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.

Application of the Finite Element Method in the Analysis of Composite Materials: A Review

Damage accumulation mechanism of composite laminates subjected to repeated low velocity impacts

Effects of braiding architectures on damage resistance and damage tolerance behaviors of 3D braided composites

Thermoplastic natural fiber reinforced composites are particularly attractive and ideal materials for weight critical applications, but the high melt-viscosity of the matrix hinders their full prospective utilisation. Commingled fabrics have evolved as an alternative solution to overcome the viscosity constrain and reduce the manufacturing cost by means of faster lay-up. A comparative performance evaluation was conducted in this research work on natural fibre-reinforced (jute, hemp and flax) laminates fabricated using woven, woven commingled and knitted commingled fabric architectures along with polypropylene matrix by compression moulding method. The damage behaviour of the fabricated laminates was assessed in terms of short-beam shear (SBS), drop weight impact and compression after impact (CAI) strength. The result shows that knitted commingled laminates exhibited higher SBS strength (up to 29% and 20%) and compression after impact strength (up to 37.9% and 25.3%) compared to the woven and woven commingled laminates. Nonetheless, the woven laminates ensure higher impact resistance owing to the interlacement of fibres compared to that of knitted and woven commingled laminates.

Effect of fabric architecture on the shear and impact properties of natural fibre reinforced composites

Composite structures are frequently subjected to repeated, low-velocity impacts, and these impacts usually occur at different positions of the same component, which is very common in daily use but lack of in-depth research. In the present paper, two positions at the same distance from the center of a carbon fiber reinforced polymer (CFRP) test specimen were impacted once with the same energy, respectively, and the mechanical responses during the impact and the various damages resulting from the impact were recorded. Then, the changes of the mechanical response curves were analyzed according to the damage characteristics, which revealed the influence of the four impact distances between the two impact positions and the three impact energies. The experimental results demonstrated that the impact behaviors and damage modes of the laminates were affected by the impact distance and energy in different ways. The coincidence degree of the same mechanical response curve and the separation degree of the damage region both directly indicated the correlation between the two impacts. Moreover, the maximum displacement of the specimen during the first impact reflected the difficulty level of the specimen deformation which had an important influence on the damage shape and area on the specimen. The characteristics of the critical separation distance between the two impacts were dissimilar in the case of different impact energies. Finally, semi-empirical relationships between the impact parameters and other parameters were obtained.

Experimental investigation of the double impact position effect on the mechanical behavior of low-velocity impact in CFRP laminates

Impact resistance and damage tolerance are of great significance in the design of composite structures. This study investigated the damage and failure mechanism of thin composite laminates under low-velocity impact and compression-after-impact (CAI) loading conditions. Four levels of impact energy were included in the test matrix. Delamination induced by low-velocity impact was captured using ultrasonic C-scan, and a three-dimensional (3D) digital image correlation (DIC) system was employed to measure full-field displacement during the CAI tests. Infrared thermography was also used to online monitor the thermal field variation of the test specimen during the impact and CAI process. The cross sections of typical tested specimens were inspected using an optical microscope and a scanning electron microscope (SEM). A 3D damage model that considers both interlaminar and intralaminar damage was proposed to study the complex damage and failure mechanism. Excellent correlation was obtained between the experimental results and the numerical results. The experimental results obtained from various tests and the results from the numerical simulation were combined to provide a new and deep insight of damage evolution and failure mechanisms under low-velocity impact and CAI loading conditions.

Damage and failure mechanism of thin composite laminates under low-velocity impact and compression-after-impact loading conditions

The impact resistance of fiber-reinforced polymer composites is a critical concern for structure design in aerospace applications. In this work, experiments were conducted to evaluate the impact performance of four types of composite panels, using a gas-gun test system. Computational efficient finite element models were developed to model the high-speed ballistic impact behavior of laminate and textile composites. The models were first validated by comparing the critical impact threshold and the failure patterns against experimental results. The damage progression and energy evolution behavior were combined to analyze the impact failure process of the composite panels. Numerical parametric studies were designed to investigate the sensitivity of impact resistance against impact attitude, including impact deflection angles and projectile deflection angles, which provide a comprehensive understanding of the damage tolerance of the composite panels. The numerical results elaborate the different impact resistances for laminate and textile composites and their different sensitivities to deflection angles.

Finite Element Study on the Impact Resistance of Laminated and Textile Composites.

The mechanical characterization of textile composites is a challenging task, due to their nonuniform deformation and complicated failure phenomena. This article introduces a three-dimensional mesoscale finite element model to investigate the progressive damage behavior of a notched single-layer triaxially-braided composite subjected to axial tension. The damage initiation and propagation in fiber bundles are simulated using three-dimensional failure criteria and damage evolution law. A traction–separation law has been applied to predict the interfacial damage of fiber bundles. The proposed model is correlated and validated by the experimentally measured full field strain distributions and effective strength of the notched specimen. The progressive damage behavior of the fiber bundles is studied by examining the damage and stress contours at different loading stages. Parametric numerical studies are conducted to explore the role of modeling parameters and geometric characteristics on the internal damage behavior and global measured properties of the notched specimen. Moreover, the correlations of damage behavior, global stress–strain response, and the efficiency of the notched specimen are discussed in detail. The results of this paper deliver a throughout understanding of the damage behavior of braided composites and can help the specimen design of textile composites.

Jun Xing

Papers

Damage and failure mechanism of thin composite laminates under low-velocity impact and compression-after-impact loading conditions

Finite Element Study on the Impact Resistance of Laminated and Textile Composites.

Progressive Failure Simulation of Notched Tensile Specimen for Triaxially-Braided Composites

Mesomechanical Simulation of Rate-Dependent Mechanical Behavior for Triaxially Braided Composites