MBD Simulation on a Piston Assembly
AIM : Motion Study of Piston assembly.
Objective : To creat parts of the assembly.
To make the piston assembly.
To do motion study of the piston assembly.
To make plots of linear displacement of the piston head.
To export results to excel sheet.
To superimpose all the plots.
Modelling of parts
The details about the geometry of all the parts of the piston assembly is show in the video.
There are total of 5 parts in this piston assembly , these are
1. Piston
2. Connecting rod
3. End cap of connecting rod
4. Crank
5. Wrist pin
After all the parts are made make the piston assembly by inserting these parts in the assembly design.
provide all the necessary mates so that the parts movement is in the required direction only .
Motion Study Of Piston Assembly
We are required to do the motion study of pistion assembly in three different cases or condition .
The conditon stated are as follows
Wrist Pin Offset - The position of the wrist pin is going to be varied as followed. But the center of the axis of the piston head and the crank are coincident to each other (i.e) They are on the same plane in all the three cases.
"0" mm Offset - Run a simulation as seen in the video.
10 mm Positive Offset - If the crank rotation is in the Clockwise direction.
10 mm Negative Offset - If the crank rotation is in the Clockwise direction.
| Sl.No |
Wrist Pin Offset ` |
Crank Speed (Rpm) |
| 1 | "0" mm | 2000 |
| 2 | 10 mm Positive | 2000 |
| 3 | 10 mm Negative | 2000 |
Results And Plots
The plots of linear displacement of piston head in all the three cases are shown below.
PLOT 1
The linear displacement of the piston head when wrist pin offset is set to "0"mm.
The conditons / data given to calculate the plots are
Crank speed = 2000 rpm
Frames per sec = 7200
Use precise contect
Direction of rotation is clockwise.
PLOT 2
The linear displacement of the piston head when wrist pin offset is set to "10"mm positive .
the conditons / data given to calculate the plots are
Crank speed = 2000 rpm
Frames per sec = 7200
Use precise contect
Direction of rotation is clockwise.
PLOT 3
The linear displacement of the piston head when wrist pin offset is set to "10"mm negative.
The conditions are kept same here which are
Crank speed = 2000 rpm
Frames per sec = 7200
Use precise contect
Direction of rotation is clockwise.
SUPERIMPOSITION OF ALL THE PLOTS
In the plot above
Blue curve represent the 0mm offset condition.
Orange curve represent the positive 10 mm offset condition.
Grey curve represent the negative 10 mm offset condition.
It can be concluded from the above graph that when a positive offset of 10mm is give the time taken by the piston to reach TDC and BDC states is increases as compared to other two cases.
When a negative offest of 10 mm is provided to the wrist pin the time taken to reach the TDC and BDC increases as compared with 0mm offset condition but drecreases as compared with the positive offset.
Here is drive link .
This link consist of a folder which contains the parts of the assembly and the results that are exported to the spread sheet.
https://drive.google.com/drive/folders/1U9jmxju7Ak_lEkbgtX03PQRmaxl2GKYy?usp=sharing