S8-1 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation SECTION 8 CWELD AND CFAST CONNECTORS

S8-2 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation

S8-3 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation CONNECTOR MENU In the Elements menu, with the Object set to Connector the type can be either Spot Weld or Fastener The method determines whether nodes on the surfaces will be specified directly or projected from a single point The Format options choose how the weld will connect to the surfaces Connector Properties are specified in a secondary form Preview generates a plot showing the connected nodes and a sphere proportional to the weld diameter

S8-4 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation SPOT WELD n Although originally intended to be a spot weld element, the CWELD is actually a connector element, not simply a spot weld element n It allows you to make connections from point to point, point to patch, and patch to patch (ELEMID, ELEMPAT, PARTPAT) n Properties of the weld are specified: u Material u Diameter u Length is automatically calculated n Internally, flexible connections are created between a bar element with the specified properties and the selected surface elements. The weld does not add stiffness to the surface elements.

S8-5 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation DEFINITION METHOD n Two methods can be used to define Spot Weld (CWELD) locations u Projection: specifies a node or point in space that is to be projected onto the two surface patches of the connector to determine the end points, GA and GB l The point specified for the Projection method is projected onto each surface patch l Nodes are generated at those locations, and the Pierce Nodes, GA and GB, are assigned the new node ids. u Axis: specifies nodes directly for GA and GB l Nodes specified for the Axis method define the GA and GB piercing nodes directly

S8-6 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation DEFINITION METHOD Projection Method: Axis Method: A location is entered here, then projected onto the two surfaces to be welded. Here, the nodes to be pierced by the weld on each surface are specified directly.

S8-7 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation n Prop to Prop (PARTPAT format) u Properties associated with shell elements defining the connectivity of the weld (one pair per connector) u Depending on the pierce locations (GA and GB) and the weld diameter, the number of connected elements may range from one element up to a 3x3 element patch u Multiple connector locations may be specified for a single property pair. The same pair will be used for each connector created. PROP TO PROP

S8-8 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation PROP TO PROP Multiple locations may be specified Property Sets identify surfaces to be connected (each surface must have a unique property set)

S8-9 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation PATCH TO PATCH n Patch to Patch (ELPAT format) u Shell elements are selected on each surface defining the connecting surface patches (one pair per connector) u Depending on the pierce locations (GA and GB) and the weld diameter, the number of connected elements may expand to up to a 3x3 element patch

S8-10 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation PATCH TO PATCH Patches of elements are specified for each surface

S8-11 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation ELEM TO ELEM n Elem to Elem (ELEMID and ALIGN formats) u Top and Bottom shell elements are specified defining the surface patches for the weld u If not specified, then both GA and GB are required (ALIGN format) u Otherwise, one top/bottom element pair per connector is required. Regardless of GA, GB, and the weld diameter, only a single element per patch is connected.

S8-12 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation ELEM TO ELEM ELEM to ELEM may make non symmetric connections Only a single element is connected, even if multiple elements are specified in the patch.

S8-13 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation NODE TO NODE n Node to Node (GRIDID format) u Topology of each surface patch must be specified l Tri3, Tri6, Quad4, Quad8 u Nodes (GAi and GBi) are specified defining the connecting surface patches (one list pair per connector) u The surface patches are defined as 3/6 node triangle or 4/8 node quad regions, the topology of which is indicated by SPTYP u If Node List B (GBi) is blank, then a point-to-patch connection is created.

S8-14 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation NODE TO NODE Specific nodes are connected The element type must be specified for each surface

S8-15 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation Each connection property must be given a unique name The weld diameter must be specified The material for the weld must be chosen from existing materials SPOT WELD PROPERTIES

S8-16 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation FASTENER (CFAST) CONNECTORS n The GUI for creating, modifying, showing, and deleting fasteners (CFASTs) is consistent with that described previously for the Spot Weld (CWELD) Connector n There are two primary differences: u CFAST only has two formats, PROP and ELEM l Analogous to PARTPAT and ELPAT of CWELD respectively u PFAST properties are different than PWELD properties l Stiffness values are entered for all six degrees of freedom l The element stiffness coordinate system may be specified l Lumped Mass of fastener can be entered directly

S8-17 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation PROP TO PROP Multiple locations may be specified Property Sets identify surfaces to be connected (each surface must have a unique property set)

S8-18 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation PATCH TO PATCH Patches of elements are specified for each surface

S8-19 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation FASTENER PROPERTIES Each connection property must be given a unique name The fastener diameter must be specified The connector coordinate system must be specified Stiffness values must be entered for all three translations and all three rotations. The lumped mass of the fastener may be specified

S8-20 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation APPLICATION FORMS Connectors can be modified by setting the action to Modify A single connector may be selected from the screen or entered from the keyboard. (Note that if multiple connectors are selected, then only the data that has common values amongst the selected connectors shall be modifiable. All other controls will be disabled.) Selecting a connector with the action set to Show generates a spreadsheet of connector information.

S8-21 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation APPLICATION FORMS Connectors can be deleted by setting the action to Delete and the option to either Any or Connector Then connectors may be selected from the screen or entered from the keyboard.

S8-22 PAT328, Section 8, September 2004 Copyright 2004 MSC.Software Corporation EXERCISE Perform Workshop 7: CWELD and CFAST Connectors