Continuous temperature rise simulation
Hello, I aim to simulate the thermal stress experienced from 25°C to 115°C, and to accurately reflect the temperature-dependent characteristics of the material's modulus and coefficient of thermal expansion (CTE), I have defined a TABLEM1 to outline the temperature variation curves for material parameters, which are then referenced in MATT1.
To ensure the temperature-dependent behavior of the material is fully considered, I have adopted a nonlinear static analysis method, carrying out the simulation in stages. In the first step, I simulate the temperature rise from 25°C to 30°C; based on the results of the first step, I proceed with the temperature rise from 30°C to 80°C; based on the results of the second step, I continue with the temperature rise from 80°C to 100°C, and so on, until reaching 115°C. In each step, I use the tempd parameter to set the respective temperatures.
However, during the temperature rise from 80°C to 100°C, the following warning occurred: *** WARNING # 1086 Multiple and inconsistent definitions for TEMP(INITIAL). Moreover, the results indicate that thermal stress increased during the temperature rise from 30°C to 80°C, but decreased during the temperature rise from 80°C to 100°C. I suspect that the abnormal results are related to the aforementioned warning.
Additionally, I attempted a linear transient dynamic analysis, where I set up a temperature rise curve TABLED1, and a final temperature of 115°C, and then referenced these in tload1. The program returned an error: Thermal load is not allowed in linear transient subcase.
Subsequently, I also tried a nonlinear transient dynamic analysis, setting up the temperature dependency of modulus and CTE, and this time the calculation was successfully completed. For comparison, I also conducted a linear static analysis, where the material parameters were set to the elastic modulus and CTE at 115°C. The results showed that the results of the nonlinear transient dynamic analysis are almost identical to those of the linear static analysis. This leads me to conclude that in the nonlinear transient dynamic analysis, although the temperature dependency of the material is considered, it seems to only account for the modulus and CTE at the final temperature, and does not consider the material properties at intermediate temperatures (such as 30°C, 80°C, etc.).
In summary, how should I proceed with continuous temperature rise thermal stress calculations while fully considering the material properties at different temperatures? Thanks for any suggesstions!
Best Answer
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Hi. I must say (hopefully it does not arrive too rude) that it seems like an unnecessary complex (and maybe prone-error) approach.
How about doing a nonlinear static subcase (only one) with a temperature dependent load and fixed increments? Quite easy to do it with Simlab, btw. It manages a lot of the abstraction for the user...
1
Answers
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Hi. I must say (hopefully it does not arrive too rude) that it seems like an unnecessary complex (and maybe prone-error) approach.
How about doing a nonlinear static subcase (only one) with a temperature dependent load and fixed increments? Quite easy to do it with Simlab, btw. It manages a lot of the abstraction for the user...
1