Characterisation of bending mechanics in uncured laminated materials using a modified Dynamic Mechanical Analysis

TL;DR

This paper introduces a modified DMA method to measure the bending mechanics of uncured carbon fibre prepreg, aiding in process modeling and defect prevention during manufacturing.

Contribution

A novel modification of DMA combined with Timoshenko beam theory to characterize viscoelastic bending mechanics of uncured prepreg materials.

Findings

Temperature and rate-dependent shear stiffness values obtained.

Method enables parametrization of process models.

Provides insights for optimal manufacturing conditions.

Abstract

Understanding the bending mechanics of uncured carbon fibre prepreg is vital for modelling forming processes and the formation of out-of-plane wrinkling defects. This paper presents a modification of standard Dynamic Mechanical Analysis (DMA) to characterise the viscoelastic bending mechanics of uncured carbon fibre prepreg using Timoshenko beam theory. By post-processing DMA results, the analysis provides temperature and rate-dependent values of inter and intra-ply shear stiffness for a carbon fibre laminate and each individual ply with experimental results for AS4/8552 presented. The new methodology provides a means to parametrise process models, and also gives an indication of optimal manufacturing conditions to enable defect-free forming and consolidation processes.