Low-Velocity Stone Impact Simulation of Glass Fiber Reinforced Thermoplastics for Diesel Engine Oil Pans under Different Temperature Conditions

As environmental regulations continue to evolve, lightweight and high-performance materials have gained increasing attention in the automotive industry. While the shift from metallic to polymer-based engine components contributes to improved fuel efficiency and lower emissions, such transitions also require careful assessment of structural durability under real-world conditions. In this study, a thermoplastic oil pan was developed with design features optimized for impact resistance, including longitudinal and transverse ribs, integrated baffles, and reinforced mounting surfaces. A finite element model of the oil pan was developed in Hypermesh and simulated using Altair Radioss to assess its performance under localized stone impacts, which were modeled using a 17 mm diameter, 6 g rigid sphere. Two impact scenarios—targeting ribbed and non-ribbed regions—were evaluated under three temperature conditions: −40 °C, 23 °C, and 100 °C. Five glass fiber–reinforced thermoplastic composites (PA6-GF30, PA66-GF30, PPA-GF30, PBT-GF30, and PA9T-GF30) were analyzed in terms of energy absorption, maximum local displacement, and damage behavior. The results showed that rib structures effectively reduced crack formation and localized stress, especially at lower temperatures. Performance depends on impact location, so no single material ranks best in all cases; ribbed regions tend to favor PA6/PA66, whereas non-ribbed regions can favor PPA/PBT. Although no physical tests were conducted, the material modeling was supported by experimental data in the literature. This study contributes to the growing body of knowledge on lightweight thermoplastic oil pans and offers a practical methodology for evaluating their impact performance under service-like conditions.