Optimization of a B-pillar with tailored properties under impact loading

Abstract

Within the study's scope, the impact performance of a boron steel B-pillar with three different hardness values and six different B-pillar designs with tailored properties was compared in crashworthiness. Impact simulation results were compared in terms of spe-cific energy absorption and peak crushing force values of the B-pillar. “Upper part T500 and lower part O25 heat treated B-pillar” gave the highest specific energy absorption. “Upper part O25 and lower part T25 heat treated B-pillar” resulted in the lowest peak crushing force and gave the second highest specific energy absorption. This pillar was used in optimization studies to maximize specific energy absorption and minimize peak crushing force. The single-objective optimization problem was solved with Adaptive Re-sponse Surface Method and Sequential Quadratic Programming methods. Specific ener-gy absorption value increased by 47.7% from 1.32 to 1.95 kJ/kg compared reference de-sign for both techniques. Multi-objective Genetic Algorithm and Global Response Sur-face Method were utilized to solve the multi-objective optimization problem, and similar Pareto front curves were obtained. For both methods, the optimal B-pillar with max spe-cific energy absorption increased the specific energy absorption by 51.5% from 1.32 to 2.00 kJ/kg compared to the reference design. However, peak crushing force increased 14.9% from 63.7 to 73.2 kN. Optimal B-pillar could be used in the automotive industry.

Keywords

• B-pillar
• Boron steel
• Crashworthiness
• Optimization
• Spesific energy absorption (SEA)
• Peak crushing force (PCF)
• Tailored property

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