19 Replies Latest reply on Jun 25, 2010 12:52 PM by 1-RZ0XRD

    SimulationXpress Displacement Coordinates

      I am fairly new to using SimulationXpress.  I've been using the version from Solidworks Professional 2009 to observe how a part will deform as I increase the applied load.  I did not optimize my design, and clicked on the "show me the displacement distribution in the model" radio button in the results tab.  I notice a maximum displacement of XX.XXX mm depending on what magnitude of load I applied, but am curious as to in which direction this "displacement" is.  I then clicked on "generate an HTML report" hoping that there was additional information as to which direction the maximum displacement is in.  I noticed in the "displacement" section of the report that it has a minimum displacement value, a minimum displacement location, a maximum displacement value, and a maximum displacement location.  The locations are described in what I believe to be coordinates (xx.xxx, yy.yyy, zz.zzz).  Is this correct?  My problem is that I am finding that when I vary the applied load, say from 0.1psi to 25psi, the displacement value increases, as expected, but the displacement coordinates remain the same.  What is the reason for this?  Any information would help.  Thanks

       

      Michael

        • Re: SimulationXpress Displacement Coordinates
          Ameer Chilakala

          HI,

          while using the solidworks simulationXpress, it will show resulant displacement only i.e. URES is resulant displacement of X,Y & Z dispalcements.

           

          Regards,

          Ameer.C

            • Re: SimulationXpress Displacement Coordinates

              Why is it that the displacement cooridinates (x, y, z) do not change no matter how much load I apply?  What I am finding strange is that the URES resultant displacement value increases as my applied load increases, but my displacement coordinates do not change.  I do not think the URES is describing the displacement of the (x, y, z) displacement coordinates because the displacement coordinates given are not even on the model that I am loading.  It is a point in free space.

                • Re: SimulationXpress Displacement Coordinates
                  Anthony Botting

                  Hi Michael: I believe you are looking at the starting coordinates of the location of the node, before loading. So, to get the final coordinates (position of the node after loading), just add the calculated displacement values for x, y and z, to the starting coordinates.  Hope this helps. In the Professional version you can view displacements in local or global x, y and z directions, too.

                    • Re: SimulationXpress Displacement Coordinates

                      The coordinates given cannot be the location of the node before loading beacuse the (x, y, z) location is actually in free space and not even a part of the model I am loading.  So at first, I thought the coordinates may describe the end location of the node that sees the maximum displacement, but those coordinates do not change with respect to the load. 

                       

                      For example, with a pressure of 2 psi applied, I would get URES: 0.29335mm and Location: (0.19772, -1.9658, 2.9678), then under a pressure of 20 psi applied, I would get URES: 2.9335mm and Location: (0.19772, -1.9658, 2.9678).

                       

                      So the URES resultant displacement changes by a factor of 10 which is expected, but that location (0.19772, -1.9658, 2.9678) which isn't on the deformed model does not change.  This really confuses me as to what the location coordinates are describing.

                        • Re: SimulationXpress Displacement Coordinates
                          Anthony Botting

                          Hi Michael: Something strange is going on. The "location" is supposed to be the location relative to the global coordinate system, or origin, on the SolidWorks FM tree. I was able to draw sketch lines from the origin in X, then Y and Z and dimension them according to the "location" posted in the HTML report, and it matches-up with the location on a model that I created, of maximum or minimum deflection, or stress, as appropriate. Can you attach a copy of your model here (zip file) and I can take a look at it on this machine. Could be a bug you found! I am running SW 2010, x64 edition, SP3 (we have found there can be Service Pack-specific, and even edition-specific issues).

                            • Re: SimulationXpress Displacement Coordinates

                              Sure, I've attached one of the models I'm having this problem with.  I just tried it again and same issue.  The displacement location is not even on the model.  Let me know if you get different results.  Thanks

                                • Re: SimulationXpress Displacement Coordinates
                                  Anthony Botting

                                  Hi Michael: Yes, I did get different results. For a pressure of 2 psi, I got a max displacement at location (-1.75,1.97,-2.06), which is on the model. I also got a URES number of 1.399mm. This is really, really strange. It is best to turn-in this item to your VAR. I cannot diagnose why it gives me different results as this would have to go to the developers at SolidWorks Corp. to find out. I noticed when I opened the model, however, it says the model is from "...a previous version...", but would not tell me which version. I am running SW 2010, SP3, x64 edition. Do you need help locating your VAR?

                                    • Re: SimulationXpress Displacement Coordinates

                                      Thanks for taking the time to run that Anthony.

                                       

                                      Wow that is very strange.  I was using SW 2009 Professional, but I just installed SW 2010 Professional SP4 x32 edition and am getting the same results.  I get a max displacement at location (-0.186796, 1.42187, -2.21138) with a URES of 1.39519 mm.  I will be contacting my SolidWorks distributor tomorrow.  What is a VAR?So let me get something straight, so when I get this working I'll know the correct way to interpret the data.  In your case, the location (-1.75, 1.97, -2.06), on the model, is the part of the model that will undergo the biggest deformation.  A deformation of URES = 1.399 mm.  So now my question is, in which direction is that displacement of 1.399 mm?  If the node location (-1.75, 1.97, -2.06) is the INITAL location of the node that will undergo the biggest displacement, how can I calculate where its final location will be after deformation?

