1. Torsion Testing Become familiar with Tinius Olsen Torsion Tester (10,000 in-lb capacity) ASTM E-143 Test Method Draw Shear Stress-Strain Curve Determine Material Properties in Torsion Ductile or Brittle Failure ? Compare results from Tensile, Poisson’s & Torsion Test 2024-T351 Al-Cu Alloy Specimen

2. Torsion Data Sheet

3. Computing the Slip Angle

4. Manually Recorded Data  R0  L0  T =(  R -  R0 )-(  L -  L0 )  slip =  H -(L H /L T )  T  cor =  H -  slip

5. Shear Strain and Stress  =Radians(  cor )*D/2/L H  =16T/  /D 3

6. Integrating Computer Data  slip = constant  cor =  H -  slip

7. Selecting Computer Data Head Angle = 30.00 deg When Protractors taken OFF Max Torque = 1931 in-lb

8. Entire Stress Strain Curve

9. Elastic Curve

10. Proportional Limit =G* 

11. Proportional Limit Plot columns H, I, & J

12. Key Ideas - Torsion Shear strain formula is valid in both elastic & plastic region Torque formula is valid in linear elastic region ONLY Thus, shear stress formula is valid until proportional limit After proportional limit, shear stress formula overestimates stress.

13. Torsion Results

14. Comparing Tensile vs. Torsion Results

15. Comparing Lab 1, 2, & 3 Experimental Results

16. Failure Surface – Torsion Test

17. Lab #3 Report due NEXT WEEK Cover Page + Abstract Data Sheet Spreadsheet Plot #1: Entire Shear Stress-Strain Curve Plot #2: Shear Modulus Plot #3: Proportional Limit Material Property Tables (two tables) + Fracture Surface Comments and Conclusions