The development of a structural magnesium instrument panel (IP) beam is presented in this paper. This magnesium IP was designed to be a structural load bearing member in a crash event. Unlike many IPs in production today, this IP helps mid-engine vehicles achieve certain FMVSS 208, US NCAP, IIHS and OEM standards for occupant crash protection.
In typical front engine vehicles, the front-end structure absorbs the crash energy with the sandwiched engine acting as rigid body to resist the crash loads and intrusion into passenger compartment. However, in mid engine vehicles, the front-end structure is inadequate to fully absorb the crash energy and at the same time resist intrusion. Without a structural IP beam to resist crash loads, it is unlikely that mid engine vehicles can successfully meet the FMVSS 208, US NCAP, IIHS and OEM standards for occupant crash protection.
With that in mind, this magnesium IP was designed as a structural load-bearing member. In a crash event, the IP beam is designed to withstand significant amount of crash loads emanating from the front-end structure, without causing appreciable failure. The IP beam helps secure the integrity of the front-end structure and prevent unacceptable intrusion into the passenger compartment. Some objective performance criteria were established for the IP beam. Finite element simulations were performed to evaluate the IP’s performance in frontal (full & 40% offset) and dynamic side impact conditions. Besides occupant crash protection, the IP was also designed to meet typical NVH targets.
With packaging constraints, the challenge was to design an IP beam that uses minimal space but at the same time meets the crash and NVH targets. Numerous challenges had to be overcome to develop the final design. In this paper, the authors discuss in detail the design issues, material assumptions, manufacturing constraints, performance requirements and analysis methods that went into the development process.