Stochastic Thermal Properties of Laminates Filled with Long Fibers.

Jan Turant

doi:10.3390/ma14102511

Abstract

In this paper, the stochastic parameters of the effective thermal conductivity of multilayer composites are considered. The examined specimens of composites were built with a different number of layers and each had a different saturation density of a composite matrix with fibers. For each case of laminate built with a prescribed number of layers and assumed saturation density, 10,000 tests of its effective thermal conductivity were carried out using numerical experiments. It was assumed that the fibers located in each layer were rectilinear, had a circular cross-section and that they could take random positions in their repeatable volume elements (RVEs). In view of the mentioned assumptions, the heat flux passing throughout a cross-section of a composite sample, perpendicular to the fibers’ direction, was considered. The probability density functions were fitted to the obtained data and then the chosen stochastic parameters of the effective thermal conductivity coefficients were determined.

Highlights

A material’s properties are determined during physical tests
The shown distributions were created with the following parameters: saturation density, 0.35; number of layers, 5; and number of repeatable volume elements (RVEs), 10 in each layer
To evaluate the most probable magnitude of an effective thermal conductivity, the modes were calculated in each investigated case of the laminate

Summary

Introduction

A material’s properties are determined during physical tests. The kind of test depends on the kind of properties that are being determined. Typical material properties include mechanical, thermal, optical and electromagnetic properties. In the case of composite materials composed of known materials with known properties, virtual tests of their properties can be conducted with accuracy depending on the quality of the physical and mathematical models of a phenomenon and the quality of the solving procedure. It should be pointed out that the properties of composite materials cannot be determined with the same precision as typical structurally uniform materials such as steel. The stability of a composite material’s properties is not so obvious and depends on the properties of the components but on the arrangement of the components too

Methods

Results

Discussion

Conclusion