Modelling of 3D solid & 2D shell elements

purichmunlowpurichmunlow Member
edited October 2020 in Structures

I am performing a static analysis on a wing of an aircraft. A problem that I am encountering is the modelling of solid elements with shell elements.

As shown in picture 1, the loads are not transferred to the entire structure of the wing that is why the stress is super high as it is concentrated at the wing attachement region where the lug is shown in the picture 2.

picture 3 shows that the mesh is of 2D and 3D elements is connected. I also used bonded contact for the 3D elements and 2D shell elements. For both lugs.

Picture of properties of bonded contact.

Lug 2

Fixed supports at holes of the 2 lugs.

I just do not understand why the loads are not transfering to other regions of the structure of the wing. Could anyone help out with this problem? The stress is too high 14000 MPa!!! beyond the yielding stress of the material which is 520MPa!!!

Maybe the problem lies with the connection of 2D & 3D elements?

Answers

  • rkumbharrkumbhar PuneForum Coordinator

    Hi @purichmunlow You can try different settings in 'Constraint type' in Bonded contact advanced options to check wich one gives better result. Probably 'Distributed, inside pinball egion' could work best.

  • purichmunlowpurichmunlow Member
    edited October 2020

    @rkumbhar Thank you for your suggestion! I appreciate it. I tried all the options that you suggested but still did not work out. Any other suggestions you could provide? Any other ways to model this?

  • rkumbharrkumbhar PuneForum Coordinator

    Hi @purichmunlow , Any reason you believe its not working? Are you just checking highest stresses in the model. There can be the other reasons for higher stress like large deflection is off, or linear material. The contact area is very close to the support. You should have very fine mesh both on solid face as well shell edge in contact.

    To check if the contact is properly working or not, you should plot the stress on the contact face. The bending stress should look symmetrical on the contact face.

  • It is always better to apply similar dof elements at the joints. May be shell to shell or solid to solid. Other than that, If other methods are used like MPC or CE, or coupling - then you need to test your model very carefully, for ensuring the accuracy of the results. Basic FEA fundamental theories shall be applied to get the correct result. There is no shortcut to that.

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