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Part A - Calculate thermal stress Learning Goal: To solve for thermal stresses in statically indeterminate bars subject to a temperature change. Most materials change in size when subjected to a temperature change. For a temperature change of a homogenous isotropic material, the change in length of a bar of length L due to a temperature change AT can be calculated as dt = QATL, where a is the linear coefficient of thermal expansion—a property of the material the bar is made from. For a member that is not constrained, this expansion can occur freely. However, if the member is statically indeterminate the deflection is constrained. Thus, changes in temperature will induce internal thermal stresses. The compatibility condition is that the changes in length due to the temperature change and to the induced stress must cancel each other out, NL dr + Op=0, where Op with N being the induced internal normal AE force, positive for tension. If the bar originally has no internal normal forces and the temperature decreases by AT = 40 K, what is the thermal stress developed in the bar? Express your answer with appropriate units to three significant figures. View Available Hint(s) o = 52.0 MPa Submit Previous Answers ✓ Correct Part B - Multiple materials 1 The right half of the bar from Part A is replaced with a material that has a2 = 3.2x10-5 but the same modulus of elasticity (Figure 2). What is the thermal stress developed for the K entire bar when the temperature decreases by AT = 40 K from a temperature where there is no stress in the bar? Express your answer with appropriate units to three significant figures. View Available Hint(s) НА th o PE ? مع o= 114.400 MPa Figure < 2 of 2 > Submit Previous Answers А B X Incorrect; Try Again; 3 attempts remaining < Return to Assignment Provide Feedback nonnon