The use of experimentally-determined impact force as a damage measure in impact damage resistance and tolerance of composite structures

摘要

An instrumented drop-weight impact rig, ultrasonic C-scan and CAI test rig form a basic experimental system needed for the quantitative investigation of impact damage resistance and damage tolerance assessment. It is shown that it is essential to have an impact rig designed with certain traits along with other selected impact conditions so that dominant damage mechanisms occurring during impact can be identified with the threshold forces of recorded impact force--time curves. The so-determined impact force data are used to study impact damage resistance. It is demonstrated that the ratio of measured threshold impact forces is a useful alternative to residual compressive strength usually used for damage tolerance assessment. This provides a fast and cheap technique without resort to complex and expensive CAI tests.