7 Replies Latest reply on Dec 19, 2013 7:27 PM by Shaun Densberger

    Need help with a load simulation

    Andi H

      Im absolute beginer on this am hoping for a step by step instructions. I need to do a load stimulation and see how the parts will behave under a certain amount of load 2500 lbs

       

      I never used or was trained or have any idea on how simulation is supposed to work

       

      Between the two brackets mounts an actuator so how so I go about setting up simulation in this model?

       

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        • Re: Need help with a load simulation
          Shaun Densberger

          First things first: what do you want to analyze? Actuator force needed? Stress during actuation? Deflection during actuation?

          • Re: Need help with a load simulation
            Jared Conway

            hi andi, we offer a service called mentoring of you're looking for real indepth step by step help on this analysis. feel free to contact me at jared@hawkridgesys.com if it is something you're interested in pursuing. but certainly myself and the others can help you out here as well. i'd suggest giving some more details about what this is, what you want to learn, how it is connected to other things...etc. the loading condition is really just one part of this.

             

            shaun is leading you in the right direciton. the first would need motion the second would need static analysis.

             

            if you're just getting started with simulation this is going to be a tough one. i'd highly recommend getting through the tutorials before moving much further forward. especially if you're talking static analysis. you've got a mixed mesh situation and i think you'll have a challenging time getting the analysis setup.

            • Re: Need help with a load simulation
              Andi H

              I want to see how the upper L structure will behave under the load. The actuator is not a problem I want to see the rigidity of the upper L frame. I can not share too much details or whole model

                • Re: Need help with a load simulation
                  Jared Conway

                  we also offer consulting services if you need quick turnaround.

                   

                  if it was me:

                  1. fix the model somewhere

                  2. create a link between the 2 brackets where the actuator is (assumption is that it is much stiffer than the rest of the model)

                  3. apply your load

                  4. mesh with solid elements (assumption is that you need first order numerical accuracy and that you've confirmed that all the parts are touching and there are no interferences)

                    • Re: Need help with a load simulation
                      Andi H

                      Here is the thing this is not my product. I am the 3d designer I was asked if I could do a stress analaysis I dont have to do it and hiring others is not my responsibility. I have been wanting for a long time to start using stimulation and understand it but havent had much time.

                        • Re: Need help with a load simulation
                          Shaun Densberger

                          Since you don't have to do it, let me ask you this: what are the implications if you don't do the analysis, compared to if you do the analysis? How much confindence is going to be placed on the results of this analysis? If you performed an analysis and the results suggested that you could place 5 times as much weight on it, would you start modifying the design?

                           

                          I ask all of this because at face value, this can be a rather tricky analysis to do correctly. FEA companies (and particularly the FEA packages from CAD companies) have gotten rather good at creating a UI environment that makes it relatively easy for someone with no experience to "run an analysis" that gives "results". The problem is, if there are some complex (even intermediate) physical interactions taking place in the real system, and these were not properly modeled/idealized in the finite element model, then your results can be complete garbage. This is even more true if the person doing the analysis doesn't have a classical engineering background from either a degree or equivalent (static, mechanics of materials, etc). The old adage still applies: "FEA makes a good engineer great, and a bad engineer dangerous." I'm not saying this to discourage you, but rather to make sure you go into this under the right pretenses. I've seen people apply fixed constraints because it seemed "good enough" and got results suggesting a FS of 3, when in reality it was closer to 0.75; all of this was because they constrained the model incorrectly. Just keep these two points in mind: (1) always assume your analysis results are wrong until you can show otherwise and (2) always do a sanity check on your results with some sort of close-form hand calculation (even simple upper/lower limit calculations).

                           

                          Now, to get to your analysis, let's start simple and work our way up. I'd make an assembly that just has components that move (the l-shaped bar, the piece of square tubing, the machined piece with the 8 holes in it, and the bracket for the actuator) to start with. I'd then remove all of the fillets you have (for now). Once you have that, post some isometric view of the model from different angles and we can go from there.