Using Topology Optimisation to reduce the stiffness of a material

- April 13, 2019 at 3:39 pm
  
  JamesdeV
  Subscriber
  
  Good day,
  
  My goal is to reduce the equivalent young's modulus of elasticity of 3D Printed Ti-6Al-4V (roughly 113.8 GPa) to that of human bone (roughly 15 GPa). To do this one would have to create some sort of lattice structure. Is it possible to set a desired young's modulus in the topology optimization function?
  
  Thank you very much!
- April 13, 2019 at 3:59 pm
  
  peteroznewman
  Subscriber
  
  Good day James,
  
  Since you have a part with a cross-sectional area A and length L, you know the desired force F for a fixed displacement D that would result in an equivalent Young's Modulus E. The formula for a rod in tension is:
  
  F = AE/L * D
  
  So you would just set F as a target value.
- April 13, 2019 at 5:03 pm
  
  JamesdeV
  Subscriber
  
  Hi Peter,
  
  I should probably have elaborated more in my original post. The purpose of this titanium alloy structure will be for biomedical use. It will thus have multiple load directions and I hope to match the stiffness of the alloy to bone's in these directions.
  
  I should also say that I have very little experience with using Ansys and have been watching every video I can get my hands on.
  
  Thank you very much!
- April 14, 2019 at 4:26 pm
  
  Sandeep Medikonda
  Ansys Employee
  
  Topology-Lattice optimization is a way forward. However, the goal/objective is to minimize the compliance or in other words maximize the stiffness of the structure.
  
  But you can specify various stress, mass/volume or displacement constraints to optimize your structure. Refer to these resources:
  
  Article 1
  
  Article 2
  
  https://www.youtube.com/watch?v=umGn-LPfIRI
- April 15, 2019 at 7:03 am
  
  JamesdeV
  Subscriber
  
  Thank you very much Sandeep!
- April 14, 2020 at 7:56 pm
  
  ShivaFar
  Subscriber
  
  Hello James,
  
  I was wondering if you could find a way of minimizing the stiffness? I am also looking into maximizing the thermal compliance for insulating structures.
- April 14, 2020 at 8:22 pm
  
  JamesdeV
  Subscriber
  
  Hello ShivaFar
  Yes, by using a combination of displacement and mass reduction constraints.
  
  You can use the software to determine the displacement of your model with the desired stiffness for an applied load.
  
  In the topology optimisation you can then set the calculated displacement as a displacement constraint and then iteratively reduce the retained mass percentage untill you have achieved the desired stiffness.
  
  I haven't worked with thermal compliance in ANSYS but if you have any more questions regarding the stiffness please do ask!
  
  Regards
- April 14, 2020 at 11:20 pm
  
  ShivaFar
  Subscriber
  
  Thank you very much, James!