There are a number of simulation/analysis software products available for conducting motion and FEA studies. However, the ability to conduct them both, as well as optimizing assemblies is a tall order, especially for mere mortals and non-CAE specialists. With a relatively short learning curve, for this evaluation SimWise 4D proved its mettle for handling motion, FEA, and optimization in one comprehensive package.

What is known today as SimWise 4D began when Design Simulation Technologies (DST) acquired a license from MSC Software Corp. to the MSC.visualNastran 4D (vn4D) product. That software traces its roots to the Working Model 3D product developed by Knowledge Revolution, which was acquired by MSC in 1999, extended to include FEA capabilities, and renamed Working Model 4D.

SimWise Animations

Let’s see what SimWise 4D can do and how it does it.

**Getting Started with SimWise 4D**

I performed this evaluation on a GoBOXX G1840 mobile workstation with an Intel i7 CPU, 16 GB RAM, and Windows 7 Ultimate 64-bit OS. As with other technical software evaluations, this machine proved to have the necessary computing horsepower to perform all of the tasks called upon.

As with most new technical software applications, the best place to start is usually with the tutorials that come as part of the product. In this case, SimWise 4D has a nice series of tutorials available that will get you up to speed with basic operations in short order.

Although it is CAD neutral, I evaluated SimWise 4D Version 9.0 with SolidWorks 2014 parts and assemblies, and other CAD plug-ins are available, including Autodesk Inventor, Solid Edge, and SpaceClaim.

The plug-ins let you transfer complete assembly models including constraints to SimWise with a single click. During the transfer process associativity links are created that connect the SimWise model to the CAD assembly. If a change is made to the CAD assembly it can be re-exported to SimWise and only the changed portion of the model is updated in SimWise. Assembly constraints are mapped to SimWise constraints and, where possible, multiple lower order assembly constraints are converted to single higher order SimWise constraints.

**SolidWorks Associativity With SimWise**

I was impressed with the high level of associativity that SimWise 4D had with SolidWorks. From within SolidWorks when you start the SimWise add-in, and you choose Connect, SimWise for SolidWorks maps the assembly components and constraints into SimWise bodies and joints, and creates a new, linked model with a .wm3 file extension in the directory where the CAD files are located. As SimWise translates the geometry, the progress is displayed in the Preparing Simulation dialog.

When the export is complete, the SimWise program opens and displays the CAD Associativity dialog, listing the SimWise objects that are associated with objects in the SolidWorks model. You then use SimWise’s Constraint Navigator for examining relationships among bodies, subassemblies, and constraints so that you can verify and modify your simulation model.

As you iterate through constraints or bodies, SimWise isolates the relevant objects so that you can focus on a particular body or a constraint. This process was a real time saver.

**Motion + FEA + Optimization Add Up to Comprehensive Capabilities**

SimWise 4D combines SimWise Motion (for 3D kinematic and dynamic motion simulation) and SimWise FEA (for linear static, normal modes, steady state thermal, and buckling FEA analysis) resulting in a comprehensive integrated mechanical simulation product. SimWise 4D provides the same capabilities as found in SimWise Motion and SimWise FEA separately, but the integration produces a coupled Motion and FEA capability that computes the stresses resulting from the dynamic loads induced by the motion of an assembly. A lot to ask for, but SimWise 4D delivers.

**Step 1: Motion Simulation**

SimWise Motion takes a design comprised of assemblies of moving parts and simulates the kinematic and dynamic motion of the design allowing you to evaluate its function and performance.

SimWise Motion lets you start with an assembly designed in several CAD systems (I used SolidWorks 2014) or one created using SimWise’s basic geometry creation capabilities. The physical properties of each of the parts in the assembly will be calculated and if assembly constraints are present in the CAD mode, they will be automatically converted to SimWise constraints.

To make your simulation closely reflect the real word, SimWise Motion lets you add various motion characteristics to your model. SimWise Motion supports motors, actuators, gravity, realistic contact between bodies, springs, friction, damping, and other generated forces.

**SimWise Motion Flowchart**

Running a simulation is relatively simple by specifying how long you want the process to run and then clicking the calculator icon to compute your motion results.

SimWise Motion calculates several types of results that you can use to verify the operation of a design. Animations provide the visual feedback needed to understand if your design will work properly. However, what truly sets SimWise Motion apart from a generic animation package is the ability to provide accurate, physics-based, engineering data associated with the movement of the assembly. Result vectors and plots of displacement, velocity, acceleration and forces, provide the numerical information needed for fully understanding the performance of a design. As you make design changes, you can compare the data to verify and confirm design improvement.

SimWise Motion helps you answer the question “Does my design really work?” However, its real utility is realized when it is coupled with SimWise FEA. The reaction forces that were calculated by SimWise Motion are automatically applied to an FEA model created by SimWise FEA, so you can see the stresses that result from the movement of the assembly. Not only can you answer with, “Does it Work?” you can also answer “Will it Break?”

**Step 2: FEA**

SimWise FEA is a finite element analysis tool that performs stress, normal modes, buckling, and heat transfer analysis on mechanical parts. It is automated and handles much of the complexity associated with FEA for new users while also providing more advanced features for users who understand the Finite Element Method.

