10 Replies Latest reply on Jul 9, 2014 10:05 AM by Clemence Wiart

    Plot stress along defined line

    Clemence Wiart
    Clemence Wiart Jun 25, 2014 9:18 AM

      Hello to all,

       

      I am pretty sure this question is basic and the answer straightforward, so please be nice! (I am new to Solidworks).

       

      Here is my problem. I am applying torsion to a notched cylindrical specimen, and I would like to plot the stress from the center of the notch to the tip.

      I found that I could apply some probes myself, and then have a graph of stress vs. # probes.

      However, what I wish to do is have specific values.. what I mean is I would like to obtain the stress at specific points. From 0mm (the center of the notch) to Xmm (the tip) by steps of 0.1mm (or less).

      I have attached a screenshot of what I have at the moment, maybe it'll clear up what I'm trying to explain.

       

      Is there any way to achieve this?

       

      Thank you in advance for your help

       

      Screen Shot 2014-06-25 at 2.16.38 PM.png

        • Re: Plot stress along defined line
          Shaun Densberger
          Shaun Densberger Jun 25, 2014 8:26 PM (in response to Clemence Wiart)

          I found that I could apply some probes myself, and then have a graph of stress vs. # probes.

           

          You can also create a plot along the curve. For example, to create a von-Mises stress along the curve, you'd right click on on the von-Mises stress definition (Stress1 by default), go to 'Probe', select 'On selected entities' under 'Option" at the top, selected the curve in the 'Results' box, hit 'Update' below, then hit the 'Plot' button under 'Results Options'.

           

          However, what I wish to do is have specific values.. what I mean is I would like to obtain the stress at specific points.

           

          The plot points are the values at nodes along the curve, so if you wanted results every 0.1 mm or less, then you'd need to define your mesh such that you have nodes spaced 0.1 mm or less along the curve (such as a mesh control along the edge with the corresponding element size definition).

           

          From 0mm (the center of the notch) to Xmm (the tip) by steps of 0.1mm (or less).

           

          To only plot along half of the curve, you'd first need to create a Split Line to sub-divide the surface, thereby sub-dividing the curved edge. You could skip this part and just plot all of the values along the edge and then export them to Excel if you wanted to avoid the Split Line for whatever reason.

            • Re: Plot stress along defined line
              Clemence Wiart
              Clemence Wiart Jun 26, 2014 7:02 AM (in response to Shaun Densberger)

              Hi Shaun and Jared,

               

              Thank you for the reply. However, I can't seem to select the curve. I can only select the entire face of the notch. Maybe it's due to how I sketched the part in the first place?

              I sketched the outline of a rectangle with a notch and then used the revolution function to have a notched cylinder.

               

              Anyway, when I select the surface and then click on Update, it gives me about 50 000 different points.. I don't know if I can extrapolate the points of a single curve from this data.

               

              And, Jared, I am working on my master's thesis and I need to base my first values on the ones found by the previous master's student. He used Abaqus and determined the stress applied in the notch at the locations I previously mentioned.

              I just need to check them to make sure I am in the same range before I move on to other mechanical tests.

              Also, I am basing my experimental values on papers that use that same method.

               

              And, finally, I have never used vertices with splitlines.. if you could briefly explain how to do it?

               

              Thank you so much to both of you for taking the time to help me out!

                • Re: Plot stress along defined line
                  Jared Conway
                  Jared Conway Jun 26, 2014 11:53 PM (in response to Clemence Wiart)

                  screenshots would really help here.

                   

                  you can't use curves for plotting, it has to be real geometry. ie create a curve and project it with a splitline.

                   

                  regarding splitlines with vertices, draw a square, split line. you have 4 vertices. use the concept with a different type of sketch that lets you create vertices wherey ou want to measure.

                   

                  however based on your description of why you need those particular values, i'm surprised that a probe that is saved as a sensor isn't enough. it should give you the numbers to check ify ou are in the ballpark without being exactly the same locatino as the other report.

                    • Re: Plot stress along defined line
                      Clemence Wiart
                      Clemence Wiart Jul 3, 2014 4:43 AM (in response to Jared Conway)

                      Hi Jared,

                       

                      Thanks for the post, but I still don't see how to add those splitlines. I've tried adding points all along the curve in a sketch but they stop appearing as soon as the probe is on.

