1 / 37

Lab #2 Report due TODAY

Lab #2 Report due TODAY. Individual Data Processing and Individual Write Up Lab #2 Report is due TODAY by midnight Answer Multiple Choice Questions ONLINE TODAY by midnight Answer Student Survey ONLINE TODAY by midnight

Download Presentation

Lab #2 Report due TODAY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. Lab #2 Report due TODAY • Individual Data Processing and Individual Write Up • Lab #2 Report is due TODAY by midnight • Answer Multiple Choice Questions ONLINE TODAY by midnight • Answer Student Survey ONLINE TODAY by midnight • Submit the Lab Report #2 in the drawer labeled “MECE204-Strength Lab” under M. E. Mail Folders

  2. Torsion Testing • Circular Cross-section Only • Determine Material Properties in Torsion • Draw Shear Stress-Strain Curve • Ductile or Brittle Failure ? • ASTM E-143 Test Method • Compare results from Tensile, Poisson’s & Torsion Test • Become familiar with Tinius Olsen Torsion Tester (10,000 in-lb capacity)

  3. Sign Convention

  4. Assumptions Perfectly linear-elastic behavior Circular x-section (solid or hollow) Small rotations Constant length Constant diameter

  5. No deformation A highly deformable member A circular x-section A grid of parallel circles and longitudinal lines on the outer surface

  6. After Deformation Two torques are applied Circles remain circles Longitudinal lines become twisted All angles are equal End x-section remains flat

  7. Angle of Twist A prismatic circular member Fixed at x = 0 Other end is FREE Loaded by a torque at the free end Angle (x) - angle of twist It depends on x: /x=constant

  8. Shear Strain After Before

  9. Shear Strain Distribution max = c  max - occurs on the outer surface  = (/c)  max Result valid also for circular tubes within the material Valid for plastic deformation also 9

  10. Shear Strain Distribution

  11. Shear Strain & Angle of Twist  =  *  / L max =  * D / 2 / L

  12. Shear Stress Distribution - Elastic Deformation only • X-section: linear distribution • Complimentary stresses in action • Shear stress occur on axial planes (normal to the x-section 12

  13. Shear Stress & Torque- Linear Elastic Deformation Only  = T *  / J max = T * D / 2 / J

  14. Modulus of Rupture tmax,psi gmax, rad Shear Stress-Strain Curve Slope = Dt/Dg = Shear Modulus, G Figure 3.2 Typical shear stress-strain diagram from a Torsion Test

  15. Linear Elastic Region – Shear Modulus

  16. Failure Surface – Tensile Testing

  17. Failure Surface – Torsion Test

  18. Brittle Failure – Torsion Test

  19. n t N V P Stresses on an Inclined Plane in an Axially Loaded Member • Seek for equilibrium after cutting along the oblique plane x

  20. Maximum Stress – Uniaxial Tension

  21. Comparing Tensile vs. Torsion Results

  22. Measuring Angle of Twist T=(R-R0)-(L-L0)

  23. Torsion Data Sheet

  24. Computing the Slip Angle

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

  26. Shear Strain and Stress =Radians(cor)*D/2/LH =16T//D3

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

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

  29. Entire Stress Strain Curve

  30. Elastic Curve

  31. Proportional Limit =G*

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

  33. 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.

  34. Torsion Results

  35. Comparing Tensile vs. Torsion Results

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

  37. Lab #2 Report due TODAY • Individual Data Processing and Individual Write Up • Lab #2 Report is due TODAY by midnight • Answer Multiple Choice Questions ONLINE TODAY by midnight • Answer Student Survey ONLINE TODAY by midnight • Submit the Lab Report #2 in the drawer labeled “MECE204-Strength Lab” under M. E. Mail Folders

More Related