ANALYSIS OF LOAD OSCILLATIONS IN INSTRUMENTED IMPACT TESTING

This work deals with the dynamic fracture tests of the 3-point bending notched specimen. The apparent frequency of the load oscillations is investigated for different materials (steel, aluminium, PMMA and Al2O3 ). It is shown that the contact stiffness between the striker and the specimen plays a predominant role in the vibrating aspect of the impac t. The 2 degrees of freedom (dof), intensively used in the literature, can predict the oscillations qualitatively, but cannot realistically model ail the details of the vibrations of the specimen. A numerical m odel with several dof is considered by means of a modal analysis and a nalyzed through the experimental program. (C) 1998 Elsevier Science Lt d. All rights reserved.