Tensile proportional limit ௦ ? ? sample equation

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Tensile Proportional Limit: 𝑡𝑒𝑛𝑠𝑖𝑙𝑒 𝑝𝑟𝑜𝑝𝑜𝑟𝑡𝑖𝑜𝑛𝑎𝑙 𝑙𝑖𝑚𝑖𝑡 = ௦௛௘௔௥௜௡௚ ௣௥௢௣௢௥௧௜௢௡௔௟ ௟௜௠௜௧ ଺଴% Sample Equation (at rupture): 𝑡𝑒𝑛𝑠𝑖𝑙𝑒 𝑝𝑟𝑜𝑝𝑜𝑟𝑡𝑖𝑜𝑛𝑎𝑙 𝑙𝑖𝑚𝑖𝑡 = ଷଵ଺଻଼ ଺଴% = 52796.9 𝑝𝑠𝑖
5 7. Sketches/Graphs Table 3 is to be used to compare the average mechanical properties of the steel rod against the mechanical properties that were calculated using the data collected during the experiment. The pertinent data can be seen in Tables 1 and 2. The values of tensile and proportional limit will be compared along with the values of ultimate shearing strength. Table 3: Average Mechanical Properties Figure 6: Rod Failure Sketches Figure 6 shows a sketch of the steel rod after failure. The steel rod was subject to a torsional force. The rod failed due to an overload of torsion which resulted in the rod cracking nearly straight through the rod toward one of the ends. 8. Conclusion/Analysis In this experiment the effects of a torsional force on a mild steel rod were successfully observed and the values of modulus of rigidity, approximate ductility of specimen, modulus or rupture, ultimate shear strength, tensile proportional limit, and mode of failure were calculated. Table 4 shows the analysis of the data collected compared to the average mechanical properties data in Table 3. For the purposes of this experiment the average mechanical properties of 0.2% Carbon Cold Rolled Steel were used to compare to the experimental values obtained from the mild steel rod. When using the average properties as the known value and comparing that to the experimental values obtained a 12% error can be seen for both the tensile proportional limit and the shearing proportional limit and a 6% error for the ultimate shear strength.
6 Table 4: Comparison of Experimental vs. Average Values In order to obtain similar results, it would be helpful to have more detailed information on what kind of steel has been used. For example, in this experiment the only information that was provided was that the rod was a mild steel rod. It would have been helpful to know further information so that the values for average mechanical properties could have been more accurately compared and so that the experiment could be repeated to obtain similar results if desired. Appendix 1 – References Hibbeler, R. C. (2017). Mechanics of materials (10th ed.). Boston: Pearson. Appendix 2 – Torsion Test Lab Data Experimental Value Average Properties Percent Error (%) Tensile Proportional Limit (psi) 52,797 60,000 12.01 Shearing Proportional Limit (psi) 31,678 36,000 12.01 Ultimate Shear Strength (psi) 55,908 60,000 6.82

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