STP1380: The Difference Between Total Absorbed Energy Measured Using an Instrumented Striker and that Obtained Using an Optical Encoder

    Manahan, MP
    President, MPM Technologies, Inc., State College, PA

    Stonesifer, RB
    Owner, Computational Mechanics, Inc., Julian, PA

    Pages: 17    Published: Jan 2000


    Abstract

    The application of optical encoders in Charpy impact energy measurement has improved significantly the accuracy of “dial energy” determination. Instrumented strikers offer an alternative method of energy measurement which is accurate and reproducible for both conventional and miniature specimen testing while providing additional useful information such as general yield load, peak load, brittle fracture load, and brittle fracture arrest load. It has been observed that the total absorbed energy measured using these two technologies, while generally in good agreement, sometimes differs by a significant amount. The instrumented striker total absorbed energy has been found to be higher or lower than the optical encoder energy depending on the ductility of the test specimen and other factors. This paper examines and provides explanations for these energy differences. A summary of mechanisms for pendulum energy loss, other than in fracturing the test specimen, is provided along with estimates of the amount of energy which may be associated with each mechanism.

    Keywords:

    impact testing, instrumented striker, absorbed energy, optical encoder


    Paper ID: STP14394S

    Committee/Subcommittee: E28.07

    DOI: 10.1520/STP14394S


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