3 Replies Latest reply on Jun 9, 2016 7:49 AM by James Riddell

    Reaction Force not Equal Entered Force

    Hekmat Ismail

      I used Elastic Support as a Fixture ( to represent Suspension sustem in trailer ) but surprised that the reaction force not matching the entered force.

       

      Reaction Force.png

        • Re: Reaction Force not Equal Entered Force
          James Riddell

          They shouldn't be 'exactly' equal.  There are moments, shear and bending that all need to be taken into account for you Fx=Fy=M=0 equation.  Better question: do your hand calculations balance (presuming they have been done.)

            • Re: Reaction Force not Equal Entered Force
              Hekmat Ismail

              Dear Riddel,

              thank you for your sharing.

              About Reactio with applied force, they shoud be equal in static analysis cause the hand equations ((Sum (F)= 0     &    Sum (M) =0)).

               

               

              The Problem is  Solved,

              the problem was in Mechanical properties cause:

              I created Custom material for some compenents with infinte young modulus and very low desity ( young modulus= 200 X E-12 GPA, Density= 10 Kg/M3) I made these assumptions to assume this body is very stiff ( no Deformation ) and Ignored weight.

              It seems this theory didn't work and the reaction forces goes wrong.

              I didn't use rigid body cause it reject fixtures on it.

               

              when I recorrected the Material to be normal one for steel which is:

              young modulus : 200 GPA

              Density : 7850 Kg/M3

              Yeild strength : 345 Mpa for Steel ASTM A572 Grade 50

              I got correct reactions deviation 0.1 %.