Mohr circle excel template

Laboratory 7 Principal Strains and Stresses OBJECTIVE: The goal of lab 7 is to determine principal strains and stresses from rosette analysis, flexure formula, and Mohr’s circle. LAB WORK: Follow the procedure in the previously given lab instruction for setting up the P-3500 (Strain Indicator) Measurement procedure 1. Measure the distance from the center line of the rosette to the loading point on the free end of the beam (L). 2. Measure the width (b) and thickness (t) of the beam with a micrometer. 3. Using the cantilever beam flexure formulae , calculate the load P, to be applied at the free end of the beam for a stress value of σ = 15000 psi. 4. Back the calibrated loading screw and insert the beam into the Flexor with the gaged end in the clamp, and with the gage on the top surface. 5. Connect the lead wires from the rosette to the binding posts of the flexor as per the wiring diagram given in the handout. Be careful when handling the wires. 6. Connect one of the common leads from the flexor (#1) to the S- binding post of the strain indicator. 7. Connect the other common lead from the flexor (#2) to the D-120 binding post of the strain indicator. 8. Connect the independent lead from Gage Element 1 (#3) to the P+ binding post of the strain indicator. 9. After balancing the strain indicator amplifier, set the gage factor to the value given on the strain gauge. 10. With the beam unloaded set the instrument to RUN. 11. Adjust the balance control of the strain indicator until the digital readout indicates precisely zero (there may be some fluctuation; if so, note the average reading). Do not adjust the balance control again during the experiment. 12. The initial reading for the strain Gage Element 1 should now be recorded on the worksheet as 0με (or the averaged reading from the step above). 13. Turn the strain indicator off, and disconnect the independent Gage Element 1 (#3) lead from the P+ binding post; leave the common leads connected. 14. Now, connect the cable lead from Gage Element 2 (#4) to the P+ binding post and then turn the instrument on. 15. Without adjusting the balance controls, note the reading on the indicator display. 16. This is the initial reading for Gage 2, and should be recorded on the worksheet. 17. Turn the strain indicator off, and disconnect the independent Gage Element 2 (#4) lead from the P+ binding post, leaving the common leads connected. 1 18. Connect the cable lead from Gage Element 3 (#5) to the P+ binding post and turn the instrument on. 19. Without adjusting the balance controls, note the reading on the indicator display. 20. This is the initial reading for Gage 3, and should be recorded on the worksheet. 21. After recording the initial reading for Gage Element 3, leave the gage connected and apply the previously calculated load ‘P’; Hang the weights on the free end of the beam. 22. Record the exact weight ‘P’ on the work sheet and record the indicated strain for Gage Element 3 in the table. 23. With the load on the beam, turn the strain indicator off and remove the Gage Element 3 (#5) and replace it with the Gage Element 2 (#4) to the P+ binding post. 24. Turn the strain indicator on and record the indicated strain for Gage Element 2 in the table. 25. With the load on the beam, turn off the strain indicator and remove the Gage Element 2 (#4) and replace it with Gage Element 1 (#3) to the P+ binding post. 26. Turn the strain indicator on and record the indicated strain for Gage Element 1 in the table. 27. With the last gage still connected to the instrument, remove the load from the beam. The strain indicator readout should now indicate the same (within a few με) as the initial reading for this gage. 28. Finally, use a protractor to measure the counterclockwise angles between Gage 1 axis and lateral and longitudinal beam axes. LAB FUNDAMENTALS AND REPORT Table of See Template Contents Goal of lab 7 Introduction Principal stresses, principal strains, principal angle, and principal planes with necessary figures and equations Method Equipment/Materials Equations Procedure Results and Discussion Present principal strains and stresses and principal angles for individual analysis methods. Compare test results (rosette and Mohr’s) with theoretical principal stresses (flexure formula).