11 Replies Latest reply on Apr 17, 2013 3:46 PM by Jerry Steiger

    Aluminum Bracket Analysis

    Ameya Wadekar

      Friends and Solid Works Experts,

       

      I have been trying to solve this problem since couple of days and i need some direction from you guys.

       

      This is the bracket on which i am running a linear static study:

      (Isometric View)

      1013970X-Step 3.JPG

       

      Front View

      1013970X-Step 3.JPG

       

      Given below is the schematic of assembly where this bracket is used:

       

      Schematic.jpg

       

      Basically this bracket holds a part through 4 vacumm cups ( on one side) , the total mass of the part is 80 Kg and accelration forces are 270N acting horizontal through each of these 8 vacumm cups. ( I assumed that total mass is equally supported by all 8 cups hence 80/8=10Kg (100N) force acting through each cup)

       

       

      I basically want to find out if the stress due to these forces are not causing the bracket weld to fail. ( Cause some of these brackets failed at our customer site)

        • Re: Aluminum Bracket Analysis
          Ameya Wadekar

          I did a Linear Static Study and treated the forces acting  through these 4 points as "Remote Loads-Direct Transfer" and attached them to the highlighted face below because that is where the assembly holding the vacumm cups is attached to (See Schematic Sketch Below)

          1013970X-Step 3-Remote Load Face.JPG

           

          Schematic Sketch of the whole Setup:

          (4 Cups in Front and 4 Cups Behind the Plane)

           

           

          Firstly Untitled.jpg

          • Re: Aluminum Bracket Analysis
            Ameya Wadekar

            When i ran the Linear Static Analysis it is giving me very high stress values, i feel there is some thing i am doing wrong.

             

            I am especially interested in the region marked below with line (on the circular face):

             

            1013970X-Step 3 stress.JPG

             

             

             

             

            Can anyone guide me on how can i check (by hand calculation) if Solid Works is giving me right value.

             

            Thanks in Advance,

            Ameya

              • Re: Aluminum Bracket Analysis
                Jared Conway

                its a good idea to check the stresses with hand calculations but i think before you go down that route you have to ask yourself what this problem looks like as a free body diagram?

                 

                it seems like you're reversing the problem. fixing the end that is connected to the part and then applying the forces that are normally on the part on the side of the bracket that is held by the cup assembly. that is fine but you haven't told us anything about how you've restrained the model.

                 

                i think once we know that, we'll have the information to guide you better.

                 

                off the top of my head a few things i'd look at are the assumptions made with a remote load/rigid transfer. also, how is your mesh, do you have sharp corners? how many elements are actually affected by that high stress?