A Geo Surface Contact is a General Geometry Contact which can analyze the contact between any kinds of geometries. The geometry can be a rigid body or a flexible body and they can have any kind of shapes.
Geo Surface contact analyzes the all possible contact points and output the all useful contact information such as the contact point, contact force, contact direction, and penetration. If the action geometry is a sphere, Geo Sphere contact is recommended to analysis more quickly and accurately. To see about the Geo Sphere contact,
click here.
Note
RecurDyn does not maintain existing surface contacts. Instead of those, Geo Surface contact is recommended.
In the case of Geo Surface contact, solid, shell, and surface geometry types are supported about rigid body and patch set is supported about flexible body without base and action geometries when creating.
Solid(Shell, PatchSet), Solid(Shell, PatchSet)
Solid(Shell, PatchSet): Selects a solid or a shell or a patch set to define a base solid.
Solid(Shell, PatchSet): Selects a solid or a shell or a patch set to define an action solid.
Name: Defines the name of base geometry. The base geometry can be modified from the Working Window by clicking Gr.
Figure 6.316 Preview of the normal directions, contact patches and nodes.
Normal Direction: Defines the normal direction of a base geometry for a contact as shown in the above figure.
The contact is available in the specified direction.
As selecting Up or Down, the user can change the contact direction of a base geometry.
If this page is activated, the normal direction is automatically shown on the Working Window.
Calculate Pressure: Calculates contact pressure for surface type geometry. Contour file is created when this option is activated. Note that CalculatePressure option is supported only for rigid body surfaces.
The calculated pressure result is calculated on each node. Pressure is calculated by an area and a force projected to the node. The force value for pressure is calculated by the forces that occur around the node. And the area value for pressure is calculated by the patches and size of the patches around the node.
Preview: If this option is checked, the patches making the contact surface are shown on the Working Window as shown in the above figure.
Node Contact: If this option is checked, the node in the checked part makes node contact with the other surface. Geometrical definition of Node Contact follows below figure.
Figure 6.317 Definition of Node Contact Pattern [Surface Type]
Contact Geometry: Accesses the Surface Patch dialog box as shown in the below figure.
Surface Name: This shows the name of the selected base contact geometry.
Surface Type: Select the Triangle for the triangle faceting or select the Quad for the quad-dominant faceting.
In the Triangle type, the contact surface is approximated to multiple triangular patches. On the other hand, in the
Quad type, the contact surface is approximated to multiple triangular and quadrilateral patches.
Bounding Buffer Length: This value is used when the contact pre-search is performed with base and action bounding box. The bounding buffer length defines the offset length of bounding box compared to the real bounding box as shown in the below figure. This value is automatically calculated but can be modified by the user.
Additionally, if you click Cal., this value is updated with the recommended default value.
Figure 6.319 Definition of Bounding Buffer Length
Plane Tolerance Factor: Specifies the surface tolerance factor as a value from 0.01 to 10. A smaller value produces more refined patches. If the factor is closer to 0, the number of triangular patches are increased. And if the factor is closer to 10, the number of triangular patches are decreased.
Max. Facet Size Factor: Specifies the max. facet size factor as a value from 0.01 to 10. This value controls the maximum size of triangular or quadrilateral patch length. Even though box geometry, if this value is defined (checked), box geometry can be used with lots of triangular or quadrilateral patches as shown in the below figure.
Figure 6.321 Example of Plane Tolerance Factor, Max. Facet Size Factor and Quad Surface Type
Cubic Cell Size: Shows the number of cubic cells dividing a contact bounding box in each direction. This value is automatically calculated but can be modified by the user.
Edge Contact
if this option is checked, the contact force by the base and action edges is calculated. In order to perform the reasonable contact analysis in some models such as the below figure, “Edge Contact” option must be used. Detail geometrical definition of Edge Contact follows right part of below figure.
