Defining Spring Properties for 2D and 3D Models
There are a few differences you should be aware of when you define extensional and torsional stiffness properties for springs on the Spring Property Definition dialog box:
Extensional stiffness
The extensional stiffness of the spring resists the stretching or compression of the spring.
• For 3D models, you specify extensional stiffness for Kxx, Kyy, and Kzz.
• For 2D models, you specify extensional stiffness only for Kxx and Kyy.
• For plane strain, plane stress, and axisymmetric models, you specify extensional stiffness for Kxx, Kxy, and Kyy.
Torsional stiffness
The torsional stiffness of the spring resists the twisting of the spring.
• For 3D models, you specify torsional stiffness in Txx, Tyy, and Tzz.
• For 2D plane strain and 2D axisymmetric models, you specify torsional stiffness only in Tzz.
• For 2D plane stress models, you do not specify torsional stiffness. A spring in a 2D plane stress model does not contribute to rotations when the engine calculates results.
You can specify coupling stiffness for the spring only in native mode by clearing the Compute Coupling Automatically check box on the Spring Property Definition dialog box.
Coupling stiffness (for native mode only)
The coupling stiffness of the spring couples the stretching of the spring with torques applied to the spring and couples the rotation of the end points of the spring with the forces applied to the spring.
• For 3D models, you specify coupling stiffness with KTxx, KTyy, KTzz, KTxy, KTxz, KTyx, KTyz, KTzx, and KTzy.
• For 2D plane strain and 2D axisymmetric models, you specify coupling stiffness with KTxz and KTyz.
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If you edit a spring stiffness property that couples displacements with rotation (KT field), with a non-zero value in independent mode, Creo Simulate resets all the coupling stiffness values to zero.
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