# Jump condition for elasticity on an interface **URL:** \ **Category:** General Discussion\ **Created:** [May 22, 2025, 2:19pm UTC](https://community.freefem.org/t/jump-condition-for-elasticity-on-an-interface/3930 "2025-05-22T14:19:28Z")\ **Posts on this page:** 1\ **Showing post:** 10
**Author:** ![fb77](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.freefem.org/fb77/32/3796_2.png) [@fb77](https://community.freefem.org/u/fb77)\ **Post date:** [May 24, 2025, 11:03am UTC](https://community.freefem.org/t/jump-condition-for-elasticity-on-an-interface/3930/10 "2025-05-24T11:03:37Z")
It is not clear to me what transmission conditions you want to set on the interface between the two regions. If it is u\_0=u\_1 and \sigma\_0 N=0 (\sigma\_0 the stress from the region 0), it means that you can first solve u\_0 on region 0 with Neumann BC, then solve u\_1 on region 1 with nonhomogeneous Dirichlet condition u\_1=u\_0. If the conditions are more complicate and really coupled, an example is > [@Problem in implementation of DG code for Stokes-Darcy interface problem](https://community.freefem.org/t/problem-in-implementation-of-dg-code-for-stokes-darcy-interface-problem/3616/6): > > Sorry for the DG implementation the code was wrong. A correct version is [composite-space-DGStokesDarcy.edp](https://community.freefem.org/uploads/short-url/nJQLZPcMuzN3uLBzurdFy3y66jO.edp) (4.4 KB) The description of the problem and corresponding coupling interface conditions is in the pdf file in the beginning of that discussion. The interface is considered either as a boundary of the domain above (boundary label 5 of Th1 `int1d(Th1,5)`), either as a boundary of the domain below (boundary label 3 of Th2 `int1d(Th2,3)`), depending if the test function corresponds to the unknown in the domain above or below. These interface integrals can involve unknowns from both domains. --- _[View the full topic](https://community.freefem.org/t/jump-condition-for-elasticity-on-an-interface/3930)._