Learning Forum

[IqbalHaikal]

Let's say the temperature is 20C and -35C. I've already included the Isotropic secant coefficient of thermal expansion on the rail pad material properties. Do I need to match the steady-state thermal analysis system with a static structural analysis system in order to get the result?

[peteroznewman]

nSet the reference temperature for all the materials and the Environment Temperature in the Static Structural model to 20 C. Therefore, there is zero strain at 20 C.nApply a Thermal Condition to All Bodies of -35 C to see the thermal strain develop.nYou don't need to run a Steady State Thermal model to simulate a constant temperature load.n

[IqbalHaikal]

How to set reference temperature for all material and environment temperature to 20C?

[peteroznewman]

nClick on the Static Structural branch of the Outline. The Environment Temperature is in the Details window.nIn Workbench, open the Engineering Data cell. On the material where you defined the Isotopic Secant Coefficient of Thermal Expansion, there is a column for Temperature.nI recommend you read this blog before you build your model.nhttps://www.padtinc.com/blog/secant-or-instantaneous-cte-understanding-thermal-expansion-modeling-ansys-mechanical/n

[IqbalHaikal]

I've already read the blog you suggested before. But I did not understand the coefficient of thermal expansion. The coefficient of thermal expansion depends on the temperature, right? Let's say I've already put the coefficient of thermal expansion for temperature 23C which is 0.000165 /C, can I use the same coefficient value for temperature 20C? Let's say my reference temperature is 23C and I want to observe the deformation at a temperature of 20C and -35C.

[IqbalHaikal]

I have a problem regarding this observation. When I observe deformation of the rubber rail pad at temperatures 20C and -35C, the deformation at temperatures -35C is higher than 20C. Supposedly the deformation at temperature -35C is lower than deformation 20C, do you have any idea how to solve this? n

[IqbalHaikal]

Is the support we applied will affect the deformation (at temperatures 20C and -35C) outcome?

[peteroznewman]

nYes, the fixed support affects the deformation under a thermal condition.nThere is zero deformation at 20C because that is the reference temperature. There is only deformation at -35C, that is expected.nIf the CTE is a constant value, in other words, it is not temperature dependent, then you just need that one value and it is used for all temperatures. Most metals have an almost constant value of CTE between 20 C and -35 C.n

[IqbalHaikal]

Let's say I need to observe deformation at a temperature -35C, -20C, 0C, 20C, and 52C. My reference temperature is 23C. So, I need to put 23C on the CTE engineering data cell and environment temperature at the static structural branch as a fixed. Then, I just change the temperature (-35C, -20C, 0C, 20C, and 52C) at thermal conditions. Am I right? n

[peteroznewman]

nFor a constant value of CTE (not temperature dependent), yes, that is all you do.n

[IqbalHaikal]

Hello Peter, do you have any ideas regarding this problem I have a problem regarding this observation. When I observe deformation of the rubber rail pad at temperatures 20C and -35C, the deformation at temperatures -35C is higher than 20C. Supposedly the deformation at temperature -35C is lower than deformation 20C, do you have any idea how to solve this??n

[peteroznewman]

nLet's say the CTE is 0.001/C and consider a 100 mm long piece of material and 23 C is the reference/environment temperature.nSet the temperature to 20C, which is a -3C change so the part shrinks by 0.3 mm.nSet the temperature to -35C, which is a -58C change so the part shrinks by 5.8 mmnThe deformation at -35C is larger than the deformation at 20C. This is the expected behavior.nn

[IqbalHaikal]

I'm still stuck on this problem. Do you have any idea how to make sure the deformation at -35C is lower than the deformation at 20C. Let's say I want to put 23C as my reference temperature. Hope you can help me n