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Posted by: bobthedog

01/22/2007, 08:32:51

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Please can someone try and answer these thanks. Taper pins may be obtained from 0.8 mm to 22.5 mm in diameter the taper in all sizes being 6.35 mm per 30.5 cm or 1 in 48 on the diameter. What does this mean exactly then?

What is shear as in in shear stress is it the cutting away of an rod shaft or what?

Tensile stress is this like pulling stress then?

Calculate the thickness t and width b of a cotter used in conjunction with a rod of diameter d

Let ft tensile stress
fs shear stress
fc crushing stress

Assume failure to occur due to

a tearing at the section through the cotter

Load P = pidpower2/4 - dtxft

b shearing of the cotter double shear

Load p = 2xbxtxfs

c Crushing of the cotter

Load P = dxtxfc

If the material is mild steel shear stress may be taken as 4/5 tensile stress and crushing stress as twice tensile stress

So shear stress may be taken as four fifths of tensile stress is that right?

fs = 4/5xft and fc = 2xft

for equal strength equate b and c

2xbxtxfs = dxtxfc
2xbxtx4/5xft = dxtx2ft
b = 10/8xd = 1.25d

from which equating a and c pixdpower2/4-dxtxft=dxtxfc

from which t = pixd/12 = 0.26d.

However is it just us or does 3.1416x1.25/12 not equal = 0.33 how did the course text get 0.26 then?

It has fs=4/5xft that is 4/5 x ft but what is 4/5 how is this worked out on a calculator? As in 4

also what is 10 how is this worked out on a calculator



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