A new design of a 2D twill woven composite front firewall for electric vehicles

As the automotive industry shifts toward electric vehicles (EVs), reducing weight has become critical to improving energy efficiency and driving range. Traditional steel components, while robust, significantly increase vehicle mass, leading to higher energy consumption. Composite materials, especially carbon fiber-reinforced plastics (CFRP), offer a compelling alternative—combining high strength, stiffness, and corrosion resistance with remarkable weight savings. However, designing composite structures for EVs remains challenging due to their multi-scale nature and anisotropic properties.

This study tackles this challenge by focusing on the front firewall, a crucial structural component in high-performance electric sports cars. Unlike conventional metals, woven composites require a multi-scale design approach, considering fiber behavior at microscopic levels while ensuring structural integrity at the macro level. Previous research has largely concentrated on meso-scale mechanics, leaving a gap in holistic design strategies for real-world automotive applications.

The research team developed a multi-scale modeling and hierarchical optimization strategy for a 2D twill woven composite (2DTWC) firewall. By integrating micro-, meso-, and macro-scale analyses, they accurately predicted mechanical properties, achieving a maximum error of just 7% compared to experimental data—a significant improvement over traditional methods.

The optimized composite firewall demonstrated 36% weight reduction compared to conventional designs while increasing overall stiffness by 26%. This breakthrough not only enhances vehicle efficiency but also improves crashworthiness and durability. The study also introduced a hierarchical optimization process, combining free-size optimization, size optimization, and composite shuffling to refine material layout for maximum performance.

The implications of this research extend beyond firewalls: (1) Scalability: The multi-scale approach can be adapted to other composite EV components, such as doors, roofs, and chassis structures. (2) Manufacturing Efficiency: By optimizing fiber orientation and layering, production waste can be minimized, lowering costs. (3) Next-Gen EVs: The methodology supports the development of ultra-lightweight, high-performance electric sports cars and even urban EVs seeking extended range. Future work could explore real-time adaptive optimization for dynamic load conditions or hybrid composites integrating recycled fibers for sustainability.

This study marks a pivotal advancement in composite design for electric vehicles. By bridging the gap between microscopic fiber behavior and macroscopic structural performance, the proposed multi-scale hierarchical optimization strategy delivers a lightweight, high-strength firewall solution. As automakers push toward greener, more efficient transportation, such innovations will be instrumental in shaping the next generation of EVs—proving that cutting-edge materials science is key to a sustainable automotive future.

Reference

Author: Junfei Yan ^a b, Jian Song ^a, Bengang Yi ^a, Yi Quan ^a, Cheng Xu ^a, Wenyuan Gong ^a, Zhaojun Du ^a, Tengyong Liu ^a, Changchun Xie ^a, Darong Liang ^a, Zihao Pu ^a, Zhexuan Dong ^a

Title of original paper: Multi-scale analysis and hierarchical optimization design of a 2D twill woven composite front firewall for electric vehicles

Article link: https://doi.org/10.1016/j.geits.2025.100251

Journal: Green Energy and Intelligent Transportation

https://www.sciencedirect.com/science/article/pii/S2773153725000015

DOI: 10.1016/j.geits.2025.100251

Affiliations:

a Automotive Engineering Research Institute, Byd Auto Industry Company Limited, Shenzhen 518000, China

b School of Mechanical Engineering, Shandong University, Shandong 250100, China