The tensile strength of the core material in a sandwich structure can be determined using the flat-wise tension fixture shown below.
The sandwich is bonded between two aluminium bonding blocks with holes drilled in them. These blocks then fit into grips (as shown on the left and right) that are screwed into the test machine. The grips can swivel to accommodate for any misalignment during testing. The sample is then loaded until fracture occurs. The maximum force is divided by the cross-sectional area to get the tensile strength.