THE NIST CENTER FOR NEUTRON RESEARCH WITH THE BT8 ENGINEERING DIFFRACTOMETER IS INVOLVED IN NEUTRON DIFFRAC…

Public award description

THE NIST CENTER FOR NEUTRON RESEARCH WITH THE BT8 ENGINEERING DIFFRACTOMETER IS INVOLVED IN NEUTRON DIFFRACTION MEASUREMENTS DURING MECHANICAL TESTING OF MATERIALS. THIS WORK INVOLVES DEFORMING MATERIALS USING HIGHLY SPECIALIZED MECHANICAL TESTING FRAMES AND RECORDING THE RESPONSE. A KEY MATERIAL RESPONSE IS THE EVOLUTION OF THE STRAINS (BOTH ELASTIC AND PLASTIC STRAINS) IN ALL DIRECTIONS, WHICH ARE CORRELATED WITH THE EVOLUTION OF OTHER RESPONSES SUCH AS THE APPLIED LOAD AND CURRENT TEMPERATURE. THE SURFACES OF THE TEST PIECES ARE NOT PERFECTLY PLANER AND WILL TEND TO MOVE IN SPACE DURING THE TESTING, AND THE STRAIN FIELDS MAY NOT BE HOMOGENEOUS OVER THE SURFACE. THE CURRENT STATE OF THE ART METHOD FOR THE NON-CONTACT MEASUREMENT OF SURFACE STRAIN FIELDS (IN THE COMBINED ELASTIC AND PLASTIC STRAIN RANGE) IS DIGITAL IMAGE CORRELATION (DIC). THE NON-CONTACT CHARACTER OF THE MEASUREMENT IS KEY FOR AVOIDING INTERFERENCE WITH THE NEUTRON BEAM. THREE-DIMENSIONAL (3D) DIC IS REQUIRED TO ACCURATELY MEASURE THE 3D SHAPE AND MOTION OF THE TEST PIECE RELATIVE TO THE CAMERA POSITIONS.