Dimensional stability of thermoset composites: process simulation and optimization

Objectives

Method description

firstly, to develop a thermo-chemo-viscoelastic finite element code able to simulate the complex transformation taking place in the thermoset polymeric matrix composite throughout the manufacturing process. The finite element code is 3D and transient, and it couples four different physical components: the thermal model, the chemical model, the viscoelatic structural model and the composite compaction model.
secondly, to combine the finite element code with recent advances in finite-element based optimization techniques to optimize the manufacturing process (i.e., reduce the process time) while maintaining an acceptable part quality (i.e., keeping the residual stresses below a critical threshold value).

Graduate students involved in this project

Qi (Joyee) Zhu

Danny O'Brien

Min Li

Illustrative results

Thermo-chemical modeling of the manufacturing of a uni-directional composite laminate with varying thickness. The top and middle figures respectively present the temperature and degree-of-cure fields 70 minutes into the curing process. As expected, due to the exothermic reaction taking place in the composite, the center portion of the thicker part of the laminate experiences a "temperature spike". This phenomenon is further illustrated in the bottom figure, which presents the evolution of the temperature computed at three representative locations A, B and C (defined in the top figure) in the laminate. The blue curve corresponds to the applied temperature.

Process-induced dimensional change and stresses in a 90 degree composite corner (the fibers are oriented perpendicular to the Y-Z plane), showing the springforward process.