Learn . Create . Succeed

Coordinate System Based on the Center of Mass

2012-02-03T15:42:58-05:00

About two week ago I was wondering if it was possible to make a coordinate system that was based off of the location of the center of mass. I figured that this would be useful so that it would be possible to place a part in an assembly with respect to its center of mass. This would allow that part to be perfectly balanced on another part or assembly thus creating more stability in the assembly if it were to be made. This is just one of the benefits that I saw from being able to locate a coordinate system there. At the time I was pretty sure that it could not be done as there was no way from the mass properties to set the center of mass as a coordinate system. However, the other day I was playing around in SolidWorks and that same thought came to me so I decided to investigate it further. After searching through most of the SolidWorks menus and attempting this in as many ways as possible I finally figured it out. This is how to make a coordinate system based on the center of mass of a part in SolidWorks 2011.

I first created a rectangular block which will represent my part that I want the coordinate system in. This was created in the positive section of the coordinate system
The next step is to create equations.
Under Tools click equations
Click Add and type “CenterMassX =” (this will be the center of mass in the x direction)
Then click the downward pointed arrows at the bottom right of the screen
From there scroll down and select SW-CenterofMassX

Then click ok. This just set a variable that is equal to the center of mass in the x direction

Repeat this for the center of mass in the y and z direction making sure to define them so you know which direction is which

Now you should have 3 equations like mine shown below

10. The next step is to create reference lines for where the new coordinate system will be

11. A line was drawn on the front plane in the positive x direction.

12. Using Smart dimension, dimension the length of this line

13. When the modify box pops up click the down arrow on the left side of the box

14. Select link value and under the name drop down select your variable for the center of mass in the x direction.

15. This dimension is now linked to that of the dimension for the center of mass in the x direction

16. Next a plane was inserted on that line using the point not on the origin and the line itself as the references.

17. A line was drawn on that plane in the positive y direction.

18. Dimension this line the same way as was done in steps 12-14 but this time select the variable for the center of mass in the y direction

19. Another plane was inserted on that free end

20. Finally a line was drawn on that plane in the positive z direction.

21. Dimension this line the same way as was done in steps 12-14 but this time select the variable for the center of mass in the z direction

Note: What has just been created was a line in the direction of each axis of the coordinate system. I tried doing this in a 3D sketch but it had problems when it came to having a center of mass that had a negative direction with respect to the origin.

22. At this point we now have a point that we can create a new coordinate system

23. Under the features tab click reference geometry and then select coordinate system

24. For the origin select the point that is the free end of the line that was just created.

25. Select the line that we drew in the positive x direction for the x axis and the line drawn in the positive y direction for the y axis.

26. That is all that is needed to create the coordinate system

27. Now you have a coordinate system based on where the center of mass is which is seen below

28. If you add another feature such as a boss extrude to the original block and rebuild the part, that new coordinate system will then update.

29. To verify that it is indeed the center of mass just go to the evaluate tab and then click the mass properties option.

30. A pink origin should show up at exactly the same spot as your new coordinate system, see modified part below

The method that was just explained can be used on any part and it does not have to be inserted at the end of all the features. As long as the part is rebuilt it will update accordingly. Sometimes the document may need to be rebuilt again depending on if the new axis updated. Try making a part and inserting it in an assembly and use that coordinate system as a reference when mating that part. You can download my model that I used below. I hope you enjoy

Ian Jutras

Worcester Polytechnic Institute

Mechanical Engineering 2013

French Students Excel in STEM Education with Support from SolidWorks VAR CadWare

2012-02-03T11:43:43-05:00

Before Science, Technology, Education and Math (STEM) became a well used acronym in US education, French students learned to use SolidWorks as a visualization tool in order to understand concepts in simple machines, laws of physics, mathematics, and how things work. In middle school and high school usually there is not a SolidWorks CAD class directly, instead students use SolidWorks to explore areas of science and technology. Now SolidWorks is used for the national Baccalauréat (or BAC), the french high school exam required for post secondary studies.   At the university level, engineering students with this strong modeling and analysis background excel in competitions. For example, the Ecole Nationale Supérieure des Technologies Industrielles des Mines d'Alès won the most sustainable design prize at both the 2011 French and European Shell Eco Marathon.

With over 5,500 middle schools and over 2,200 technical and vocational schools, training centers, engineering schools and Higher Education and Universities, SolidWorks French Value Added Reseller, CADWARE is a major partner for educational institutions for modeling software and 3D simulation used in classrooms and for construction technology.

