Characterization of adhesive joints under ballistic shear impact

In this paper, we study the ballistic impact strength and energy absorption of single lap joints in predominantly shear (Mode II) loading. The behavior of two adhesives, namely a methacrylate and an epoxy, with steel adherends is presented. The developed ballistic shear test is analogous to the static single lap-shear joint test and uses an apparatus that is commonly used in ballistic penetration tests. The testing approach is coupled with a non-linear finite element parametric study to estimate the mechanical properties of the adhesives under ballistic loading. The finite element stress analysis results indicate that the shear failure stresses of both adhesives are much greater under ballistic loading than under static loading. In addition, the shear ballistic tests also show greater strength and energy absorption than the adhesive joints tested in Mode-I dominant ballistic impact. Though both the epoxy and methacrylate adhesives used in this study have similar static shear strengths, the shear strength of the epoxy under ballistic shear was found to be significantly higher than that for the methacrylate.