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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
application/octet-stream1-D spherical coordinate
1d_sphere.pde (1.4 k)
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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 In either case, the PDEs are no longer valid.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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