Revision as of 17:15, 9 January 2008

The following article describes the use of the element.quad4i command. This command defines a four-node non-conforming quad based on the work of R.L. Taylor, P.J Beresford & E.L. Wilson<ref>R.L. Taylor, P.J Beresford and E.L. Wilson, "A non-conforming element for stress analysis", International Journal for Numerical Methods in Engineering, Vol. 10, pp.1211-1219 (1976)</ref>.

Syntax

element.quad4i(id,node1,node2,node3,node4,mat)

where

Examples

Mesh distortion test

Mesh distortion test.

The example code can be found here.

===========================
|alpha |STD      |QM6     |
+------+---------+--------+
| 0.00|   0.2424|   1.0000|
| 1.00|   0.1274|   0.6174|
| 2.00|   0.0846|   0.5337|
| 3.00|   0.0703|   0.5271|
| 4.00|   0.0597|   0.5044|
===========================

Patch Test

Patch test.

The example code can be found here.

=================================================
|   |     Analytical      |     Numerical       |
+---+----------+----------+----------+----------+
|id |ux        |uy        |ux        |uy        |
+---+----------+----------+----------+----------+
|  5|  0.025150|  0.017600|  0.025150|  0.017600|
|  6|  0.047100|  0.032500|  0.047100|  0.032500|
|  7|  0.058150|  0.041600|  0.058150|  0.041600|
|  8|  0.039850|  0.029000|  0.039850|  0.029000|
=================================================

Comments

Nodes, material and section must be already defined. This element can be only used in plane strain/stress analysis.

Theory

Implementation

The implementation of this element follows closely the work of T.J.R. Hughes<ref>T.J.R. Hughes, "The Finite Element Method: Linear Static and Dynamic Finite Element Analysis"', Prentice-Hall Inc., Englewood Cliffs, New Jersey, 1997, pp.243-248.</ref>

Notes

<references/>

See also

• node module.
• material module.
• section module.
• element module.
• User guide.