Ever wanted to put a Center Mark on an Isometric view in a drawing ?
You can’t do it with the regular “Center Mark” tool, but the video below shows a pretty good solution…
VIDEO — ISO CENTER MARK .mp4
And here is the .sldblk file I created… ISO CENTER MARK .sldblk
In my opinion, one of the most underutilized tools in SolidWorks Simulation is the Design Study. Design studies allow you to easily set up a number of ‘what if’ scenarios and run them all with the click of a button. Sure, it might take a couple extra minutes to set up a few parameters, but the extra setup time will pay off handsomely later.
Let’s take a look at the effects of varying mesh size for a stress concentration. The first step is to create and run a Simulation Study to verify the model setup and boundary conditions. Second, set up a parameter for the global element size. Third, create a design study, using that parameter as a variable. Finally, add a constraint; in this case we’ll use the maximum stress from the Simulation study we previously created. When these steps are complete, run the design study and all of the scenarios with the click of a button!
Setting up a Parameter can be done in (at least) two ways. From the Evaluation tab of your Command Manager, you can left-click the down arrow on the Design Study icon and choose ‘Parameters’. Alternately, from your Simulation feature tree, you can right-click on “Parameters” and choose ‘Edit/Define…’. The keys to creating a Parameter are to provide a name, choose the appropriate category, then link that parameter to the item you want to vary in the design study. In this example, I want to link the Parameter to ‘Global Element’ size, so I’ll click on the Mesh icon from my Simulation study feature tree.
The next step is to insert a Design Study into your model. Use the down-arrows to add the Element Size variable to the Design Study. In the second column, I chose to use discrete values for element size. These can be typed in using a comma to separate values. In the Constraints section, use the pull-down menu to add a Simulation Data Sensor to the model, specifically to monitor the maximum stress. Be sure to choose the Simulation study you want the sensor to reference for data. Then un-check the ‘Optimization’ box and click ‘Run’.
When the Design Study is finished running all of the scenarios, you will have a plot for each constraint utilized. In the picture below, the stress plot from one of the scenarios is shown. I’ve also added a ‘Local Trend Graph‘ to show the stress concentration model does, indeed, show a diverging solution with regards to stress.
I could have arrived at the same information in a couple of ways not utilizing a Design Study. The most common method I encounter is a user creating ten Simulation studies, then manually meshing each with a different Global Element size. That is, quite simply, a waste of time! The extra few minutes spent creating Parameters and properly defining a Design Study can be done much faster than creating several individual studies. I’m certain with a little investigation you can find plenty of uses for this powerful tool. Now go make your products better with SolidWorks Simulation!
This is a follow-up post to a question that I was asked recently about THIS blog entry: http://www.3dvision.com/wordpress/2012/04/14/strengthening-ribs-in-sheetmetal-new-in-sw2012/
The question was basically “HOW do I MAKE a rib like that ?”
Easy !
Start out with this:
Then create your “Rib TOOL” as a separate BODY in the file…
Then you can use the INSERT–FEATURES–INDENT command to use that “Rib Tool” body to create the indentation in the sheet metal part.
You will then of course want to do a DELETE BODY on the Rib Tool body (just select the body in the tree and hit Delete on the keyboard), and then add any fillets (don’t forget both sides) if you want them to make it look something like this when finished.
Here is a link to the actual SolidWorks part file (2013 version) if you need more guidance: Sheetmetal REMOVE FACES
There you go !! Easy when you know how… 
I want to clear something up that is very confusing about making SUB-WELDMENTS.
I personally had swayed people away from the Sub-Weldment functionality for quite a while, because after you went to all the trouble to get all the properties you wanted in your Cut-List Items, you would lose it all when you made a sub-welment,
NO LONGER THE CASE AS OF SW2012 !!
Trust me, it DOES work, BUT it is somewhat confusing HOW to do this the CORRECT way…
The thing to remember with this is that the BODIES do NOT store any properties, only the Cut-List Item FOLDERS do.
So if you have never done an UPDATE to the cut-list first, you cannot expect the properties (that don’t exist yet) to propagate down to the sub-weldments like they are supposed to !
It sounds obvious when I explain it that way, but it was very confusing to me for a while, and I know it is still confusing to new users…
HERE are the steps TO SUCSESSFULLY MAKE A SUB-WELDMENT:
1. Go and create your weldment as normal
2. Update the cut-list
3. Ctrl+Select the BODIES you want to make into a sub-weldment (either from tree or from screen with bodies filter)
4. Rt+Clk, CREATE SUB-WELDMENT
5. Then UPDATE THE CUT-LIST AGAIN !!!
(you will end up with 3 levels in the folder which seems strange, but it DOES inherit the properties into the Sub-Weldment like it is supposed to…)
This will even take the properties with the sub-weldment if you save it out to a separate part file (using rt+clk, insert into new part on the sub-weldment), and they will be tied/related back to the original weldment file for updating !
