STP613

    Digital Computer Controlled Threshold Stress Intensity Factor Fatigue Testing

    Published: Jan 1976


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    Abstract

    The integrity of many structures depends on their resistance to fatigue crack propagation which is a function of the stress intensity factor. Furthermore, there appears to be a threshold level of the stress intensity factor range, ΔKth, below which crack growth is greatly inhibited.

    This paper describes a test method used to determine crack growth rate data in the region of this threshold value. The technique utilizes crack opening displacement as the controlled variable.

    Control is provided by programming a digital minicomputer to supply the command signal to the closed-loop servocontrolled test system. Use of the computer allows continuous operation and automatic data acquisition and reduction with a minimum of operator surveillance.

    Keywords:

    fatigue (materials), computers, test equipment, fatigue tests, fatigue crack growth


    Author Information:

    Kaisand, LR
    Mechanics of materials engineer and development engineer, Materials and Processes Laboratory, General Electric Company, Schenectady, N.Y.

    LeFort, P
    Mechanics of materials engineer and development engineer, Materials and Processes Laboratory, General Electric Company, Schenectady, N.Y.


    Paper ID: STP27908S

    Committee/Subcommittee: E08.03

    DOI: 10.1520/STP27908S


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