Multilayer assemblies with surface depressions and methods of producing and using them

A method comprising:

• disposing a first porous fiber reinforced thermoplastic layer on a first surface of a core layer to form a multilayer assembly, wherein the first porous fiber reinforced thermoplastic layer comprises a web of open celled structures formed by a plurality of reinforcing materials held together with a thermoplastic material;
• and
• applying a first stimulus to a first surface of the multilayer assembly to provide a plurality of first depressions in the core layer and across the first surface of the multilayer assembly, wherein the applied first stimulus forces the first porous fiber reinforced thermoplastic layer into the plurality of first depressions in the core layer to enhance bonding between the first porous fiber reinforced thermoplastic layer and the core layer.