A very good presentation in production engineering

1. CENTRE OF PRESSURE
, IT’S DETERMINATION
, AND IMPORTANCE

2. WHAT IS CENTRE OF PRESSURE ?
Center of pressure is the term given to the origin of force vector which represents
the sum of all forces acting between a force applicator and supporting surface.The
center of pressure corresponds to the single intersection point of a family of lines
about which the moments of distributed forces of either side of a line in
equilibrium.

3. DETERMINATION OF CENTER OF PRESSURE
In case of a irregular shaped punch the summation of
irregular shearing forces on one side of the ram may
generally exceed the forces on the other side .This
results in a bending moment in the press ram and
undesirable effect and misalignment. It is therefore
necessary in case of irregular shaped punches to find
out the exact center of pressure, and lay out the
punch position on the punch holder in such a way that
the center of pressure and center of ram hole or the
center line of the shank are in the same straight line.

4. PROCEDURE OF CALCULATING COP
1) Draw an outline of the actual cutting edge as
shown in the figure
1) Divide the areas XX and YY at right angles
in a convenient position. If the figure is
symmetrical about the line, let this be one of
the axes. The center of pressure in this case
be same as the axis.

5. PROCEDURE OF CALCULATING COP(Contd.)
3) Divide the cutting edge into line elements,straight line areas numbering them
1,2,3 etc.
4)Find the lengths of these elements, say 111,12,13 ,etc.
5)Find the CG of the lengths 1-1, 1-2,1-3 etc. In the case of a semicircular
arc,the CG is given by 2r/π from the center of the circle.
6)Find X1, X2 etc and Y1, Y2,etc , ie the distance of the CG from each line
elements XX axes respectively.

6. PROCEDURE OF CALCULATING COP (Contd.)
7) Calculate the distance X of the center of
pressure from the YY axes by the formula.
X=(11X1+12X2+13X3+...)/(L1+L2+L3+...).
8) Similarly find.
Y=(L1Y1+L2Y2+L3Y3+....)/(L1+L2+L3+..)
Thus the exact position of the centre of
pressure is determined.

7. IMPORTANCE OF CENTER OF PRESSURE
It is important for the engineers to know about center of pressure, since it allows
them to easily balance the lift on objects like aircrafts etc., Because center of
pressure is the average location where the average weight of an object, is except
this time is the location of the average pressure.
The center of pressure is where the forces of lift and drag are exerted, therefore it
is important to calculate the center of pressure of a object.

8. THANK YOU!