crank offset piston simulation.

                                Geneva wheel assignment

Introduction:this assignment is about studying the mechanism of a Geneva      wheel mechanism and making a 3D model of it .the task is make a model on the given dimensions and perform a motion analysis study in mbd solid works ,making plots were to understand how the mechanism works and what are their properties so that without the any mechanical laboratory  testing ,this can be help for all engineering application so that they don’t need to waste money on testing .

Procedure

started with modelling the 3D model of the of internal Geneva wheel .modelled the driven and driver part separately using the sketch option and then extruded  the part ,saved those part separately ,a new assembly is created and the driven and driver wheels are included and constrained in such a way that they move properly according to our needs so constrains are made using the mate option

after mates satisfy our need a new motion study is created and under the drop down list box motion analysis is chosen then to the axis of the driven wheel motor torque is given as input ,then mechanical contact between then are declared in that same option materials are also chosen as swell ,after doing all this calculates button is pushed then the compiler creates the animation of the study

plots:

angular displacement vs time

where the displacement increases for every -180 degrees to+180 degrees then suddenly drops down to 180 degree

contact forces vs time

we see small peaks in the plot which shows the contact the driver wheel makes  with a face of the driven wheel

precise contact

this check box increase the accuracy of contact forces,but at the cost of longer time interval compared to normal

results for 10rpm

60fps

 contact forces time interval

 for normal 8sec-527 intervals

for precise contact 8sec-490intervals

with precise contact(angular displacement of driven wheel)

Without precise contact (angular displacement of driven wheel)

With precise contact(contact forces)

without precise contact

results for 20 rpm

120fps

Contact force time interval

For normal 8sec-998 intervals

For precise contact 8sec-972 intervals

We also see that with increase of frames per second the time interval is also getting doubled nearly

Without precise contact

   With precise contact

we see here that contact forces are getting little varied compared to normal results

some of the spread sheet plots -20rpm