General Mechanical

General Mechanical

Modal analysis in ANSYS

    • Fran1908


      I have recently started using ansys software. I am trying to simulate a structure that refers to a floating floor (equivalent to a mass-spring system). The structure consists of a first granite solid on which is supported a rubber sheet and, in turn, on this, is supported a steel sheet. The analysis I want to carry out is a modal analysis to find out the frequencies corresponding to the vibration modes of the system. I would like to know if when defining the material, is it enough to define the density, Young's modulus and Poisson's coefficient, or is it necessary to define some other parameter? Secondly, what would the contacts between the different solids be like (type, behaviour and formulation)? And thirdly, what would be the boundary conditions necessary to perform the analysis?

      Thanks in advance

    • Erik Kostson
      Ansys Employee
      Yes, for linear analysis like modal, we only need those material parameters (rho, E, and v).
      See this course for details:
      As for contact we can only use linear type of contacts since modal is a linear analysis (so we can not have nonlinear contacts).
      See the help manual for the different type of contacts and choose the most appropriate one - one can always start with a bonded contact (for all parts). This course is relevant also:

      Finally I assume you can fix the base of the large grey block - ultimately try to have as similar boundary conditions as possible as in the real experimental modal test.

      Also see this nice course for modal analysis:
      And this course on how to get started with mechanical:

      All the best

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