Multi-objective optimisation of the cure of thick components

G Struzziero,A.A Skordos

doi:10.1016/j.compositesa.2016.11.014

Abstract

This paper addresses the multi-objective optimisation of the cure stage of composites manufacture. The optimisation aims to minimise the cure process duration and maximum temperature overshoot within the curing part by selecting an appropriate thermal profile. The methodology developed combines a finite element solution of the heat transfer problem with a Genetic Algorithm. The optimisation algorithm approximates successfully and consistently the Pareto optimal front of the multi-objective problem in a variety of characteristic geometries of varying thickness. The results highlight the efficiency opportunities available in comparison with standard industrial cure profiles. In the case of ultra-thick components improvements of up to 70% in terms of overshoot and 14h in terms of process time, compared to conventional cure profiles for ultra-thick components, can be achieved. In the case of thick components reduction up to 50% can be achieved in both temperature overshoot and process duration.

Highlights

The continuous expansion in utilisation of thermosetting composites and their adoption as a high performance solution in large complex structures has generated an increased impetus for minimising process costs whilst maximising product quality
It should be noted that these regions do not necessarily correspond to clustering of design parameters, i.e. it is possible that neighbouring points in the objective space arise from significantly different locations in the parameter space
It is expected that within a specific application legacy information implies a relative importance between the different objectives, unconditioned multi-objective optimisation can uncover new efficiency opportunities

Summary

Introduction

The continuous expansion in utilisation of thermosetting composites and their adoption as a high performance solution in large complex structures has generated an increased impetus for minimising process costs whilst maximising product quality. The selection of cure profiles in order to minimise the cure time and process costs has been investigated in the literature in the context of single objective optimisation studies [1,2,3,4,5,6] In these investigations considerations related to part quality, such as temperature overshoot or excessive thermal gradient, have been incorporated through the use of constraints. A comprehensive treatment of the problem requires simultaneous consideration of the different objectives related to quality and cost This has been carried out in the literature by combining objectives in a weighted sum in a single process performance metric [13,14]. Skordos / Composites: Part A 93 (2017) 126–136 of thick and ultra-thick characteristic composite component geometries

Cure simulation

A2 Ad E1 E2 Ed m n1 n2 b Tg0 Tg1 k

Multi-objective optimisation method

Results and discussion

Conclusions