FEM Analysis of Mechanical and Structural Properties of Long Fiber-Reinforced Composites

Abstract

This chapter deals with studies of the mechanical properties of samples from long fiberreinforced composite structures that would contribute to the optimization of the developed constructions made of them. First, the basic issues of composite structures reinforced with long fibers (carbon or glass) and generally of composites with the specification of parameters that would lead to the optimization of mechanical properties with respect to the theoretical strength are presented. Further, the possibilities and methods of measurements of composite reinforced with carbon and glass fibers are described. This is followed by the introduction of analytical models for the description of the transversal isotropic composite, where these mathematical relations allow the determination of unknown elastic constants and they are also important for the verification of numerical models. Finally, it is comprehensively outlined the problems of creating a numerical model of advanced composite fibrous structure for determining the mechanical properties, both through the description of the continuum, and complex numerical model with a structural configuration enabling approach to allow closer interaction among fibers and matrix. Compared to the averaged values obtained from experimental samples, numerical simulations show a similar trend of stress on strain, with results obtained from simulations.

Flexural testing of carbon FLP composite bars with annular and square cross section

“…The mechanical loading of composite causes many different processes in the inner structure that varies with the actual deformation as is mentioned also in (Petrů, 2017). Therefore, it is necessary to simplify or neglect some characteristic features in modeling of such structures and determination of all unknown parameters is necessary.…”

“…First, these processes have to be verified by experimental measurements. For model simulation a different numerical methods as finite element method (FEM), discrete element (DEM), boundary element method (BEM) or finite volume method (FVM) are available (Petrů, 2017). The comparison of experimental measurements results with FEM analysis will be presented in this paper.…”

Numerical Modeling of the Effects of Fiber Packing and Reinforcement Volume Ratio on the Transverse Elasticity Modulus of a Unidirectional Composite Material Glass / Epoxy

“…The boundary conditions based on the lines (or face) of symmetry in the RVE are used in several research works, for example [9,12,14].…”

“…Most theories of homogenization are limited to a few idealized mathematical models of two-phase systems. Many analytical approaches have been developed over the years [6][7][8], and comprehensive bibliographic studies have been published on the prediction of longitudinal and transverse elastic modulus of unidirectional composites, the estimation of the reinforcement factor ξ and the use of the model of Halpin-Tsai to determine the transverse elasticity modulus E2 [9][10][11][12][13][14][15][16][17][18].…”

Determination of shear modulus for fiber composite using experimental-calculation methods

“…Therefore, the determination of mechanical properties is very important [2]. The properties of composites depend on the reinforcement -in which direction there are more fibers, in that direction the strength is higher [3,4]. If it is necessary to obtain a material that works well in tension or bending in a predetermined direction, the fibers should be laid along the lines of normal stresses action (Fig.…”