Arbitrary-Reconsidered-Double-Inclusion (ARDI) Model to Describe the Anisotropic, Viscoelastic Stiffness and Damping of Short Fiber-Reinforced Thermoplastics

Alexander Kriwet,Markus Stommel

doi:10.3390/jcs4020037

Abstract

Current state of the art, simulation methods to determine the frequency-, temperature- and humidity-depending stiffness and damping do not show an accurate prediction of the structural dynamics of short-fiber-reinforced thermoplastics. Thus, in the current work the new developed Arbitrary-Reconsidered-Double-Inclusion (ARDI) model has been used to describe the stiffness and damping. Thereby, a homogenization equation has been used to derive the transversal-isotropic stiffness and damping tensors. By rotating and weighting these tensors using orientation distribution functions (ODF), it is possible to create a material database. A validation of the developed ARDI model was performed on bending vibration specimens under variation of the fiber direction, temperature and humidity, to investigate the structural dynamics. In general, the comparison of the results of the simulation and experiments shows a good correlation of the eigenfrequencies and the amplitudes. The main differences in the simulation can be traced back to the used modelling of the damping behavior.

Highlights

Engineering plastics have become an important component of modern industry as a construction material, due to their good mechanical properties at low weight
Current state of the art, simulation methods to determine the frequency, temperature- and humidity-depending stiffness and damping do not show an accurate prediction of the structural dynamics of short-fiber-reinforced thermoplastics
A validation of the developed ARDI model was performed on bending vibration specimens under variation of the fiber direction, temperature and humidity, to investigate the structural dynamics

Summary

Introduction

Engineering plastics have become an important component of modern industry as a construction material, due to their good mechanical properties at low weight. The challenge is to describe the microstructural mechanics of the short glass fiber-reinforced plastics in a suitable material model for a reliable prediction of the structural dynamics behavior. Assuming that the fibers have an ellipsoidal shape, the local stress and strain fields of the individual phases in the composite were calculated with a localization equation. This describes the mean-field theory according to the Mori-Tanaka model [3] and builds the basis for extended models like Hill’s self-consistent model [4], Benvenistes reformulation of the Mori-Tanaka model [5] or the second-moment mean-field homogenization model of Dogri et al [6]

Methods

Results

Conclusion