THE MECHANISMS OF INTERLAMINAR CRACKING IN THICK RESIN TRANSFER MOLDED COMPOSITE CYLINDERS

A method is presented which predicts residual radial stresses in thick resin transfer moulded laminated cylinders due to polymerisation shri nkage of the curing resin, isolating the cure kinetics and stress anal ysis results in a radial heat transfer model and a thick cylinder shri nkage model, respectively. Mechanical properties of resin and laminate at progressive degrees of cure have been measured and used to identif y the mechanisms causing interlaminar cracking and high residual stres ses. Mouldings of thick tubular sections with different laminate const ructions have verified the theoretical analysis indicating that interl aminar cracking can occur due to differential shrinkage in the radial and circumferential directions because of constraints imposed in the c ircumferential direction by the glass preform. (C) 1998 Elsevier Scien ce Limited. All rights reserved.