Thank you Jean Luc and your team for helping so many students and educators achieve their goals. Marie

Ballpoint Pen in SolidWorks

2012-02-02T08:38:14-05:00

This pen was a fun assembly to model. For the most part, it was quite an easy job. The only challenging part was the cap, and I was able to complete it using a loft feature, a mirror feature, and plenty of fillets. Suppress the distance mate to remove the cap. Enjoy the model, and thanks for viewing!

Dave Knight

Worcester Polytechnic Institute

Mechanical Engineering, 2013

Download Pen

SolidWorks Mentor Races with STEM Education Tutorial and the Ten80 Challenge

2012-01-27T15:39:15-05:00

When Jeremy Losaw, NASCAR Racing Engineer and SolidWorks Mentor for the Ten80 STEM Racing Challenge sent me this video, I could not help but ask to share it with all of you.

Jeremy also sent me the part model he created in SolidWorks.

You can download the SolidWorks model. Download Mini

Jeremy learned SolidWorks 98 at Union College and was a member of the FSAE team. I love SAE collegiate events. SolidWorks sponsors the SAE events and I have learned a great deal from these young student engineers, especially as we developed our SolidWorks SAE curriculum with the University of Wisconsin FSAE racing team.

.Jeremy is the perfect mentor, he has worked in designing carbon fiber machines to NASCAR Racing parts. Jeremy's outreach goes beyond the middle school and high school students too. He helps out for the Clemson FSAE Racing team in his free time. Marie

STEM - Science Technology Engineering and Math is truly integrated into the Ten80 Racing Challenge.   This project makes physics and math exciting and fun.

With mentors like Jeremy and support from the US Army and NASCAR, Ten80 is certain to drive students towards science and engineering. Marie

Fire Extinguisher

2012-01-22T09:37:20-05:00

For today's post I decided to make a fire extinguisher. This was a really fun project to build. I was not sure exactly sure how the inside of the fire extinguisher worked but with some research and some designing on my end this is what I came up with. My idea is there is a CO2 canister that when the handle is squeezed it punctures the canister releasing the CO2. This then compresses the fluid that is in the can. When the handle closes this also open a value. The extinguishing liquid travels up the tube and out towards the fire. The tank was created using a revolve feature as the entire part was symmetrical about the vertical axis.   The top of the extinguisher was created using a number of extrusions and a swept feature for the threads. This part was rather fun to make as there were a lot of different contours and cuts that I needed to make so that it would be functional. The hose on the inside and outside were both created using sweeps with the thin option. This allowed me to create just the outside profile and then set the thickness that I wanted for the entire tube. Another part that was a challenge was the part that connected the CO2 canister as well as the inner hose. This part needed to have ports that would let the CO2 out as well as a hole for the hose. The ports were created using a revolved cut so that they would be tangent to the dome on the inside of this part. The dome was made so that the escaping CO2 gas would be channeled out through these ports. I included a section view of the model so that you would be able to see the inside. Feel free to download the model and take a closer look. Enjoy!

Ian Jutras

Worcester Polytechnic Institute

Mechanical Engineering 2013

Download Fire Extinguisher

Fire Sprinkler with Flow Simulation with SolidWorks - Revised

2012-01-17T06:58:59-05:00

For this post, I decided to take the fire sprinkler that I posted on December 18^th and run a flow simulation with it. In order to do this I first had to suppress the glass tube that would hold the water back. This simulates the heat from a fire expanding the liquid inside and breaking the glass. Before being able to run the simulation I needed to make a containment part around the head of the sprinkler and also put a lid on the open end by the threads. This was done in order to run the analysis as an internal flow. To set up the actual simulation I first set up the computational domain so that it was a little larger then my whole assembly. For the general settings I set the analysis type to internal, the fluid to water, and left the rest of the settings to their defaults. From there, I needed to set up my boundary conditions. These specify what the input and outputs to the system are. For the input of the system, I selected the inside face of the lid and used a static pressure that was in a normal direction to the lid. I then selected the internal faces of the containment part and set those to the environmental pressure which I left set to the default. I also set the faces that were in the direct line parallel to the lid as an ideal wall. From there I meshed and ran the simulation. Once it had finished solving I inserted a flow trajectory using the internal face of the lid with 500 points showing the pressure of the water. This is seen in the image above. The result has some abnormalities that aren’t what I expected but that could be caused by how I set up the simulation. I hope you enjoy.

Ian Jutras

Worcester Polytechnic Institute

Mechanical Engineering 2013

Download Fire Sprinkler with simulation

SolidWorks Brazilian Blog Hosts Contest for Students and Teachers

2012-01-15T04:10:19-05:00

SolidWorks Brazilian Blog http://solid3d.blogspot.com/ celebrates its 1 year anniversary with a great promotion for Brazilian students and teachers. With over 1 million views, solid3d.blogspot.com is the creation of SENAI educator José Cardoso Junior.

