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The applicability and limitation of several quadratic strength theories were investigated with respect to 2D-C/SiC and 2.5D-C/SiC composites. A kind of damage-based failure criterion, referred to as D-criterion, is proposed for nonlinear ceramic composites. Meanwhile, the newly developed criterion is preliminarily validated under tension-shear comb...
Citations
... It is known that low contact angles indicate a better degree of wettability of the CF surface. 29 The improvement in carbon fiber surface suggests that microwave treatment changes the surface properties of carbon fibers. Also, the wetting energy of the CF after MwMA increased by approximately 23%. ...
In this work microwave micro arcing (MwMA) has been utilized to engineer the surfaces of carbon fibers (CF) to enhance the interfacial bonding of resulting PEEK based composites. The CF were subjected to MwMA at different power levels ranging from 360 W to 900 W for 60 s to engineer their surfaces. The influence of MwMA on CF at various power levels was analyzed using SEM, contact angle measurement, AFM scans, and XPS study. Subsequently, MwMAed CF reinforced PEEK composite laminates were developed using compression molding. The MwMA on CF increased the surface wetting energy by 38% at 540 W microwave power level. XPS analysis suggested that MwMA at 540 W introduced oxygen containing functional group (C-O and C = O), which are likely responsible for increasing the adhesion between CF and PEEK polymer. The current study suggests that MwMA CF at 540 W showed an increment in tensile strength, flexural strength, interlaminar shear strength, and impact strength nearly by 22%, 61%, 28%, and 98% respectively. The MwMA method is novel method to improve the surface properties of carbon fibers and shows the potential use in structural applications.
... Several types of failures occur in composite materials, including tensile, compressive, shear, interlaminar, and delamination failures. Composite material failure criteria are mathematical equations that predict when a failure occurs in composite materials [30,31]. Determination of these failure criteria is important in CFRP composite design to ensure that the material has sufficient strength and durability for its intended use. ...
Carbon-fiber-reinforced polymers (CFRPs) are a composite material popular for thin-walled structure applications because of their advantages over other materials. In this study, numerical simulation analysis based on the finite-element method to identify the tensile behavior of CFRP woven material has been carried out. The method used has been verified and validated using a benchmarking procedure with the results of previous research. Errors in the simulation results are less than 10%, indicating a valid method that can be used for further research. The stress–strain distribution of each layer, the effect of ply orientation on tensile strength, the comparison of failure criteria used, and the comparison of several types of reinforcements often used have been investigated. The results showed that the characteristics of each inner layer received tensile loading visualized in the form of stress strains. Choosing the right layer angle on CFRP woven can affect the performance and strength of the material. Failure criteria that are appropriate to specific application conditions are important. Puck criteria can be used for simple applications, which require only the analysis of the main stresses in the material. Tsai–Hill and Tsai–Wu criteria can provide more accurate predictions and are better suited for loading conditions and more complex material types. Carbon fiber has better characteristics when compared to S-glass and E-glass.
... 15 The damage-based failure criteria were proposed for the modelling of inelastic behavior of similar composites. 16,17 Furthermore, according to the in situ X-ray tomography characterization of LSI C/C-SiC, significant strain oriented in through-thickness direction and their localizations were observed at small applied stress. 18 However, some important mechanical properties of C/C-SiC, especially in ±45° direction, have still not been investigated in detail, and the appropriateness of various failure criteria for the prediction of strength under different loadings should be explored. ...
The paper presents experimental characterization and theoretical predictions of elastic and failure properties of continuous carbon fiber reinforced silicon carbide (C/C‐SiC) composite fabricated by Liquid Silicon Infiltration (LSI). Its mechanical properties were determined under uniaxial tensile, compression, and pure shear loads in two sets of principal coordinate systems, 0°–90° and ±45°, respectively. The properties measured in the 0°–90° coordinate system were employed as the input data to predict their counterparts in the ±45° coordinate system. Through coordinate transformations of stress and strain tensors, the elastic constants and stress‐strain behaviors were predicted and found to be in good agreement with the experimental results. In the same way, three different failure criteria, maximum stress, Tsai‐Wu, and maximum strain, have been selected for the evaluation of the failure of C/C‐SiC as a type of genuinely orthotropic material. Based on the comparisons with experimental results, supported by necessary practical justifications, the Tsai‐Wu criterion was found to offer a reasonable prediction of the strengths, which can be assisted by the maximum stress criterion to obtain an indicative prediction of the respective failure modes.
... To reduce cost on time-consuming experiments, prediction of tensile properties is possibly carried out using the mechanics of composite models methods and numerical methods [19]. Generally, several elastic constants of composite may be accurately tested by experimental measurement, but this research method is usually expensive and time consuming. ...
... Nevertheless, the comparison study of experimental and prediction model on the random discontinuous composites under critical length are limited, especially on natural fibre reinforcement over a range of fibre volume fractions (V f ) and fibre lengths (l f ). This research focused on several models to produce the accurate calculation on the tensile properties of composites [8,19,20]. The Tsai-Pagano, Christensen and Cox-Krenchel models had been used to predict the elastic constants, while the predictions of tensile strength were carried out by using Hirsch and Bowyer-Bader models [8]. ...
