# meaning of compliance

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Hi,

Could you please write me the meaning of compliance, because unfortunately I don't understand it  . What is weighted compliance?

Sanyo

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Sanyo,

In OS, compliance is strain energy. In general, when a force is applied, a displacement results.
Compliance, force, and displacement can be represented by the following equation.
C = FT * U
where
C is compliance (strain energy)
FT is the transpose of force
U is displacement

see TTF - Define an OptiStruct optimization problem with an enforced displacement subcase.

The weighted compliance is a method used to consider multiple subcases (loadsteps, load cases) in a classical topology optimization. So use this when you need to see the effect of many subcases (loadsteps, load cases).

The response is the weighted sum of the compliance of each individual subcase (loadstep, load case), this means-
You would typically input a weighting factor (multiplier) for the compliances of individual subcases (loadsteps, load cases), this factor is multiplied with the individual compliance of each subcases (loadsteps, load cases) and then this product is added together,
So now you have the total compliance, with you deciding how much each subcases (loadsteps, load cases) should contribute to the total compliance using the weighting factor.

coatkuanteen likes this

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Hello my name is Eduardo , I would like to increase the strain energy in an impact event, I am using 1D elements, can I use compliance as a mesure of the strain energy?

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Could you please explain what exactly you are trying to accomplish?

Strain energy response is not available, but you can use frequency response as the frequency is directly proportional to stiffness.

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Yes of course, we are trying to design a structure capable of dissipating kinetic energy and converting internal energy as elastic deformation, plastic deformation etc. It does not matter that the fibers of the structure are broken, the important thing is the amount of energy capable of being transformed. We have tried to do this by restricting the stress using the static response in 1D elements and minimizing the mass. But we get this error message from the image. How can we maximize the strain energy using the optimization? Thank you very much for answering our questions.

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