Force: Spring Damper

Format

<Force_SpringDamper
       id               = "integer"       
       i_marker_id      = "integer"       
       j_marker_id      = "integer"       
       stiffness        = "real"       
       damping          = "real"       
       length           = "real"       
       preload          = "real" 
/>

Attributes

id: Element identification number (integer > 0). This number is unique among all Force_SpringDamper elements.
i_marker_id: Modifies the Reference_Marker at which the force or torque is applied. This is designated as the point of application of the force.
j_marker_id: Modifies the Reference_Marker at which the reaction force or torque is applied. This is designated as the point of application of the reaction force.
length: Modifies the free-length or the installed (reference) length of the spring. It has to be strictly positive. A zero or negative value is not allowed.
stiffness: Modifies the spring stiffness. For translational spring-dampers, this has units of force/unit translational deflection. For rotational spring-dampers, this has units of torque/radian. Note that stiffness > 0. A negative value is not allowed.
damping: Modifies the damping coefficient. For translational spring-dampers, this has units of force/unit translational deflection velocity. For rotational spring-dampers, this has units of torque/unit angular deflection velocity.; Note that damping > 0. A negative value is not allowed.
preload: Modifies any assembly or pre-load in the spring-damper. This is the force or torque when the distance or angle between the I and J markers is equal to the value specified by length.; A positive value implies a force that tends to increase the distance or a torque that tends to increase the angle (repulsive), and vice versa.

Example

<Force_SpringDamper
     id        = "105001"
     length    = "334.12"
     stiffness = "138.444"
     damping   = "0."
     preload   = "0."
/>