What are the major failure modes of sandwich structures? What are the causes of each failure mode?
1) Facing Failure – Caused due to insufficient panel thickness, facing thickness, or facing strength;
2) Transverse Shear Failure – Caused when either the shear strength of the core or panel thickness is insufficient;
3) Core Local Crushing – Caused when compressive strength of the core material is too low;
4) Panel Buckling – Caused when either the panel thickness of core shear stiffness is too low;
5) Shear Crimping – Caused when either the shear modulus of the core materials or the shear strength of the adhesive is too low;
6) Face Wrinkling – May occur depending on the relative strength of the core in compression and adhesive in flatwise tension;
7) Intracell buckling – Occurs where the skins or faces are very thin and the cell size is large. This effect may cause failure by propagating across adjacent cells, thereby inducing face wrinkling.
How many of them did you already know? Do you have any other to add? Let us know in the comments!
Bibliographical Reference:
Advanced Composite Materials for Aerospace Engineering – Processing, Properties and Applications, Page 169.