Reply To: Analyzing displacement-strain discrepancy in layered shell element.

[Avnish Pandey]

Hi,

Hope by homogenous, you mean a single layer plate. And by sandwich you mean there are at least 3 layers comprising different materials.

If that is the case, then the strains will differ. The sandwich plate, with its layers, behaves differently under load due to the variation in material properties through the thickness and higher stiffness. For a single layer plate the bending and shear stiffnesses are coming from one layer. Whereas for a layered structure, the stiffnesses are summed for the number of layers (A,B,D matrices you might have heard of, check any composites textbook). These factors combined lead to distinct strain patterns despite both plates being bent by the same amount.

One thing you can test out. Try using the same material for the homogenous plate and the layers of the sandwich. You may observe the two deflecting by the same amount for the same loading and same thickness.

Best