## 7. Generic prismatic (PR) elements

PR elements define prismatic elements in R3. B2000++ node indices are positive integers and they must belong to the same branch. The element local x-axis xelement is defined by r21 = p2 - p1, with p2 being the coordinate of the vertex n2, and p1 the coordinate of the vertex n1. The element local z-axis zelement is defined by the vector product r21 . r31, with r31 = p3 - p1, and p3 being the coordinate of the vertex n3. The element local y-axis yelement is then obtained by the vector product zelement . xelement. Figure 34. PR6 element connectivity Figure 35. PR15 element connectivity

The element faces are numbered in counter-clockwise direction, as seen from outside the element. Thus, the element face normals (and the element face local z-axis) always point out from the element. The first 2 nodes of the element face connectivity list define the element face local x-axis xface. The element face local y-axis is defined by yface = r21 . r31, with r21 = p2 - p1 and r31 = p3 - p1, p1 being the coordinate of the element face connectivity node 1, p2 of node 2, and p3 of node 3. The element face local y-axis yface is then defined by zface . xface. Figure 36. PR element face numbering

Table 10. PR element face node connectivity

 Face 1: n1 n3 n2 n1 n3 n2 n9 n8 n7 Face 2: n4 n5 n6 n4 n5 n6 n10 n11 n12 Face 3: n1 n2 n5 n4 n1 n2 n5 n4 n7 n14 n10 n13 Face 4: n2 n3 n6 n5 n2 n3 n6 n5 n8 n15 n11 n14 Face 5: n3 n1 n4 n6 n3 n1 n4 n6 n9 n13 n12 n15

The element edge node connectivity of PR elements are defined as follows: The first 2 nodes of an element edge connectivity list also define the element edge local x-axis xedge, the axis running from the first to the second node. The figure and table below display the element local edge numbering, the orientation (direction) of the edge local x-axis, as well as the element nodes defining the edges. Figure 37. PR element edge numbering and orientation

Table 11. PR element edge node connectivity

 PR6 PR15 Edge 1: n1 n2 n1 n2 n7 Edge 2: n2 n3 n2 n3 n8 Edge 3: n3 n1 n3 n1 n9 Edge 4: n4 n5 n4 n5 n10 Edge 5: n5 n6 n5 n6 n11 Edge 6: n6 n4 n6 n4 n12 Edge 7: n1 n4 n1 n4 n13 Edge 8: n2 n5 n2 n5 n14 Edge 9: n3 n6 n3 n6 n15