# Compliance on displacement control model

**URL:** <https://discourse.julialang.org/t/compliance-on-displacement-control-model/120934>\
**Category:** New to Julia\
**Tags:** optimization, finite-element, gridap\
**Created:** [October 4, 2024, 5:46pm UTC](https://discourse.julialang.org/t/compliance-on-displacement-control-model/120934 "2024-10-04T17:46:37Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![mary](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mary/32/53139_2.png) [@mary](https://discourse.julialang.org/u/mary)\
**Post date:** [October 4, 2024, 5:46pm UTC](https://discourse.julialang.org/t/compliance-on-displacement-control-model/120934/1 "2024-10-04T17:46:37Z")

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Hi,  
I have a domain with applied displacement BC. To find the compliance I read this in a paper  
“due to equilibrium requirements and the use of displacement control, the components of the external force  
vector, f F , are zero. Therefore this expression simplifies to C(ρ, zN ) = f^TD uD” fD and uD are dirichlet forces and displacement. In this case then why we should solve for u as we already know the uD?  
thank you

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**Author:** ![eldee](https://avatars.discourse-cdn.com/v4/letter/e/b5a626/32.png) [@eldee](https://discourse.julialang.org/u/eldee)\
**Post date:** [October 7, 2024, 6:49pm UTC](https://discourse.julialang.org/t/compliance-on-displacement-control-model/120934/2 "2024-10-07T18:49:28Z")

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Hi,

As far as I can tell this question does not seem to be related to the Julia programming language. You’re then much more likely to get an answer by posting it on some physics forum. Linking to the paper you’re referring to, might also help.

By the way, note that in Markdown you can include LaTeX via dollar signs: e.g. `$C(\rho, z_N)$` renders as C(\rho, z\_N).