(a) What is meant by the term “transient” in the Transient Thermal Study? (b) Ex
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(a) What is meant by the term “transient” in the Transient Thermal Study? (b) Explain the fundamental analogy between “Mesh Size” and “Time Increment” from a modeling approach. Be sure to discuss the modeling resolution. (c) Explain how it is possible to have thermal stress without thermal strain. (d) Explain how it is possible to have thermal strain without thermal stress. (e) Is it possible to have both thermal stress and thermal strain? Explain briefly. (f) What are the units for thermal expansion coefficient? Explain briefly.
1. Overview. In this tutorial, you will evaluate the transient material response of a coffee pot in a thermal study. A Word or PDF document containing your results will be submitted for each tutorial. 2. Transient Thermal Study Complete the SolidWorks Simulation tutorial labeled "Thermostat" (Figure 1) The tutorial is located in the "Frequency, Buckling, and Thermal" section. After opening the assembly file, be sure to select the "Partial" study. Then, complete the remainder of the tutorial. FIGURE 1. Tutorial AssemblyExplanation / Answer
a) There are two types of thermal studies, steady-state and transient. If you create a thermal study dependent on time, and would like to use the temperature results as the load in a static study, you would carry out a transient analysis.
b) The realtion between mesh size and time step in transient heat transfer study is defined by the thermal diffusivity. This is the heat propagation "speed" through the material. If the conductivity of the material is quite small, the heat will propagate less into the body and if this depth is of the order of the element size, you will get oscillations in the temperature profile, because you can not capture the solution. The critical time step is a direct result of the non-dimensionalization of the heat transfer by the conduction equation: L=sqrt(k*dt/(rho*Cp)).
c) and d) If you increase the temperature, the atoms will gain the kinetic energy and vibrate from their mean positions. Because of this vibrations, they tend to take more space than usual. We know that stress is internal resistive force. We are letting the material for free expansion we are allowing the atoms to gain that extra space without any problems. Since no resistance is there, no stress is developed. If, however, we are trying to restrict the movement, we have to put a force for that. A similar resisting force will be generated from the material and hence the stress.
e) Yes, as explained above.
f) It is the ratio of the fractional change in size of a material to its change in temperature and uses the SI unit inverse kelvin (K1 or 1/K) or the equivalent acceptable non SI unit inverse degree Celsius (1 or 1/).
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