Elastomer-metal Interface stresses
Elastomer-metal Interface stresses
(OP)
I am modelling a elastomer bonded to a metal in ABAQUS. An ideal bond between them (using tie constraints) is assumed. When I ran the analysis, I got high stresses at the interace and upon refining the mesh, the stress values continued to rise. My questions are
1) How believable are the stress values at the interface
2) What is a good method to check for convergence
Regards
Biomedman
1) How believable are the stress values at the interface
2) What is a good method to check for convergence
Regards
Biomedman





RE: Elastomer-metal Interface stresses
What you have "discovered" is a known singularity in the mathematical theory of linear elasticity that occurs at the interfaces of dissimilar materials (boundary layer effect). The singularity is due to the fact shear stress is being transferred between the two materials, however, shear stress cannot be supported on the free edge. Therefore, the mathematical theory tends to infinity near the free edge. High stresses actually happen in real life, however, when the yield stress is reached, linear elastic theory is no longer valid, and the stresses are not infinite. As long as you are using a linear solution, the stresses will continue to climb with increasing mesh density.
pj
RE: Elastomer-metal Interface stresses
At the material discontinuities, the node values are way higher than those at the element integration points. What does that mean and which do I look at?
Biomedman
RE: Elastomer-metal Interface stresses
In real life, there are plenty of applications where elastomers are bonded to metals where failure of the adhesive layer does not occur. Linear finite element analyses for such applications should therefore be interpreted carefully, as some of the assumptions in linear elastic theory may not be directly applicable for elastomeric materials.
pj
RE: Elastomer-metal Interface stresses
I'm sorry I can't tell you how to solve this problem, I'd like to know myself, but (a) it CAN be solved, using FEA (one of our suppliers used to have a consultant who analysed our designs and he was very very good) and (b) when you learn how to do it you will have a very worthwhile skill.
Cheers
Greg Locock
RE: Elastomer-metal Interface stresses
This would automatically decrease the stresses at the interface, as is always the case in "real-life"...