Continuous Fiber Reinforced Polymer Composites Research Articles

Anisotropic Strength Approach for Wear Analysis of Unidirectional Continuous FRP Composites

Based on the anisotropic strength failure criteria, a model is introduced to predict the wear behavior of unidirectional continuous fiber reinforced polymer composites (FRP) for arbitrary fiber orientations. This approach, which includes the influence of the friction on the failure strength, is initially validated by comparison to experimental data for T300/Epoxy. The benefits of the model and trends for variation of wear with fiber orientations are subsequently ascertained and discussed.

Two-Dimensional Anisotropic Contact Behavior of Unidirectional Continuous FRP Composites

Using an explicit expression for the Barnett-Lothe tensors, an analytical method is introduced for determining the contact characteristics of anisotropic composite materials. The influence of arbitrary fiber orientations on the contact pressure distribution for unidirectional continuous fiber-reinforced polymer (FRP) composites is investigated. To demonstrate the proposed analytical method, the frictional sliding contact between a unidirectional FRP composites and a rigid parabolic cylinder is analyzed. Based on the theoretical results for different fiber orientation angles, the relationships between the contact characteristics of fiber-reinforced plastics and their tribological performance are analyzed and discussed.

Analysis of Composite Molding Using the Homogenization Method

In this paper, we present an application of the homogenization method to the analysis of Resin Transfer Molding (RTM) and Structural Reaction Injection Molding (SRIM). RTM and SRIM are relatively new molding processes for manufacturing continuous fiber reinforced polymer composites. First, the mold flow is analyzed. In the molding process, the resin experiences significant temperature changes as it fills the mold and forms a free boundary with air as it pushes out the air. In addition, the flow domain is the mold cavity packed with fiber perform, which is a porous medium. Here, the homogenization method is used to model the non-isothermal flow through porous media with free boundaries. A computer program is developed which is capable of simulating a three-dimensional mold flow using the finite element approximation. An example is provided for a three-dimensional part. Then, an analysis of the residual stress developed in the curing stage is given. The curing stage starts when the mold is completely filled...

Effect of Asperity-Scale Tensile Stresses on the Wear Behavior of Normally Oriented Fiber-Reinforced Polymer Composites©

Wear of unidirectional continuous fiber-reinforced polymer composites with fiber orientation normal to the contact plane, sliding over scribed stainless steel disks having a controlled surface topography, is investigated in relation to the tensile stresses developed near the contact region. The composite is modeled as a transversely isotropic half-space whose effective elastic moduli are estimated from composite micro-mechanical considerations. The scribed disk is treated as a rough surface whose controlled topographical features serve as model hemispherical indenters against the composite. With friction coefficients obtained from, the wear experiments, the tensile stress field at and below the composite surface is estimated. From this, an estimate of the theoretical depth of fiber-matrix separation (fiber debonding) is calculated based on the composite transverse tensile strength. A correlation between the wear rate and theoretical depth of debonding was shown for several composites. Presented at the 48t...

Controlled energy dissipation in fibrous composites. II: Microscopic failure mechanisms

Mechanical properties and microscopic fracture mechanisms of continuous fiber reinforced polymer composites were investigated. Perforated polyimide films (e.g. Kapton®) were added between composite prepreg layers to modify the interlaminar bonding strength. Addition of highly perforated films can increase the toughness of unidirectional glass/epoxy composites without an appreciable reduction in strength. The fibrous composites studied exhibit two fracture modes (compressive and tensile) when failed by three-point bending. In general, the compressive failure mode preceded the tensile failure mode. Real-time acoustic emission (AE) analysis was found to provide more fracture information which is otherwise not discernible from mechanical testing alone. The crack initiation stress level and the subsequent crack propagation mode were identified by real-time AE during deformation and by post-failure scanning electron microscopy fracture surface analysis.