Assignment

1. Students will run the experiment in combined lab groups.  Half of the groups will perform the experiment together at the same torsion machine, while the other half perform the experiment at the second torsion machine.  This will give large groups in some cases, but there is generally not time to run the test multiple times at the same station.  The test procedures are based on ASTM E143.
    
   • Data Sheet
   • Experimental Procedures
      
     
     
2. While the torsion samples are twisting to fracture, the entire class will perform a direct shear test on the Instron 4485.  The test procedures are based on ASTM ASTM B769.
    
3. Plot a torque vs. angle of twist curve.  Include enough data to show the fully plastic torque.  Determine the slope of the straight line portion of the curve.  Be sure to stay below the theoretical limit of linear-elastic action.  Determine the modulus of rigidity G using the slope.  Determine the shearing yield point τ_YP using the value of fully plastic torque T_FP.  The reference value for the shearing yield point should be one half of the tensile yield point you obtained during the tension test on A36 steel.
    
   • Original Data Sheet
   • Sample Results
   • Sample Calculations
      
4. Summarize your results, as per your teachers' instructions, and submit at the start of the next lab class.