Characterising the hot drape forming process and the effect of fibre shearing on the mechanical properties of highly draped composite components

摘要

The hot drape forming process has been identified as a potential method of reducing manufacturing costs. This process consists of forming flat laminates into components incorporating comples curvature. Intra-ply shearing occurs during the forming process which has a detrimental effect on the mechanical properties of the final component. This paper outlines development trials conducted to identify the most significant parameters affecting the forming process. These were shown to be: vacuum rate, laminate geometry and forming temperature. The effect of intra-ply shearing is demonstrated through structural testing of hemispherical formed components. Two techniques are used to predict the effect of intra-ply shearing; Classical laminate theory and modified rule of mixtures. These methods are incorporated into a finite element analysis which is compared to the experimental data from the hemisphere tests. The modified rule of mixtures produced the most accurate results, however, further refinement of the finite element model is required.