Rubber Compression -Load Deflection Curve 1

[ConorWalsh]

hey all, Thanks for the help so far. I got the rubber seal to compress by having a rigid surface ome into contact with it.

Abaqus is quite friendly to use I am finding.

However, I was wondering if I could get assistance on two other topics.

1: How can I generate a Compression Load Deflection Curve of My seal or at least get the necessary data output so that I can generate this plot myself.

2: How can I get a value for the contact area after compression of the rubber seal and the rigid surface.

Very much appreciated

Thanks

Conor

 

[DickButkus]

1. This test is extremely difficult to do accurately. The friction effects can have a large influence on your test data. In order to properly run this test you need frictionless platens. You can try and lube them, but you have to observe your puck accurately when running the test - if there is ANY bowing or curvature along the sides of the puck then the part is not in uniaxial compression. Assuming you can get this data, it may be entered as uniaxial test data as negative tensile data. Start with you most negative test data and work your way back to zero, then you can include your continually increasing tensile data.

Your compression data and tensile data should be tangent through zero. Plot this data out and make sure that there is not a "kink" in the data at the origin. Also, watch out for permenant set and mullins effect. Rubber is a very difficult material to test.

There is a good lab in Ann Arbor, Michigan which can generate this data for ABAQUS for a few hundred bucks. They use an equiaxial specimen to generate test data. Since they are familair with ABAQUS they can provide the data in an ABAQUS friendly format. I believe the name of the firm is Axel Products, but I hear they have been very busy lately. I think ARDL can also generate the data, but I don't know if they will put it into an ABAQUS format.

2. There is an output variable to do just this. In the step module create new HISTORY output. One of the output variable identifiers (CAREA ?) will be the area in contact. There is also a total force in contact as well as center of contact, resultant forces due to contact and many more.

Good luck,
KF9RI