Design criteria of multilayer fibers reinforced composite in bulky 3D loaded applications

In this research paper the design criteria of 3D loaded bulky shapes made from multilayer short carbon fibers reinforced epoxy using compression molding is studied. Five different design criteria are discussed with different limiting stress and strain values. The first criterion is based on the fibers local stresses; the second criterion depends on the interfacial bonding strength; the third criterion is the conventional failure one derived from the composite average strength. In addition to this the Hashin damage criteria are applied on the fiber and matrix of the composite. The mathematical models of the short fibers reinforced composites strength and interfacial bonding strength are reviewed. A finite element model is introduced to estimate the local stresses on the fibers, interfacial bonding stresses between the fibers and matrix, and the average composite stresses. The finite element model is checked on a representative volume element (RVE) of the composite with general fibers orientation and loading direction. The results obtained from the FEA analysis is used to check the design with the five design criteria, and compared with the tensile specimen from the experimental work as well. Finally, the finite element analysis and design criteria are applied on a 3D loaded bulky shape used in plumbing inspection chambers made from short fiberglass filled calcium carbonate reinforced polyester. The validated model and design criteria are checked on the results of the inspection chamber results.