Characterisation of inter-ply shear in uncured carbon fibre prepreg

Understanding the inter-ply shear behaviour of uncured carbon fibre prepreg is fundamental to avoiding process-induced defects during manufacturing of large-scale components. Shear tests for AS4/8552 are compared to a one-dimensional viscoelastic–plastic model for inter-ply shear. The paper presents a methodology capable of determining the parameters of temperature, rate and pressure required for minimum resistance to movement of a prepreg. Investigating the joint strength and friction values individually shows that friction increases with temperature, contrary to previous work, and that the new value of joint strength is predominant at lower temperatures. Rate dependent variables are strongly linked to the resin behaviour, confirming the need for a viscoelastic model. Simple application to industrial scenarios is discussed along with more complex process modelling.