Characteristics of an improved boundary insert for sandwich panels with lattice truss cores

Abstract

Composite sandwich panels with lattice truss cores have dramatic static and dynamic characteristics, which are widely used in aerospace industry. Owing to the inability to sustain localized loads of joining, valid inserts are required to enable the interconnection of the sandwich panels. The present study develops a novel boundary insert parallel to the facesheets for pyramidal lattice truss core sandwich panels. Analytical-mechanical models are addressed for the proposed boundary insert subjected to in-plane pull-out, in-plane shear as well as out-of-plane shear loads and experimental tests are carried out to characterize mechanical behaviors. Failure sequences and mechanisms are discussed comprehensively and good correspondence is obtained with analytical prediction. Finite element simulation models are developed for visualization of internal load distribution. Experimental results show that significant improvements in load capacities can be achieved by the developed boundary insert compared with the interconnection concepts for honeycomb sandwich panels.