SEDL / STP / STP563-EB / STP32183S

Procedures and Problems Associated with Reliable Control of the Instrumented Impact Test

Ireland, DR
Assistant director, Materials Engineering, Effects Technology, Inc., Santa Barbara, Calif.

Pages: 27    Published: Jan 1974

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Abstract

The inherent characteristics of the instrumented impact test are discussed. The hammer energy is reduced by deforming the test specimen, accelerating the specimen from rest, Brinell-type deformation at the load points, vibrations of the hammer assembly, and elastic deformation within the machine. The limitations of the electronic components can affect the test results. The superimposed oscillations on the apparent load-time signal derived from the instrumented tup are best controlled by varying the initial impact velocity. Dynamic load cells must be calibrated by dynamic loading and then be checked by comparisons of dynamic and static test results for a strain-rate insensitive material. The analysis of instrumented tup signals for determination of various energy, deflection, and load values must be done with a clear understanding of dissolution of hammer energy, electronic limitations, and superimposed oscillations.