# CONTACT

The CONTACT function returns a scalar result associated with a Force_Contact element.

## Format

CONTACT(id, jflag, comp, rm)
CONTACT(id, index, rm)

## Description

Two definitions of the CONTACT function are available:
CONTACT (id, jflag, comp, rm)
This form returns the force and torque components specified by comp for a Force_Contact element in the coordinate system specified by rm.
CONTACT (id, index, rm)
The second form can be used to monitor maximum penetration depth, average point of contact, normal and friction force, and so on, based on the index. Vector components are always computed in the coordinate system specified by rm. This form always reports the contact forces on the I body as defined in the contact modeling element.

## Arguments

id
The ID of the Force_Contact element.
jflag
jflag set to 0 or 1 means that forces and moments are reported at the CG of the I or J body, respectively.
comp
Determines the component of contact force that is returned by the CONTACT function when specified in the form CONTACT(id, jflag, comp, rm). comp can be specified as follows:
1
Magnitude of force due to all incidents of the specified Force_Contact element.
2
X-component of the force due to all incidents of the specified Force_Contact element.
3
Y-component of the force due to all incidents of the specified Force_Contact element.
4
Z-component of the force due to all incidents of the specified Force_Contact element.
5
Magnitude of torque due to all incidents of the specified Force_Contact element.
6
X-component of the torque due to all incidents of the specified Force_Contact element.
7
Y-component of the torque due to all incidents of the specified Force_Contact element.
8
Z-component of the torque due to all incidents of the specified Force_Contact element.
index
Determines the quantity that will be returned by the CONTACT statement when specified in the form CONTACT(id, index, rm). index can be specified as follows:
1
Penetration depth for the specified contact force element. In case of multiple contact areas, the maximum penetration depth is returned.
2
The average X position of the contact point. This is expressed in the coordinate system defined by rm.
3
The average Y position of the contact point. This is expressed in the coordinate system defined by rm.
4
The average Z position of the contact point. This is expressed in the coordinate system defined by rm.
5
The X component of the total normal force expressed in the coordinate system defined by rm.
6
The Y component of the total normal force expressed in the coordinate system defined by rm.
7
The Z component of the total normal force expressed in the coordinate system defined by rm.
8
The X component of the total tangential force expressed in the coordinate system defined by rm.
9
The Y component of the total tangential force expressed in the coordinate system defined by rm.
10
The Z component of the total tangential force expressed in the coordinate system defined by rm.
11
The magnitude of the total contact area.
12
The total number of contact points.
13
The total number of contact patches between the I and J body graphics.
14
The average penetration depth.
15
The maximum penetration velocity.
16
The average penetration velocity.
17
The maximum slip velocity.
18
The average slip velocity.
19
The friction power, defined as the sum of the slip velocity multiplied by the norm of the tangential force.
$\sum _{i}{v}_{\text{slip}}^{i}‖{f}_{\mathrm{t}\text{angential}}^{i}‖$
RM
Force and moment components are resolved in this coordinate system. RM=0 specifies a global coordinate system.

## Example

<Post_Request
comment = "Form 1: Total Contact Force"
id      = "1"
type    = "EXPRESSION"
expr1   = "CONTACT(90,0,1,0)"
expr2   = "CONTACT(90,0,2,0)"
expr3   = "CONTACT(90,0,3,0)"
expr4   = "CONTACT(90,0,4,0)"
expr5   = "CONTACT(90,0,5,0)"
expr6   = "CONTACT(90,0,6,0)"
expr7   = "CONTACT(90,0,7,0)"
expr8   = "CONTACT(90,0,8,0)"
/>
<Post_Request
comment = "Form 2: Other Contact Results"
id      = "1"
type    = "EXPRESSION"
expr2   = "CONTACT(90,6,0)"
expr3   = "CONTACT(90,7,0)"
expr4   = "CONTACT(90,8,0)"
expr6   = "CONTACT(90,9,0)"
expr7   = "CONTACT(90,13,0)"
expr8   = "CONTACT(90,14,0)"
/>