# Nonlinear problem on Elastic couplings.

Question asked by Stefan Tenev on Feb 24, 2014
Latest reply on Apr 2, 2014 by Jared Conway

Hi, everyone. I have a problem with nonlinear simulation of elastic coupling. I want to simulate the deformation of the elastic element (rubber) with 80 Nm torque. Everytime I get a different error of the simulation. I was trying everything  to get done, but that simulation it pissing me off. Can anyone help me for that? Now I will write every option and settings, that I have given to the simulation.

1. Nonlinear simulation study.

2.Simulation properties.

2.1. Autostepping.

Initial time increment - 0.01;

Min - 1e-008; Max - 0.1;

2.2 Geometry nonlinearity options.

Use large displacement formulation.

2.3. Solver.

Direct Sparse.

2.4. Incompatible bonding options.

More accurate.

Control - Force;

Iterative - NR;

Integration - Newmark;

Do equilibrium iteration every - 1 step;

Maximum equilibrium iterations - 30;

Convergence tolerance - 0.001;

Maximum incremental strain - 0.01;

Singularity elimination factor - 0.

3. Material properties.

3.1. Coupling - ANSI 1020.

3.2. Elastic element - Rubber.

Model Type: Hyperelastic - Mooney Rivlin;

Poisson Ration - 0.4995;

Thermal Expansion Coefficient - 0.00066 /K;

First constant - 5.79 N/mm^2;

Second constant - 1.45 N/mm^2;

Mass Density - 1000 kg/m^3;

Tensile Strenght - 13.79 N/mm^2.

P.S. I was trying with Stress - Strain Curve, too.

4. Connections.

4.1. Component Contacts - Global Bonded Contact with Compatible Mesh.

4.2. Contact Sets - No penetration (for all faces); Surface to Surface; Friction - 0.8.

P.S. Contact face between eight cylindrical faces and thumbs of coupling is 100 mm^2.

5. Fixes.

5.1. Half of the coupling is fixed.

5.2. On a bore of the other half of the coupling is set on Fixed Hinge.

6.1. On a bore of the same half of the coupling is set 80 Nm torque.

7. Mesh.

7.1. Standart mesh - size 6.5 mm; tolerance - 0.15 mm; draft quality mesh.

7.2. Mesh control of the Rubber - size 3 mm; a/b - 1.5.

I am attach picture of the coupling.