Shape Memory Alloy (SMA) Simulation in Ansys Mechanical: Part 1
Hello, this is MingYao from Ozen Engineering. In this video, I will demonstrate how to simulate shape memory alloys, specifically nitinol-type materials, using ANSYS Workbench Mechanical.
Available Models in ANSYS
ANSYS provides three different shape memory alloy models:
- Super Elastic Model
- Two Shape Memory Effect Models
Setting Up the Super Elastic Model
We'll start with the super elastic model as it's the simplest. Here are the steps and information required:
- Create a new material called Nitinol.
- Input the following parameters:
- Young's Modulus: 60,000
- Poisson's Ratio: 0.36
- Transformation Strains:
- Austenite to Martensite Start: 520
- Austenite to Martensite Finish: 600
- Martensite to Austenite Start: 300
- Martensite to Austenite Finish: 200
- Maximum Transformation Strain: 7%
- Elastic Modulus of Martensite Phase: 60,000
Simulation Setup
We'll simulate a nitinol bar, 20 millimeters in length, using the super elastic model:
- Assign the material to the model.
- Generate a mesh.
- Set up a four-step analysis:
- Stretch the material.
- Return to normal.
- Compress the material.
- Return to normal.
- Configure the simulation settings:
- Turn off large deflection.
- Use small deflection for compression to prevent buckling.
- Apply displacement only in the Y direction, setting X and Z to 0.
- Use tabular data for Y-axis displacement:
- Start at 0, pull by 3 millimeters (15% strain), return to 0, compress by -3 millimeters, and return to 0.
- Enable auto time stepping with 20 points per step for better resolution.
Analyzing Results
After running the simulation, examine the following:
- Deformation and stress plots.
- Force versus deflection curve:
- Plot force in the Y direction against displacement.
- Adjust the chart to focus on relevant data.
Adjusting Material Properties
Experiment with different material properties:
- Change transformation stress values.
- Adjust martensite stiffness (e.g., reduce to 30,000).
- Modify the tension-compression ratio (e.g., 20% difference).
Conclusion
The super elastic model in ANSYS provides robust capabilities for simulating shape memory alloys. It allows for different stiffnesses between austenite and martensite phases, varying tension-compression values, and customizable transformation stresses. This model is efficient and converges well.
In the next video, I will cover the shape memory effects models, which are more complex. Stay tuned for more details.
Thank you for watching. If you found this video helpful, please subscribe to our YouTube channel. For more information on modeling shape memory alloys, contact us at info@ozeninc.com.
Hi, this is MingYao from Ozen Engineering. In this video, I will be looking at how we can simulate shape memory alloys, or nitinol-type materials, in ANSYS Workbench Mechanical. ANSYS has several shape memory alloy models available: three of them.
Let's create a new material called nitinol and see the options. There's a super elastic model and two shape memory effect models. I will start with the super elastic model because this is the easiest one.
To use this model, we need to input the following information: * Young's modulus: 60,000 in millimeters and MKS unit * Poisson's ratio: 0.36 * Transformation strains: + Austenite to martensite transformation start and finish + Martensite to austenite start and finish + Maximum strain for the transformation: 7% * Elastic modulus of the martensite phase: 60,000 We have an example material here, so I will use the ANSYS example.
We start at 520 and go to 600, then on the downward slope, we go from 300 down to 200. Now, let's set up the simulation: * ANSYS Mechanical * Bar of nitinol: 20 millimeters in length * Assign the material: super elastic model * Generate a mesh * Fixed support on one side * Four-step analysis: stretch, return to normal, compress, and return to normal * Turn large deflection off * Linear with large deflection on * Treat this as a small deflection problem * Move only in the y direction * Start at 0, pull on it by 3 millimeters, then go back to 0 * Solution settings: program control, turn on auto time stepping, 20 points within each step Solve the simulation and look at the force versus deflection curve.
In the next video, I will be talking about the shape memory effects, another more complicated model, with two variations. Thank you for watching this video. If you like it, please subscribe to our YouTube channel.
If you are interested in modeling shape memory alloy, nitinol material, and you don't know how to do it, please subscribe to our YouTube channel. If you want to learn more about it, please contact us at ozeninc.com. Thanks, and have a great day.
