Category Archives: Tech Tips

When you create a Static Simulation study and you want to fix a bracket to an immovable object by bolting to that immovable object you should use ‘Foundation Bolts’, this way you don’t have to model a stationary object and the bolts. The only prerequisite for Foundation Bolts is that you have a reference geometry plane to attach them to. Here are the steps to use Foundation Bolts:

1) Insert a Coincident Reference Geometry plane from the Insert menu > Reference Geometry > select Plane. Add the Reference Plane to the bottom of your bracket using Coincident or a distance whichever best represents your model. Most likely Coincident.

2) Right click over ‘Fixtures’ in the Simulation Study tree and select ‘Foundation Bolt’.

3) Pick the top edge of a single hole where your first bolt goes and also select the Reference Plane that you created back in step 1). Adjust the Nut Diameter and Nominal Shank Diameter if needed. Change Material, Strength Data and Pre-load as needed.

Hint: If you create your holes with Hole Series at the assembly level, SOLIDWORKS will prompt you if you would like “to add Bolt connectors to all holes in the Hole Series?”

4) Repeat step 3) for the remaining bolt hole locations. You can also copy the Foundation Bolt that is in your Fixtures folder and paste additional copies, changing the selected edge in the edit definition for each one. Each Foundation Bolt fixture needs to be attached to a different bolt hole edge. Copy/Paste will save time with all of the setting changes you may have made on the first Foundation Bolt but remember to change the edge selection.

5) The final step is to prevent your bracket from going through your foundation. If doing a Static study then you can add a contact set of a virtual wall between the bottom of your bracket and the plane you created back in step 1). If you are doing a non-linear then you would need to model a foundation and fix the geometry and add a contact set between the foundation and the bottom of your bracket.

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As computer specifications increase out in the market it is natural for anyone to want to apply all available resources to increase their job productivity.  We will discuss how RAM is utilized in SOLIDWORKS Simulation.  The common misconception with a computer that gets an increase of RAM is that it will increase your performance speed of your simulations.  This is in fact incorrect, although increasing the amount of RAM may slightly increase speed as a side effect, it is primarily meant to increase the number of degrees of freedom (DOF) that can be calculated on any given Simulation study.  If this fact is not known or clear, users may become puzzled as to why when solving their Simulation studies they notice in the Windows Task Manager that only a small portion of the RAM on the machine is being used.  In most cases the answer to this is that the study may not need all of your RAM to run the calculation.

There are many factors that contribute to the amount of RAM Simulation will use that involve the setup of your study.  Anything from the combination of options you check-boxed  in the study properties, to the constraints you have created in your study may affect your DOF.  We will review three major contributing factors that directly affect the DOF.  To begin with, since Simulation only uses the amount of RAM it needs, the mesh size and order of your mesh in your study is an important factor in determining the amount of RAM the system will utilize.  Having a coarse mesh with the Draft Quality Mesh option turned on (1st order elements) will typically amount to the least RAM usage while having a fine mesh with a high quality mesh (2nd order elements) combination will cause the most RAM being used.  Next, since not all studies use the same kind of elements to mesh your model, element types can play a role in RAM usage.  Solid tetrahedral elements will typically take up the most RAM due to the amount of calculation nodes it utilizes, where as beam elements will use the least amount of RAM.  Shell elements fit somewhere in between the two element types in RAM usage in a typical Simulation.  Most importantly, it boils down to the total number of DOF the element types yield: 3 DOF per node for solid elements and 6 DOF for Shell and Beam elements.

Since the majority of the RAM used in Simulation involves the DOF calculated in the study, there is one more factor that we need to consider.  This is the type of solver the Simulation utilizes.  There are two major solver types utilized in SOLIDWORKS Simulation, Direct Sparse and FFEPlus.  Direct sparse requires much more RAM than the FFEPlus Iterative solver.  It has been documented that the Direct Sparse solver for a linear static study will use about 1 Mb for every 200 DOF while the FFEPlus solver is significantly less demanding at around 1Mb for every 2000 DOF (SOLIDWORKS Knowledge base, S-037675).

After reviewing how RAM is used in Simulation as a best practice it is always better to have more RAM than not enough.  Not enough RAM may result in an “Out-Of-Core Solution” warning message that indicates the amount of RAM currently available is not sufficient to store all the data needed to perform the calculation.  At that point the study will begin to use the Virtual Memory (paging file) on your hard drive to continue the calculation.  This will severely reduce your calculation speed to the data transfer rate of your hard drive.  Having More RAM available on your computer will eliminate the risk of this potential performance bottleneck.

If you do run out of RAM during calculation, in 2014 and future versions of Simulation, there is another solver type available called “Large Problem Direct Sparse” which uses enhanced memory-allocation algorithms for data caching to help calculate simulation problems that exceed the RAM limitations of your computer.  This solver type is only available for Static and Nonlinear studies at the moment but is a good start to have a solution for the calculation of large scale studies that normally would not solve in previous versions of SOLIDWORKS.

 

 

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When a SOLIDWORKS part or assembly contains multiple Simulation Studies the time it takes to load the model can increase. There is an option in SOLIDWORKS 2014 and newer to only load basic information for a Simulation study.

To disable the loading of Simulation data first enable the SOLIDWORKS Simulation add-in. Then select Simulation -> Options and uncheck the “Load all Simulation studies when opening a model” option.

The Simulation study data will then only be loaded into memory when a specific study is activated.

Since this is a System Option the setting will apply to any SOLIDWORKS file that contains a study being opened on the computer making the settings adjustment.

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One of the biggest issues when simulating toolpath in CAMWorks, is the accuracy of the stock definition.  It is an important piece of the simulation to verify things like collisions and depth of cut.  However, in the past, there has been issues when trying to simulate a part with many different setups.  For the stock definition to look right, you had to start the simulation with the first setup and go through all setups until you reached the one you were interested in.  One new feature with the 2014 release of CAMWorks is the ability to Shift select the “Simulate Toolpath” command to invoke a WIP (Work in Process) stock definition.

 If the <Shift> key is pressed while selecting the “Simulate Toolpath” command you will be able to select your WIP stock definition. This will automatically look backward to any features that were machined before and create an accurate stock definition for that particular setup without actually simulating those previous features..

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Did you know that with SOLIDWORKS, there is no direct way to save an individual custom material that originated from another computer?  Let me give you a common scenario:  You are a consultant and you get a part file sent over.  That part file has a custom material that you are required to use on another design.  The best workaround using SOLIDWORKS is to get the original custom materials database from your customer (materials.sldmat) and point SOLIDWORKS to that additional database in Tools > Options > File Locations > select ‘Material Database.’  If that is not an option you are left having to manually create the custom material.

If you happen to own any version of SOLIDWORKS Simulation, you can use its natural workflow for creating a study to pull and create the custom material you want for use in your own materials database.  Simply open a new Simulation study on either your existing part or assembly file (the model with the custom material you want to copy) and choose “Apply/Edit Material” in the Simulation study tree.

Simulation will create a temporary file-specific custom materials database sub-folder with the same name of the part or assembly you are working on and will include all the custom materials that were assigned to the model.  In the example above the creation of the Simulation study added a sub-folder called “crank-arm” as was the name of the assembly.   At this point you can copy and paste the custom material you want to include in your own database.  Be sure you do this before you close the Simulation study.

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