Structural Modules with Improved Crash Performance Using Thermoplastic Composites

A new group of composite materials “Advanced GMT” which are used for the economic production of light weight complex shaped parts in the automotive industry are presented. Advanced GMT consist of a combination of different technical textiles such as woven or stitched fabrics and non-woven mats which are impregnated with a polypropylene resin to a laminate. The laminate is flow molded to complex shaped components with a total cycle time of 30 to 60 seconds using standard equipment.

The use of advanced GMT for weight saving and performance improvement of structural modules is discussed. Examples of such modules include hatchback or side door modules, front-end modules, bumper beams with integrated energy absorbers (crash cones) or spare wheel wells and structural elements in the power train. Common for all these type of modules or components is the need for geometric freedom in the design, crash worthiness including high specific energy absorption and ductile failure behavior, structural stiffness and economic production of large series.

A case study of a side door module is presented. Aspects of the functional integration is shown with the complex features of the part allowing mounting of several elements such as side window railings, the lock, speakers etc. The versatility of advanced GMT is shown by a comparison in the crash behavior of the door module. The addition of local reinforcement of advanced GMT to a GMT structure increased the crash energy absorption with 300%, without weight increase.