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Simple Linear Thermal Expansion Theory vs Model
Posted 3 feb 2022, 13:00 GMT-5 Structural Mechanics Version 6.0 1 Reply
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I'm modelling thermal expansion in a 2D beam with 10mm width (L0) and 0.1 mm height. The volume reference temperature is 25 degC and the beam is at uniform temperature of 45 degC for a dT of 20 degC. The thermal expansion coefficient is 23e-6 1/K (alpha).
From a simple 1D thermal expansion calculation: dL/L0 = alpha x dT = 23e-6 1/degC x 20 degC = 4.60e-4 also, dL = alpha x dT x L0 = 23e-6 1/degC x 20 degC x 0.01 m = 4.60e-6 m
However, in my model, I get dL/L0 = 5.75e-4 (first principle strain) and dL = 5.75e-6 m (displacement).
Can anyone please help me understand the discrepancy between the theoretical calculation and the COMSOL model? I've attached my model file.
Attachments:
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Hello Sibi,
You set up the model as plane strain. To approximate a beam, you would need to make it plane stress. When you do that, the model returns the displacement you expected.
Best regards,
Jeff
-------------------Jeff Hiller