Paper number 859

CURING STRESSES IN THICK POLYMER COMPOSITE COMPONENTS PART I: ANALYSIS

M. R. Wisnom¹, L. G. Stringer², R. J. Hayman², and M. J. Hinton²

1University of Bristol, Department of Aerospace Engineering, Bristol, BS8 1TR, U.K
2Mechanical Sciences Sector, DERA, Farnborough, Hants, GU14 0LX, U.K.

Summary

Residual stresses throughout the cure cycle in thick filament wound tubes are analysed considering the effects of thermal expansion, chemical shrinkage, orthotropic viscoelasticity, and the gelation and cure process. Good correlation with measured strains is obtained, but only if gelation is modelled. It is shown that interlaminar stresses during the cure cycle are generally low. However, if three dimensional constraint is present, significant stresses can arise due to the relatively high bulk modulus of the material even in the partially cured state. Since the strength is low early in the cure cycle, it is postulated that these stresses may be responsible for delamination.

Keywords

residual stresses, cure modelling, delamination, finite element analysis, filament winding.