Stampable, Turnable, and Drillable Surfaces


CLIENT / Applicable for	SHAPE_CONTROLLER	SHAPE_SENSITIVITY
SURF_STAMP	OK	OK
SURF_TURN	OK	OK
SURF_DRILL	OK	-

Stampable Surface (SURF_STAMP) for Shape Controller

Maintaining a stampable surface during optimization involves defining a stamping direction. The stamping domain is defined using a node group. The direction defined by the CLIENT_DIR parameter specifies the stamping direction. The link condition is defined using the following parameters:


CLIENT     = SURF_STAMP
CLIENT_DIR = <x_1>,<x_2>,<x_3>
CS         = name_of_coord_system

The main nodes are found using the standard main criterion. The stamping surface is defined using the given stamping direction and the cutting edge automatically generated by Tosca Structure. All nodes of the node group are linked to this surface.

An additional demolding direction can be included:

 
DEMOLD_DIR = <x_1>,<x_2>,<x_3>

The demolding direction must be orthogonal to the client direction. Therefore, Tosca Structure projects the demold vector onto a plane normal to the client direction.

Important:

This link condition allows the definition of stamping restrictions to arbitrary meshes. No special meshing conditions must be taken into consideration.
It is possible to define stamping restrictions for initial components that are not stampable in the beginning of the optimization procedure. However, this is not recommended because the conditions for stamping are met in the first design cycle. This might lead to large node displacements and a distorted finite element mesh.

Stampable Surface (SURF_STAMP) for Shape Sensitivity

A surface is stampable if all nodes lie in the same plane. Enforcing stampable surfaces is supported for sensitivity-based shape optimizations as well. The most important parameter is the stamping direction, defined by the CLIENT_DIR parameter. Another mandatory parameter is the main group, that defines the reference edge or cutting edge for the plane where all nodes shall be moved in. The link condition is defined using the following parameters:


CLIENT     = SURF_STAMP
CLIENT_DIR = <x_1>,<x_2>,<x_3>
CS         = name_of_coord_system
MAIN       = NDGR, main_node_group

In the figure below, the green dotted points are used as the stamping area and the green highlighted edge is used as the main group.

Important:

This link condition allows the definition of stamping restrictions to arbitrary meshes. No special meshing conditions must be taken into consideration.
The only allowed main criterion is MAIN = NDGR, <node_group>.

Turnable Surface (SURF_TURN) for Shape Controller

Maintaining a turnable surface during optimization involves defining a rotation axis. The domain that assures a turnable surface is defined using a node group; all nodes of the specified surface node group are checked for rotation symmetry in the given rotation axis. The link condition is defined using the following parameters:


CLIENT     = SURF_TURN
CLIENT_DIR = <x_1>,<x_2>,<x_3>
CS         = name_of_coord_system

The direction defined by the CLIENT_DIR and the origin of the coordinate system specify the exact position and direction of the rotation axis.

The main nodes are found using the standard main criteria. In addition, the criteria MAIN = AUTO is available for compatibility reasons with sensitivity-based shape optimization. It can be seen as an alias for MAIN = MAX. The turning surface is defined using the given rotation axis and the cutting edge automatically generated by Tosca Structure. All nodes of the node group are linked to this surface.

Important:

This link condition allows the definition of turning restrictions to arbitrary meshes. No special meshing conditions must be taken into consideration.
The referenced coordinate system must lie exactly on the rotation axis as the algorithm always orientates the surface toward the coordinate system. If nonsymmetrical effects occur during optimization, the correct position of the coordinate system must be checked.
It is possible to define turning restrictions for initial components that are not turnable in the beginning of the optimization procedure. However, this is not recommended because the conditions for turning are met in the first design cycle. This might lead to large node displacements and a distorted finite element mesh.

Turnable Surface (SURF_TURN) for Shape Sensitivity

The SURF_TURN manufacturing constraint for sensitivity-based shape optimization can be used to achieve a turnable or rotational symmetric surface.

The important parameters are the rotational axis CLIENT_DIR, together with the origin, specified by a coordinate system CS. Next, the specification of "driving" area (MAIN) is a necessary part of the setup. It can either be defined by providing a node group (NDGR, <node group name>), which gives very good control, or by letting Tosca find an appropriate area, which is very simple on the setup side but can fail for complicated surfaces.

The link condition is defined using the following parameters:


CLIENT     = SURF_STAMP
CLIENT_DIR = <x_1>,<x_2>,<x_3>
CS         = name_of_coord_system
MAIN       = NDGR, main_node_group | AUTO

In the figure below, the green dotted points are used as turning area and the blue highlighted edge is used as the driving area.

Important:

This link condition allows the definition of turning restrictions to arbitrary meshes. No special meshing conditions must be taken into consideration.
The turnable surface must be connected. Otherwise, define two or more commands: one for every disconnected area.
The command item MAIN = AUTO simplifies the setup, but it fails in some cases: Think of the node coordinates being expressed in cylindrical coordinates with the rotation axis as the z-direction. Then all nodes having the same radius coordinate, must be specifiable in at least one of the other two coordinates. For example, a "donut" like shape is impossible. Unfortunately such a failure is not detected, which leads to the recommendation to use the MAIN = NDGR, .. option.
When using the command item MAIN = AUTO, a new node group with name _<DVC_IdName>_SurfTurn_AutoMain_ is created, where <DVC_IdName> is the ID_NAME of the DVCON_SHAPE command triggering the SURF_TURN manufacturing constraint.

Drillable Surface (SURF_DRILL)

The drill restriction is a combination of the turning and the demolding restriction. Maintaining a drillable surface during optimization involves defining the drill axis and the drill feed. The drilling domain is defined using a node group; all nodes of the specified surface node group are checked for drilling in the given drill direction. The link condition is defined using the following parameter:


CLIENT     = SURF_DRILL
CLIENT_DIR = <x_1>,<x_2>,<x_3>
CS         = name_of_coord_system
ANGLE      = <real> (0° < angle < 45°)

The direction defined by the CLIENT_DIR and the origin of the coordinate system specify the exact position and direction of the drill axis, the angle specifies a minimum surface angle.

The shape of the drilling surface can be specified with an additional undercut tolerance. The term 'drilling surface' in this case should be interpreted in a more general sense.

 UNDERCUT_TOL = <real> (>0)

Important:

This link condition allows the definition of turning restrictions to arbitrary meshes. No special meshing conditions must be taken into consideration.
The referenced coordinate system must lie exactly on the rotation axis as the algorithm always orientates the surface toward the coordinate system. If nonsymmetrical effects occur during optimization, the correct position of the coordinate system must be checked.
It is possible to define turning restrictions for initial components that are not turnable in the beginning of the optimization procedure. However, this is not recommended because the conditions for turning are met in the first design cycle. This might lead to large node displacements and a distorted finite element mesh.