Hope this helps !
Remember, as an alternative to actual “sub-weldments” done this way you can always just make a weldment, make another weldment, and then stick them into an assembly together. The above method just keeps it ALL in ONE multi-body weldment PART file. And NOW IT WORKS THE WAY IT SHOULD !
A great feature of Thermal studies with SolidWorks Simulation Professional is the ability to utilize other thermal study results as an input for transient analysis. This allows us, for instance, to analyze the response of a heating or cooling process on our components and assemblies. This is done by editing the properties of the study, changing the study type to Transient, checking the box for ‘Initial temperatures from thermal study’ and choosing the appropriate study as an input. (It is easier done than written!)
The other options, when setting up a transient thermal analysis, are the total time to analyze the heating or cooling cycle and how often you want to have a result data point. For more advanced thermal analysis, if the input thermal study is another transient analysis, you can choose which time step from the input study to begin with for the next thermal study. This is especially beneficial when stringing together complex power, heating or cooling curves.
Here is where the troubleshooting begins. The most common error message we encounter with transient thermal studies is “Incompatible initial temperatures”. The wording of this error message does not provide a clear indication of what is wrong. Fortunately, the ‘fix’ is very simple.
As Engineers, we usually tweak each and every analysis, usually by refining the mesh in one area or another, even between studies. When using thermal studies for inputs to transient analysis, this is not a good thing! Getting past the cryptic wording of this error message, what it really means is the meshes for each study are not identical. So if you see this error message, the ‘fix’ is to drag-and-drop the mesh from your input study into the new study. This guarantees that the meshes are identical, allowing your transient thermal analysis work to continue. Now go make your products better with SolidWorks Simulation!
Want just a little more guidance of “where” you are at in a Drawing in SolidWorks ?
TURN ON THE RULERS !!
Most people have no idea about this option, so don’t be embarrassed. :-)
Just go up to the VIEW pulldown menu, and towards the very bottom turn on RULERS !
Don’t forget you also have the cursor coordinate numbers at the bottom of the screen… The rulers are just easier toquickly look at and understand where you are on the sheet, especially if you are zoomed in.
This is great for when you are sketching on a drawing or using snapping with the grid on a drawing.
Here’s a feature that you might not use too much or even know about. The “Fill Pattern” patterns a feature or a predefined cut shape in a defined area. This is great for weight reduction or ventilation.
In the image below, you can see that you can pattern selected features or create a seed cut. The seed cut has the 4 predefined shapes that are created on the fly. You just need to specify the size of the seed and it can take care of the rest.
You can specify the “buffer zone” or “margins” that the pattern can be created in. That is the area of clearance around any of the edges. In the image below you can see the holes are no closer than 0.25″ to the model edges. This option is set in the “Pattern Layout” and is the third box down.
That great but what if you only want the pattern in a certain area and there are no model edges around. Well all you need to do is create a closed sketch and select just the sketch and NOT the face. You don’t need to split the face with the sketch or anything.
If you would select both the face and the sketch, it will create the fill pattern on the face and NOT inside the sketch.
*The large circle is just a sketch that is shown and not a model edge.
The fill pattern was added in 2006 and hopefully will help you be more productive.
Wondering why sometimes in SolidWorks 2012 you have to hit the ESC key multiple times to exit out of the Smart Dimension command ?
Think there is something wrong ?
Turns out you are just missing out on some new functionality with the Dimension command in SolidWorks 2012 !
The ESC key will let you “back up” thru your picks that you have made in the Smart Dimension command.
Let’s say you selected two things to dimension between and then decide you don’t like what you selected for one of them… In 2011 and before you would have to just ESC to exit out of the Smart Dimension command, then hit the Smart Dimension button again to start over, and then pick what you wanted.
NOW in SolidWorks 2012, if you have “mis-picked” (or changed your mind) you can hit ESC once to UN-pick your last pic, ESC again to UN-pick the previous pick, etc. etc. until you have un-picked what you don’t want and then just pick the correct items.
All without exiting and restarting the Smart Dimension command !
Pretty great when you know how to use it !!
Is it worth the extra 75 dollars for a long tube header versus a short tube?
Let’s start answering this by examining how an exhaust header works, and why you would want one. Headers are one of the easiest bolt-on accessories you can use to improve an engine’s performance. The goal of headers is to make it easier for the engine to push exhaust gases out of the cylinders.
To further understand why the exhaust manifold has an impact on performance let’s review the combustion cycle of a gasoline engine.
