kim tran (kimngoc999)
Member Username: kimngoc999
Post Number: 5 Registered: 06-2009
| Posted on Wednesday, July 01, 2009 - 07:40 am: | |
Hi all, Can any one help me?? I want to work out the displacement distribution in a composite with 3 different material.(material 1|material 2|material 3). 1. How to assign displacement (u) at the boundary of material 1 and material 2 is discountinuous( CONTACT or JUMP command???) 2. how to assign displacement(u) at boundary of material 2 and material 3 is smooth(i.e. dr(u)=0) and countinuous. thank you
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Robert G. Nelson (rgnelson)
Moderator Username: rgnelson
Post Number: 1273 Registered: 06-2003
| Posted on Wednesday, July 01, 2009 - 07:35 pm: | |
1. The FlexPDE parser does not accept POINT CONTACT boundary conditions. We will investigate and correct this. 2. Discontinuous displacement sounds weird. It means either that a gap has opened between the materials, or the materials are overlapped (occupying the same space). In either case, the PDEs are no longer valid. 3. Assigned displacements are imposed using the VALUE(u) boundary condition. 4. You should not expand divergence operators. FlexPDE forms cell integrals of second order derivative terms by parts, generating surface integrals. These surface integrals are assumed to be continuous across cell interfaces. If you break up the terms of a divergence, creating first-order terms, energy conservation will be violated.
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