Figure 6.322 Definition of Edge Contact Pattern [Surface Type]
Advanced Settings: Accesses the Advanced Settings dialog box as shown in the below figure.
Smooth Node Contact: In the case of Surface type as Geometry type, this option is activated. If this option is checked, the smooth contact algorithm is applied in node-to-face collision pattern and the corresponding face is smoothed by using the bi-cubic Hermite surface equation. The bi-cubic Hermite surface equation is generated by using the node position and surface normal direction at node. If user selects this option, the edge contact is not recommended in most cases because the smooth option is applied in the action and base node contacts.
Use CPM: CPM is the abbreviation of Consistent Penetration Method. If this option is checked, the contact force at each contact point is divided by the total number of contact points. As a result, although user uses different facet or element size for the geometry,
total contact force magnitude remains in similar level. This means that the user does not need to change the contact stiffness or contact damping parameters when the user uses different mesh or different faceting values for the same geometry. On the other hand, if this option is unchecked, the contact force is applied for the all contact points with given contact parameters.
No. of Max Contact Point: Defines the number of max contact point for output. User can define this value from 1 to 5000. This value only affects Force Display and RPLT data about contact points.
Generate the contact output file(*.con): When this option is checked, RecurDyn creates the contact output file which contains position and orientation information of contact reference frame and contact point information with respect to global inertia frame. Based on the contact reference frame information, user can transform contact information from global inertia reference frame to contact reference frame. In particular, RecurDyn/Solver reports all contact-related information in order of contact force magnitude to the text file. The format is as follows:
Z Euler Angle of Output Reference Marker from
Global
8
X_EulerA
X Euler Angle of Output Reference Marker from
Global
9
Z_EulerA
Z Euler Angle of Output Reference Marker from
Global
10
X_ConPos
Position X of Calculated Contact Reference Frame
from Global
11
Y_ConPos
Position Y of Calculated Contact Reference Frame
from Global
12
Z_ConPos
Position Z of Calculated Contact Reference Frame
from Global
13
X_NorDir
Normal Direction X of Calculated Contact
Reference Frame from Global
14
Y_NorDir
Normal Direction Y of Calculated Contact
Reference Frame from Global
15
Z_NorDir
Normal Direction Z of Calculated Contact
Reference Frame from Global
16
X_TanDir
Tangent(Friction) Direction X of Calculated
Contact Reference Frame from Global
17
Y_TanDir
Tangent(Friction) Direction Y of Calculated
Contact Reference Frame from Global
18
Z_TanDir
Tangent(Friction) Direction Z of Calculated
Contact Reference Frame from Global
19
Pen
Penetration Depth
20
PenVel
Penetration Depth Velocity or Relative Velocity
in Normal Direction
21
TanVel
Relative Velocity in Tangent Direction
22
FricCoeff
Friction Coefficient
23
NorForce
Normal Force Magnitude
24
FricForce
Friction Force Magnitude
Force Display: Graphically displays the all contact force vectors (the sum of the normal and tangential contact force) at each contact point up to the No. of Max Contact Point as shown in the below figure.
Figure 6.324 Option of Contact Force Display (Force Vector, Force Component X, Y, Z, Normal Force and Friction Force)
Force Vector (default), Force Component X, Y, Z, Friction Force and Normal Force can be displayed using toggle option.
The reference marker can select when display the Force Component X, Y, Z.
In Geo contact, the accumulated contact force result (FM,FX,FY,FZ,TM,TX,TY,TZ ) is only evaluated for the action body. the accumulated contact force result (FM,FX,FY,FZ,TM,TX,TY,TZ) is evaluated w.r.t. the
Ground.InertiaMarker when the “*.Generate the contact output file.(*.con)” is not checked. If user checks the “*.Generate the contact output file.(*.con)”, the user can specify the output reference frame for the accumulated contact force (FM,FX,FY,FZ,TM,TX,TY,TZ) for the action body. In the case of contact point results, they are sorted in order of contact force magnitude.
