SOLIDWORKS Simulation Nonlinear Material Model Type Setup

Article by Jackie Yip on Jan 05, 2023

This guide demonstrates how to change and update material types in a SOLIDWORKS Simulation nonlinear study to depict more accurate stress and deformation results. 

The nonlinear study type focuses on the deformation that is no longer linear throughout the calculation (beyond the yield strength). While a static study is common, a nonlinear study allows users to incorporate changes to the stress-strain beyond this area. 

The image below shows that not only is the slope different, but it also exhibits a slight curve/bend. If the stress calculated goes beyond the yield, we can consider the model to be deforming in the plastic region.

Typical Stress-Strain Diagram in SOLIDWORKS Simulation

Static Setup with Linear Elastic Model Type

To demonstrate the differences, we’ll first create a simulation using the Static Study type. When setting up the material, there is an option to change the model type, which controls how the material behaves along a stress-strain curve. The Static Study only uses the linear elastic method, which means that the stress-strain relationship will always be linear even if it goes past the yield.

SOLIDWORKS Simulation Static Setup Linear Elastic Model Type

Once we solve the study, we’ve obtained max stress of 46.2 MPa.

SOLIDWORKS Simulation Linear Elastic Model Study

Nonlinear - Linear Elastic Model Type

In SOLIDWORKS, a nonlinear study type is available with a Simulation Premium license. When copying the study, we have the option to copy our static study setup into our new study.  

Nonlinear Study Option in SOLIDWORKS Simulation

By editing the material, we can go to the model type to verify that a nonlinear study has more options available. In this example, we’ll stick with the same linear elastic isotropic type to check whether our results differ.

SOLIDWORKS Simulation Linear Elastic Isotropic Model Type

Nonlinear Linear Elastic Model Type SOLIDWORKS Simulation

The results show virtually the same max stress value in the nonlinear study. 

Nonlinear – Plasticity Von Mises

We’ll now shift our focus to demonstrate how to use the plasticity of a material type to obtain a different but more accurate solution. Here, we can edit the material and switch the model type to Plasticity – von Mises. The key difference is that we’ll now assign a tangent modulus value which will alter the stress-strain relationship beyond the yield. For starters, the value is typically 10% of the elastic modulus, which means that the max stress value should decrease if the material deforms in this region.

SOLIDWORKS Simulation Model Type Setup Nonlinear Plasticity von Mises

Given that the tangent modulus is a singular value, the slope will still act as linear beyond the yield strength. But since it no longer follows the same trajectory, we can use this value for filling in the missing data points by interpolating this relationship. For more on this relationship, visit this SOLIDWORKS help page

SOLIDWORKS Simulation Yield Stress Chart

The max stress reported is now 29.2 MPa, which is less than the 46.2 MPa from using the linear elastic type before. We can also see that other areas in our model are exhibiting different stress values due to the type of deformation occurring.

SOLIDWORKS Simulation Nonlinear Plasticity von Mises Study

Nonlinear – Custom Stress-Strain Curve

Another good option for switching to the plasticity model type is to define our own stress-strain curve. This curve will define the positive stress-strain relationship starting at zero and all the way to the point where stress reaches its ultimate tensile strength. Once the plasticity model type is selected, select the Create stress-strain curve button to input the values. 

Previously, the tangent modulus value assisted with interpolating this effect, but given that we have multiple data points, we can control the slope at any given point.

Create Stress-Strain Curve in SOLIDWORKS Simulation

SOLIDWORKS Simulation Stress-Strain Curve Chart

Viewing the curve can show slight variations between each point in the plastic region. Since we decided to enter the data, the tangent modulus value defined earlier is no longer in effect.

Nonlinear Custom Stress-Strain Curve Type SOLIDWORKS Simulation

Our final value max stress reported for this is 21 MPa. While our stress is still increasing, the rate is less than the tangent modulus resulting in a smaller stress value than previously.

Conclusion

Given the opportunity to run the analysis multiple times, using the nonlinear study with the plasticity material type can highlight more precise results once the stresses go beyond yield. For better interpolation of the curve beyond yield, SOLIDWORKS Simulation allows users to input their own data, which can be stored in the material library to be reused at any given moment.

SOLIDWORKS Simulation Nonlinear Material Model Type Setup Tutorial

Video Demonstration

GoEngineer YouTube Video SOLIDWORKS Simulation - Nonlinear Material Model Type Setup Check out our YouTube video that explains more best practices when using nonlinear material model types in SOLIDWORKS Simulation. 

Become An Expert

Learn a wide range of nonlinear structural/mechanical analysis topics in the official SOLIDWORKS Simulation Premium: Nonlinear Training course. Both in-person and online options are available. 

SOLIDWORKS Simulation Training Courses Available at GoEngineer

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About Jackie Yip

Jackie Yip is a Technical Support Engineer at GoEngineer. When Jackie isn’t assisting customers or teaching a SOLIDWORKS Essentials class, he enjoys road biking and keeping up on the latest tech trends.

View all posts by Jackie Yip