Author(s)

S.P. Joshi

Abstract

Impactor dynamics and contact modelling in impact problems S.P. Joshi Mechanical and Aerospace Engineering Department, University of Texas at ABSTRACT A low velocity impact induced damage assessment requires knowledge of con- tact behavior, transient elastic wave propagation, crack nucleation, and propa- gation and interaction. Each of these aspects are discussed in this paper. It is emphasized that the temporal and spatial distribution of impact load influences the stress field in the vicinity of impact where crack nucleation takes place and therefore plays an important role in defining impact induced fracture initiation. It is argued that static indentation laws may be employed to couple target (plate) dynamics with the impactor dynamics if the impact duration is an order of mag- nitude higher than the time taken by the longitudinal wave to travel through-the- thickness of the target. The transverse normal stress remains compressive in the near impact region and is negligible in the

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