It imports geometry from a CAD system (in my case SolidWorks) and lets you add specific structural and thermal entities to the model resulting in a functional structural prototype of a design. It simulates that prototype using physics- and mathematical-based techniques and presents the results of the simulation in graphical and numerical formats. SimWise FEA can display FEA results as shaded contours, deformed shapes, or animations. In addition to these engineering values, SimWise FEA also calculates factors of safety and errors in the stress results and both of these can be displayed as shaded contours. With the results you can determine whether a design is robust enough to operate as intended or if modifications are needed.

SimWise FEA has a rich set of functional objects that are added to a CAD model to build functional prototypes. These objects include:

• Concentrated loads, distributed loads, torques, and pressures

• Restraints and enforced displacements

• Prescribed temperatures, conductive and convective heat flux, and radiation.

All of these values can be driven by the SimWise formula language. All of these objects are applied to the underlying geometry, not to nodes and elements as in traditional FEA products, and I found this approach to be much more straightforward.

SimWise uses a fast iterative finite element analysis solver that takes advantage of multi-core processors and which is based on a Preconditioned Conjugate Gradient method. SimWise FEA exclusively uses ten-node tetrahedral elements and the solver is optimized for this type of problem.

**Step 3: Optimization**

One of the things that intrigued me most about SimWise 4D was its Optimization capabilities.

Once you know a design will work and is strong enough to operate safely, you can consider making trade-off between product attributes in the areas of weight, cost, manufacturability, and performance. SimWise 4D contains an optimization engine that iterates through many design alternatives looking for design parameters that meet all targets and criteria.

SimWise Optimization is a tool that extends the Motion and FEA simulation capabilities by letting users determine the best set of model input variables necessary to achieve a desired simulation and design goal. Variables can be anything such as spring constants, coordinate and body positions, and forces. Goals can range from minimum motor torque, desired spring constant, or minimum acceleration.

Optimization in SimWise 4D consists of the following basic steps:

1. Creating and assigning parameters that will be used as optimization variables.

2. Creating meters that will be used as optimization goals and constraints. These meters will be used in defining both the Goal and constraints for the optimization

3. Defining the optimization study.

4. Running the optimization and updating the mode.

SimWise 4D and Space Claim: The Future of Simulation

The three main components to the optimization study are:

• Parameters – The values that will be changed to achieve an optimized objective. These can be any type of SimWise value, such as the stiffness of a spring, or the location of a joint.

• Objective – The value(s) to be optimized. Any SimWise quantity that can be displayed on a meter can be an objective.

• Constraints – Place bounds on the optimization. Any SimWise quantity that can be displayed on a meter can be used as a boundary.

Note: the term “constraint” used here is not the same as a SimWise model feature constraint. It is a boundary used in attempting to satisfy the optimization goal.

The optimization process uses values of the parameters that are within their user-specified range and checks for all possible solutions in that range using the number of iterations specified. If the value of the parameter results in a solution where both the constraint and goal are satisfied, the solution is marked as “Feasible.” On the other hand, if either the constraint or the goal are not satisfied, the solution is marked as Infeasible. All solutions are assigned a Rank, with 1 being the best design configuration.

An interface called the Optimization Manager allows you to control the setup, running, and post-processing of an optimization study.

Although described earlier, the optimization process consists of the following basic steps:

1. Defining parameters (variables)

2. Defining meters to be used in establishing the boundaries for the constraint(s) and criteria for the goal(s)

3. Using the Optimization Manager to:

• Specify which parameters to use in the optimization study

• Specify one or more goals

• Specify one or more constraints

• Specify the number of evaluations

For example, a goal could be to optimize the location of a spring end attachment so that the maximum torque on the motor is less than or equal to 5000 N-mm.

For interpreting goals, all values smaller than the maximum meter value are better and more desirable in achieving a goal.

For interpreting constraints, from the motor example above, the design goal is achieved by looking for solutions only where a coordinate location falls within the specified range, and the constraint criteria are satisfied.

As the optimization runs, the engine chooses different values for the parameters and runs multiple Motion, FEA, or Motion+FEA simulations. The search algorithms in the optimization engine guide the choice of parameter values. The data from each run are preserved and can be reviewed. Each run is ranked in terms of how it meets the optimization criteria and the rankings can be used to arrive at the final values used for your design.

The example design is considered “Feasible” only if the coordinate values fall within the specified 90mm to 180mm range, and the torque values for the motor are less than or equal to 5000 N-mm. Otherwise, the design is marked “Infeasible,” and more design iterations are required to make it “Feasible.”

Along with Motion and FEA, I found this Optimization capability to be SimWise’s greatest assets and differentiators.

**Summary and Final Thoughts**

If you design complex products that require an understanding of motion and stress effects and analysis, then you should consider SimWise 4D for optimizing your designs. In one comprehensive package, SimWise 4D lets you perform all of these functions while maintaining bi-directional associativity between the CAE simulation/analysis and CAD modeling environments

Admittedly, there are a lot of simulation and analysis tools available on the market today, but most are difficult to learn/use, have limitations, and products are outgrown in the quest for more advanced capabilities. SimWise 4D overcomes all of these problematic issues with its ease of use, as well as comprehensive features and functions for motion, FEA, and optimization studies. It’s also a product that can grow as your simulation needs grow more sophisticated.

Pricing for a node-locked license of SimWise 4D starts at $4,995; annual maintenance starts at $995.

For More Information: SimWise 4D

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