VM-WB-MECH-052

VM-WB-MECH-052
Velocity of Pistons for Trunnion Mechanism

Overview

Reference:Any Basic Kinematics book
Solver(s):

Ansys Mechanical

Analysis Type(s):Rigid Dynamic Analysis
Element Type(s):Multipoint Constraint Element

Test Case

The Trunnion mechanism has the following data (all distances are center-to-center distances):

  • Crank radius OA = 100 mm and is oriented at 30 deg to Global Y Axis

  • AB = 400 mm

  • AC = 150 mm

  • CE = 350 mm

  • EF = 300 mm

  • Constant Angular Velocity at Crank = 12.57 rad/s

  • Center of Trunnion is at distance of 200 mm from line of stroke of Piston B horizontally and 300 mm vertical from Center of Crank

  • Find the Velocity of Piston (F) at the 180 deg from Initial Position

  • Find the Velocity of Piston (B) at the 180 deg from Initial Position

Figure 67: Schematic

Schematic

Material PropertiesGeometric PropertiesLoading
E = 2e11 Pa
ν = 0.3
AB = 400 mm
AC = 150 mm
CE = 350 mm
EF = 300 mm
Constant angular velocity at crank = 12.57 rad/s

Analysis

Analysis done using graphical solution.

Consider the Space Diagram, Velocity Diagram at the 180° from Initial Position.

Figure 68: Schematic

Schematic

Results Comparison

ResultsTargetMechanicalError (%)
Velocity of Piston (F) mm/s501.8497.04-0.949
Velocity of Piston (B) mm/s955959.720.494