Prediction of elastic anisotropic thermo-dependent properties of discontinuous fiber-reinforced composites

Abstract

This study focuses on the micromechanical prediction of temperature-dependent elastic properties of a composite made of a polypropylene matrix reinforced with discontinuous glass fibers. Firstly, an experimental investigation of the mechanical behavior is presented. Specimen are cut from injection-molded rectangular plates using a pattern based on fiber orientation. The microstructure is investigated by X-ray tomography at the specimen center and an average orientation tensor is calculated. Tensile tests are performed over a temperature range from ambient temperature to 85℃ and dispersion of mechanical properties is rather low; moreover, they are representative of the ones measured out of an industrial injected part. Then, the evolution of elastic properties with orientation and temperature is analyzed and compared with numerical predictions calculated with Mori–Tanaka homogenization scheme.

Mean Value-Amplitude Method for the Determination of Anisotropic Mechanical Properties of Short Fiber Reinforced Thermoplastics

“…Despite short fibers with a length typically between 0.2 and 0.5 mm, a pronounced fiber alignment may result from the injection molding process. The local fiber orientation distribution affects the mechanical as well as the thermomechanical properties throughout the plate [1,2]. To exploit the full capability of the material, the anisotropic behavior must be considered in the design process.…”

“…Figure 1 provides some examples, showing the same analyzed specimen. The determination of statistical fiber orientation is possible prior to component design by using suitable process simulation software [6,[8][9][10][11] or on an existing component by imaging techniques such as X-ray microcomputer tomography (µCT) [2,7]. An advantage of the first method is an affordable prediction, while the second method analyzes the real microstructure and, thus, it is free from deviations by theoretical assumptions.…”

“…However, such specimens have a defined microstructure and thus do not allow for the determination of orientation-dependent properties. Therefore, the machining of specimens from injection molded plates in different directions allows for testing in different directions with regard to the molding direction, i.e., the main fiber orientation [2,14]. Nevertheless, properties obtained using machined specimens provide an average value of the material volume within the gauge length, i.e., a pronounced core-shell layer microstructure instead of a distinctive fiber orientation [15,16].…”

Mesoscale modeling and biocompatibility of nano-hydroxyapatite reinforced ultra-high molecular weight polyethylene composite

“…Lopez et al predicted temperature-dependent elastic properties of polypropylene glass fiber composite. 31 The elastic properties were determined in different directions and different orientations. Lala et al predicted the elastic modulus of particulate reinforced epoxy composite.…”