Paper number 690

THE EFFECT OF TOOLING MATERIAL, CURE CYCLE, AND TOOL SURFACE FINISH ON SPRING-IN OF AUTOCLAVE PROCESSED CURVED COMPOSITE PARTS

Göran Fernlund and Anoush Poursartip

Department of Metals and Materials Engineering, The University of British Columbia 309-6350 Stores Road, Vancouver, B.C., Canada, V6T 1Z4

Summary

The purpose of this paper is to demonstrate the effect that the tooling material, the tool-surface condition, and the cure cycle can have on the spring-in of curved composite laminates. A set of experiments was performed with T800H/3900-2 carbon/epoxy composite C-channels made on aluminum tooling with different surface treatments and cured using both single-hold and double-hold cure cycles. The experiments were also simulated using the composites process modelling software COMPRO. Measurements of flange spring-in on the manufactured C-channels showed that the spring-in varied as much as a factor of two between the different specimens, and that there is a complex interaction between flange spring-in and the tooling material, the tool surface treatment, and the cure cycle. The predictions of flange spring-in from COMPRO was found to be about 20% too high in general, but all the observed trends were accurately predicted.

Keywords

spring-in, autoclave processing, deformations, modelling, finite element analysis, COMPRO.