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Exam 2 Equation Sheet - Classes

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! = Mc<br />

I<br />

! = Tr<br />

J<br />

$<br />

" ! = " 1<br />

#"<br />

&<br />

2<br />

%<br />

! = P A<br />

( ) 2 + (" 1<br />

#" 3 ) 2 + (" 2<br />

#" 3 ) 2<br />

2<br />

direct shear: ! = P A<br />

rectangular section: A = bh , I = bh3<br />

12 , ! = 3V<br />

2A<br />

round section: A = !d 2<br />

1<br />

'<br />

2<br />

) "!<br />

= " 2 2<br />

x<br />

+ 3# xy<br />

(<br />

( ) 1 2<br />

4 , I = !d4<br />

64 , J = !d 4<br />

32 , ! = 32M<br />

"d 3 , ! = 16T<br />

"d 3 , ! = 4V<br />

3A<br />

Mohr’s circle: center : c = ! x + ! y<br />

2<br />

R =<br />

#<br />

%<br />

$<br />

! x<br />

"! y<br />

2<br />

&<br />

(<br />

'<br />

2<br />

2<br />

+ ) xy<br />

S e<br />

= k a<br />

k b<br />

k c<br />

k d<br />

k e<br />

k f<br />

S e<br />

! S e<br />

! = 0.504S u<br />

for steels<br />

stress concentration: K f<br />

= 1 + q( K t<br />

!1)<br />

normal stresses: n = S e<br />

! a<br />

normal stresses: Goodman: 1 n = ! a<br />

S e<br />

+ ! m<br />

S u<br />

finite life: S= aN b or N =<br />

S 1<br />

! $ bwhere (0.9S<br />

# & a = u<br />

) 2<br />

and b = ! 1 " a%<br />

S e<br />

3 log " 0.9S %<br />

u<br />

$ '<br />

# S e &<br />

shear stresses: Goodman: 1 n = ! a<br />

+ ! m<br />

, S su = 0.67S u S sy = 0.577S y , S se = S e with k c =.59<br />

S se<br />

S su<br />

surface finish factor: k a<br />

= aS ut<br />

b<br />

Surface<br />

Factor a<br />

Exponent<br />

Finish<br />

S ut , kpsi S ut , MPa b<br />

Ground 1.34 1.58 -0.085<br />

Machined or cold drawn 2.70 4.51 -0.265<br />

Hot-rolled 14.4 57.7 -0.718<br />

As-forged 39.9 272 -0.995<br />

size factor: Rotating shaft, bending and torsion: k b<br />

=<br />

( d 0.3) 0.11 " d " 2in<br />

0.91d !0.157 2 < d "10in<br />

( d 7.62) 2.8 " d " 51mm<br />

1.51d !0.157 51 < d " 254mm<br />

axial: k b =1<br />

For a rectangular cross section: d e = 0.808 (h b) 1/2<br />

1.0 bending<br />

load factor: k c<br />

= 0.85 axial<br />

0.59 torsion


GEARS:<br />

HP = T ! rpm<br />

5252<br />

(T: ft-lbs) V =<br />

!dn<br />

12<br />

HP =<br />

W t V<br />

33000<br />

W t<br />

=<br />

T<br />

d 2<br />

d = N P<br />

d = mN<br />

(P=pitch)<br />

! 1<br />

! 2<br />

= N 2<br />

N 1<br />

T 1<br />

T 2<br />

= N 1<br />

N 2<br />

T 1<br />

! 1<br />

= T 2<br />

! 2<br />

W r<br />

= W t<br />

tan!<br />

! = K v<br />

W t<br />

P<br />

FY<br />

K v<br />

= 1200 + V<br />

1200<br />

W a<br />

= W t<br />

tan!<br />

(V: ft/min)<br />

Table 14-2<br />

Values of Lewis Form Factor Y<br />

Number of Y Number of Y<br />

Teeth<br />

Teeth<br />

12 0.245 28 0.353<br />

13 0.261 30 0.359<br />

14 0.277 34 0.371<br />

15 0.290 38 0.384<br />

16 0.296 43 0.397<br />

17 0.303 50 0.409<br />

18 0.309 60 0.422<br />

19 0.314 75 0.435<br />

20 0.322 100 0.447<br />

21 0.328 150 0.460<br />

22 0.331 300 0.472<br />

24 0.337 400 0.480<br />

26 0.346 rack 0.485<br />

SPRINGS:<br />

D = OD ! d k = F ! = d 4 G<br />

8D 3 N a<br />

C = D K B<br />

= 4C + 2<br />

d<br />

4C ! 3<br />

n = S sy<br />

!<br />

1<br />

n =<br />

! a<br />

S se<br />

+ ! m<br />

S su<br />

! = K B<br />

8FD<br />

"d 3<br />

8F<br />

! a<br />

= K a<br />

D<br />

B<br />

"d ! = K 8F m<br />

D<br />

3 m B<br />

!<br />

"d 3 a<br />

= ! " ! max min<br />

2<br />

! m<br />

= ! max + ! min<br />

2

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