*Written by: Jared Spaniol, Application Engineer*

SOLIDWORKS offers many different products and packages that range from technical communication to simulation to bringing designs to life with SOLIDWORKS Visualize. It’s good to know there are so many options that all work in unison and can be utilized to make your job easier, but it can be difficult to know what’s in each product line and what each option can do. This makes selecting the correct package to meet a company’s needs challenging. Hopefully I can clear up some of that confusion regarding the SOLIDWORKS Simulation packages today.

Similar to how the packages of SOLIDWORKS 3D CAD are arranged, there are three tiers to the SOLIDWORKS Simulation solutions as well. These tiers are broken down into SOLIDWORKS Simulation Standard, Professional, and Premium.

Figure 1 (below) illustrates a breakdown of what is included in each package of Simulation.

**Simulation Standard** mainly contains a linear static analysis tool along with a few extras, like trend tracker and fatigue analysis.

**The Simulation Professional** package offers a variety of different simulation options that are value-added such as Frequency, Buckling, Thermal, and Drop Testing, among other useful features. The Simulation Professional package is relatively straightforward. For example, if you need to find out how hot a heat sink on a PCB gets, then a thermal analysis fits your needs, and therefore you would need the Simulation Professional package.

The main difference between the packages that may be confusing is the difference between a linear analysis (Simulation Standard) and a nonlinear analysis (Simulation Premium). The question that comes up a lot is, “what type of analysis do I really need to perform?” or more specifically, “do I need to run a nonlinear analysis to solve this simulation?”.

The answer to these questions can be complicated, but can be simplified by knowing a few key pieces of information and a little theory behind simulation.

First, there are three assumptions to be aware of that would make your analysis linear in nature. These three assumptions are as follows…

- The material is linear elastic, i.e. the part returns to its original shape after the load is removed.
- Deformation of the material is relatively small when compared to the original shape and dimensions of the model.
- Loads are constantly applied to the model, i.e. slow and gradual loading. This includes separate parts not contacting one another due to the loads.

If one or more of these assumptions are violated, then the relationship between force and displacement is nonlinear and the analysis becomes nonlinear in nature, as shown by the red graph lines in Figure 2.

There are also three types of nonlinearities to be aware of that are parallel relationships to the assumptions listed above. These are

- geometric nonlinearities
- material nonlinearities
- boundary nonlinearities

This means that if you can identify one of more of these types of nonlinearities within your model then a nonlinear simulation is required.

For example, if I were to compare two identical simulations, one with a steel part and one with a rubber part, assuming the yield strength of the steel material hasn’t been exceeded, the steel part could be solved with a linear simulation using the standard package, but because the rubber material is nonlinear, a material nonlinearity, that would automatically qualify for a nonlinear analysis and SOLIDWORKS Simulation Premium would be required.

Use these questions as a guide when determining if you need a nonlinear analysis.

- Has the maximum stress of the model exceeded the yield stress of the material?
- If yes –> nonlinear analysis

- Has the model experienced any large deformations?
- If yes –> nonlinear analysis

- Does the material have a linear region in its’ stress strain graph?
- If no –> nonlinear analysis

- Is the load application constant, i.e. no dynamic loading is taking place?
- If no –> nonlinear analysis

- Does the stiffening or softening of the model change as it deforms?
- If yes –> nonlinear analysis

- Are any parts contacting each other and/or causing no-penetration contacts to change shape?
- If yes –> nonlinear analysis

Keep in mind that every analysis can technically be solved using a nonlinear simulation, but not every analysis can be solved using a linear simulation. Knowing the difference and using the correct tool for the job will simplify things and ultimately save time.

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