Discretisation and Interpolation - The Boundary Element Method with Programming - page 40

ȟ

2

Ș

(ȟ 0,Ș 1) 3

3 3

3

z

ȟ

2

y

1

1

(ȟ 1, Ș 0)

(ȟ 0,Ș 0)

2 2

1 1

x

Figure 3.13 Triangular linear element in global and local coordinate system

As can be seen in Figure 3.14 the shape functions are represented by planes.

Figure 3.14 Shape functions of linear triangular boundary element

It is also possible to define a triangular element with a quadratic shape function. The
shape functions for the mid-side nodes are given by

N
N
N

41
4
41

[[K
[K
K[K

4

(3.22)

5

6