Variable Translational Spring
Tension-compression spring with variable stiffness.
Description
The Variable Translational Spring block represents a tensile-compression spring with variable stiffness. The value of the variable spring stiffness coefficient is input to the K input port. The spring stiffness value is equal to the product of the value at port K and the value of the relative linear displacement between the two non-directional ports. A minimum spring stiffness value prevents unphysical values from occurring.
The spring force value satisfies the following expression:
where
-
- is the force transmitted through the spring between the two non-directional ports;
-
- spring stiffness coefficient;
-
- minimum permissible spring stiffness coefficient;
-
- the relative displacement between the two non-directional ports, defined as ;
-
- initial spring deformation;
-
- absolute displacement of the non-directional port R;
-
- absolute displacement of the non-directional port C.
The block applies equal opposite spring forces to the two non-directional ports. The sign of the spring force acting on port R is equal to the sign of the relative linear displacement between the two ports. A positive translational velocity corresponds to a positive force acting on port R and a negative force of the same magnitude acting on port C.
Ports
Conserving
#
R
—
slave port
translational mechanics
Details
A non-directional progressive mechanical port connected to the positive end of a spring. The positive direction is from port R to port C.
Program usage name |
|
#
C
—
base port
translational mechanics
Details
A non-directional progressive mechanical port connected to the negative end of a spring. The positive direction is from port R to port C.
Program usage name |
|
Input
#
K
—
variable spring stiffness
scalar
Details
Variable coefficient of spring stiffness.
Data types |
|
Complex numbers support |
No |
Parameters
Parameters
#
Minimum spring rate —
minimum spring stiffness factor
N/m
| lbf/ft
| lbf/in
Details
The minimum permissible spring stiffness coefficient. If the stiffness value at port K is less than this value, it is equated to it. The value of this parameter must be greater than zero.
Values |
|
Default value |
|
Program usage name |
|
Evaluatable |
Yes |