Hyperelastic Simulations
In some cases, typically used material models for metals, such as homogeneous isotropic linear elastic or bilinear elastic-plastic characteristics, do not satisfy the material behavior of plastic parts. Rubber materials, for instance, need to be represented by hyperelastic materials. Generally, they show significantly higher strains than metals.
A buffer device will be used to demonstrate the application of the curve fitting method to utilize material testing data. Furthermore, a nonlinear analysis considers the material fitting method to be a very important part of the material testing process.
ANSYS Workbench provides the technical framework for efficient modeling and solving techniques. This includes:
- Hexahedron meshing
- Reduced model size due to symmetry properties
- Auto time stepping
Geometry of the Buffer Device
The geometry of the buffer device is determined by the diagram. A sweep mesh of hexahedrons is enabled. Since there are several symmetry planes with respect to the geometry and the loading condition, it is allowed to consider only one-eighth of the whole buffer geometry. Then, a structural mechanical block is dragged onto the geometry.
Material Definition and Curve Fitting
Entering the engineering data allows the user to define a new material. The basis should be the strain-stress data of a uniaxial tension test. The next step involves choosing an appropriate material model to use the curve fit function.
When do I use which material model? The answer is when you use the curve fit function. Let's have a brief look at the available hyperelastic material models:
- Phenomenological models
- Micromechanic models
We distinguish between nearly or fully incompressible and compressible models. Various models are implemented in ANSYS Workbench. When considering nearly or fully incompressible material models, the main criterion of selection is the expected strain range. Some are valid up to strains of 30%, 200%, 300%, or 700%. In this case, we choose the 5-parameter Mooney-Rivlin model.
We solve the curve fit and copy the calculated values to the material model. The curve fit correlates perfectly to the experimental data.
Mechanical Simulation
The next steps are material assignment and the mechanical simulation. Key considerations include:
- Memory optimization and fees for lives
- Methods for monitoring data pipe reduced
- Design requirements and meshing options
- Boundary and loading conditions, including a frictionless support representing the symmetry plane and a static pressure
Since we expect large deformations, this option should be activated. This means that equilibrium iterations are calculated with respect to the deformed shape. We ensure that the outer time stepping is active, allowing the load increment increase from substep to substep to be chosen by an implemented algorithm.
During and after solving, we can check the convergence monitor. It shows that not every increase of the load increment achieved a convergent solution, so the load increment was adjusted.
Post-Processing
Typical post-processing objects include total deformation and equivalent elastic strain. The total deformation results in the following effect:
- The equivalent elastic strain reaches 10.4 mm
- The equivalent elastic strain reaches a value of 24%
Conclusion
To summarize, ANSYS Workbench provides various hyperelastic material models. Combined with convenient pre- and post-processing and efficient solver technology, assemblies can be analyzed expeditiously. Now it's up to you to benefit from the ANSYS Workbench implemented hyperelastic material models and to gain more knowledge of your part or assembly.
In some cases, typically used material models for metals, such as homogeneous isotropic linear elastic or bilinear elastic plastic characteristics, do not satisfy the material behavior of plastic parts. Rubber materials, for instance, need to be represented by hyperelastic materials.
Generally, they show significant higher strains than metals. A buffer device will be used to show the application of the curve fitting method in order to use material testing data.
Furthermore, a nonlinear analysis considers the material fitting method to be a very important part of the material testing process. ANSYS Workbench provides the technical framework for efficient modeling and solving techniques.
This means that among others, hexahedron meshing, a reduced model size due to symmetry properties, and auto time stepping are used. Let's start with the geometry of the buffer device. What is the geometry of the buffer device?
The geometry of the buffer device is determined by the clearly visible features from this diagram. A translucent block based on niece's design from November 2021 is used. A sweep mesh of hexahedrons is enabled.
Since there are several symmetry planes with respect to the geometry and the loading condition, it is allowed to consider only one eighth of the whole buffer geometry. Then a structural mechanical block is dragged onto the geometry.
Entering the engineering data allows the user to define a new material. The basis should be the strain stress data of an uniaxial tension test. The next step would be choosing an appropriate material model to use the curve fit function. Now, the question is, when do I use which material model?
The answer is, when using the curve fit function, choose an appropriate material model. When regarding nearly or fully incompressible material models, the main criterion of selection is the expected strain range. Some of them are valid up to strains of 30, 200, 300, or 700%.
In this case, we choose the 5-parameter Mooney-Rivlin model. Solve the curve fit and copy the calculated values to the material model. We can see that the curve fit correlates perfectly to the experimental data. Next, enter the mechanical simulation.
The next steps are material assignment and the mechanical simulation. Gas markups and electrical weaknesses are considered. The higher this pressure is, the higher the sample wear efficiency.
At a certain point, Zigick carefully tracks the unit equipment based on the mechanical simulation components. Next, look at memory optimization and fees for lives. Methods for monitoring data pipe reduction, SUB-percent, design requirements, and IP-'2260 vs.
Meshing options, boundary, and loading conditions are considered. The latter ones consist of a frictionless support representing the symmetry plane and a static pressure. Since we expect large deformations, this option should be activated.
This means that equilibrium iterations are calculated with respect to the deformed shape. We make sure that the outer time stepping is active, which means that the increase of the load increment from substep to substep is chosen by an implemented algorithm.
During and after solving, we can check the convergence monitor. It shows that not every increase of the load increment achieved a convergent solution, so that the load increment was adjusted. Typical post-processing objects are the total deformation and, for instance, the equivalent elastic strain.
The total deformation results in the following effect. After the Django DeepStream samples are fully speeded, the peak RapidStream dungeon is less elegant.
Unlike the 800 above and below the acoustic bedboard, the elastic strain reaches a value of 10.4 mm, whereas the equivalent elastic strain reaches a value of 24%. To summarize, ANSYS Workbench provides various hyperelastic material models.
Combined with convenient pre- and post-processing and also efficient solver technology, assemblies can be analyzed expeditiously. Now it's up to you to benefit from the ANSYS Workbench implemented hyperelastic material models and to gain more knowledge of your part or assembly.
The title of the talk is "Hyperelastic Simulations."
