General Mechanical

General Mechanical

Temperature and frequency dependent damping of materials

    • M_Emin

      I am currently working on my bachelor's thesis, which focuses on improving the mechanical damping of pipes and pressure vessels using material damping (such as constrained layer damping) to reduce vibrations. Is there a possibility in Ansys to simulatively determine the frequency- and temperature-dependent loss factor tan d or the damping property of a material over frequency and temperature? If so, which material parameters would I need for this?

      If this is not possible simulatively: can I enter the measurement results of a dynamic-mechanical analysis (DMA) or a dynamic-mechanical-thermal analysis (DMTA) from the laboratory into Ansys and simulate the damping property of a material on a pipe in a specific temperature and frequency range?

       Is there a way to import damping values from a curve into Ansys. Before ordering materials for hammer excitation or shaker tests, I would like to simulate their damping properties. For example, can I enter the values from the following diagram into Ansys?

    • Mike Rife
      Ansys Employee
      let's start here: please see the following Ansys help section.
      Ansys Help -> Mechanical APDL -> Material Reference -> Chapter 8 Understanding Field Variables. Section 8.1 has a table that lists the type of variables (temperature, frequency, position etc) and what material models support those variables.
      Then see the following help section:
      Ansys Help -> Mechanical APDL -> Theory Reference -> Chapter 14 Analysis Tools -> 14.3 Damping Matrices. This section discusses what type of damping is available for each analysis type.
      Once you know what type of analysis you want to do you can look up what types of damping are available. Then from there see which of those damping types can be a function of temperature or frequency. There is an example in the Field Variable of defining Young's Modulus as an function of global X and Y position if you need an sample of how to define the material with a variable dependency.
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