Core shear is the most common failure mode of a sandwich panel. Imagine bending a phone book: the pages slide past each other. That sliding is shear. If the foam is too weak, the top skin will buckle and the bottom skin will stay put, causing a sudden, catastrophic crack.
- Prevention: Select a foam core with a Shear Strength rating higher than the expected load. For heavy truck floors, use >1.2 MPa shear strength foam.

