HIGH-SPEED LUMBER GRAIN ANGLE MEASUREMENTS FOR TENSILE STRENGTH ESTIMATION

MORE ACCURATE TENSIL STRENGTH ESTIMATION FOR STRUCTURAL LUM-BER COULD BE AN IMPORTANT PART OF THE MSR (MACHINE STRESS RATING) SORTING PROCESS IN MODERN LUMBER MILLS. TODAY'S MSRMETHODS WHICH MAVE NOT CHANGED MUCH IN 25 YEARS HAVE PROVED THEMSELVES ECONOMICALLY SOUND THROUGHOUT MUCH OF N. AMERICA AND THE REST OF THE WORLD. EVERYONE IN THE CHAIN INCLUDING PRODUCER, STRUCTURAL COMPONENT MANUFACTURER, AND ULTIMATE CONSUMER BENEFITS ECONOMICALLY FROM THIS MEANS OF MORE EFFI-CIENTLY UTILIZING THE FORESST RESOURCE. STILL, EVEN IN MSR LUMBER GRADES THERE IS LARGE VARIABILITY IN TENSILE STRENGTHMUCH OF WHICH COULD BE REMOVED IN THE SORTING PROCESS IF AC-CURATE GRAIN ANGLE MEASUREMENTS COULD BE MADE AT PRODUCTION SPEEDS. RECENT RESEARCH REPORTED BY THE AUTHORS HAS SHOWN HOW TO USE GRAIN ANGLE INFORMATION FOR ESTIMATING TENSILE STRENGTH. THE PROPOSED RESEARCH COVERS THE ONLY REMAINING UNKNOWN; HIGH SPEED GRAIN ANGLE MEASUREMENT. IF SUCCESSFUL, THE OUTCOME WILL BE THE FIRST MAJOR STRIDE FORWARD IN SORTING LUMBER SINCE BENDING MODULUS OF ELASTICI-TY WAS FIRST USED COMMERCIALLY TO BEGIN THE MACHINE STRESS RATING PROCESS IN THE EARLY 1960'S