Finite Element Method in Structural Mechanics - Interpolation or Shape Functions

Interpolation or Shape Functions

Let be the vector of nodal displacements of a typical element. The displacements at any point of the element may be found by interpolation functions as, symbolically:

where

= vector of displacements at any point {x,y,z} of the element.
= matrix of shape functions serving as interpolation functions.

Equation (6) gives rise to other quantities of great interest:

  • Virtual displacements consistent with virtual nodal displacements:
  • Strains in the elements:
where = matrix of differential operators that convert displacements to strains using linear elasticity theory. Eq.(7) shows that matrix B in (4) is
  • Virtual strains consistent with element's virtual nodal displacements:

Read more about this topic:  Finite Element Method In Structural Mechanics

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