Multi-level computational -experimental system for the analysis of strength and stiffness of elements of structures from composites reinforced by short fibers

The paper describes a multi-level computational -experimental system for the analysis of strength and stiffness of elements of structures from composites reinforced by short fibers, which combines the orientation models of reinforcing fibers, the mechanical characteristics of anisotropic material and the finite element model of the product. The experimental validation of the system is presented on the basis of the research of the stiffness and strength of the samples of the lugs of two sizes from composites reinforced by short fibers PEEK 90HMF20, cut from the plate along and across the casting direction. A casting model, which predicts the orientation of reinforcing fibers, was developed in Moldex3D system. Verification of the casting model was carried out using an experimental evaluation of the structure of the material by electron microscope TESCAN VEGA. The mechanical model of anisotropic material was developed in the Digimat system by the reverse engineering method based on the processing of experimental results of the samples cut from the plate at angles of 0 °, 45 ° and 90 ° to the casting direction. The finite element model of the lugs taking into account the anisotropy of the material in each cell was developed in the ANSYS Workbench system with the connection of the Digimat CAE module. The article describes that the Tsai-Hill criterion for transversely isotropic bodies (3D), using the setting of the first pseudo-grain failure (FPGF), makes it possible to reliably predict the load-carrying capacity of designs made by casting from composites reinforced by short fibers.