Wrong Displacement

mirko088
mirko088 Altair Community Member
edited October 2020 in Community Q&A

hi I have a problem with my model. I am applying forces to a helicopter blade but I get a displacement of about 8 meters when I should have values below one meter. The forces that I enter are the gravity (grav card), the centrifugal force (rforce card) and the thrust along z equal to 7786N. If I run the analysis without the thrust I have displacements of the order of millimeters while when I put the thrust I have absurd displacements. I tried to insert it in different ways both in point and distributed load. Someone can help me?

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Answers

  • tinh
    tinh Altair Community Member
    edited May 2020

    Could you share *.fem file?

    Can you estimate displacement theorically?

  • mirko088
    mirko088 Altair Community Member
    edited May 2020

    This is the link for the file https://www.dropbox.com/s/jyui40asdiajkjm/remeshtot.hm?dl=0 ( too big for upload in the forum). 
    I cannot evaluate displacements theoretically but I know the range within which I must be less than one meter. In my analyzes I obtain displacements along z (axis perpendicular to the length of the blade) greater than 6 meters,

    Thank you tinh

     

  • tinh
    tinh Altair Community Member
    edited May 2020

    Did you confirm unit of force and material parameters?

  • mirko088
    mirko088 Altair Community Member
    edited May 2020

    The model is in mm , so E and G are expressed in MPa instead the density in tonn. The force is in N . To verify the integrity of the model I performed a modal analysis  and the first 3 frequencies the modes are those typical of an cantilever beam. 

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