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TR.13.1 Plate and Shell Element Incidence Specification

This set of commands is used to specify elements by defining the connectivity between joints. REPEAT and REPEAT ALL commands are available to facilitate generation of repetitive patterns.

The element incidences must be defined such that the model developed represents one single structure only, not two or more separate structures. STAAD.Pro is capable of detecting multiple structures automatically

General Format

ELEMENT INCIDENCES (SHELL)
i1 nA nB nC (nD) ( TO i2 i3 i4 )
REPEAT n ei ji
REPEAT ALL n ei ji

Description

ELEMENT INCIDENCES SHELL must be provided immediately after MEMBER INCIDENCES (if any) are specified.

ParameterDescription
i1 Element number (any number up to six digits).

If MEMBER INCIDENCE is provided, this number must not coincide with any MEMBER number.
nA … nD
Note: Refer to G.5.1 Plate and Shell Elements for additional details on element incidences. Nodes nA … nD correspond to IJKL vertices.
Clockwise or counterclockwise node (i.e., joint) numbers which represent the element connectivity.

Element incidence

Note: nD is not needed for triangular (3-noded) elements.

The following parameters are needed if elements are to be generated:

ParameterDescription
i2 Last element number to which elements are generated.
i3 Element number increment by which elements are generated. Defaults to 1 if omitted.
i4 Joint number increment which will be added to incident joints. Defaults to 1 if omitted.
The REPEAT command causes the previous line of input to be repeated n number of times with specified element and joint increments. The REPEAT ALL command functions similar to the REPEAT command, except that it repeats all previously specified input back to the most recent REPEAT ALL command; or to the beginning of the specification if no previous REPEAT ALL command had been issued. Use REPEAT ALL 0 0 0 to start a set of elements that will be repeated if you don’t want to repeat back to the last REPEAT ALL.

The following data is needed if REPEAT or REPEAT ALL commands are used to generate elements:

ParameterDescription
n Number of times repeat is to be carried out.
ei Element number increment.
ji Joint number increment.

The PRINT ELEMENT INFORMATION command may be used to verify the element incidences provided or generated by REPEAT and REPEAT ALL commands. Refer to Element Information for details.

Tip: Use the Post Processing facility to verify geometry graphically.

Example 1: Single Elements

Individual element incidences:

ELEMENT INCIDENCE
* Four nodes designates a quadrilateral element
1 1 2 7 6
* Three nodes designates a triangular element
2 3 4 8

Example 2: Generate Multiple Elements

ELEMENT INCIDENCE
* Generate quadrilateral elements
3 8 9 11 10 TO 8 1 2
* Note: here, the element and joint increments have been specified

* Generate triangular elements
9 1 3 7 TO 14
* Note: here, the element and joint increments default to 1


Parent topic: TR.13 Plate and Solid Elements
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