Improving Modal Frequencies in Class 5 Truck Fuel Cell Tank Structure through Topology Optimization

<div class="section abstract"><div class="htmlview paragraph">In addition to electric vehicles (EVs), hydrogen fuel cell systems are gaining attention as energy-efficient propulsion options. However, designing fuel cell vehicles presents unique challenges, particularly in terms of storage systems for heavy hydrogen tanks. These challenges impact factors such as NVH (noise, vibration, and harshness) and safety performance. This study presents a topology optimization study for Hydrogen Energy Storage System (HESS) tank structure in Class 5 trucks, with a focus on enhancing the modal frequencies. The study considers a specific truck configuration with a HESS structure located behind the crew cab, consisting of two horizontally stacked hydrogen tanks and two tanks attached on both sides of the frame. The optimization process aimed to meet the modal targets of this hydrogen tank structure in the fore-aft (X) and lateral (Y) directions, while considering other load cases such as a simplified representation of GST (global static torsion), simplified side impact, and angled impact. By utilizing solid and shell elements, as well as Frequency Response Function (FRF) analysis, various load paths and configurations were explored to identify efficient designs that meet the modal targets and structural requirements. The optimized structure was verified and translated into a feasible and manufacturable design.</div></div>