Question

The shape functions are physically represented by _____

(a) Triangular co-ordinates

(b) ξ-,η-Co-ordinates

(c) Area co-ordinates

(d) Surface co-ordinates

I have been asked this question at a job interview.

Origin of the question is Two Dimensional Problems in chapter Two Dimensional Problems using Constant Strain Triangles of Finite Element Method

Answer 1

Right choice is (c) Area co-ordinates

For explanation: The shape function is a function which interpolates the solution between discrete values obtained at the mesh nodes. Therefore appropriate functions have to be used and as already mentioned; low order typical polynomials are used in shape functions. The shape functions are physically represented by area co-ordinates.