VM195

VM195
Toggle Mechanism

Overview

Reference:G. H. Martin, Kinematics and Dynamics of Machines, 2nd Edition, McGraw-Hill Book Co., Inc., New York, NY, 1982, pp. 55-56, fig. 3-22.
Analysis Type(s):Static Analysis (ANTYPE = 0)
Element Type(s):
Multipoint constraint Revolute Joint Elements (MPC184)
3D 2 Node Beam (BEAM188)
Spring-Damper Elements (COMBIN14)
Linear Actuator Elements (LINK11)
Input Listing:vm195.dat

Test Case

Determine the maximum force (Fmax) of a toggle mechanism acting upon a resisting spring.

Figure 299: Toggle Mechanism Problem Sketch

Toggle Mechanism Problem Sketch

Material PropertiesGeometric PropertiesLoading
E = 1 x 109 N/m2
t = 0.1 m
Ks = 166.67 N/m
Ka = 100/d N/m
α = 36.87°
Fa = 100 N

Analysis Assumptions and Modeling Notes

This beam is modeled with a square cross-section (width/height is set to 0.1m).

A linear actuator is used to apply a force, Fa, and move the toggle mechanism. The actuator force is increased by 2% to ensure complete mechanism motion. The actuator must expand a distance, d = 2.4928 m, to move the mechanism to the maximum force position. Either a force or a displacement could have been applied with the actuator.

The maximum force exerted by the mechanism upon the spring occurs when the lower links are colinear and parallel to the input lever. The revolute joint connecting the two lower links locks up when a stop engages, after a rotation of 2 α degrees, to simulate the self-locking behavior of the mechanism.

Results Comparison

TargetMechanical APDLRatio
Fmax-133.33-133.32[1]1.000
UY, Node 4-2.40-2.401.001
UX, Node 90.800.801.000

  1. Spring force in element 10 (COMBIN14)