Modeling of fiber-reinforced plastics taking into account the manufacturing process

In a joint project of the EMI and Fuji Heavy Industries Ltd. a method for the modeling of fiber-reinforced plastics was developed, taking into account the manufacturing process. Within this study, an approach for a detailed characterization and modeling of a fiber reinforced plastic is described and presented by the example of a PPGF30 material. The characterization of the orientation dependent material behavior includes tensile tests at different strain rates as well as tensile-unloading, compression and shear tests in 0°-, 45°- and90°-direction. Also, quasi-static and dynamic three-point bending tests are performed and act as validation tests for the simulation model. For further validation of the method and to evaluate the simulation model's approximation to reality, dynamic three-point bending tests are performed on a component with a ribbed structure. Regarding the modeling of the mechanical behavior, the fiber orientation distribution is taken into account by means of injection molding simulations, both in the sample plate and the component. These simulations provide information about the orientation state at discrete material points in terms of an orientation tensor. By means of the eigenvalues and the respective eigenvectors of the orientation tensors, the degree of anisotropy and the principle fiber direction are defined. However, the degree of anisotropy is considered in a gradual manner by defining several material classes, each covering different ranges of the greatest eigenvalue. This is a very time consuming approach, because for each material class, one set of parameters has to be calibrated iteratively. The impact of considering the degree of anisotropy on the simulation results is therefore investigated as well. Another crucial aspect within this work is the development of a program to automatically translate and map the injection molding simulation results to appropriate variables in the structural simulation model. Furthermore, high-resolution CT-scans of the sample plate and the component are created in order to perform a fiber analysis of the real material and hence to verify the injection molding simulation results.