MotionView User's Guide

Spring Dampers Panel - Preload Tab

Spring Dampers Panel - Preload Tab

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Spring Dampers Panel - Preload Tab

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The Preload tab on the Spring Dampers panel allows you to specify the preload characteristics of a linear coil spring or torsion spring.  Spring dampers with curve or expressions do not have separate properties since their force/torque characteristics are determined by the functions which define their stiffness properties.

spring_damper_preload

Spring Dampers panel - Preload tab for a coil spring

Use:

To:

Preload

specify the force in the linear coil spring when it is at a modeled length.  Refer to the Notes (below) for additional details.

Free length

specify the actual free length of the spring.  Refer to the Notes (below) for additional details.

Use Distance
Between Points

set the Free length value as the distance between two end points of the spring.

Preload for Linear Torsion Springs

spring_damper_preload_torsion

Spring Dampers panel - Preload tab for a torsion spring

Use:

To:

Preload

specify the torque produced by the linear torsion spring when it is at a specified angular displacement, Free Angle.

Free Angle

specify the angular displacement produced when a torque is applied to the linear torsion spring.

Notes:

1.Preload is the initial force or torque in the spring in the modeled position.  The total preload can be specified by using either the Preload value, the Free Length value, or a combination of the two.

spring_damper_panel_preload_tab_ex1

2.The total preload Fp is applied as the summation of Preload P and the force due to change in length K* (Lo –l); where K is the stiffness, Lo is the free length, and l is the modeled length of the spring (refer to the figure above).
•For example, if the two end points of the defined spring (modeled length of spring) is 100 mm and the free-length is specified as 110, that represents the spring in a pre-deflected state by 10mm and the effective preload is 10*K; where K is the stiffness of the spring.
•If the Preload value is specified in addition, this force is also added to the total Preload.
•In another example, if the two end points of the defined spring (modeled length of spring) is 100 mm and the free-length is 0.0, that means in the current state the spring is in an extended state by 100mm and the preload to that effect (-100*K) is applied.
3.MotionView creates a coil spring damper with a default value free-length as the distance between two end points.