Numerical and experimental investigation of Nylon66 (PA66) reinforced recycled carbon fiber composites and aluminum foam for application in vehicle crashworthiness and occupant protection per various FMVSS regulations

Abstract

In the past decade, there has been an increase in the usage of advanced composite structures and metal foam filler materials for a wide range of applications in the automotive industry, primarily due to their correct strength, stiffness, and energy absorption. In addition, these materials offer high impact resistance compared to traditional metals and foam materials like PU/IMPAXX. However, due to the destructive nature of the crashes, the costs involved in testing physical car models are escalating every year. For this reason, numerical simulations, particularly Finite Element Analysis (FEA), significantly lower the costs associated with physical model testing. The goal of this research is to investigate two different engineered materials; namely Nylon66 reinforced recycled carbon fiber (PA66 RCF), and aluminum metal foam, for crashworthiness applications. To achieve this goal, it is essential to have a library of mechanical properties with materials of interest. Firstly, the coupon level tests such as tensile, three-point bending, and compression are performed. The experimental test data is numerically validated to have a working and scalable LS-DYNA material card for the component level and full-scale simulations. Secondly, the component level simulations are performed on empty thin-wall square PA66 RCF tubes and aluminum foam-filled tubes to understand the compressive behavior of the materials and later compared against the empty thin-wall and aluminum foam-filled steel square tubes. Finally, full-scale dynamic simulations are performed according to the federal motor vehicle safety standards (FMVSS) NO.208, NO.214, NO.301R, and NO.216a using the LS-DYNA FE code. The materials are utilized in various regions of the vehicle including the front bumper, side driver door, rear bumper, and roof panel of a compact sedan finite element model. This study quantifies deceleration loads, energies, and compartment intrusion. It is demonstrated that applying PA66 RCF and foam materials significantly reduce compartment loads and intrusions. Therefore, both materials are shown to exhibit promising results in improving vehicle crashworthiness and occupant protection of ground vehicles.