Crush Analysis of Compression Modeled Chopped Fiber Tubes

Abstract

Chopped fiber reinforced thermoplastic composites can be very useful in developing lightweight high strength recyclable components for automobiles. Such parts can be produced using injection or compression molding process. In general compression molding is preferred as it can help retain the fiber length compared to injection molding process. The longer fiber results in improved structural properties. A computational method is introduced for the virtual simulation of performance of chopped fibers in polymer composites. This new approach did lead to the development of a specialized Multi-Scale Material Characterization of composite system comprising of: a) chopped fiber material modeling based on nano-mechanics failure theory considering fibers as inclusion, b) micro-macro mechanics, and damage failure theory, c) tensor stiffness averaging technique; and d) structural durability and damage tolerance (D&DT) analysis under crush service loading. The material model established in MCQ-Chopped is integrated/coupled with FEA with GENOA platform software to perform Multi Scale Progressive Failure Analysis (MS-PFA). The crush modeling of composite crushed tube was test validated using GENOA software in 3 distinct integrated steps using, such as follows: a) Characterizing Material Properties - of composite materials composed of chopped fibers using MCQ-Chopped and validating against Toyota coupon test data; b) Mapping and Transformation - of statistical average tensor orientation from unstructured Moldex3D detailed model to LS-DYNA FE solver. In this regard GENOA platform software algorithm was used to perform 3D models data management and visualize the mapping error between two dissimilar meshes. And c) De-Homogenized Multi-Scale Progressive Failure Dynamic Analysis (MSPFDA) was employed to capture the damage and failure at multi scale levels, namely micro (constituents fiber/matrix) and macro through-the-thickness. The simulation results are compared with test provided load vs. displacement and acceleration vs. time curve. In addition the software prediction provided the damage and fracture evolution and the contributing failure mechanism. Keywords: Compression Molding, Chopped Fiber, crushed tube, De-homogenized modeling, Tensor orientation stiffness, Effect of defects, Strain Rate Effect.