This preview has intentionally blurred sections. Sign up to view the full version.
View Full DocumentThis preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: 1. The bars of the truss are made of steel. Each bar has a crosssectional area of 1.25 inz. If the
ultimate strength of the steel is 40 ksi, determine the maximum magnitude P of the loads that can
be applied to the truss for a factor of safety of 2.0. Z%=©
be :IJSP
.. ZMDZO
} b‘d’ ’ .
P(8)+OJSP(¢+) =C><(3)
C74: LLP
3
£Fx=o
D)“. r. Lil? £0de umber has 4W: WSW load? 2 At room temperature (70°F) a 0.02in. gap exists between the ends of the rods shown. At a
later time when the temperature has reached 320°F, determine (a) the normal stress in the aluminum rod, and ”1,2 I”
(b) the change in length of the aluminum rod. —lﬂin  1‘
l
r‘ lUIn.~———>
”(W
., 3,
f
l t
‘ W A h t H , é QUmMcﬂMWWmumsmMiSHmﬂ
bum/limp .\lumimnn Sminlu'Ss shrl ' ' ,\ 2.5 I3 \= 1.2m“
g :1 Q , :: O< OJ QT L d 1: milar “WIN 1: w ‘28.“ ~< Hm“;
t ‘ ,_ _ (1': m: >: In "ﬂ? (r = 9.6 x In“ﬁw
= 6.3 no (Lsextz) /°F 30quq3n : qbvc low" (Belle) 2 clout m uﬁmn4he'ﬁwnmdsﬁmmkiJlxtuu&QEC(Uiéwwlﬂ
W oppoSﬂC, ﬂare». P 'Wﬁjﬁd Sad —_ P}: : M, = ”‘1’“0‘4’)
P {4.6; (9'3’UOHval05) (Pli’l Kip)
Seep: Poe) ’ = aggxquP
1‘2—(2’8'7‘i03) (Sdti'SS'tk) — (Scalp l’géSi‘P) :O‘Olin Sextet—“ow, P2 (0‘83ldtp p i
(NSlrcssm WW 0151 ‘— 41.5?
(bl Sci=O~03994\IZ>¢\6%((0L53): 0.0%“? I?) l 22,4 ks} (twp) ) J rm, Wm. stainless DLCCI smart IS 3 m long. When it is rotating at 60 rad/s, it transmits 30 kW of power from the engine E to the generator G. Determine the smallest diameter of the shaft if
the allowable shear stress IS Tallow = 150 MPa and the shaft is restricted not to twist more than 0.08 rad. (Assume G=75 GPa)
, _ P (My  “0.: = I50
ﬁdg
d; W 2 9.51mm
77 (I60)
Wok mug/mist 954008
_ TI Ll
¢= 1*: 3— 31d (J 3‘51 500x103 x3000 .3 39.9 mm i
Tl" (O\QS)')Q(15X‘03) W dJHOMM ~r. ne—stresseo concrete beams are sometimes manufactured in the following manner. High
strength steel wires are stretched by a jacking mechanism that applies a force Q as shown in part
(a) of the ﬁgure. Concrete is then poured around the wires to form a beam, as shown in part (b).
After the concrete sets properly, the jacks are released and the force Q is removed (part (c)),
leaving the beam in the prestressed condition with the wires in tension and the concrete in
compression. time] x» him If the prestressing force Q produces an initial
stress 00 = 620 MPa in the steel, the modulus of
elasticity for steel is 12 times as large as the
modulus of elasticity for concrete (E, = 12 EC), “‘3
and the crosssectional area of the steel wires is .
1/50 the crosssectional area of the concrete (A, = _ it ~ .: .
l/SO AC), ﬁnd the ﬁnal stresses 0's and 0C in the L V
two materials. ...
View
Full Document
 Spring '08

Click to edit the document details