Process modeling and characterization of thermoset composites for residual stress prediction

Abstract

A computational process modeling framework is presented to predict performance-altering residual stress generation at the microscale. A comprehensive material characterization effort is carried out as a function of the resin temperature and curing state, resulting in a novel material database. For a prescribed cure cycle, in-situ elastic modulus evolution, chemical and thermal strains, and random fiber distribution are shown to significantly influence residual stress generation. The results also show that a full process modeling analysis that includes the complete cure cycle (instead of the standard approach of just considering post-processing cool-down) is necessary to accurately predict manufacturing-induced residual stresses.

Keywords:

• Residual stress
• micromechanics
• process modeling
• curing
• thermosets
• material modeling
• finite elements

Acknowledgments

This material is based upon the work supported partially by the National Science Foundation under grant number IIP—1362022 (Collaborative Research: IUCRC for Wind Energy, Science, Technology and Research) and the Air Force Office of Scientific Research and the National Science Foundation under grant number IIP—1826232. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. The authors would like to thank NASA for their support of this research under grant numbers 80NSSC19K1246 and NNX17AJ32G. The authors would like to acknowledge the WindSTAR Industrial Advisory Board (IAB) members Steve Nolet, Amir Salimi (TPI Composites Inc.) for their technical contributions and Paul Ubrich, Nathan Bruno, Mirna Robles (Hexion Inc.) for their technical insight to the project and providing the resin material.

Disclosure statement

No potential competing interest was reported by the authors.