SMALL GAGE LENGTH LASER EXTENSOMETER

OPTRA WILL DEMONSTRATE A SMALL GAGE LENGTH LASER EXTENSOMETER CAPABILITY FOR USE WITH SMALL TEST PIECES AND/OR FRACTURE ANALYSIS. THE EXTENSOMETER WILL USE AN ARRAY DETECTOR TECHNIQUE WHICH WILL (A) ALLOW SIMULTANEOUS MONITORING OF STRAIN AT A LINEAR ARRAY OF POINTS ON THE SURFACE, AND (B) ALLOW FRACTURE GROWTH TO BE ACCURATELY MONITORED WITHOUT A PRIORI KNOWLEDGE OF THE EXACT LOCATION OF THE FRACTURE. GAGE LENGTHS RANGING FROM 0.01 INCH TO 0.25 INCH WILL BE POSSIBLE USING THIS TECHNIQUE. THE SYSTEM WILL APPROACH MICROSTRAIN RESOLUTION AND WILL HAVE AN ELECTRICAL BANDWIDTH SUFFICIENT FOR HIGH FREQUENCY CYCLIC TESTING. THE SYSTEM WILL BE ABLE TO MEASURE INPLANE SHEAR STRAIN AS WELL AS IN-PLANE AXIAL STRAIN, AND WILL ALLOW ANALYSIS OF BOTH MODE I AND MODE II FRACTURE GROWTH. THE SYSTEM WILL BE NON-CONTACTING, WILL GENERALLY REQUIRE NO SAMPLE PREPARATION, AND WILL BE IDEALLY SUITED TO HIGH TEMPERATURE STUDIES.