112
Chapter 2
i
0
/
~~
349.6
ksi
/
~~
/368
ksi
o~
,
,
?~>~/!
0
1 O0
200
300
~rn ksi
Figure 2.40 ~r - ¢~ curve £or E~J]oy metal pulley belt.
~ ~2"]1/2
~ Ec [~c~ + z~ + zrj
2 2
0.0015
c -- -- E = 30 × 106 r = unknown Example 2.14
2
~c +0.0001/3
0.0222
]E
~r
c
0.0015
-~- -t-0.03 ---r
4-0.5% 0.005?
~c = 0.0222c ~e = +0.03E ~r = 4-0.005?
~s -- ~/~ Ec [(0.03)2 + (0.0222) 3 + (0.005)2]~/2
2 r
(2.124)
~s 4-0.0377
(2.125)
s
Using the coupling equation Eq. (2.42) along the slanted line.
S - s
96,000 - s
(2.126)
t= [~] -[(15,000 psi) 2 + (0.0377s)2]
1/ 2
t2 =
(96,000 - s)
2
(15,000) 2 + 1,4213 x lO-3s
2
(96,000) 2 - 2(96,000)s + 2 =(15,00002 + 1.4213 x lO-3(ts)
2
[1 - 1.42131 x 10-3t2]s 2 - 2(96,000)s + [(96,000) 2 - (15,000t) 2] = 0
-B 4- [B 2 - 4AC]
1/ 2
S~
2A