Dynamic characterization of layered and graded structures under impulsive loading

Relatively thick graded and layered structures have significant potential a rmor applications, and have recently been manufactured with some degree of consistency. The mechanical behaviors of the individual layers within such a structure play an important role in determining the structure's resistanc e to impact. This work examines layered and graded plates made of metal-cer amic composites with the volume fraction of ceramic reinforcement varying t hrough the thickness. In a previous work (Acta Mater 46 (1998) 5633), the r esults of high-strain-rate experiments have been used to develop a model fo r the viscoplastic response of metal-matrix composites of varying volume fr action. Using this model, numerical results are presented on the propagatio n of large amplitude stress waves through layered and graded structures. Th e results show that the wave propagation within layered and graded structur es involves a complex coupling of elastic and viscoplastic response. It is demonstrated that the choice of gradation has great significance for impact applications. (C) 2001 Elsevier Science Ltd. All rights reserved.