In the words of SolidWorks, “Sensors monitor selected properties of parts and assemblies and alert you when values deviate from the limits you specify.”  They come in handy when creating optimization studies.  (Check out this week’s blog.)

To create a sensor, right click the “Sensors” folder in the feature manager tree.  Then, select “Add Sensor”

Next, select your sensor type.

Simulation Data: Monitors simulation results like stress and displacement

Mass Properties: Monitors things like mass, volume and surface area

Dimension: Monitors any dimension you select

Interference Detection: This option is only available for assemblies.  It will warn you if any parts (of your choosing) interfere with one another.

Proximity: This option is also only available for assemblies.  It is similar to interference detection.  It will warn you if your parts cross a line.

Motion Data: This option is only available with the motion add in turned on.  It will monitor existing result information from a motion study.

Within these options there is much to explore.  Happy hunting!

I once wrote an optimization program which found the best fillet size, thickness and angle of a two dimensional cantilever beam with a given load. It took three days to write. What I’m about to show you took me 30 minutes. It makes use of real geometry and doesn’t require programing! Enter simulation automation…

Let’s consider a scenario. You work for an amusement park ride manufacturer. Your company has begun to streamline their design process. (Good idea if you ask me.) The company would like your team to design components which will be interchangeable (like Erector Set parts). The designer you work with calls himself an artist. He wears leather pants. His ideas are nutty. It’s up to you to make real decisions. He comes to you with the part seen below and says, with a blank stare, “To date, this is my best work. Try not to taint it.”

The company will be making thousands of these parts which will be made from cast carbon steel. It is designed to hold pipes and should carry at least 3000 lbs.

Decision: you decide that the part should have a safety factor of two. (The stress should not be higher than 120 MPa.) This means that the part should be able to hold at least 6000 lbs. without failing.

You setup an initial study to benchmark the current design.

You might not know this, but SolidWorks includes FEA tools with every package it sells. Chances are you probably don’t use these tools. You might think they’re too complex. Or, maybe, you’re on the other side of the fence and think these Xpress tools are too limited. Let me show you why you should be using these tools all the time.

To illustrate my point, let’s use a simple example of a link as seen in the picture above. Is it going to be strong enough? Wait, strong enough for what? What material should it be made of? Shouldn’t I know these things before I begin a simulation?
The answer is no! None of that matters. Actually, these are the wrong questions.
Don’t get me wrong. Down the road, these things will matter. But for right now, we shouldn’t be too concerned with these questions. Instead, let’s look at this in a different way. So, what are the right questions?
Answer: How can we make this part stronger?
When you boil static simulation down, the only two variables to play with are geometry and material. Since we aren’t concerning ourselves with material, let’s see how we can make changes to the geometry to improve upon what we have.
First, let’s create a simulation to get a baseline stress result. Startup Simulation Xpress and go through the wizard.

We are giving away iPad2′s with seats of SolidWorks Premium! Undoubtedly, this is the best thing you’ve heard all week. I mean, think about it. You can get a Christmas present for your wife AND you can keep the iPad2!

Before I go on, let me field some questions.

Q. Does SolidWorks run on an iPad2?
A. No.

Q. Does Simulation run on an iPad2?
A. No.

Q. Okay, so, can these products interact at all?
A. Yes they can! Personally, I’m aware of three apps you might find interesting.

1. 3DVIA mobile app
This app is designed to take 3d models and superimpose them onto pictures taken with your device. (I wish I had this app when I was moving furniture for my grandma.)

2. CADFaster
This app allows SolidWorks users, as well as non CAD users, to view files that are placed on a cloud based system. I can see this app being very useful for a traveling manager who needs to make approvals.

3. SolidWorks World
Maps, calendars, classes – OH MY! Yes, you will look pretty cool at SolidWorks World with your iPad2.

Get yours before the offer expires on November 30th!

Let’s discuss the difference between the linear solver and the dynamic solver with a case study. Take the example of an engineer slamming his head on his desk after getting poor simulation results from his linear solver.

In scenario #1, the engineer lightly places his head on his desk then proceeds to slowly press down with his body weight. The force value, F, represents the maximum amount of force he can transmit through his neck.

In scenario #2, the engineers head starts a distance of 2 feet from his desk. The engineer proceeds to accelerate his head towards his desk with the aforementioned force value, F. After he comes into contact with the desk, his neck continues to transmit the force until his head comes to a complete rest against the surface.

Now, in both scenarios, the engineer’s neck transmits the same amount of force, F. However, the second scenario will produce higher levels of cranial stress at specific instances in time. The higher stress is related to momentum. The engineer recognizes this and proceeds with scenario #2 until the desired level of masochistic indulgence is achieved.

If we were to simulate these events, design scenario #1 could be adequately achieved with either the static solver or the dynamic solver and the results would be the same. However, if we were to run scenario #2 with a static solver, we would get the same result as we would with scenario #1. Obviously, the static solver has limitations.

The linear solver only sees the last moment in time; when things are at rest. Thus, we have two data points, the beginning and the end.

On the other hand, the dynamic solver is aware of the time in-between the beginning and the end. As a result, we are left with a much more complete picture.

For a moment, let’s sidestep the slamming head on desk approach, as this practice is no longer necessary. Let’s use the example of a cantilever beam with a weight of one hundred pounds suspended from the end.

For the linear study, let’s consider the case of loading the end very slowly. The results of this simulation are shown below.
The maximum displacement is 58 mm.

For the dynamic study, let’s consider that the weight will take .05 seconds to reach its maximum value of 100 pounds and will then level out. The maximum displacement results of this simulation are shown below.
The maximum displacement is 93 mm. This is an enormous jump from 58mm. Obviously, we’d want to study the dynamic simulation results over the static.