Following on the first 2 parts of my SolidWorks Simulation topics, Meshing Advice in SolidWorks Simulation (Part 1 of 5) and Mixed Meshing in SolidWorks Simulation (Part 2 of 5), I'm going to present the new interface and functionality of contact sets in SolidWorks Simulation 2009. I'll also provide a refresher and description of what these are, and why they are important.
Any time we venture into assembly (or multi-body part) analysis, we have more than one component. Each possible interaction between components is described with a Simulation feature, such as contact set or connector. In Simulation Training, we treat in-depth three types of contact sets: bonded, no penetration, or free. It's easy to visualize these three types: components glued together, having a friction/contact interaction, or ignore each other completely.
An example is a dual-cantilever situation, with a downward point load on the free end of the upper beam. Remember we're dealing with small deformations, so we're working with just one possible contact set where the two bodies touch. I have setup a study with two pieces of half-inch plate (solid mesh). I ran this study with three contact options. The displacement contour plots below clearly demonstrate the difference:
Figures 1 & 2 - Setup and Displacement results - inches, true scale, front view
Since we're interested in moving into mixed meshing, let's expand our discussion. Treat both plates as shells - modeled as SolidWorks surface bodies:
Figure 3 - Surface model with same Simulation conditions
Global Contact does not apply with this model (as it did above with the solid mesh) as the surfaces are not coincident. For the un-initiated, Global conditions apply only to initially touching or overlapping faces. And now that we're on the same page: there are exceptions to this in 2009. Usually, if any gaps exist between components, then that interface will be treated as free unless a local contact set is defined.
Figure 4 - If you specify a local ‘no penetration' set with shells, Simulation will take the virtual thickness into account. With this type of contact the result is the same as the above solid mesh:
Moving on, there is some more new functionality with Sheet Metal (see Part 2). Even though the sheet metal component is meshed as a mid-plane shell, coincidence with the solid model is still respected, thus global contact applies. See the second example below:
The backing plate is a Sheet Metal plate, and is fixed on all edges. The brackets are regular solid bodies and have a 500lbf downward load applied each. They are mated coinciden
t in my assembly. Side view after meshing:
Global bonded will apply with these components. Check out page 130 of the SolidWorks Simulation 2009 What's New document for some more examples. I mention this every time because everyone should peruse this PDF at least once a year when upgrading. In 2009, this Global setting also extends to include mixed meshing: face/edge of shell to a solid or another shell, and face/edge of shell with a structural member (beam). However this technology is not perfect and I have found that many beam-to-shell interactions must still be defined with local contact sets.
It's easy to forget to define a local contact set, or sometimes global bonded isn't sticking, or we have gaps of which we are unaware. Any of these situations could result in rigid body motion which means a failed solve. Make it standard practice to enable ‘soft spring' when solving preliminary studies. If your model is a huge local-bonded model you can also use a Frequency study type to locate any ‘loose' components. Save time by running initial studies with draft-quality mesh.
Quick test: count how many unique interactions there are between the three components in the above model. Assuming small deformations, there will be two. It's pretty obvious based on the geometry this will be a bolted connection. When setting up an analysis, it's tempting to put in all the detail right away. In this case, I would need four bolt connectors and no-penetration contact. Remember anytime you use a pin or bolt connector, those components should not also be bonded.
Working with large models, I've found it's sometimes easier to start with everything bonded. Make sure everything is working and solving before complicating and severely elongating the solve with no-penetration sets. It's always easier to start simple and add features in a step-wise fashion (e.g. contact sets and bolt connectors).
The extension of this mindset applies to components that may or may not contact depending on deformation. No-penetration formulations take a substantial computational effort. So a typical workflow for me is to leave such an interaction as ‘free'. After solving, check the true scale displacement for interference or penetration between components, adding in no penetration as necessary and re-solving.