                                        • Re: SimulationXpress Displacement Coordinates
                                          Anthony Botting

                                          Hi Michael.

                                          You're welcome, but apparently one of us does not have the  correct answer. I just ran it again and got yet a different answer!  There is definitely a problem - (I believe with this particular database).

                                          You are right, you cannot find the exact x, y and z New Location coordinates in the "Xpress" version. That's part of the SolidWorks marketing engine- they want you to buy the "Professional" product where they allow you to plot the x, y and z components of displacement (Ux, Uy and Uz). Here in Xpress, you have URES = square-root of [(Ux)^2 + (Uy)^2 + (Uz)^2].

                                          The "VAR" is "Value Added Reseller" of SolidWorks software. They are  supposed to  provide support to you if you bought "subscription". We are  one of  those (Texas Engineering Systems).

                                            • Re: SimulationXpress Displacement Coordinates

                                              Oh no, three different answers from three simulations...Oh ok, I think our VAR is Next Level, so I will be connecting with them either today or tomorrow.  I would expect URES = sqrt[ (Xf - Xi)^2 + (Yf - Yi)^2 + (Zf - Zi)^2 ] where the final coordinates after deformation of the node that experiences the most dislacement is (Xf, Yf, Zf) and the node's initial location is (Xi, Yi, Zi).

                                               

                                              So whats the final conclusion on the displacement coordinates?  Are they the final coordinates after deformation or initial coordinates before deformation?

                                                • Re: SimulationXpress Displacement Coordinates
                                                  Anthony Botting

                                                  The values shown in the Simulation Professional version are the individual, Cartesian coordinate system, calculated displacements: (Xf-Xi) =Ux,(Yf-Yi)=Uy,(Zf-Zi)=Uz. In the SimulationXpress version, they only show you the Resultant, URES (which are those quantities squared, then added, then take the square root). So the answers you seek are buried and not available in SimulationXpress version. You can see the starting coordinates: <Xi, Yi, Zi>, and the URES for that location. That's it. I hope that's clear (they want you to buy the Simulation Profession version). Does that make sense?

                                                   

                                                  Note: You could also upgrade to a product called "SolidWorks Premium". This has the "Static-only" analysis, but you get all the data you seek. Plus, you get other products with SolidWorks Premium (need to ask your VAR on that, or just check the web site "product matrix"). If you buy the "Simulation Professional", you get static, frequency, thermal, etc.

                              • Re: SimulationXpress Displacement Coordinates
                                Ameer Chilakala

                                Hi,

                                 

                                i am able to get the same location of URES under varying the load magnitudes.

                                kindly find the word documents which shows results on your part and some example part what i have done.

                                 

                                Presently i am using Solidworks 2010 Xp Sp 3.1. Windows 2002 version.

                                 

                                Message was edited by: Ameer Chilakala

                                  • Re: SimulationXpress Displacement Coordinates

                                    Yes, I see how the URES value changes, but the location stays the same, but I still find it strange how the location isn't even on the model.  In your beam bending example, the coordinates of the max displacement are (25, 30, 203.625), and since your beam is only 200 long, that would mean the point (25, 30, 203.625) is located in free space near the end of your beam.  This would lead one to assume that it notes the final location of the node that experiences the maximum displacement, but if so, why is that final location always constant no matter what the URES is?

                                  • Re: SimulationXpress Displacement Coordinates

                                    So, I called my VAR, and apparently, the displacement coordinates are in fact the location of the node that experiences the most displacement.  The reason the coordinates are the same no matter what the load is, is because SolidWorksXpress automatically scales your deformation so it looks the same for every load applied.  Therefore, the location of the node that experiences the most displacement is always "in the same place" after scaling.  This was discovered when my VAR tried changing the scaling factor on the full version.

                                     

                                    I am still trying to see if I can get away with just using SolidWorksXpress.  I figure if I take the displacement coordinates and multiply them by the scaling factor, they should be correct.  I'll check by seeing if the square root of the sumation of the differences of the intial and final node locations after scaling equals the given URES value.

                                    • Re: SimulationXpress Displacement Coordinates

                                      My latest conclusion:

                                       

                                      My assumption to scale the displacement coordinates was wrong.  If they would scale anything, they would scale the actual displacement (ie. the difference between the initial and final locations of the node that experiences the maximum displacement).  Therefore, I have drawn this new conclusion:

                                       

                                      URES = sqrt{ [(Xf-Xi)/SF]^2 + [(Yf-Yi)/SF]^2 + [(Zf-Zi)/SF]^2 }

                                       

                                      where (Xf, Yf, Zf) is the final location, (Xi, Yi, Zi) is the inital location, and SF is your scaling factor.

                                       

                                      The URES should equal the magnitude of the scaled initial and final coordinates, but this is actually not the case.  The URES calculated by the above equation actually has a ~5.3% difference with the given URES value from SimulationXpress.  Currently, I am uncertain of where this discrepancy is coming from.  Using the scaling factor again, we can determine the actual final coordinates of the maximum displaced node.

                                       

                                      Xactual = (Xf-Xi)/SF + Xi

                                      Yactual = (Yf-Yi)/SF + Yi

                                      Zactual = (Zf-Zi)/SF + Zi

                                       

                                      So this is my best solution to finding the actual displacement coordinates.  If anyone has an idea of where the 5% error may be coming from, let me know.