General Mechanical

General Mechanical

Need for the coupling of beam and shell co-rotation

    • manu87
      Subscriber

      Hi,everyone. Here I try to couple a beam end with a cylinder(meshed with shell181), and rotate them along the longitudial axis, shown as the following picture. The end node of the beam is applied an axial compression and be rotated. The coupling between the beam and cylinder is made by the internal multipoint constraint(MPC), But, as the uncompatible freedems between beam(ux uy uz rotx roty rotz) and shell element(ux uy uz rotx roty rotz,but the freedom of rotz is fictitious) ,the cylinder cannot be rotated.So how can I make it? thanks


    • maurya
      Subscriber

      Hello Manu


                           Beam is always a line element and cylinder as you mention is surface( thats why shell181 element) .


      You can provide contact easily.


      Attache archive file(https://studentcommunity.ansys.com/thread/saving-sharing-of-working-project-files-in-wbpz-format/) to understand the problem.


      mention the version of ansys.


      You used the word "rotate them"  both bodies are having torque/moment ?.


      regards


      Deepak


       

    • manu87
      Subscriber

      Hi manurya. Thank you for you reply. Sorry for the trouble resulting from the information I missed. As shown in the picture, the assembly is rotated only by the end of the beam.. However, due to the uncompatible freedems between beam(ux uy uz rotx roty rotz) and shell element(ux uy uz rotx roty rotz,but the freedom of rotz is fictitious), the rotional freedom is always zero when a rotational speed is applied on the end node of the beam. Do you have any idea on handling this problem?


      Regards


      manu

    • sk_cheah
      Subscriber

      I'm guessing the problem is with your MPC184 with KEYOPT(1)=0 (default) has only translation DOF. Here's my take with CERIG. 



      Kind regards,
      Jason


       


      ! Twists Cylinder made of Shells
      /prep7
      et,1,181 ! shell181
      et,2,4 ! beam4 (old)
      mp,ex,1,210e3
      mp,nuxy,1,0.3
      r,1,0.01
      r,2,100,40,40

      ! geometry and mesh
      r = 20
      L = 100
      tol = 0.0001

      csys, 1
      k, 1, r, 0
      k, 2, r, 120
      k, 3, r, 240
      k, 4, r, 360
      k, 5, r, 0, L
      l, 1, 2
      l, 2, 3
      l, 3, 4
      l, 1, 5
      adrag, 1, 2,3,,,, 4
      csys, 0

      mat,1 ! shells
      type,1
      real,1
      mshkey,1
      aesize, all, 6
      alls
      amesh,all

      type, 2 ! beams at ends
      real, 2
      *get,nmax,node,0,num,max
      n,nmax+1,0,0,0
      n,nmax+2,0,0,-L
      n,nmax+3,0,0,L
      n,nmax+4,0,0,2*L
      e,nmax+1, nmax+2
      e,nmax+3, nmax+4

      ! connects using cerig
      alls
      nsel,s,loc,z,0-tol,0+tol
      cerig, nmax+1, all, all
      nsel,s,loc,z,L-tol,L+tol
      cerig, nmax+3, all, all

      !! Boundary Condition and solve
      /solu
      alls
      antype, static
      d,nmax+2,all,0
      d,nmax+4,rotz, 0.01
      solve

      /post1
      set,last
      plnsol,rot,z
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