Underbody shield materials that can provide an underbody shield with high impact resistance are described. In some configurations, an underbody shield composition comprises a porous core layer comprising a plurality of reinforcing fibers, a lofting agent and a thermoplastic material. In some instances, the underbody shield composition may also comprise a film such that an underbody shield produced from the composition can withstand at least 50 individual impacts as tested using a SAE J400 protocol.

The invention relates to a process for producing a composite structure comprising a main structure and an external shell connected to the main structure, where the main structure comprises a molded foam obtainable from prefoamed foam particles and the external shell comprises a hollow structure open at one end or at two opposite ends, and where a frictional connection is formed between the molded foam and the hollow structure.

A combined material honeycomb core and methods of manufacture are presented. The combined material honeycomb core comprises a plurality of cells arranged in columns and rows formed of multiple materials, the multiple materials comprising a metallic material and either a second metallic material or a non-metallic material.

A combined material honeycomb core and methods of manufacture are presented. The combined material honeycomb core comprises a plurality of cells arranged in columns and rows formed of multiple materials, the multiple materials comprising a metallic material and either a second metallic material or a non-metallic material.