For you professionals out there, let me point out some key interface changes with Simulation 2009 contact sets. First, when defining local no-penetration contacts, the formulation type is not specified by default and the selection may even be hidden. All local sets are node-to-surface type by default, unless specified otherwise. Make sure and enable the option ‘Show advanced options for contact set definitions' under Simulation > Options > Default Options > Mesh. There is also an option to ‘Improve accuracy for contacting surfaces with incompatible mesh' which will force local sets to be surface-to-surface formulation.
If you are interested in SolidWorks Simulation Training, keep an eye on our Training Calendar for the next upcoming offering. I encourage everyone interested in getting started quickly to attend and learn about contacts and much more. Also, make sure and update to service pack 3.0 as soon as you are able since there are a few issues I've seen with earlier versions and mixed meshing. As always, if you are seeing any strange behavior or need support, give the Alignex Help Desk a call or contact us on our Support Webpage.
Often when the time of year rolls around to upgrade to
SolidWorks 2009 there are a couple key members of the family that are forgotten in the upgrade.
One item that is often overlooked is the Solid Network License (SNL) Manager. When in an SNL environment new version current SNL Manager software and a new license file must be installed for each version of SolidWorks. Each of these items can be obtained through the customer portal. As a side note licenses for previous versions can be managed with the latest version. For example the 2009 license manager will distribute a license to 2008 SolidWorks on the client PC. This makes upgrading the license manager software a great place to start your upgrade and also assures that it is not overlooked and downtime is very limited.
Another often forgotten, yet equally important piece to the puzzle is the Solidworks Workgroup PDM Vault. This must also be upgraded to match the current version of SolidWorks. A 2008 Vault will be unable to properly communicate with SolidWorks 2009 and vice versa. So it is critical to keep these items in sync. Planning ahead is important in a Workgroup environment to limit any down time. It is best to set aside a certain timeframe that will allow ample time for updating the vault and all client PC's with limited impact to the users. This is usually done overnight or during the weekend at many Alignex customer installations.
Remembering these two items can be the difference between a seamless, successful upgrade and a frustrating day of fire fighting. So make a note and don't forget the extras during your next upgrade!
Cole McLeod
Application Engineer
Alignex, Inc.
So far,
SolidWorks 2009 has been a fantastic release and now
Service Pack 1 is available. This is the time when many of our users begin the process of upgrading to the new version. Already, the first wave of installation-related questions has hit the help desk.
Preparing for an upgrade to a new major release is not a trivial task. There are many considerations that are beyond the scope of this article. That said, I want to make this recommendation to all users and administrators:
Do a little ‘Fall Cleaning' before making the switch to SolidWorks 2009 (or even if you aren't planning on upgrading anytime soon). Important Note: If you are unfamiliar or uncomfortable with any of these procedures, be sure and consult your IT gurus. Make sure to set a Windows restore point before any major system maintenance. This is not an exhaustive list of maintenance tasks, just some things that I see many of our users neglecting.
1. Each new release requires a new graphics-card driver. This driver may be a different version than the latest OEM driver. Download the latest drivers here.
2. While you're on that page, be sure and check out the "SolidWorks System Requirements" links. Each year the requirements may increase as the power and technologies are expanded. How long has it been since your last new desktop? A typical engineering department has a two- to three-year hardware lifecycle.
3. Clear out your Windows temporary directory:
a. Start > Run > %temp%
b. Most of these files can be deleted safely
c. If you don't feel comfortable deleting these, run the Disk Cleanup utility in the System Tools program group.
4. Defrag your hard drive. You'll find the Disk Defragmenter tool in the Windows Accessories/System Tools program group. Let this run overnight several times a month.
5. Uninstall the Bloat-Ware! Software such as iTunes, RealPlayer, etc, are fun but also can cause unnecessary processes to startup when Windows boots and cause an overall performance degradation. Leave those at home or create a clean partition for running SolidWorks.
6. Watch the scope of your Windows Desktop Search. See that little blue magnifying glass icon in your system tray? When it's glowing, it's indexing and impacting your hard drive and CPU performance. Make sure its search paths are limited to your local SolidWorks file locations. You can remove it from the Start Up program group so it doesn't run everything Windows boots.
