This test practice covers compression residual strength properties of composite sandwich panels, which have been subjected to quasi-static indentation or drop-weight impact per Test Method D 7766/D 7766M prior to application of compressive force. NOTE: When used to determine the residual strength of drop-weight impacted plates, this test method is commonly referred to as the Sandwich Compression After Impact, or SCAI, method. This practice supplements Test Method D7136/D7136M with provisions for testing sandwich specimens. Several important test specimen parameters (for example, facing thickness, core thickness and core density) are not mandated by this practice; however, repeatable results require that these parameters be specified and reported. The method utilizes a flat, rectangular composite sandwich panel, previously subjected to a damaging event, which is tested under edgewise compressive loading using a stabilization fixture. Note: The damage tolerance properties obtained are particular to the type, geometry and location of damage inflicted upon the panel. The properties generated by this test method are highly dependent upon several factors, which include specimen geometry, layup, damage type, damage size, damage location, core material and boundary conditions. Thus, results are generally not scalable to other configurations, and are particular to the combination of geometric and physical conditions tested. This test method can be used to test undamaged composite sandwich panels, but care should be taken to prevent undesirable failure modes (such as end crushing).
composite materials; sandwich composites; sandwich construction; compression after impact; compression testing; compressive residual strength; damage tolerance
ASTM D30.09 has developed D7766 Standard Practice for Damage Resistance of Sandwich Constructions, and desires an additional, corresponding standard practice that addresses damage tolerance of sandwich constructions. The proposed standard is in response to this expressed need.
The title and scope are in draft form and are under development within this