Adams Car Package > Shared Material > Dialog Box - F1 Help > Create/Modify Contact Definition

Create/Modify Contact Definition

(Template Builder) Build → Contact Definitions → New/Modify Shared Dialog Box

Creates or modifies a contact definition. Learn about contact definitions.

For the option:	Do the following:
Tips on Entering Object Names in Text Boxes.
Contact Name	If creating a contact definition, enter a name for it. If modifying a contact definition, enter its database name.
Type	Select one of the following: ■left/right - Define either the left or the right contact, and your template-based product creates the corresponding opposite contact by default. ■single - Define a non-symmetric contact.
Select one of the following options:
I Contact Solid	Enter the name of an existing geometry object valid for use in a contact.
I Flexible Body	Enter the name of an existing flexible body.
Select one of the following options:
J Contact Solid	Enter the name of an existing geometry object valid for use in a contact.
J Flexible Body	Enter the name of an existing flexible body.
J Matching Name	Enter the name of the object that will be matched either at assembly or runtime.
Road Graphics	N/A. This selection will create a contact with the road object after the model has been assembled.
If you selected J Matching Name & I Flex Body, the following options will be available:
J Object Type	Select one of the following: ■Contact Solid ■Flexible Body
Force Display	Select to create dynamic force graphics for animation. If this option is selected, choose the color of the force graphics.
If creating a new contact definition, the following options will be available:
Contact Parameters	Select one of the following: ■Create - Define the contact parameters. ■Use Existing - Select an existing contact parameters array.
Normal Force Type	Select either: ■Impact Force - To define the normal force based on an impact using the IMPACT function. ■Poisson Force - To define the normal force as restitution-based. This option is not available with Flex Body to Solid and Flex Body to Flex Body type of contacts. ■User Defined - To define the force based on a User-written subroutine. Learn about the types of Contact Force Algorithms and also see Learning More about the Contact Detection Algorithm.
If you select Impact Force, the following four options will be available:
Stiffness	Enter a material stiffness that is to be used to calculate the normal force for the impact model. In general, the higher the stiffness, the more rigid or hard the bodies in contact are. Note: When changing the length units in Adams View, stiffnesses in contacts are scaled by (length conversion factor**exponent). When changing the force unit, stiffness is only scaled by the force conversion factor.
Force Exponent	Adams Solver models normal force as a nonlinear springdamper. If the damping penetration, below, is the instantaneous penetration between the contacting geometry, Adams Solver calculates the contribution of the material stiffness to the instantaneous normal forces as: STIFFNESS * (PENALTY)**EXPONENT For more information, see the IMPACT function in the Adams Solver online help.
Damping	Enter a value to define the damping properties of the contacting material. Consider a damping coefficient that is about one percent of the stiffness coefficient.
Penetration Depth	Enter a value to define the penetration at which Adams Solver turns on full damping. Adams Solver uses a cubic STEP function to increase the damping coefficient from zero, at zero penetration, to full damping when the penetration reaches the damping penetration. A reasonable value for this parameter is 0.01 mm. For more information, see the IMPACT function in the Adams Solver online help.
If you select Poisson Force, the following two options will be available:
Penalty	Enter a penalty value to define the local stiffness properties between the contacting material. A large penalty value ensures that the penetration of one geometry into another will be small. Large values, however, will cause numerical integration difficulties. A value of 1E6 is appropriate for systems modeled in Kg-mm-sec. For more information on how to specify this value, see the Extended Definition for the CONTACT statement in the Adams Solver online help. Note: The penalty value of 1.0E+06 is recommended value for users who have no prior experience with restitution based contacts. Experienced users will find values that are both smaller and larger that are applicable to their models.
Restitution Coefficient	Enter the coefficient of restitution, which models the energy loss during contact. ■A value of zero specifies a perfectly plastic contact between the two colliding bodies. ■A value of one specifies a perfectly elastic contact. There is no energy loss. The coefficient of restitution is a function of the two materials that are coming into contact. For information on material types versus commonly used values of the coefficient of restitution, see the table for the CONTACT statement in the Adams Solver online help.
If you select User Defined, the following two options will be available:
User function	Specify the user parameters to be passed to a User-written subroutine CNFSUB. For more on user-written subroutines, see the Adams Solver online help.
Routine	Specify an alternative library and name for the user subroutine. Learn about ROUTINE Argument.
The following option is available for all choices:
Friction Force	Select to model the friction effects at the contact locations using the Coulomb friction model, no friction, or as user-defined subroutine. The Coulomb friction model models dynamic friction but not true stiction. For more on friction in contacts, see Contact Friction Force Calculation. In addition, read the information for the CONTACT statement in the Adams Solver online help.
If you selected Coulomb or Stiction and Sliding for Friction Force, define the following options:
Friction Mode	Specify whether the friction effects are to be included at run time: ■On ■Off (not available for Stiction and Sliding) ■Dynamics Only
Static Coefficient	Specify the coefficient of friction at a contact point when the slip velocity is smaller than the value for Static Transition Vel. For information on material types versus commonly used values of the coefficient of static friction, see Material Contact Properties Table. Excessively large values of Static Coefficient can cause integration difficulties. Range: Static Coefficient 0
Dynamic Coefficient	Specify the coefficient of friction at a contact point when the slip velocity is larger than the value for Friction Transition Vel. For information on material types versus commonly used values of the coefficientof the dynamic coefficient of friction, see Material Contact Properties Table. Excessively large values of Dynamic Coefficient can cause integration difficulties. Range: 0 Dynamic Coefficient Static Coefficient
Stiction Transition Vel.	Enter the stiction transition velocity. For more on friction in contacts, see Contact Friction Force Calculation. In addition, read the information for the CONTACT statement in the Adams Solver online help. Range: 0 < Static Transition Vel. Friction Transition Vel.
Friction Transition Vel.	Enter the friction transition velocity. For more on friction in contacts, see Contact Friction Force Calculation. In addition, read the information for the CONTACT statement in the Adams Solver online help. Range: Friction Transition Vel. Static Transition Vel. > 0
If you selected Stiction and Sliding for Friction Force, define the following option:
Max Stiction Deformation	Enter the maximum distance allowed in the stiction regime. Range: Max Stiction Deformation > 0
If you selected User Defined for Friction Force, define the following two options:
User function	Specify the user parameters to be passed to a user-written subroutine. For more on user-written subroutines, see Adams Solver online help.
Routine	Enter the name of the function to call. The default is CNFSUB.
	Select to display a dialog box where you can add multi-line comments to any entity, to describe its purpose and function. Your template-based product displays different comments dialog boxes, depending on the entity type for which you want to record comments: ■If recording comments for modeling entities in Standard Interface, your template-based product displays the Entity Comments dialog box. ■If recording comments for any other entity type, your template-based product displays the Modify Comment dialog box. Learn about Recording Comments.