﻿ Dialog: Function-Block: Spring-Force

# Dialog: Function-Block: Spring-Force

## Spring FB dialog-box

Use a Spring FB to apply a force between two Points, that are the Spring's Anchor-Points

Configure Power Source

#### Spring-Force dialog-box Spring Parameters ☑ Enable Spring Force check-box. Click to enable the Spring FB.

Spring-Rate:

Spring-Force / linear unit difference [SI: N/mm] that the Anchor-Points deviate from the Free-Length. [see Force Units and Linear Units].

Free-Length:

The 'natural-length' of the Spring, as it would be if it were not joined to the Anchor-Points.

If the distance between Anchor-Points > Free-Length, then the Force-Vector [due to the Spring-Rate only] will Pull Anchor-Points together [o>>>|<<<o]

If the distance between Anchor-Points < Free-Length, then the Force-Vector [due to the Spring-Rate only] will Push Anchor-Points apart [o<<<|>>>o]

If the distance between Anchor-Points = Free-Length, then the Force-Vector [due to the Spring-Rate only] = 0

Constant-Force:

A positive force will PULL Anchor-Points together [o>>> + <<<o]

A negative force will PUSH Anchor-Points apart [o<<< — >>>o]

Velocity Parameters Coulomb Friction Force: [Ff = μ.Fn ] A Constant Force that is opposite to the direction of the motion. This parameter is intended to be similar to a Friction Force. However, it is NOT exactly Friction Force, because this force is not a function of the 'Normal Force'. Note: Friction Force is not a Kinetostatic Force. Viscous Coefficient: [Fv α V [ N/(mm/s) ] A Force that is proportional to the relative velocity between the Points. The Force is opposite to the direction of motion. E.g.: If the Damping Coefficient = 4 and the Velocity is +100mm/s, [anchor points moving away from each other’], then force pulling the points together is a force of 400N. Drag Factor: [Fd α V2] [ N/((mm/s)2 ) ] A Force that is proportional to square of the relative velocity between the Points. For example, air resistance. The Force is opposite to the direction of motion. E.g. If the Drag Factor = 4, and the Velocity = +100mm/s [anchor-points moving away from each other’], then force pulling the points together is a force of 40000N.

#### Input-Connector and Output-Connectors

Note: It is not necessary to connect wires to the input-connector or a wire from its output-connectors.

Input-Connector

Use the input-connector to apply a bespoke force-function between the Spring's Anchor-Points. The force-function might be designed as a 'Motion'. The data at the output of a Motion FB has units of mm or degrees. The data at the input-connector of the Spring FB must have units of Force units [N].

Use a Maths FB to convert any data-type to units of Force.

TOP output-connector

Reports the Dimension, Velocity and Acceleration relating to the distance between the Spring's anchor-points.

Bottom output-connector

Reports Total Applied-Force between the Spring's anchor-points.

 o Total Applied-Force = Force at the Input-connector + Force that results from the parameters as set in the Spring FB dialog-box - parameters are defined below.

or

 o Driving-Force = Linear Motive Force, if you configure the Spring FB as a Linear Motor -

Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd