SolidWorks UK

Mass Participation Factor

When you want to perform a linear dynamic problem (small displacement analysis with linear elastic materials), the technique used in SolidWorks Simulation is called modal analysis and requires a frequency analysis to be run first.

This inevitably requires you to choose how many natural frequencies you want to solve for (the more you include, the more accurate your solution but the longer it will take to solve). But how do you know if you have chosen sufficient modes? One useful check is to plot the Mass Participation Factors.

The Mass Participation associated with each mode represents the amount of system mass participating in that mode. Therefore, a mode with a large effective mass is usually a significant contributor to the system’s response. By plotting the Mass Participation you can see just how important each mode is.

One common rule of thumb is that a mode should be included if it contributes more than 2% of the total mass. Another is that a Cumulative Mass Participation factor of 0.8 in the predominant direction of vibration is recommended (this is found at the bottom of the list).

However as with all of these rules, some judgement has to be made and they should not always constitute the final check. For example, with dynamics it is also important to ensure that you have a suitable spatial and temporal description of your modeshapes and loading.

Technorati Tags: Simulation tips & tricks,Linear Dynamics,Mass Participation

How to manage File Custom Properties

I love tips and applications that make life easier... Here is one from our tech support team on how to manage File Customer properties.

Just follow the steps and see how easy it is to create, update, delete Custom Properties on a set of documents without opening SolidWorks. 

Here is the zip file with the application:Download Custom Property Manager V1.2

    

Thanks Jerome, great tip!

 

 

Dimension This!

One of the enhancements in 2009 that I try to use more and more is the snappily titled “Enable on screen numeric input on entity creation…” or Add Dimension to you and me!

Found in the system options under sketch, this option will add a check box to automatically add dimensions to sketch geometry when you create them. This means you can create your geometry to the correct size straight away.

The above image shows the creation of a rectangle, SolidWorks prompts for the height, type the value and either hit tab or enter to add a width dimension.

A Quick “Add Dimension” tip!!

Adding dims automatically can sometimes (if you add too many) lead to an over defined sketch. Using the Alt key stops SolidWorks adding the dimension. Automatic relations will still be added!!

Note: “Alt d” will toggle the Add dimension tick box on and off.

Hope you find this tip useful!!

Technorati Tags: Tips and Tricks,SolidWorks

Top three Flow Tips

Here are three top tips for all you flow users out there.

1. Use the Check Geometry command (Flow Simulation – Tools – Check Geometry…) to make sure there are no invalid contacts and that your fluid volume is greater than zero. If the fluid volume is zero or there are invalid contacts then these issues will have to be corrected before proceeding any further.
2. If there is a wall with fluid on both sides make sure you select the Optimise Thin Walls Resolution check box in the Initial Mesh command. 
3. The first time you run an analysis use the default setting 3 for the Level of initial mesh and unselect the Solve check box. SolidWorks Flow simulation will only run the meshing process. If the mesh is satisfactory and you have enough memory then Continue the calculation. If there is a problem with the mesh then advanced mesh settings or simplifying the model may be required.

Hope this helps!!

Technorati Tags: Flow simulation tips,SolidWorks Flow Simulation

Interesting Design Initiative...

Design Bugs Out: UK’s top designers and manufacturers to help control the risk of Healthcare Associated Infections by making hospital furniture and equipment easier and quicker to clean!

Take a look at the winning design and prototypes! Share your thoughts!

Useful link:

http://www.designcouncil.org.uk/en/Design-Council/Files/Landing-pages/Design-Bugs-Out/

What do I get out of it?

As part of my job I regularly get people telling me they want to use simulation for this or that, and it got me thinking, “what is the biggest benefit people get from using these tools?”

Having a random dig through some websites this week I found an old paper done by someone at MIT in 2006, who interviewed hundreds of SolidWorks simulation users (via the web of course, oh, and they were COSMOS users at the time) to find out exactly that information. And the results were staggering…well at least to me anyway.

Initially I was not surprised to hear that 99% of users found an increase in productivity by using simulation methods, that’s why we do it. But how do you define productivity? Well, the largest percentage of people cited improved product quality as the biggest outcome of using simulation, closely followed by a reduction in the number of prototypes, a reduction in product weight/costs, reduced time to market, and finally a reduction in recalls. Not bad.

OK, you might say, but by how much do these productivity increases benefit the customer in the long-run? Each company was asked to define how much of an improvement was found in each of these areas. And our survey says…

1. the average increase in product quality was reported as 26%!!! That’s a massive increase if you ask me. Consider your product, which probably works ok and has done so for many years. Now imagine trying to make it 26% better. Hmmm…I thought so.
2. the average reduction in prototypes was 25%. Now that’s only 1 in 4, which I expected to be a bit higher really, but I guess it depends on how costly your prototypes are. However add to that an 18% reduction in physical testing and it now becomes clear how to save money on the old wooden models and crash test dummies (oh yes, we’ve come on a bit since then haven’t we?).
3. 23% increase in time to market!!! Another wow. That’s got to be quick.
4. and finally 9% fewer product recalls, which is always a good sign when trying to protect your brand in the marketplace.

So there we have it. I was impressed by the numbers and I hope you are too. After all, who wouldn’t want to see those levels of productivity gains in their company in these depressing times?

Technorati Tags: Simulation benefits

Interested in Sustainable Product Design?

Listen to this 7min podcast

SolidWorks Technical Manager, Kishore Boyalakuntla, explains the concept of Sustainable Design and the role of SolidWorks in engineering Sustainable Design products.

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Have a look at the videos.

Simulation starters

Hello from the world of SolidWorks Simulation, my name is Tony Eckersley and yes I really do look like that picture in real life. Thanks Justin!!

Let me introduce myself first, I live in the North West of England and whenever possible help our resellers provide the highest level of service to customers who want to branch out into simulation.

I am actually new to SolidWorks and so in the past few weeks I have been out and about visiting a number of customers who are interested in starting down the simulation route – and a few who are already there. I thought I’d start by sharing a little anecdote with you that will get us going. There is one common and fundamental question that keeps coming up when people think about using simulation.

“How do I know my answers will be right?”

Good question really isn’t it, after all if you can’t be sure of this, why bother at all? In reality though, there are two important things that are overlooked and usually make it alright on the night.

Firstly, the resellers work very hard to provide you with training to make sure you know how to use the tools properly and support you once you've begun. I know this because I’ve seen the effort they put in! They will help you get started in the right direction – whatever that requires.

Secondly, whenever I show a customer a simulation that isn’t doing what they expect, it doesn’t take more than a few seconds before someone points it out. That tells me one thing. You know your products better than anyone else (handy really) and this knowledge normally tells you if everything is running along pretty smoothly, or if you need to seek a bit of help.

In reality, with all the help on hand, it’s never usually that difficult to get into the swing of things and then you are ready to take on the world. Well, that’s how I look at it anyway.

A quick way to find under defined sketches!

Making sketches fully defined is good practice, it makes changes more predictable. SolidWorks has an option to always use fully defined sketches.

I’m sure I am like a lot of SolidWorks users who prefer the freedom of creating sketches without having to always fully define them… this allows for more flexibility when you are designing and trialling ideas.

Once you decide on an idea you may want to go back and define those sketches… but how do you find them? Well you could open up all sketches in turn, or check the sketch name for a (-) symbol: this means the sketch is under-defined.

However there are a couple of other quick ways to find all under defined sketches:

Method 1 – SolidWorks Design Checker:

If you have SolidWorks Professional then you can add in the Design Checker. This tool allows you to build checks for parts, assemblies and drawings to check many different criteria from fonts and spelling to mate errors. One of the checks that this tool allows you to add is the Fully Defined Sketch Check.

Simply add this to your standards file and then run this check on the active document. The Design Checker provides a list in the task pane that highlights all sketches that are under defined.

Method 2 – Go To

Use the “Go To” option to quickly find those under defined sketches.

Right click on the feature manager and select “Go to” click start from the top. Type (-) and hit “Find Next.” Keep clicking Find Next to find all the under defined sketches.

Now you have found them… go and fully define them

Technorati Tags: Under defined sketch,SolidWorks Tips and Tricks,Tips and Tricks