9 Replies Latest reply on Jun 14, 2011 9:42 AM by Theo Linders

    Can i lift 2000 pounds with this part?

    CLIFF MINES

      I ran a load simulation on this part, but do not understand what the results say. Could someone help?

        • Re: Can i lift 2000 pounds with this part?
          Deepak Gupta

          I just run a quick Simulation study suing SimulationXpress and found that FOS of the part is below 1 (red area  of the part in the attached picture) and in my opinion, the part may not be safe to lift 2000 pounds.

            • Re: Can i lift 2000 pounds with this part?
              CLIFF MINES

              Basically you should look at the Factory of Safety portion of the Results folder. If the red area extends to the outside of the material the potential for failure is there?

                • Re: Can i lift 2000 pounds with this part?
                  Wayne Matus

                  Cliff,

                   

                  Simulation is a serious subject and mistakes made can be as devistating as killing people, so running simulation and intrepeting results are critical producing products that are safe to use and last the design life of the product. If you are not an expert in simulation, then you should work with one until you become one yourself.

                   

                  Simulation Xpress is a scaled down version of Simulation. You are limited in how you constrain your models and the results you see.  It should only be used as a first pass analysis. The problem I have with it is that I do not know how accurate the results are with. It depends on how close you can simulate real world loading conditions. That being said, I cannot tell you what safety factor you should have on your part if you are using Simulation Xpress as the tool.

                   

                  If you are using Simulation, then there are several questions to ask yourself when you intrepret your results. Do you have the loads and boundary conditions applied properly? Do you have a fine enough mesh in the high stress areas to fully capture the actual stress? Once you can answer yes to these questions, What will be the mode of failure? Will it be shear stress, tensile stress, compressive stress, or von mises stress?

                   

                  If the part is subject to cyclic loading, then you either need to have your safety factor low or do a fatigue analysis on the part.

                   

                  Here is results using Simulation using a hinge support and the safety factor is above 1 around the support but less than 1 inside the bend. When I ran with the default mesh size, the minimum safety factor was 1.26.

                   

                  Simulation is easy to use, but remember garbage in - garbage out.

                  x684-Study 1-Results-Stress1.analysis.jpg

                    • Re: Can i lift 2000 pounds with this part?
                      Russ Johnston

                      This is a very scary thread.  As Wayne says "Simulation is a serious subject and mistakes made can be as devistating as killing people..."  I don't think anyone should make any comments on wether the design of this bracket can carry 2000 lbs.  Not unless you have really good insurance.

                        • Re: Can i lift 2000 pounds with this part?
                          CLIFF MINES

                          I had a structural engineer run the numbers, and he rated it at 1000 pounds. I do not know the safety factor he applied, but just lookng at the part I figured it would be more. I plan on having the part sent off and certified with a load rating by an independent company before going into production. That being very costly, I want to optimize the design to handle as much weight as possible, and not being an engineer but a product designer, I am having trouble understanding the results simulation express gives.

                           

                          I woould like to say thanks to all that have posted. Safety is very important, I probably should have posted my question differently. BTW at the bottom of the results SolidWorks gives a nice disclaimer about the program not being an "answer" to the question, but a guide to help find it.

                           

                          Thanks

                          • Re: Can i lift 2000 pounds with this part?
                            Kelvin Lamport

                            With bend rads that small, it is indeed scary.

                    • Re: Can i lift 2000 pounds with this part?
                      David Anderson

                      cliff,

                       

                      to understand the problem, need to know

                       

                      1. the interface for the slot/flange, is it clamped along the length of the slot.

                      2. direction of pull. i.e is it parallel to the slot or along y or?

                      3. interface to load. how does is the load supported by the part?

                       

                      otherwise you are throwing darts.

                       

                      best,

                       

                      dave

                        • Re: Can i lift 2000 pounds with this part?
                          Theo Linders

                          hi,

                           

                          the bending radius is always a big issue but there are other things you need to take in account.

                          I don't know how many cycles there are using this tool but maybe it can be important to think

                          about componenfatigue too.

                           

                          The other thing is load. You talk about 2000 pounds but is is static or dynamic.

                          never forget when a guy in a crane lifts a weight he just won't lift in gently. He will fix the

                          part to the load and then lift it, just like that.

                          I think it is important to get a higher factor of safety here.

                          Does the load move over people (this can be a reason to calculate a higher FOS too)

                           

                          good luck

                          Theo