Coordinate systems in FEM

1. Dr. A. S. Sayyad
Professor & Head
Department of Structural Engineering
Sanjivani College of Engineering, Kopargaon 423603.
(An Autonomous Institute, Affiliated to Savitribai Phule Pune University, Pune)
Finite Element Method
In Civil Engineering
Coordinate systems
used in FEM

2. Coordinate systems used in FEM
Three different coordinate systems are used in the finite element analysis
1) Local Co-ordinate system 2) Global Co-ordinate system
3) Natural Co-ordinate system
Local Co-ordinate System
When for each element in FEM, a separate coordinate system is used for deriving
element properties it is called as Local Co-ordinate system.
Element
formulation

3. Coordinate systems used in FEM
Global Co-ordinate System
The coordinate system is used to define the point in the entire structure is
called as Global Co-ordinate system.
System
formulation

4. Coordinate systems used in FEM
Natural Co-ordinate System:
Natural Co-ordinate System is a coordinate system which permits the
specification of a point within the element by a set of dimensionless numbers,
whose magnitude never exceeds unity.
• Maximum value of ordinate is +1 and Minimum is -1
• In this coordinate system, origin is always assumed at the center of element.