CET345W_LAB#3.Materials Testing Laboratory

Department of Engineering Technology CET 345W Materials Testing Laboratory Experiment No. 3 – Torsion Test Old Dominion University Civil Engineering Technology Department Kaufman Hall, Room 149 Norfolk, VA 23529 Table of Contents 1. Summary 2 2. Procedure 3 3. Equipment 4 4. Experiment Requirements 6 5. Required Data 7 6. Sample Calculations 10 7. Sketches/Graphs 13 8. Conclusions/Analysis 15 9. Appendix 16 1. Summary This test aims to teach the students how to conduct a torsional test on a round steel bar. The student will use the data from the 10k torsional machine to find the angle of the property at every 300 torque intervals. As torque is applied gradually at a constant speed, the students will see how the torque causes shear stress from the power on the transmitting members in the machine. The bar will continue twisting until the steel bar factures. At the maximum stress level, the students will see the round steel bar break as a result in failure. The test will show the shearing stress strain relationships are principle interest in connection with torsional loading. The plane sections of the round steel bar will remain plane after twisting. The circular section of the bar is the only one which the relationships can be applied to correction factors and can be employed for other shapes. 2. Procedure 1. With a micrometer caliper determine the mean diameter of the steel specimen near its mid-length. Assume the shearing proportional limit is 0.6 of the tensile proportional limit and the shearing modulus of rupture as equal to the tensile strength. Check with the instructor to ascertain tensile strength of the specimen. .........................................continued,..............................................