The present invention describes a hollow structural body such as an automotive unibody or frame rail that is reinforced with a reinforcing material such as a polyurethane foam by inserting into a portion of the structural body a bulkhead-containing insert, which, in combination with the structural body at the place of insertion, creates a containment region for the reinforcing material. Uncured reinforcing material can then be added to the containment region and cured.
The present invention solves a problem in the art by providing structural reinforcement to be easily and precisely placed within the structural body to provide, for example, enhanced crash resistance or improvements in acoustical properties.