So, dphi = dphi/d(xyz), right? Also, that means if I apply the boundary force that depends on the dphi, on the face with nodes 0,1,2,3, ; it seems nodes 4,5,6,7 could also get non-zero nodal force, right?
Thanks, On Fri, May 16, 2014 at 2:20 PM, John Peterson <[email protected]> wrote: > The derivatives of the Lagrange shape functions are nonzero on the element > faces. This is why you are seeing dphi_face != 0 > > > > On May 16, 2014, at 12:07 PM, walter kou <[email protected]> wrote: > > > > Hi all, > > > > Really appreciate it if any one can tell what get_dphi() is for the > element > > at the boundary, and point out the reason for my issue. > > > > > >> On Thu, May 15, 2014 at 10:58 PM, walter kou <[email protected]> > wrote: > >> > >>> Hi all, > >>> > >>> For the 2D boundary element of the 3D domain, what is dphi_face = > >>> fe_face->get_dphi(); ?? > >>> > >>> The strange thing to me is as below: > >>> > >>> 1) I use Hex8 for the 3D box, thus get 2D quad4 at the boundary face > >>> (i.e. side element) . Notice the side element is shown below with > nodes on > >>> the x-y plane: > >>> > >>> /************ show the nodes on boundary element: side-element > >>> [side-elem]:node: 0 coordinates:(x,y,z)=1,0,0 > >>> [side-elem]:node: 1 coordinates:(x,y,z)=1,1,0 > >>> [side-elem]:node: 2 coordinates:(x,y,z)=2,1,0 > >>> [side-elem]:node: 3 coordinates:(x,y,z)=2,0,0 > >>> > >>> 2) I print out the Jxw- face, phi_face dphi_face. > >>> > >>> 3) Why do I get non-zero dphi_face[*][*](2)? should dphi/dz ==0 since > the > >>> 2D face is on the x-y plane? > >>> > >>> 4) Why is dphi_face[7][3](2) is non-zero, even nodes 4-7 are not on the > >>> face? > >>> > >>> 5) Is dphi-face[*][*](0,1,2) = dphi/d(x,y,z) for both bulk and > boundary > >>> elements? > >>> > >>> Thanks > >>> > >>> /*************** show Jxw_face, phi, dphi > >>> > >>> Jxw_face[0]:=0.25 > >>> Jxw_face[1]:=0.25 > >>> Jxw_face[2]:=0.25 > >>> Jxw_face[3]:=0.25 > >>> > >>> phi_face[0][0]:0.622008 dphi_face[0][0]:(x,y,z)=(-0.788675, -0.788675, > >>> -0.622008) > >>> phi_face[0][1]:0.166667 dphi_face[0][1]:(x,y,z)=(-0.211325, -0.788675, > >>> -0.166667) > >>> phi_face[0][2]:0.166667 dphi_face[0][2]:(x,y,z)=(-0.788675, -0.211325, > >>> -0.166667) > >>> phi_face[0][3]:0.0446582 dphi_face[0][3]:(x,y,z)=(-0.211325, > -0.211325, > >>> -0.0446582) > >>> phi_face[1][0]:0.166667 dphi_face[1][0]:(x,y,z)=(0.788675, -0.211325, > >>> -0.166667) > >>> phi_face[1][1]:0.0446582 dphi_face[1][1]:(x,y,z)=(0.211325, -0.211325, > >>> -0.0446582) > >>> phi_face[1][2]:0.622008 dphi_face[1][2]:(x,y,z)=(0.788675, -0.788675, > >>> -0.622008) > >>> phi_face[1][3]:0.166667 dphi_face[1][3]:(x,y,z)=(0.211325, -0.788675, > >>> -0.166667) > >>> phi_face[2][0]:0.0446582 dphi_face[2][0]:(x,y,z)=(0.211325, 0.211325, > >>> -0.0446582) > >>> phi_face[2][1]:0.166667 dphi_face[2][1]:(x,y,z)=(0.788675, 0.211325, > >>> -0.166667) > >>> phi_face[2][2]:0.166667 dphi_face[2][2]:(x,y,z)=(0.211325, 0.788675, > >>> -0.166667) > >>> phi_face[2][3]:0.622008 dphi_face[2][3]:(x,y,z)=(0.788675, 0.788675, > >>> -0.622008) > >>> phi_face[3][0]:0.166667 dphi_face[3][0]:(x,y,z)=(-0.211325, 0.788675, > >>> -0.166667) > >>> phi_face[3][1]:0.622008 dphi_face[3][1]:(x,y,z)=(-0.788675, 0.788675, > >>> -0.622008) > >>> phi_face[3][2]:0.0446582 dphi_face[3][2]:(x,y,z)=(-0.211325, 0.211325, > >>> -0.0446582) > >>> phi_face[3][3]:0.166667 dphi_face[3][3]:(x,y,z)=(-0.788675, 0.211325, > >>> -0.166667) > >>> phi_face[4][0]:0 dphi_face[4][0]:(x,y,z)=( 0, 0, > 0.622008) > >>> phi_face[4][1]:0 dphi_face[4][1]:(x,y,z)=( 0, 0, > 0.166667) > >>> phi_face[4][2]:0 dphi_face[4][2]:(x,y,z)=( 0, 0, > 0.166667) > >>> phi_face[4][3]:0 dphi_face[4][3]:(x,y,z)=( 0, 0, > 0.0446582) > >>> phi_face[5][0]:0 dphi_face[5][0]:(x,y,z)=( 0, 0, > 0.166667) > >>> phi_face[5][1]:0 dphi_face[5][1]:(x,y,z)=( 0, 0, > 0.0446582) > >>> phi_face[5][2]:0 dphi_face[5][2]:(x,y,z)=( 0, 0, > 0.622008) > >>> phi_face[5][3]:0 dphi_face[5][3]:(x,y,z)=( 0, 0, > 0.166667) > >>> phi_face[6][0]:0 dphi_face[6][0]:(x,y,z)=( 0, 0, > 0.0446582) > >>> phi_face[6][1]:0 dphi_face[6][1]:(x,y,z)=( 0, 0, > 0.166667) > >>> phi_face[6][2]:0 dphi_face[6][2]:(x,y,z)=( 0, 0, > 0.166667) > >>> phi_face[6][3]:0 dphi_face[6][3]:(x,y,z)=( 0, 0, > 0.622008) > >>> phi_face[7][0]:0 dphi_face[7][0]:(x,y,z)=( 0, 0, > 0.166667) > >>> phi_face[7][1]:0 dphi_face[7][1]:(x,y,z)=( 0, 0, > 0.622008) > >>> phi_face[7][2]:0 dphi_face[7][2]:(x,y,z)=( 0, 0, > 0.0446582) > >>> phi_face[7][3]:0 dphi_face[7][3]:(x,y,z)=( 0, 0, > 0.166667) > > > ------------------------------------------------------------------------------ > > "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE > > Instantly run your Selenium tests across 300+ browser/OS combos. > > Get unparalleled scalability from the best Selenium testing platform > available > > Simple to use. Nothing to install. Get started now for free." > > http://p.sf.net/sfu/SauceLabs > > _______________________________________________ > > Libmesh-users mailing list > > [email protected] > > https://lists.sourceforge.net/lists/listinfo/libmesh-users > ------------------------------------------------------------------------------ "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE Instantly run your Selenium tests across 300+ browser/OS combos. Get unparalleled scalability from the best Selenium testing platform available Simple to use. Nothing to install. Get started now for free." http://p.sf.net/sfu/SauceLabs _______________________________________________ Libmesh-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/libmesh-users
