Multiscale Modeling of Residual Stress Development in Continuous Fiber-Reinforced Unidirectional Thick Thermoset Composites

Abstract

The primary objective of this research is to develop a multiscale simulation framework to arrive at more realistic estimates of cureinduced residual stresses in the vicinity of the fiber-matrix interface in thick thermoset composites. The methodology involves simulations at the part level-employing homogenized rendering of the composite using micromechanics approach-within a finite element framework to obtain part-level temperature and degree-of-cure gradients and strains, and imposition of this information as boundary conditions at the mesoscale simulations, employing microstructural representative volume elements (RVE). A simple implementation of the multiscale framework, involving simulations at the part as well as the RVE levels, is demonstrated in the context of a thick, unidirectional continuous-glass-fiber-reinforced thermoset composite. The trends in the mesoscale residual stresses estimated by employing different RVE-level thermal and thermomechanical boundary conditions-displaying different degrees of coupling between the global and part-level simulations-are then examined. Significant differences are observed in the estimates of mesolevel cure-induced residual stress evolution obtained from simulations with a conventional symmetric RVE and those obtained by employing the multiscale approach involving detailed boundary conditions that realistically account for global thermal and mechanical strain histories.

Effect of residual-stress evolution during curing process on fatigue-life of fiber-reinforced polymers

“…The kinetics model for curing process has been taken for a polyester resin from Patham et. al 7 . Although, the mechanical properties of these cured resins differ significantly, both the resin systems exhibit similar fashion kinetics and follow Arrhenius equation during curing process.…”

“…There have been many studies to understand the volumetric change and development of residual stress during the curing process. 1,7,8 However, many of these studies assume an oversimplified constitutive behavior of the resin, 7,9,10 thus leading to unrealistic (over-predicted) residual stresses in the composites. Raheem et al 11 studied the effect of different curing conditions on properties like hardness, thickness, and residual stresses.…”

Analysis of Composite Structures in Curing Process for Shape Deformations and Shear Stress: Basis for Advanced Optimization

“…The coefficient of thermal expansion (CTE) is different in different directions for composite materials. Previous experimental studies have shown that the CTE of resin-dominated directions is much higher than that of fiber-dominated directions [20,21]. The stresses get built up on the fiber-matrix, lamina-laminate, and structural levels.…”