Study On Hygrothermal Residual Stress Of Carbon Fiber/epoxy Resin Composites With Finite Element Analysis And Micro-raman Spectroscopy Characterization

Due to its excellent integrated performance, Carbon fiber reinforced epoxy resin matrix composites (CF_L/EP) are widely applied in the field of national economy,national defense construction and so on. But moisture absorption behavior of CF_L/EP decreases their mechanical properties during the long-term service, while moisture absorption induced stress field is one of important effect factors. In our present study, the ABAQUS finite element analysis software was explored to simulation and analysis the stress field of CF_L/EP composite after moisture absorption. Simultaneously the stress value was measured by using Micro-Raman Spectroscopy technique (MRS). Therefore, this study both from theory and experiment supplies significant references for strength evaluation and life forecast of CF_L/EP composites during the service process.First, in this paper the analysis of stress field of CF_L/EP composite after moisture absorption was conducted by using ABAQUS finite element analysis software. The stress variation and regularity of CF_L/EP composite was studied respectively at different time and temperature. Simultaneously, the stress simulation in two different fiber distribution models (standard hexagon model and fiber randomly distribution model) was compared. The results showed that the stress in the composite was gradually increased with moisture absorption time prolonged. Furthermore, the composites at 80℃reach saturation ahead of time than at 37℃, but the saturation moisture absorption capacity of the former was bigger then the latter. The stress in the fiber randomly distribution model was higher than the standard hexagon model. Consequently, the fiber randomly distribution model was better matching the reality condition.Then, according to the principle that when the carbon fibers were subjected to stress/strain, its roman characteristic peak would shift and the frequency shift happened which always exhibited linear relation with stress/strain, in our study the moisture absorption stress field of CF_L/EP composites were characterized by using MRS. The moisture absorption capacity of varied points in the composite were compared. The results showed that the stress near interface was higher than in the matrix. Simultaneously, the stress values were influenced by fiber aggregation state. The dense fiber could effectively block the water diffusion in the composite. The experimental values were well matched with the finite element simulation results which indicated that stress field of CF_L/EP composite after moisture absorption was well simulated by exploring ABAQUS finite element analysis software.