Archive for April, 2008

Sweeney Smackdown

Tuesday, April 29th, 2008

As my loyal fans know, every [randomly chosen time interval] morning I post my gripes about CAD, or the engineering world in general. In hopes that someone out there will see these problems and fix them for me. I figure I spend all day fixing other people’s problems -someone out there owes me.

  • Why does my optical mouse suddenly decide it wants to be on the other side of the screen?
  • I hate acronyms. They should be illegal. ECN, ECO, ECP, ER or PDM, PLM, ERP, LCM. Most people don’t even know the difference and use them interchangeably. IMHO, these need to be taken out of the language ASAP.
  • I remember back when I ran my company’s help desk, users would ask me to go over to their workstations to show them how to do something. I would get there and they would have their mouse on the left hand side of the keyboard…they might as well have a Mac. I look like a 4th grader trying to use a mouse left-handed ….or worse yet they don’t have a 3D mouse. Don’t you hate that twitch you get in your arm every time you reach for the 3D mouse and it isn’t there?!
  • Why are there web sites/blogs/forums where I have to create my “free user name and password” to participate? I have thousands of PIN numbers, user names, passwords, secret words…why would I want one more just so I can post a comment on a blog?

 

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

Splitting Surfaces for FEA

Monday, April 28th, 2008

Splitting a face of geometry in SolidWorks can be very useful in FEA for a number of reasons:

  1. Isolating a location to specify a load/restraintÂ
  2. Specifying areas to apply mesh control
  3. Reducing the time to solve by cutting down the areas of a no-penetration contact condition, and so forth.

There are two methods to split a face in SolidWorks that the user can exploit for analysis purposes:

a) SPLIT LINE COMMAND

Insert > Curve > Split Line

This tool can be used after creating a sketch that represents the region to be split. For example, to split a face into two, the user can draw a line running across the face, and use Split Line to create two faces by selecting the sketch and the face. The user can also draw closed contours (like circles, polygons, ellipses etc.) and split a face to match the contour. As seen in the adjoining figure, the split line tool is being used to split the face of the rectangular block into two independent faces with the help of a straight line.

Split Line Tool

NOTE: Only one closed contour can be used for every split line. Hence, to create 4 new regions, the user must create 4 split lines, with 4 underlying sketches.

b)WRAP COMMAND

Insert > Features > Wrap

This tool can be used after creating a single sketch that contains multiple closed contours. For example, if a face has to be divided into 10 different regions, the user can draw closed contours representing the 10 regions all in one sketch, and use this command to divide the face. As seen in the adjoining figure, the wrap tool is being used to split the face of the rectangular profile into multiple faces.

Wrap Tool

NOTE: Choose the sketch before entering the WRAP command, and select the Scribe option when picking the face to be split.

Once such independent faces have been created, it is very simple for a user to select the face(s) to apply different boundary conditions in COSMOS.

Vikram Vedantham

Simulation Product Manager 3DVision Technologies

Library parts – in or out of the vault?

Tuesday, April 22nd, 2008

From time to time I like to answer email I get from my many fans.

Dear Great Wizard,

My Aunt Emily just bought PDMWorks Enterprise 2008. Do you think she should include her purchase part library in the Enterprise vault?

Signed,
Wondering in Kansas

Dear Wondering,

The question of if your purchase part library should go into your PDM system has been going on for as long as scarecrows have been afraid of fire. Many argue that once the library goes into the vault, only people who have access to the vault can see the parts. While that is true; how many people need access to the library parts and not any other engineering documentation that is stored in the PDM system? So you have to figure these people are going to need in the vault for other purposes anyway so you really aren’t making much of an argument for a way to save on your licensing fees.

Let me give you a few reasons why I think the library should go in the vault:

  • If you are in a replicated environment, it is important for all locations to have access to the same library. PDMWorks Enterprise can do this for you. Granted, you could put the parts on a shared drive, but that is slow for people off site, plus you are forcing your users to design over a network -and that is like going through life needing oil every time it rains.
  • Parts in the PDMWorks Enterprise vault are searchable. You want your users to find the parts they use most often fast. If the parts aren’t in the vault, they aren’t searchable.
  • It is important to be able to click on a part and know every location it is used. PDMWorks Enterprise can do this, but only for files inside the vault. If a library part does need to change (obsolescence or supplier changes it) you need to know what assemblies may be affected.
  • As much as I hate to say it, library parts change too. For library parts revision tracking is very important. A PDM system is made to track revisions. Files not in the PDM aren’t being tracked.

Lastly, don’t worry that your library parts are suddenly going to go into your engineering workflow. In PDMWorks Enterprise, you can set your library parts to go in their own unique workflow. Thus you can keep them out of your ECN process.

I hope this helps, and please stop shouting at my flying monkeys. It frightens them.

Sincerely,

Jeff Sweeney

Jeff “The Great Oz” Sweeney
Engineering Data Specialist
3DVision Technologies

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

TIPS & TRICKS: Edit Seed Feature

Tuesday, April 22nd, 2008

Want to quickly EDIT the original / SEED feature of a pattern ?

Just Right+Click ANY instance of a pattern and choose “EDIT SEED FEATURE” from the Right+Click menu !!

Piece of cake !

Randy Simmons

Application Engineer, CSWP 3DVision Technologies

Who names these things?

Tuesday, April 22nd, 2008

Names can be a powerful thing. They can give you connotations of something before you know anything more about it.

Naming something poorly is often times a bad thing. The folks making the PDMWorks Enterprise must think there is an award for poor naming conventions.

Let’s start with the name of the product itself…the moniker PDMWorks gives users the feeling there is very little difference between PDMWorks Workgroup and Enterprise, except the Enterprise version may have a bit more in it, while in fact they are really two completely different products with different terminologies and architecture.

The name for the CAD client version was finally fixed with 2008. It used to be called “PDMWorks Enterprise for SolidWorks”, but you could use it for other CAD systems? So, so confusing.

The servers that act as file shares are called “archive servers”. In the IT world, an archive server is a machine whose whole responsibility is to hold a lot of data…data that is seldom used…for backups and errrr archiving! Thus archive servers are typically slow input/output machines. Exactly not what you want with an Enterprise archive server -with Enterprise you want machines with fast I/O because you are working with production data, data you want access to as fast as possible. [Your database server doesn't need super fast I/O -it wants a fast CPU and as much RAM as it can get its hands on.]

What’s the point? I guess there isn’t one, I had a pretty hard time coming up for names for my kids, so perhaps I shouldn’t throw stones. Then again I didn’t give them names like “banana” or “skateboard” either.

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

Nodal versus Elemental Stresses

Friday, April 18th, 2008

A common question that comes up in my training classes is : What should be examined – Nodal Stresses or Elemental Stresses?

When running a COSMOS analysis, the solver internally evaluates the stresses for each element in the model at specific locations inside the element (also called as Gaussian or Quadrature points). These points form the basis of numerical integration schemes used in Finite Element codes.

Gaussian Points

The number of points selected is determined by the type and quality of the element. The subsequent stresses obtained at the Gaussian points inside each element are extrapolated to the nodes of the element.

Now, let us consider multiple elements sharing a node. In such a case, what would be the stresses at the node, if the gaussian point inside each element contributes a stress value to that node?

Nodal Values are the averaged values of stresses at each node. The value shown at the node is the average of the stresses from the gaussian points of each element that it belongs to. In the adjoining figure, the central node would carry a stress that is an average of the 6 stresses coming from the 6 elements that it belongs to.

nodal data

NodalValues

The alternative method of displaying stresses is called Elemental Values. In this method, each element individually looks at the stresses at its nodes from the Gaussian points. The stress at the element is the average of the stresses seen at its corresponding nodes.

Elemental Values

What stresses should one examine when taking a look at the stress plot?

Since the approach to average stresses is different for the two methods, the maximum stresses in the stress plot will be different. In the above two examples, the maximum values from nodal and elemental stresses are 5 and 5.66 respectively.

The degree of difference in the values is a reflection of the coarseness of the mesh, and hence the convergence of stress results. If the values are very different, it is a reflection of the mesh being too coarse at the high stress location. Hence, the mesh needs to be refined at those locations using Local Mesh Control.

Comparing nodal stresses and elemental stresses is a way of understanding if the mesh is fine enough, and if the results have converged at the highest stress location in the geometry.

Vikram Vedantham

Simulation Product Manager 3DVision Technologies

Dear Mr. Guy that invented DimXpert

Friday, April 11th, 2008

The folks at SolidWorks always say that the product is driven by enhancement requests. I know quite a few people at SolidWorks read these blogs so this is my open letter enhancement request to them…

Dear Mr. Guy that invented DimXpert:

You are a genius. The ability to quickly put dimensions on a drawing following manufacturing guidelines (not design intent) is the greatest thing since, well since ever! Whatever you are getting paid, I am sure it is not enough because the DimXpert has saved zillions of people hours of time [and embarrassment from machinists] and helped them produce more accurate drawings.

I know you are busy, but if you have a few minutes (it’s just code right?!) I have a few enhancements I’d like you to look over:

  • Once I define my datums, don’t make me redefine them every time I restart the routine.
  • Allow me to put the created dimensions on an isometric annotation view (just one view on a drawing, fully detailed? How cool that would be!)
  • More power in the auto dimension routine. The automation still misses too many faces. (This is especially true for angled planar faces!)
    • As a sub-comment manually adding location dimensions is too many mouse clicks, I’d love to be able to use the smart dimension tool, just please highlight the datums when I am in “smart dimension” mode to help me remember what I want to smart dimension to.
  • I want to use ordinate dimensions!

Again, I love the DimXpert -those that aren’t using it are missing out, but if you could get to some of the ideas above, I’ll vote for you for “man of the year”

Sincerely,

Jeff Sweeney

CSWE Engineering Data Specialist 3DVision Technologies

PART 2 of New Virtual Component functionality in SolidWorks 2008

Wednesday, April 9th, 2008

Last month I wrote a blog entry titled “New “Virtual Component” functionality in SolidWorks 2008″ hoping to CLEAR UP some of the confusion that was going on with customers switching to SolidWorks2008. But a week or so ago I realized an important new OPTION that you probably want to have turned on for the new “Virtual Component” functionality to flow better…

Under TOOLS–OPTIONS–SYSTEM OPTIONS–EXTERNAL REFERENCES you should probably TURN ON the option “Update component names when documents are replaced”. Otherwise when you change the name of (or save internally) a virtual component the name IN THE TREE will NOT update !!

If you need more explanation about the new “Virtual Component” functionality in SolidWorks 2008 please see my blog entry from March 2008.

Randy Simmons

Application Engineer, CSWP 3DVision Technologies

Follow
Get every new post delivered to your inbox
Join other followers
Powered By WPFruits.com
Bear