The BISTOP function models a gap element.
Format
Description
It can be used to model forces acting on a body while moving in the gap between two
boundary surfaces, which act as elastic bumpers. The properties of the two boundary surfaces
can be tuned as desired.
Arguments
-
- The expression used for the independent variable. For example, to use the
z-displacement of I marker with respect to J
marker as resolved in the reference frame of the RM marker as the
independent variable, specify
as DZ({marker_i.idstring},
{marker_j.idstring},
{marker_rm.idstring}).
-
- The time derivative of the independent variable. For example, if
is specified as above, then
will be VZ({marker_i.idstring},
{marker_j. idstring},
{marker_rm.idstring}).
-
- The lower bound of
. If
is less than
, the bistop function returns a positive value.
The value of
must be less than the value of
.
-
- The upper bound of
. If
is greater than
, the bistop function returns a negative value.
The value of
must be greater than the value of
.
-
- The stiffness of the boundary surface interaction. It must be non-negative.
-
- The exponent of the force deformation characteristic. For a stiffening spring
characteristic,
must be greater than 1.0 and for a softening spring
characteristic,
must be less than 1.0. It must always be positive.
-
- The maximum damping coefficient. It must be non-negative.
-
- The penetration at which the full damping coefficient is applied. It must be
positive.
Definition
(1)
Example
<Force_Vector_TwoBody
id = "30101"
type = "ForceOnly"
i_marker_id = "30102031"
j_floating_marker_id = "30101031"
ref_marker_id = "30101010"
fx_expression = "BISTOP(DX(30102030,30101010,30101010),VX(30102030,30101010,30101010),0.5,9.5,10000000,2.1,1,0.001)"
fy_expression = "0"
fz_expression = "0"
/>