                      Screen Shot 2014-07-03 at 9.42.30 AM.png

                       

                      Also, I need to test about 100 specimens and have an FEA for all of them. Not only would this precise probing allow me to check the values from other papers but it would give me some consistency as to where I'm obtaining my stresses. For example, if I use the normal probing technique and have the measurements at points more or less on the curve at regular intervals, I'll find myself with a graph plotting stress vs. probe# (cf screenshot). And since I would need to show what these probe# correspond to in the notch, I'd have to have the screenshot of the curve with the 80-100 probes on it. Multiply this times 100 for all of my samples, it comes to a lot of screenshots. I just wish there were a simpler method where I can just have some kind of stress vs. distance plot, it would be more accurate.

                      Screen Shot 2014-07-03 at 9.38.26 AM.pngScreen Shot 2014-07-03 at 9.39.09 AM.png

                       

                      Thanks in advance

                        • Re: Plot stress along defined line
                          Shaun Densberger
                          Shaun Densberger Jul 3, 2014 3:35 PM (in response to Clemence Wiart)

                          Can you post the part file of the geometry? That'll help is determining how to divide up the surface.

                           

                          That being said, the general process is as follows:

                           

                          1. Start with the base part.

                          Base Part.png

                           

                          2. Define a closed sketch to divide the area up (and thereby divide the curve up).

                          Sketch.png

                          3. Create a Split Line.

                          Split Line.png

                           

                          4. Use the sketch and respective surface for the Split Line definition.

                          Split Line Definition.png

                           

                          5. Define a mesh control along the curve such that your nodes are spaced how you need them.

                           

                          6. Define a probe for the results you'd like to plot.

                          Probe.png

                           

                          7. Select the sub-divided curve that was created by the Split Line.

                          Probe Definition.png

                           

                          8. Press "Update" and the press "Plot" under the "Report Options" section.

                          Plot Definition.png

                           

                          You can check the "Flip edge plot" box to change which end of the curve defines the starting point.

                           

                          If, for whatever reason, you can't sub-divide your geometry using a Split Line, then you can always plot along the entire curve, export the values to Excel, and then create a plot of the subset of values in there.

                            • Re: Plot stress along defined line
                              Clemence Wiart
                              Clemence Wiart Jul 4, 2014 10:20 AM (in response to Shaun Densberger)

                              Hi Shaun,

                               

                              Wow thank you for the detailed explanation! Just one question, can I apply this to a cylindrical part? I attached one of my files with this reply, I hope there won't be any problem opening it (Solidworks 2013). I wasn't able to check it since the computer I am on doesn't have Solidworks.

                              Another question, may be a bit silly but, what is a closed sketch? Maybe I can do this on the plane that passes through the middle of my notched cylinder?

                               

                              Again thank you.

                                • Re: Plot stress along defined line
                                  Jared Conway
                                  Jared Conway Jul 6, 2014 11:50 PM (in response to Clemence Wiart)

                                  Closed sketch means not just a line.

                                   

                                  And the technique can be applied to any type of geometry. A plane could be used with the intersection split line type.

                                  • Re: Plot stress along defined line
                                    Shaun Densberger
                                    Shaun Densberger Jul 7, 2014 2:32 PM (in response to Clemence Wiart)

                                    There several ways you can probably do this, but here is what I did.

                                     

                                    1. Start with your base geometry.

                                     

                                    U-Notch Base Geometry.png

                                     

                                    2. Go to "Insert" -> "Curve" -> "Split Line"

                                     

                                    U-Notch Split Line.png

                                     

                                    3. Select "Intersection" for "Type of Split", select "Plane 1" and "Plane 2" for "Splitting Bodies/Faces/Planes" and select the curved/notched surface for "Faces/Bodies to Split".

                                     

                                    U-Notch Split Line Definition.png

                                     

                                    4. You now have a curved edge to define a mesh control and plot along. First define a 0.1 mm mesh control.

                                     

                                    U-Notch Mesh Control.png

                                     

                                    5. Mesh, solve, and then plot your quaintly of interest along this curve.

                                     

                                    U-Notch Stress Plot.png

                                     

                                    Please keep in mind that you'll need to apply additional mesh controls and go through additional steps to get converged results (you'll notice some rather large discontinuities in the stress field).

                        • Re: Plot stress along defined line
                          Jared Conway
                          Jared Conway Jun 26, 2014 12:06 AM (in response to Clemence Wiart)

                          shaun's really got it here

                          you can also create points where you want to measure using vertices with splitlines

                          but why do you need the data at such specific locations?