*TwoDContact()

Creates a 2D graphics based contact force between two bodies.

Syntax

*TwoDContact(varname, label, 
                   contact_type, 
                   coulomb_friction, 
                   BODY, 
                   b1, 
                   in, 
                   ig1,
                   ig2,
                   ign, 
                   BODY, 
                   b2, 
                   jn, 
                   jg1,
                   jg2,
                   jgn, )

Arguments

varname: The variable name of the contact force definition.; Data type: varname
label: The descriptive label of the contact force.; Data type: string
contact_type: The type of contact. Valid choices are: IMPACT|POISSON|VOLUME|USER .; Data type: keyword
coulomb_friction: Indicates the choice of using coloumb_friction . Valid choices: OFF|ON|DYNAMIC_ONLY|USER .; Data type: keyword
BODY: A keyword to indicate the body to be used for contact definition. Currently, this is the only keyword that is supported.; Data type: keyword
b1: The first body in the contact force definition.; Data type: Body
in: The number of graphic entities related to the first body in the contact force definition.; Data type: integer
ig1, ig2, … ign: The varname of graphic entities on the first body to be used for the contact force. The number of entities in this series should match in .; Data type: Graphics
b2: The second body in the contact force definition.; Data type: Body
jn: The number of graphic entities related to the second body in the contact force definition.; Data type: integer
jg1, jg2, … jgn: The varname of graphic entities on the second body to be used for the contact force. =The number of entities in this series should match jn .; Data type: Graphics

Example

*SetReal( DS_Gravity.kgrav, 0 )
 *SetReal( DS_Gravity.jgrav, -9810.0 )
 *Point( p_sph, "Point Sphere" )
 *Body( b_sph, "Sphere", P_Global_Origin, , , , )
 *SetBodyInertia( b_sph, 1, 100, 100, 100 )
 *Set( b_sph.usecm, true )
 *Curve( crv_circ, "Curve Circle", 3D, CARTESIAN, WRITE, CURVE_POINTS, CLOSED )
 *SetCurve( crv_circ, MATH, 10*sin(2*PI*(0:1:0.1)), 
 MATH, 10*cos(2*PI*(0:1:0.1)), 
 MATH, 0*(0:1:0.1) )
 *Curve( crv_edge, "Curve Edge", 3D, CARTESIAN, WRITE, CURVE_POINTS, CLOSED )
 *SetCurve( crv_edge, VALUE, 4, -100, 100, 100, -100, 
 VALUE, 4, -20, -20, -25, -25, 
 VALUE, 4, 0, 0, 0, 0 )
 *Marker( m_sph, "Marker Sphere", b_sph, p_sph )
 *Marker( m_box, "Marker Box", B_Ground, P_Global_Origin )
 *Graphic( gcrv_circ, "CurveGraphic_Sphere", CURVE, MARKER, m_sph, crv_circ )
 *Set( gcrv_circ.is_material_inside, false )
 *Graphic( gcrv_edge, "CurveGraphic_Box", CURVE, MARKER, m_box, crv_edge )
 *Set( gcrv_edge.is_material_inside, false )
 
*TwoDContact( con_sph_box_2D, "Sphere to box 2D contact", IMPACT, 
 OFF, 
 BODY, b_sph, 1, 
 gcrv_circ, 
 BODY, B_Ground, 1, 
 gcrv_edge )
 *SetContact( con_sph_box_2D, 1000.0, 2.1, 0.1, 0.1, 0.2, 0.1, 1.0, 1.5, false )

Context

Properties

The following table lists all of the properties associated with the Contact entity in MotionView:

Table 1.
Property	Returns Data Type	Description
contact_type	keyword	Valid values are: IMPACT\|POISSON\|VOLUME\|USER
coulomb_friction	keyword	ON\|OFF\|DYNAMICS_ONLY
exponent	real	Applicable for ^contact_type^ IMPACT. Specifies the value of the exponent for stiffness.
damping	Body	Applicable for ^contact_type^ IMPACT. Specifies the value of the damping coefficient.
dmax	real	Applicable for ^contact_type^ IMPACT. Specifies the value of the maximum penetration depth before full damping is applied.
friction_trans_vel	real	The value where the coefficient of friction becomes ^mu_dynamic^. When the slip velocity is between ^stiction_trans_vel^ and ^friction_trans_vel^, the coefficient of friction is in transition between the two.
id	integer	The numeric ID assigned to the entity.
id_string	string	The assigned ID in a string format.
ig1, ...ign	Graphic	The graphic entities belonging to the first body.
jg1, ...jgn	Graphic	The graphic entities belonging to the second body.
label	string	The descriptive label.
mu_static	real	The coefficient of friction when the slip velocity is less than ^stiction_trans_vel^.
mu_dynamic	real	The coefficient of friction when the slip velocity is greater than ^friction_trans_vel^.
num	integer	The last digit of the ID.
penalty	Point	Determines the local stiffness properties between materials. Larger values lead to reduced penetration between two bodies. Used with the Poisson method of normal force calculation.
rest_coeff	Point	The value representing the energy loss between the two bodies in contact. A value of one represents no energy loss and a perfectly elastic contact. Used with the Poisson method of normal force calculation.
state	boolean	Returns true or false. True if the entity is active, otherwise false.
stiction_trans_vel	real	The value where the coefficient of friction becomes ^mu_dynamic^. When the slip velocity is between ^stiction_trans_vel^ and ^friction_trans_vel^, the coefficient of friction is in transition between the two.
stiffness	real	Applicable for contact_type IMPACT. Specifies the value of the stiffness associated with the contact force.
type	string	Returns "Contact".
use_aug_formulation	boolean	Used for the ADAMS solvermode only, to use the augmented Lagrangian formulation.
varname	varname	The variable name of the contact definition.

Comments

This statement can be used to define a 2D graphical based contact force between two sets of graphics that belong to different bodies.

At least one graphic should be listed for each body in this definition for arguments ign and jgn.

contact_type determines the method used to calculate the normal force. Available methods are IMPACT, POISSON, VOLUME, and USER. VOLUME and USER are available only available for the MotionSolve solver mode. Based on the chosen method, relevant properties in *SetContact should be provided.

All ign graphics must reference the same body, and all jgn graphics must reference the same body. However the body for the ign graphics must be different than the body for the jgn graphics.

All curve graphics should be oriented in one plane.