During the exhaust stroke, back pressure robs the engine of power. The exhaust valves open at the beginning of the exhaust stroke, and then the piston pushes the exhaust gases out of the cylinder. The more resistance there is to the piston expelling the exhaust gases, the greater the power loss.
Once the exhaust gases exit the cylinder they end up in the exhaust manifold. In a four-cylinder engine, all cylinders utilize the same manifold. From the manifold, the exhaust gases flow into one pipe toward the catalytic converter and the muffler. The idea behind an exhaust header is to eliminate the manifold’s back pressure. Instead of a common manifold that all of the cylinders share, each cylinder gets its own exhaust pipe. Old hot-rodder intuition, gut feel, and experimentation lead to each pipe being the same length, and using a two into one set up. Two into one specifies that the pipe leading from two cylinders merge into one. In the case of a four cylinder, pipes from cylinders 1 and 2 lead to one pipe, and pipes from cylinders 3 and 4 lead to one pipe. Those two pipes then merge again into the collector. The two into one method “smoothes” the flow through the pipe causing less turbulence when the flow fields merge. These pipes come together in a larger pipe called the collector. By making them the same length, it guarantees that each cylinder’s exhaust gases arrive in the collector spaced out equally so there is no back pressure generated by the cylinders sharing the collector. Basically Header=Power, and we all want more power.
The 75 dollar question arose from my sister. She is considering replacing her stock exhaust manifold with an after-market header, and was wondering what was the best “bang for the buck”. After researching the topic extensively we found that across all the after-market brands the designs seemed to be the same regarding pipe routing, materials, etc. So the main question came down to should she buy the “short tube” or “long tube” header?
Both the “long tube” and “short tube” headers have equal length pipes from the engine block to the collector. Both ran a two into one method. The long tube header however claims that since it is longer by design there would be less back pressure due to a smoother flow. The differentiator was about 75 dollars, and the fact that the “long tube” header would need the catalytic converter to be moved and remounted by a muffler shop. The “short tube” header is a direct bolt in.
I couldn’t resist turning to Flow Simulation to solve this question.
We purchased the long and short tube headers, and removed the stock manifold to be able to accurately take measurements from them. The models are close but not exact without a reverse engineering tool such as a scanner or arm.
After the models were completed the next step became the boundary conditions. I was able to find a good reference guide located on line from www.donaldsonexhaust.com. Given the engine Horsepower, cubic inch displacement, and operating RPM I was able to determine Intake airflow, and exhaust gas flow in CFM.
This calculated the exhaust gas CFM to be 520.00 CFM, or 130.0 CFM per port. Please see the hand calculations below.
Yes Engineers Still Do Hand Calcs
Knowing the CFM of the exhaust leaving the cylinder allows us to compare pressure drop from the inlet to outlet across the three manifold models. The stock exhaust will be the base line for comparison.
Model Set Up:
Inlet Condition: 130 CFM per inlet port
Outlet Condition: Environmental Pressure
Surface Goals: Each Inlet Goal – Static Pressure / Mass Flow Rate
Outlet Goal – Static Pressure / Mass Flow Rate
Results:
Stock Pressure Gradient
Short Tube Pressure Gradient
Short Tube Flow Trajectories
Long Tube Pressure Gradient
Summary:
The “short tube” header is hands down the best value. Both after-market headers showed a drastic decrease in pressure drop over the stock manifold however, the “long tube” header only had an edge over the “short tube” pressure by 0.019 PSI. As a bonus the “short tube is a direct bolt in, not requiring the existing catalytic converter to be moved. As Engineers we are always worried about time and money, and are often faced with a decision regarding these two factors. From my engineering background and proof provided by flow I recommended the “short tube” header.
I love to find things that help me keep from having to do something over again. Calculators. Assembly instructions. Programmable lawn mowers.
A great SolidWorks tool in this area is Dissection – SolidWorks dissects files to make their components available for reuse. When SolidWorks files are dissected:
To use this functionality, first use File and Model search to search the folders you have specified in: Tools > Options > System Options > File Locations > Show folders for: Search Paths. Your search results will show in the Search tab of the Task Pane.
If you search returns a part, for example, you are ready to drag and drop that part into an open assembly.
Go back to the Search tab and double-click on the part and you will be presented with a list of features that SolidWorks dissected (extracted) from the part – you can drag and drop one of these features onto the existing geometry of an open part.
Go back to the Search tab and double-click on the dissected feature and you will be presented with the sketch that was used to build the feature – you can drag and drop this sketch onto a plane or face of an open part.
The source files are not changed when dissected and there is no associativity created if you were to drag a dissected feature onto a new part.
Design reuse made easy!
Follow this link to read more about it in the Help file: http://help.solidworks.com/2012/English/solidworks/sldworks/design_clipart.htm
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