hello Mr. kumar,

follow these steps:

1. create a steady state thermal analysis with sharing results to a static structural analysis.

2. first of all, run the thermal analysis then share the result with static analysis and run the static analysis to obtain the thermal stress in wing.

3. afterward, add a modal analysis and add the pre-stress (static structural) which is results of the static structural analysis to the modal analysis. if you run the modal analysis it will give the wing's modes under thermal stress.

i hope it would be helpful to solve your problem

good luck

Dear Amir,

I have already tried this approach. However, due to some unknown, it doesn't seem to give results. Whenver I take that approach, it simply fails to read the thermal effects properly.

It'd be very helpful if you could suggest some modifications to this method or an alternative method.

Thank you

I also tried this problem in APDL. I treated the aircraft wing as a cantilever beam. Even though it showed satisfactory results when the temperature load hasn't been applied, it also fails to show any effects upon the application of temperature.

I have also faced a similar issue. Maybe you can try to reduce the mesh size and make it coarser then apply thermal loads and run simulation.

Dear Abhinav Kumar ,

The method suggested by Amir Janghorban is referred to "Weak Coupling" or load transfer method which two iterations are required to be performed for solving a problem. I suggest that you choose "Strong coupling" method which only one iteration is required to be performed for solving your problem. You can choose SOLID226 or 227 depending on what type of mesh you used in your analysis using command snippet in either "Static Structural" or "Transient Structural" analysis. Insert structural BCs using functions available in "Mechanical" and thermal BCs using command snippet. Finally, perform a Multiphysics analysis and then perform the modal analysis based on that which is pretty straight forward. This way, you ensure that the results will be accurate and there is no room for error which is very common in "Load transfer" method.

Hope this answer helps.

Dear Hamidreza Ahmadi Moghaddam ,

Thank you for your useful suggestion, could you please tell that this method is eligible for modal analysis of pre-stressed structures.

Dear Amir Janghorban,

SOLID226 and 227 are eligible for modal analysis of pre-stressed structures. These elements have structural, thermal and electrical degrees of freedom which enables performing a Multiphysics simulation.

Hope this answer helps!