Follow the link Promotion: http://solid3d.blogspot.com/2012/01/promocao-1-ano-de-blog.html

These are the prizes:

1st Place:

1 license of SolidWorks Student Edition 2011-2012
1 Credit for the CSWP certification;
1 Credit for a CSWA certification;
1 essential ODL Course SolidWorks (donated by IST systems);
1 Mouse Pro 3DConnection SpaceMouse;
1 Pen of SolidWorks;
1 cap of SolidWorks.

2nd Place:

1  license of SolidWorks Student Edition 2011-2012;
1 Credit for the CSWP certification;
1 Credit for a CSWA certification;
1 ODL Course Level 1 SolidWorks (donated by SKA);
1 Pen of SolidWorks;
1 cap of SolidWorks.

3rd Place:

1 license of SolidWorks Student Edition 2011-2012;
1 Credit for the CSWP certification;
1 Credit for a CSWA certification;
1 Pen of SolidWorks;
1 cap of SolidWorks.

As a technical vocational teacher ifor over 10 years, Jose creates great tips, models, and videos on his blog. Also, his site contains information of the SolidWorks Certification exams: Certified SolidWorks Associate (CSWA), Certified SolidWorks Professional (CSWP) and Certified SolidWorks Expert (CSWE).   Qualified SolidWorks schools on subscription, may apply to become a CSWA provider at www.solidworks.com/cswa. The CSWA exam is given in Brazilian Portuguese and 10 other languages.

Oi! I don't speak Brazilian Portuguese, but translate.google.com does a good job. Luckily my daugther's engineering boyfriend is from Brazil and confirmed this translation tool for me.

Congratulations Jose for a great blog and thank you for helping out so many students, teachers and the SolidWorks Brazilian community. Marie

SolidWorks Expands the Science Fair to Amazing Products

2012-01-12T16:38:44-05:00

Students use SolidWorks to visualize great ideas for Science Fairs and Technology Fairs.   But former high school science fair winner, Ben Gullak has taken his winning project into amazing products to start his own company, BPG-Werks in just a few years.   The UNO, an electric scooter, was named one of the top 10 inventions of 2008 by Popular Science magazine.

Last year, at SolidWorks World 2011, Ben presented his BPG shredder. Before the event started, the BPG shredder was positioned on the stage. I introduced Ben to Bernard Charles, President of Dassault Systemes.  When Bernard asked, "how does it work?", Ben immediately opened his ipad to show beautiful photo realistic images created in SolidWorks. For some reason - conference centers don't like it when you start up power vehicles.

Ben has become a great example of what students can do with innovation and creativity. Sometimes you need cool examples for your classroom. His story is explored in this case study. Marie

Fire Sprinkler with Flow Simulation

2012-01-11T21:44:00-05:00

For this post, I decided to take the fire sprinkler that I posted on December 18^th and run a flow simulation with it. In order to do this I first had to suppress the glass tube that would hold the water back. This simulates the heat from a fire expanding the liquid inside and breaking the glass. Before being able to run the simulation I needed to make a containment part around the head of the sprinkler and also put a lid on the open end by the threads. This was done in order to run the analysis as an internal flow. To set up the actual simulation I first set up the computational domain so that it was a little larger then my whole assembly. For the general settings I set the analysis type to internal, the fluid to water, and left the rest of the settings to their defaults. From there, I needed to set up my boundary conditions. These specify what the input and outputs to the system are. For the input of the system, I selected the inside face of the lid and used a static pressure that was in a normal direction to the lid. I then selected the internal faces of the containment part and set those to the environmental pressure which I left set to the default. I also set the faces that were in the direct line parallel to the lid as an ideal wall. From there I meshed and ran the simulation. Once it had finished solving I inserted a flow trajectory using the internal face of the lid with 500 points showing the pressure of the water. This is seen in the image above. The result has some abnormalities that aren’t what I expected but that could be caused by how I set up the simulation. I hope you enjoy.

Ian Jutras

Worcester Polytechnic Institute

Mechanical Engineering 2013

Download Fire Sprinkler with simulation

Mechanical Ice Cream Scoop in SolidWorks

2012-01-08T09:24:11-05:00

I came across this ice cream scoop in my kitchen and couldn't resist modelling it. It is complete except for the torsion spring that adds tension to the lever. I did not model the spring because I did not want to complicate the assembly and prevent movement. Otherwise, through use of fillets and a gear mate, this assembly looks quite accurate. Thanks for viewing!

Dave Knight

Worcester Polytechnic Institute

Mechanical Engineering, 2013

Download Ice Cream Scoop