminate with a stacking sequence of 03o/45o/−45oS were compared to verify the proposed PDM-3DEP. The consistent results of the numerical and experimental data indicates that the proposed method can accurately describe damage mechanical behavior under low-velocity impact. Moreover, another type of composite laminate with a stacking sequence of 02o/902o/02o/902o/02oS is adopted for further verification. It is concluded that the proposed model can accurately analyze the mechanical responses of different composite laminates.

Optimal design of tube flexure cut-out geometries for deployment performance

A design methodology is proposed for deployable tube flexures made of ultra-thin carbon fiber composite. The methodology is developed to achieve desired stowage and deployment performance in the absence of material failure. The cut-out shape in the tube flexure is determined by means of a Bayesian optimization technique. The objective function is defined based on both desired moment characteristics and Hashin failure criteria. Multiple cut-out parameterization schemes are presented. Bayesian optimization is shown to be effective and significant performance improvements are achieved thought use of spline-based optimization in comparison to more conventional forms. The efficiency of the approach is validated via experiment.

A modified progressive damage model for simulating low-velocity impact of composite laminates

A modified progressive damage model is constructed to analyze the damage mechanics and damage development of composite laminates induced by low-velocity impact in this article. The damage modes are judged by the 3D Hashin failure criterion. A modified damage evolution model, which was constructed based on through-thickness normal strain component [Formula: see text], is implemented to describe progressive damage of composites. Cohesive elements with quadratic failure criterion and B-K criterion are applied to simulate the development of delamination. The 3D Hashin criterion and modified damage evolution model are coded in VUMAT and called in the ABAQUS/Explicit package. The damage distribution and mechanical behavior, including impactor energy, react force, displacement, predicted by numerical simulation are compared with the experimental data of different impact energies (7.35, 11.03, and 14.70 J). The numerical results and experimental data are in good agreement, which suggests that the modified damage evolution model is beneficial for studying the dynamic mechanical behavior during impact. Moreover, the influence of cohesive element thickness on numerical results is discussed. It is concluded that the cohesive element thickness should be adopted between 0.001 and 0.0075 mm.

Experiments and Finite Element Simulations of Composite Laminates Following Low Velocity On-Edge Impact Damage.

Composites are widely used in aircraft structures that have free edges and are vulnerable to impact events during manufacturing and maintenance. On-edge impact may have a great contribution in terms of the compression strength loss of composites, but the influence remains unclear. This paper presents experiments and simulations of carbon-fiber-reinforced plastic (CFRP) materials with on-edge impact and compression after edge impact (CAEI). On-edge impact damage was introduced to the composite laminates through the drop weight method with 4, 6, 8 and 10 J impact energies, respectively. A special guide-rail-type fixture was used in the compression tests in which strain–force and load–displacement relationships were obtained. A continuous-step finite element model was proposed to simulate impact and compression. Continuum shell elements and Hashin failure criteria were used to simulate in-ply damage, and interlaminar damage was modelled by cohesive elements. The model was validated by correlating the experimental and numerical results. The investigation results revealed the relationships of the damage size and residual strength with the different impact energies. The crack length and delaminated area grow with the increase in impact energy. The residual compressive strength follows a downward trend with increasing impact energy.

Study on Composite Material Failure of Reinforced Thermoplastic Pipes under External Pressure

This paper examines the mechanical properties of reinforced thermoplastic pipes (RTP) under the influence of external pressure. We used the three-dimensional (3D) thick-walled cylinder theory, combined the 3D Hashin failure criterion with the theory of the evolution of damage in composite materials, considered their nonlinear mechanical behaviors, and introduced changes in the winding angle caused by deformation to formulate a model for the progressive failure analysis of RTP. The model was used to examine the failure sequence and external pressure capacity of RTP, and its correctness was verified by a finite element model. The results show that increasing the winding angle of RTP within a certain range can improve its external pressure capacity. When the winding angle exceeded ±50°, the failure of the RTP under external pressure mainly depended on the fiber fracture of the reinforced layer. With an increase in the ply number of the reinforced layer, the external pressure capacity of the RTP increased nonlinearly and its rate of growth gradually decreased.

Progressive damage behavior of composite L‐stiffened structures with initial delamination defects under uniaxial compression: Experimental and numerical investigations

AbstractL‐shaped stiffened composite panels inevitably produce delamination defects during manufacturing and service, which seriously affect the load‐bearing performance of the structure. In the present work, a combination of experimental and numerical simulations was used to investigate the effect of initial delamination defects with three different shapes (lossless, elliptical, and circular) in the skin on the axial compression properties of carbon fiber L‐shaped stiffened composite panels. Furthermore, to predict the damage initiation and evolution process of carbon fiber‐reinforced polymer (CFRP) L‐stiffened plates under compression loading, a progressive damage model (PDM) that combines the Hashin failure criterion and the cohesive zone model (CZM) is proposed. Also, a user‐defined field variable (USDFLD) subroutine based on the Hashin failure criteria is developed in Abaqus software to study the initiation and progression of intra‐laminar damages L‐stiffened panels. Damage initiation and evolution process of skin delamination defects are predicted based on CZM. Finally, the finite element simulation results are in good agreement with the experimental measurements, which confirms the reliability of the finite element models (FEMs).

Flexural property evaluation of web reinforced GFRP-PET foam sandwich panel: Experimental study and numerical simulation

This work focus on the flexural property of polyethylene terephthalate (PET) foam-filled lattice composite sandwich panels subjected to four-point bending (FPB). The effects of different face sheet and core thicknesses on the flexural properties of the sandwich panels were analyzed. Experimental results indicated that the glass fiber-reinforced polymer (GFRP) webs can effectively prevent the sandwiches from catastrophic failure , the failure modes of the structures are dominated by foam shear, top face sheet compressive, and top face sheet-core debonding. Increasing the face sheet and PET foam thickness can effectively improve the ultimate load of the panels by 88.9% and 115.6%, respectively. An analytical model was employed to accurately predict the bending stiffness , ultimate load, and failure modes of the structures. The errors between theoretical predicted and experimental results are within 10% in terms of bending stiffness and ultimate load. Furthermore, a 3D numerical model was built to understand the failure modes and responses of the structures, a continuum damage material model for PET foam was imported into ABAQUS software by VUMAT subroutine, and Hashin failure criterion was used for GFRP. The simulated failure modes and load-displacement curves were in good agreement with experimental results.