Bulk Data Entry Defines a fastener which can be used to model connections such as spot welds, rivets, bolts and so on.


(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
SURF ID1 ID2 ID3 etc.


(1) (2) (3) (4) (5) (6) (7) (8) (9) (10)
CFASTG 22 1 17 2.5 10.0
SURF 31 32


Field Contents SI Unit Example
EID Unique element identification number.

No default (Integer > 0)

PID Identification number of a PFASTG entry.

No default (Integer > 0)

ELSET (Optional) References a JOINTG element ID if this fastener is modeled explicitly by JOINTG elements.

Default = Blank (Integer > 0)

REFNODE (Optional) Identification number of a GRID SET ID which defines the positioning nodes used to define the fastener and to generate internal JOINTG elements. This field can be used together with PJID to assign PJOINTG to internally created JOINTG elements.

Default = Blank (Integer > 0)

CID Identification number of the coordinate system for this CFASTG fastener. If this coordinate system field is not defined, an internal coordinate system is generated based on the positioning point and surface that the positioning point projected on.

Default = Blank (Integer > 0)

INFLRAD Maximum distance from the projection point on the fastener surface within which the grids on the surface should lie to be used to generate the internal RBE3 elements.

No default (Real > 0.0)

SRCHRAD (Optional) Search radius from the positioning point to find the fastening points on the surfaces.

Default = Blank (Real > 0.0)

ADJUST Controls the adjustment of local Z direction of CID.
YES (Default)
If the CID field is defined, this ADJUST field controls whether OptiStruct adjusts the local Z direction to be aligned with the surface normal direction where the projection point is located.
If the CID field is defined, no adjustment is performed for the local Z direction.
WTMETH Controls how the weights are calculated for internally generated RBE3 elements.
UNIFORM (Default)
Weights are decreased uniformly based on the distance to the fastening points.
Weights are decreased linearly based on the distance to the fastening points.
Weights are decreased quadratically based on the distance to the fastening points.
Weights are decreased cubically based on the distance to the fastening points.
PJID (Optional) Identification number of a PJOINTG entry. This field can be used in conjunction with the REFNODE field to assign PJOINTG property to internally generated JOINTG elements. If this field is not defined, the JOINTG entries are defined with RBEAM type.

Default = Blank (Integer > 0)

SURF Continuation line flag to define the surfaces to be connected by CFASTG. The surface IDs are to follow.
IDi Define the surfaces to be connected by this CFASTG entry. These IDi refer to the identification numbers of SURF Bulk Data Entries.

No default (Integer > 0)


  1. The CFASTG entry is used to define a fastener connection between two surfaces.
  2. The CFASTG entry is currently supported for:
    • Nonlinear Implicit Analysis
    • Explicit Dynamic Analysis