Accession Number : ADA328855

Title :   A Novel System for Miniature and Micro Specimen Fatigue and Fracture Testing.

Descriptive Note : Final rept.

Corporate Author : NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD

Personal Author(s) : Mercier, G. P. ; Tregoning, R. L.

PDF Url : ADA328855

Report Date : APR 1997

Pagination or Media Count : 25

Abstract : A microspecimen testing system has been developed to conduct real-time fatigue and fracture measurement on specimens less than 1 mm thick. Principal components include an interferometric-based crack opening displacement (COD) gage, a piezoelectric actuator, a resistive load cell, and an integrally machined testing cell and loading fixtures. Software has been developed to rapidly analyze interference signals and provide close-loop cyclic control. The principal system limitation is that the maximum real-time cyclic testing frequency is only 1/4 Hz for the relatively large specimens tested. System measurement resolution based on the load, COD, and load-line displacement is adequate for B = 1 mm SE(B) specimens, and illustrates the capability to test much smaller specimens. Initial system testing has indicated the following: the effects of planar rigid body motion have been simply discriminated from actual COD, compliance estimates based on these COD readings are accurate for a/W= 0.5, and system stability appears to be reasonable.

Descriptors :   *FRACTURE(MECHANICS), SOFTWARE ENGINEERING, REAL TIME, INTERFEROMETRY, PIEZOELECTRIC MATERIALS, ACTUATORS, CLOSED LOOP SYSTEMS, FATIGUE TESTS(MECHANICS), LOAD CELLS.

Subject Categories : Test Facilities, Equipment and Methods
      Mechanics
      Computer Systems

Distribution Statement : APPROVED FOR PUBLIC RELEASE