7. Clean the registry! There are plenty of utilities out there that can clean up the Windows registry. A free one that I use is ‘CCleaner', find it here. These utilities remove odds and ends from the registry and improve overall performance in some cases. The longer you have been running an installation of Windows, the more junk you accumulate!
8. Once clean, keep it clean. I use Spybot Search and Destroy as my anti-spyware application.
9. Set Windows for "Best Performance." Go to Control Panel > System > Advanced > Performance Settings > Visual Effects > "Adjust for best performance".
10. The Ultimate in "Cleanup" is always a re-installation of Windows. Even if you uninstall everything, it seems that over time the Windows environment just bogs down. The thought of reformatting scares most novice Windows users, but to most Windows Pros it is a necessity. This will completely refresh your environment. This requires a lot of backup and planning, but once you have a procedure in place, it isn't that bad (about a half-days work). Personally I keep a backup of all applications and drivers I need to install on a network location along with personal backup files.
These recommendations should keep your box running better all year long. I typically will do a complete Windows re-installation every 4 to 6 months to keep my environment in top shape. Again, be sure not to get into any of these if you are uncomfortable or unfamiliar! Alignex can't replace your IT support, so make sure they are kept in the loop anytime you plan on doing any major system maintenance. You can check out this Microsoft site for some further beginner information.
Enjoy SolidWorks 2009! As always, if you run into installation issues, please call on Alignex Support.
Brian Zias
Mechanical Application Engineer
Alignex, Inc.
Autumn is upon us and another new release of SolidWorks has been rolled out. At Alignex, we have been working with
SolidWorks 2009 since its early beta days. The word from SolidWorks corporate from the very beginning was that this release was all about performance. Many of the enhancements in 2009 are things done under the hood so to speak to achieve speed improvements. In the statistics below keep in mind that SolidWorks is using assemblies that are between 5 thousand and 10 thousand components in size.
Like many CAD users, I too am interested in performance and I wanted to test the speed claims on real world data. I use the same customer data set (a good sized assembly) that I've had since the SolidWorks 2003 timeframe. I've used this data set to test each release of SolidWorks since 2003 for stability, compatibility, and to look for regression issues. Although I can't show you the actual assembly because of its proprietary nature, I can show you some statistics from it so that you can get a sense of what it's like size wise.
Here we see the SolidWorks specific statistics like total number of parts, etc.
Below, you can see some file size statistics from this data set over different releases of SolidWorks. 2009 SP0 keeps heading in the right direction in regards to file size. This is the second smallest file size I've recorded to date! In each case the size is determined by migrating the data set from the previous release using the migration wizard in SolidWorks, and then the size on disk is recorded. 
Once the data was migrated into the 2009 format I did some quick time testing versus 2008 doing common tasks in drafting using this assembly. Keep in mind that the assembly I'm using for these tests is quite a bit smaller than the ones SolidWorks used to gage their performance increases, so I suspect that the larger the size of the assembly, the larger the scale of the performance increase you'll see.
The *most* important thing to keep in mind in all this is that I didn't have to do anything different process wise in 2009 in order to see these gains. In other words, I didn't have to use any New Commands or New Techniques in 2009 (and there are quite a few) to see these gains. These are raw gains that result from nothing more than migrating the data into the 2009 format, and then executing the same commands that I had in 2008. If you were to use some of the new capabilities in 2009 (like Speedpak) then the delta in performance would be even greater in 2009's favor. 
As always, I recommend that all SolidWorks customers give some careful consideration to making the switch before you do it. Planning and preparation are the keys to a successful rollout of a new release. If you have any questions whatsoever about this please call our helpdesk to talk over your plans with one of our certified application engineers, or get in touch with your account rep from Alignex and they can point you in the right direction.
Mack Rasmussen
Director of Technical Support
Alignex Inc.