CWELD – Weld or Fastener Element Connection
Defines a weld or fastener connecting two surface patches or points.
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(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
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CWELD |
EWID |
PWID |
GS |
TYP |
GA |
GB |
SPTYP |
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GA1/SHIDA |
GA2/SHIDB |
GA3 |
GA4 |
GA5 |
GA6 |
GA7 |
GA8 |
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GB1 |
GB2 |
GB3 |
GB4 |
GB5 |
GB6 |
GB7 |
GB8 |
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(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
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CWELD |
7 |
34 |
233 |
GRIDID |
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QT |
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55 |
56 |
21 |
22 |
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101 |
102 |
378 |
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(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
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CWELD |
7 |
34 |
233 |
ELEMID |
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15 |
16 |
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(1) |
(2) |
(3) |
(4) |
(5) |
(6) |
(7) |
(8) |
(9) |
(10) |
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CWELD |
7 |
34 |
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ALIGN |
103 |
259 |
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Field |
Contents |
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EWID |
Unique element identification number. No default (Integer > 0) |
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PWID |
Identification number of a PWELD entry. Default = EWID (Integer > 0) |
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GS |
Identification number of a grid point which defines the location of the connector. Required when TYP is GRIDID or ELEMID and GA and GB are unspecified (see comments 2 and 4). No default (integer > 0) |
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TYP |
Character string indicating how the connection is defined. GRIDID indicates that the connection is defined with grid identification numbers GA# and GB#, respectively (see comment 3). ELEMID indicates that the connection is defined with shell element identification numbers SHIDA and SHIDB (see comment 7). ALIGN indicates that the connection is defined between two shell vertex grid points (see comment 8). No default (GRIDID, ELEMID or ALIGN) |
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GA, GB |
When TYP is GRIDID or ELEMID, these represent grid identification numbers of piercing points on surface A and surface B respectively (see comment 4). When TYPE is ALIGN, these represent vertex grid identification numbers of the first and second shells respectively. No default (Integer > 0) |
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SPTYP |
String indicating types of surface patches A and B. Q indicates quadrilateral surface patch, and T indicates triangular surface patch. Required when TYP is GRIDID (see comment 5). No default (QQ, TT, QT, TQ, Q or T) |
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GA# |
Grid identification numbers of the first surface patch. GA1 to GA3 are required (see comment 6). No default (Integer > 0) |
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GB# |
Grid identification numbers of the second surface patch (see comment 6). |
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SHIDA, SHIDB |
Element identification numbers of first and second shells respectively. SHIDA is required when TYP is ELEMID. No default (Integer > 0) |
CWELD defines a flexible connection between two surface patches, between a point and a surface patch, or between two shell vertex grid points. See figure below:
Connection between two surface patches
Connection between a point and a surface patch
Connection between two shell vertex grid points
GS is ignored if TYP is ALIGN.
If TYP is GRIDID, either a point to patch (GS to GA#) or a patch to patch (GA# to GB#) connection is defined. For the patch to patch connection, GA# describes the first surface patch and GB# describes the second surface patch.
The input of the piercing points GA and GB is optional when TYP is GRIDID and ELEMID. If GA or GB are not specified, they are generated from the normal projection of GS onto the surface patches. If GA and GB are specified, their locations will be corrected so that they lie on surface patch A and B respectively. If GS is not specified, both GA and GB are required. The length of the connector is the distance from GA to GB.
SPTYP defines the type of surface patches to be connected. SPTYP is required when TYP is GRIDID to identify quadrilateral or triangular patches. Allowable combinations are:
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SPTYP |
Description |
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Connects a quadrilateral surface patch A (QUAD4 or QUAD8) with a quadrilateral surface patch B (QUAD4 or QUAD8). |
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QT |
Connects a quadrilateral surface patch A (QUAD4 or QUAD8) with a triangular surface patch B (TRIA3 or TRIA6). |
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TT |
Connects a triangular surface patch A (TRIA3 or TRIA6) with a triangular surface patch B (TRIA3 or TRIA6). |
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TQ |
Connects a triangular surface patch A (TRIA3 or TRIA6) with a quadrilateral surface patch B (QUAD4 or QUAD8). |
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Q |
Connects a grid point GS with a quadrilateral surface patch A (QUAD4 or QUAD8) if surface patch B is not specified. |
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T |
Connects a grid point GS with a triangular surface patch A (TRIA3 or TRIA6) if surface patch B is not specified. |
GA# are required when TYP is GRIDID. At least 3, and at most 8, grid IDs may be specified for GA# . Triangular and quadrilateral element definition sequences apply for the order of GA# and GB#, see below. Missing mid-side nodes are allowed.
Quadrilateral and Triangular Surface Patches as defined when TYP is GRIDID
When TYP is ELEMID, a point to patch connection is defined, GS to SHIDA or a patch to patch connection, SHIDA to SHIDB. SHIDA and SHIDB must be valid shell element identification numbers.
When TYP is ALIGN, a point to point connection is defined. GA and GB are required. GA and GB are not required when TYP is GRIDID or ELEMID.
Forces and moments are output in the element coordinate system (shown in comment 10 below).
The element x-axis points from GA to GB. The element y-axis lies on the plane created by the element x-axis and the smallest component of the element x-axis is the basic coordinate system, and is orthogonal to the element x-axis. The element z-axis is the cross-product of the element x-axis and the element y-axis.
The output format of the forces and moments, including the sign convention, is identical to the CBAR element.
Element coordinate system and sign convention of element forces
Diagnostic print outs, checkout runs and non-default setting of search and projection parameters are requested on the SWLDPRM bulk data entry. It is recommended to start with default settings.
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Guidelines for Bulk Data Entries