XANSYS Message: 42828 [Go back to message list]
[bookmark on del.icio.us]
No rating yet
Subject: Re: debonding simulation
Author: Srinath Chakravarthy
Date: 2002-10-17 15:58:00hi sashikant,
You should avoid the contact parameters and investigate material failure
say for example with glued ares/volumes. In case any of the individual
materials do not fail at maximum load then obviously your interface is
failing first. What kind of adhesive are you using ??? how thick is it
with respect to the other materials ?? Is it brittle or does it exhibit
elastic plastic behavior ?? Adhesive layers are known to exhibit
significant plastic deformation before failure.
The best way to treat interface problems is with a fracture mechanics
approach. For simple geometries and simple loading you can easily perform a
hand calculation to calculate the fracture parameters and compare this with
the results from your test which will give you an estimate the interface
toughness.
Srinath
|---------+---------------------------->
| | Sharma Shashikant|
| | | | stra.com> |
| | 10/17/02 02:33 PM|
|---------+---------------------------->
| To: "'xansys@yahoogroups.com'"
| cc:
| Subject: [xansys] debonding simulation
Hello group,
I have a difficult need here. A (rubber+steel) mount fails in a pull test
(extreme load). The physical surface visualisation is not clear enough to
say, if rubber is cracking, or the interface (adhesive joint) with steel is
failing. Is it possible to model this in ANSYS as contact in tension
problem? Contact should be active till stresses at interface is less than
bond strength in normal and shear direction, or some defined criterion.
Secondly, is there a way to define element death option, say, rubber zone
exceeding XXX% strain fails, so the software deletes those elements, OR,
makes those elements inactive to participate in stiffness matrix in
subsequent runs?
I have tried DYNA, with CONTACT_TIE_BREAK option, but, didn't yield
satisfactory results. Will anyone give some realistic values on adhesive
normal and shear allowables. I used normal as 34MPa, and Shear as 12MPa.
I tried, rubber alone with steel as boundary condition, and looked at
boundary conditions' interface strains are of the order of (tensile 90%)
compressive(27%), it's a bi-axial state, third principal strain very small.
Any other ideas on debonding simulation? I want to zero-in on adhesive vs
rubber, which one to improve to improve fatigue life.
thanks for yr time,
Shashikant Sharma
Sr. CAE Engineer
Paulstra CRC
460 Fuller NE
Grand Rapids, MI 49501, USA
Phone: 1-616-356-4697
Fax: 1-616-459-2858
e-mail: sshashikant@p...