Lightweight Vehicle Structures that Absorb and Direct Destructive Energy Away from the Occupants

Abstract

One of the main thrusts in current automotive industry is the development of occupant-centric vehicle structures that make the vehicle safe for the occupants. A design philosophy that improves vehicle survivability by absorbing and redirecting destructive energy in underbody blast events should be developed and demonstrated. On the other hand, the size and weight of vehicles are also paramount design factors for the purpose of providing faster transportation, great fuel conservation, higher payload, and higher mobility. Therefore, developing a light weight vehicle structure that provides a balance between survivability and mobility technologies for both vehicle and its occupants becomes a design challenge in this research. One of the new concepts of absorbing blast energy is to utilize the properties of “softer” structural materials in combination with a damping mechanism for absorbing the destructive energy through deformation. These “softer” materials are able to reduce the shock loads by absorbing energy through higher deformation than that of characteristic of normal high strength materials. A generic V-hull structure with five bulkheads developed by the TARDEC is used in the study as the baseline numerical model for investigating this concept. Another new concept is to utilize anisotropic material properties to guide and redirect the destructive energy away from the occupants along pre-designated energy paths. The dynamic performance of multilayer structures is of great interest because they act as a mechanism to absorb and spread the energy from a blast load in the lateral direction instead of permitting it to enter occupant space. A reduced-order modeling (ROM) approach is developed and applied in the preliminary design for studying the dynamic characterization of multilayer structures. The reliability of the ROM is validated by a spectral finite element analysis (SFEA) and a classic finite element analysis by using the commercial code Nastran. A design optimization framework for the multilayer plate is also developed and used to minimize the injury probability, along with a maximum structural weight reduction. Therefore, the goal of designing a lightweight vehicle structure that has high levels of protection in underbody blast events can be achieved in an efficient way.