Analysis of Fiber Orientation and a Simulation of Damage Fracture Prediction Using an X-ray Phase Imaging Method for Discontinuous Carbon Fiber Random Laminated Molded Products

Abstract

In chopped carbon fiber tape reinforced thermoplastic（CTT）material, the anisotropic region of fiber orientation after press molding often causes the degradation of mechanical properties and damage and fracture. This study explores means of obtaining the fiber shape and fiber orientation tensors from molded products and then predicting the CTT mechanical properties and damage fracture locations. Extensive fiber shape data obtained by X-ray CT image processing are analyzed using a simple method to create a fiber waviness model.The fiber orientation tensor of the molded product is obtained through X-ray phase imaging. The material properties of a finite element model with CTT are calculated and mapped from the fiber waviness model and orientation tensor, and damage fracture prediction is simulated. Results showed that the fracture positions of both the test and simulation agreed in specimens having large anisotropic regions. However, the specimens with small anisotropic regions did not match. Therefore, the images of strain distribution of the test piece under a tensile load were compared by cross-correlation. Results showed a large correlation between the tensile test and simulation results, thus confirmed the effectiveness of the simulation.