Development and evaluation of the sandwich flexure after impact test

Abstract

A four-point flexure after impact test method has been developed to assess the damage tolerance of sandwich structures under flexural loading. This test method, recently standardized as standard practice ASTM D8388 by ASTM International, is designed for use with sandwich specimens that have been impact damaged per ASTM D7766. The test method utilizes a four-point flexure fixture to test specimens using the methodology from ASTM D7249, along with modifications specified in the practice. The sandwich configurations investigated consisted of carbon/epoxy facesheets with a Nomex® honeycomb core. Mechanical testing was conducted to evaluate the proposed specimen design, fixturing, and test procedure. Finite element analysis was used to finalize the specimen sizing.