2011 Objective : The objective of this project is to design and build a test rig that is inexpensive and portable; which can grade the strength of small round timbers quickly and accurately, requiring minimal user input. Objective : The objective of this project is to design and build a test rig that is inexpensive and portable; which can grade the strength of small round timbers quickly and accurately, requiring minimal user input. Mobile Apparatus to Mechanically Grade Round Timbers Sponsored By: Dr. Thomas Gorman University of Idaho Current State of Grading: Visually Graded Inaccurate Logs are graded very conservatively Based on number of knots, knot size, slope of grain and major defects Given a grade of 1, 2, 3 or are marked ‘for agricultural use only’ Current State of Grading: Visually Graded Inaccurate Logs are graded very conservatively Based on number of knots, knot size, slope of grain and major defects Given a grade of 1, 2, 3 or are marked ‘for agricultural use only’ Future State of Grading: Mechanically Graded Non-destructive Simply Support the log, place a known center load, measure the deflection. Solve for Modulus of Elasticity Found that logs test with a much higher MoE than given by visual graders Future State of Grading: Mechanically Graded Non-destructive Simply Support the log, place a known center load, measure the deflection. Solve for Modulus of Elasticity Found that logs test with a much higher MoE than given by visual graders Support Load Cell Ultrasonic Transducer Hydraulic Ram Hydraulic Pump/Electronics Mechanical Engineers: David McCord, Lucas Reid Chris Wagner, Brad Tensen, Nate Stephens Special Thanks to: Dr. Jay McCormack, Dr. Thomas Gorman, Chris Bowers, Joe Plummer, Russ Porter, Joe Thompson Support Problem: There is a growing demand for small round timber (3-9in diameter) to be used in construction applications. Using visual grading techniques, timbers are currently rated at approximately half of their mechanically determined design strengths. Problem: There is a growing demand for small round timber (3-9in diameter) to be used in construction applications. Using visual grading techniques, timbers are currently rated at approximately half of their mechanically determined design strengths. Solution: Our solution to this problem was to create a test rig that mimics the design of Dr. Gorman’s in-lab tensile tester. Solution: Our solution to this problem was to create a test rig that mimics the design of Dr. Gorman’s in-lab tensile tester. 6 inch Diameter Lodgepole Pine Used in 5,000 sq-ft. Library Darby, Montana. I-Beam Computer Scientists: Stephen Fischer, Doug Drobary, Ben Adler Supports Center the log for loading, while minimizing contact stresses. I-Beam Selected to be 15x stiffer than the stiffest log that will be measured to reduce error. Hydraulic Pump/Ram Provide load used to deflect the log, can apply up to 2000 lbs Loadcell Measures load applied by hydraulics to log, accurate to ± 1.5lbs Ultrasonic Transducer Measures deflection of log off of the loadhead, accurate to ±.01 in. User Interface Automates hydraulics, while collecting data from loadcell and transducer. It also calculates the final MoE. Supports Center the log for loading, while minimizing contact stresses. I-Beam Selected to be 15x stiffer than the stiffest log that will be measured to reduce error. Hydraulic Pump/Ram Provide load used to deflect the log, can apply up to 2000 lbs Loadcell Measures load applied by hydraulics to log, accurate to ± 1.5lbs Ultrasonic Transducer Measures deflection of log off of the loadhead, accurate to ±.01 in. User Interface Automates hydraulics, while collecting data from loadcell and transducer. It also calculates the final MoE. User Interface Allows user to run experiment with minimal input. Required inputs for each test are: -Specimen ID -Preload % -Diameter-Load Limit -Span User Interface Allows user to run experiment with minimal input. Required inputs for each test are: -Specimen ID -Preload % -Diameter-Load Limit -Span