Stress solutions allow you to predict safety factors, stresses, strains, and displacements given the model and material of a part or an entire assembly and for a particular structural loading environment.
A general three-dimensional stress state is calculated in terms of three normal and three shear stress components aligned to the part or assembly world coordinate system.
The principal stresses and the maximum shear stress are called invariants: that is, their value does not depend on the orientation of the part or assembly with respect to its world coordinate system. The principal stresses and maximum shear stress are available as individual results.
The principal strains ε1, ε2, and ε3 and the maximum shear strain γmax are also available. The principal strains are always ordered such that ε1> ε2> ε3. As with principal stresses and the maximum shear stress, the principal strains and maximum shear strain are invariants.
You can choose from the following stress/strain results:
- 19.5.2.1. Equivalent (von Mises)
- 19.5.2.2. Maximum, Middle, and Minimum Principal
- 19.5.2.3. Maximum Shear
- 19.5.2.4. Intensity
- 19.5.2.5. Vector Principals
- 19.5.2.6. Error (Structural)
- 19.5.2.7. Thermal Strain
- 19.5.2.8. Equivalent Plastic Strain
- 19.5.2.9. Accumulated Equivalent Plastic Strain
- 19.5.2.10. Equivalent Creep Strain
- 19.5.2.11. Equivalent Total Strain
- 19.5.2.12. Membrane Stress
- 19.5.2.13. Bending Stress
Normal (X, Y, Z) and Shear (XY, YZ, XZ) stress and strain results are also available.
It is assumed that whatever holds true for stress applies to strain as well. However, the relationship between maximum shear stress and stress intensity does not hold true for an equivalent relationship between maximum shear strain and strain intensity.
For more information about Stress/Strain, see the Mechanical APDL Theory Reference.
Considerations
Note the following important aspects of stress and strain results:
The degree of uncertainty in the numerical calculation of Stress answers depends on your accuracy preference. See Using Adaptive Convergence for information on available options and their effect on Stress answers.
Although a rare occurrence, for results defined by the expressions EPTO and EPTT (total mechanical strains and total mechanical strains and thermal strains), Mechanical will not create contours for these expressions for an element if the element records lengths of the individual strains EPEL/EPPL/EPCR/EPTH in the result file. See the PRESOL command for complete definitions.
Mechanical does not currently support swelling strain (EPSW) and does not use it in the calculation of total strains.
Mechanical does not support standard stress and strain results for gasket results. However, if you specify a body as a gasket and the Mechanical APDL key option KEYOPT(8) is set to 1, (KEYOPT(8)=1), for the gasket element, you can view regular stress/strain result contours using a post commands snippet.