CRASHWORTHINESS, DESIGN OPTIMIZATION, DOUBLE HAT, AXIAL LOADING

• Main Author: Kahlil Gibran Reza Putra, Mochamad
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik (Rekayasa, enjinering dan kegiatan berkaitan)
• Online Access: https://digilib.itb.ac.id/gdl/view/54871
• Institution: Institut Teknologi Bandung

The increasing of accidents fatality from land, water, or air transportation makes transportation safety become a topic that is often discussed whether it is from industrial and manufacture side or from the government side. Crash box is one of the passive transportation safety systems where its function is to absorbs impact energy when collision occur. This final project will be focused on double hat crash box configuration because double hat configuration is relatively easy to manufactured and from previous research, it is shown that double hat configuration has a better crashworthiness parameter than top hat and simple square configuration. Numerical simulation and optimization will be conducted on double hat and double hat taper configuration to determine the most optimum designs that give the best crashworthiness parameter. Mean crushing force (Pm), crushing force efficiency (CFE), and specific energy absorption (SEA) will be selected as objectives for optimization process. Numerical simulation will be conducted using nonlinear explicit finite element method while for optimization, Kriging surrogate modelling method will be used. Results shown that it is more efficient to increase crash boxes’ thickness rather than its perimeter in terms of crashworthiness performance improvement. Aspect ratio parameter, which is the ratio between the width and the length of crash boxes’ cross section, can improve crash boxes’ crashworthiness although it’s not significant. Whereas, for taper angle parameter, crash boxes with taper angle tend to have a lower peak force (Pmax) but the crushing force efficiency (CFE) and specific energy absorption (SEA) improve significantly. Multi-objective optimization cannot be conducted with CFE and SEA as objectives because there is no trade-off between the two objectives. Meanwhile, for multi-objective optimization with Pm and SEA as objectives, optimization process for double hat configuration gives Pareto solution sets where the most optimum configuration is obtained at thickness (t) 3 mm, aspect ratio (a/b) 1, and perimeter (p) 203 mm. Optimization process for double hat taper configuration also gives Pareto solution sest, but there are some solutions in Pareto solution sets that are obtained from initial sample simulation results where these solutions are located on the edge of the design space. The most optimum configuration for double hat taper is thickness (t) 3 mm, aspect ratio (a/b) 1, perimeter (p) 203 mm, perimeter ratio which is a ratio between upper and lower perimeter crash boxes’ cross section (prat) 0.85, and taper angle (????) 1.45°.