When working with Abaqus, the output variables are a critical aspect of understanding and analyzing the results of your simulations. Abaqus provides a wide range of output variables depending on the type of analysis you perform (e.g., structural, thermal, electromagnetic). These variables include both nodal and element-based outputs, as well as derived quantities that provide insights into the behavior of the modeled system.
Key Output Variables in Abaqus
- Nodal Variables:
- Displacement: This includes the translational (UX, UY, UZ) and rotational (RX, RY, RZ) displacements at each node.
- Velocity: The velocity components (UX, UY, UZ).
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Acceleration: The acceleration components (UX, UY, UZ).
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Element-Based Variables:
- Stress and Strain: These include the principal stresses (S1, S2, S3), von Mises stress (SM), and the corresponding strains.
- Strain Rate: For transient analyses, this provides the time derivative of strain.
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Damage: Variables such as damage fraction (DF) and critical damage fraction (CDF) for materials undergoing damage or fracture.
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Reaction Forces:
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Constraint-based reaction forces and moments at nodes with boundary conditions.
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Contact Forces:
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Normal and shear contact forces if contact analysis is performed.
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Heat Flux and Temperature:
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Variables like heat flux (QX, QY, QZ), temperature (TEMP), and other thermal variables depending on the type of thermal analysis.
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Electrical Potential:
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For electromagnetic analyses, this includes electric potential (ELEC.POT) and other related variables.
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Field Variables:
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These include user-defined field variables that can be used to track quantities like pressure, concentration (in diffusion problems), or other custom fields.
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Error and Warning Flags:
- Abaqus provides output flags indicating convergence issues or other warnings during the simulation.
Accessing Output Variables in Abaqus
Output variables are typically stored in an Abaqus database file with a .odb extension. These files can be queried using the print command in the Abaqus Python API ( abaqus.py) or through post-processing tools like the Visualization module. You can also specify which output variables to include in your analysis by defining them in the “Output Variables” section of the job submission.
Customizing Output
You can customize the output variables in Abaqus to reduce the computational load and storage requirements by selecting only the variables relevant to your specific application. This is particularly useful for large-scale simulations where storing all possible variables may be impractical.
In summary, Abaqus provides a comprehensive set of output variables that cater to various types of analyses, allowing you to extract detailed insights into the behavior of your modeled system.