In this research, the tensile properties' performance of compression moulded discontinuous randomized zalacca fibre/high-density polyethylene under critical fibre length was analysed by means of experimental method and micromechanical models. These investigations were used to verify the tensile properties models toward the effect of fibre length and volume fraction on the composites. The experimental results showed that the tensile properties of composites had significantly increased due to the enhancement of fibre length. On the contrary, a decline in the tensile properties was observed with the increase of volume fraction. A comparison was made between the available experimental results and the performances of Tsai-Pagano, Christensen and Cox-Krechel models in their prediction of composites elastic modulus. The results showed that the consideration of fibre's elastic anisotropy in the Cox-Krenchel model had yielded a good prediction of the composites modulus, nevertheless the models could not accurately predict the composites modulus for fibre length study.
... It is therefore necessary to outline the elastic constants of a lamina and relate them to the engineering constants. The stress-strain relation of a composite lamina can be properly written in the matrix form defined in terms of Young's modulus, shear modulus and Poisson's ratio [7] ...
Material designers have extensively analyzed, utilizing failure theories, the dependability and service response of composite materials for their intended uses. To increase the precision and accuracy of performance prediction, failure theories have undergone numerous revisions. The current study uses the finite element method to predict the tensile response while also using Puck's failure criterion and the damage evolution law to composite laminates. Five non-hybrid sequences made of paperboard, ultra-high molecular weight polyethylene (UHMWPE), glass fibre, aramid fibre, and carbon fibre have been put through experimental investigation of tensile and three-point bending. The numerical analysis has been carried out using the Material Designer, ACP® and Structural Analysis modules of ANSYS® finite element software. The experimental results have been compared with the numerical results, to arrive at the set of empirical constants for the different materials.
This paper defines the structural strength criterion for 4DL-reinforced carbon-carbon materials. For this scheme, fiber reinforcement consists of four groups of reinforcing elements, three of them are located in parallel planes with the angles of 120° between them and the fourth one is normal to them. The paper addresses the first failure of the material corresponding to its yield stress, in this point, one of the material components deviates from linear elastic behavior. A composite material is considered to be non-uniform structurally and consists of a matrix and reinforcing elements, rods. Those rods, in their turn, represent a unidirectional composite. To analyze the stress-strain state of individual components of the material, a three-level elastic model is built that uses the analytic approach at the micro level, while at higher levels it uses the finite element method. For numerical calculations, a structural cell of the material is taken. The boundary conditions provide small to negligible influence of the edge effects, thus simulating the behavior of the infinite volume of the material. For the material components, local strength criteria are introduced, where the fields of the criterion quantities are averaged over the volume of the structural cell. The strength surface of the material that corresponds to its first failure is obtained, and the conclusion is made that the suggested criterion provides a reasonable agreement with the available data on the typical carbon-carbon composite characteristics. Based on the calculated dependencies of the material’s yield stress on the load direction, a procedure is suggested to identify the model parameters based on the material failure behavior analysis using standard tensile and compressive tests. Estimated discrepancies between the results calculated using the suggested criterion and those obtained using the limiting stress criterion for biaxial stress states are given. It is shown that the discrepancy may reach tens of percent and in some cases the material strength increases in comparison with that in the uniaxial stress state. The results are subject to verification tests in order to verify the model for advanced spatially reinforced carbon-carbon composite materials.
The use of composite materials in several sectors, such as aeronautics and automotive, has been gaining distinction in recent years. However, due to their high costs, as well as unique characteristics, consequences of their heterogeneity, they present challenging gaps to be studied. As a result, the finite element method has been used as a way to analyze composite materials subjected to the most distinctive situations. Therefore, this work aims to approach the modeling of composite materials, focusing on material properties, failure criteria, types of elements and main application sectors. From the modeling point of view, different levels of modeling—micro, meso and macro, are presented. Regarding properties, different mechanical characteristics, theories and constitutive relationships involved to model these materials are presented. The text also discusses the types of elements most commonly used to simulate composites, which are solids, peel, plate and cohesive, as well as the various failure criteria developed and used for the simulation of these materials. In addition, the present article lists the main industrial sectors in which composite material simulation is used, and their gains from it, including aeronautics, aerospace, automotive, naval, energy, civil, sports, manufacturing and even electronics.
Material strength under complex stress states is vital for structure design. This paper studied the strength and failure behaviour of 3D C/C composites under compression-shear coupled loads. Experiments were conducted using a modified anti-symmetric four-point bending (MAFPB) method and off-axis compression method. Two dominant failure modes were observed; 1) shear and 2) compression. Mode transitions under relatively low shear/compressive rations were also observed. Results show that the material exhibits significantly lower failure stress under shear-compressive load compared to compressive or shear strengths alone. Further analysis revealed that meso-scale geometry characteristic including tow crimps and interfacial cracks are the main inducements: (1) tow crimps lead to local bending moment and increase local shear stress, (2) matrix-tow cracks formed under shear load degrade the lateral support of axial tows, (3) matrix fibre splitting and local buckling within tows induced by compressive load further reduce the shear strength of axial tows. Failure stresses in off-axis tests are lower compared to those in MAFPB tests due to the existence of bi-axial compression. These findings show that shear failure is a weakness for the 3D C/C composite and can provide insights for further material design and structural strength analysis.
