課程名稱︰材料力學
課程性質︰系定必修
課程教師︰周元昉
開課學院：工學院
開課系所︰機械系
考試日期（年月日）︰2009六月二十二
考試時限（分鐘）：180MIN
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
PART 1
Choose the correct answer for each problem and give explanations or
calculations.Each problem has a score of 8%.No score will be granted
without explanationa or calculations.
1.Five thin-walles tubes of same material and smae wall thickness encircle
the same amount of area.If they are subjected to the same twisting moment,
which one has smallest angle of twist per unit length?
(A) ___ (B) ___ (C) __ (D) (E)
/ \ / \ | | /\
| | \___/ |__| /__\ 圓形
\___/
(正八角形) (正六角形) (正方形) (正三角形)
2.A positive twisting moment Mt of a circular shaft is defined as shownin
fig.2.The distributed external torque t(x) is positive when points in the
positive x direction.If a shaft is fixed at its right end and the twisting
moment is
Mt(x)=toL[cos(2(pi)x/L)-1]+T<x-a>^0,to=const
then the corresponding reaction at right end x=L is
(A)-2toL+T (B)2toL-T (C)2toL-T (D)-T (E) T
___________ ______________
/ | | \
\ | ---->-> +Mt <-<----| /
/ | | \
\___________| |______________/
3.If postive shearing force V,bending moment M,and distributed load q
of a slender member are defined as shown in Fig.3,which relation is correct?
___________ ______________
/ | ^ +M ^ | \
\ | ) ( | /
/ | | \
\___________| |______________/
___________ ______________
/ | | +V ^ | \
\ | | | | /
/ | | | | \
\___________| V | |______________/
--------------------------
| | | | | | | | | +q
| | | | | | | | |
_v_v__v__v__v__v__v__v__v__
/ \ ^ y
\ / |
/ \ |
\_________________________/ |__________>x
(A) b (B) (C) (D) (E)
∫ qdx=V(b)-V(a) d^2M dV b dM
a ------=q ----=q ∫ Vdx=M(b)-M(a) -----=-V
dx^2 dx a dx
4."Planes remain planes after bending"is assumption in deriving the flexural
theory of beams.If E is Young's modulus,Iis the second moment of area,M is the
bending moment ,q is the distributed load,v is the lateral deflection ,σis
the normal stress,εis the normal strain,ρis the distance measured from the
neutral axis,which item has nothing to do with the assumption?
(A)The neutral axis passes through the centroid..(B) M d^2ν (C) -y
----=---- ε=----
EI d^2x ρ
(D) d^2M (E) My
-----=q σ=- ---
dx^2 I
5. If a load pointing to the positive y direction is considered as positive,
then the load of the beam shown in Gig.5 can be expressed as
/\
/ ^\ |P
-- /^ | \ |
| / | | ^\| M(逆時針MOMENT)
Wo| /^ | | | | |
| |/_|_|_|_|_V\V________________________________
| |-->X \ | | |
-- \V | |
|----a--|--a--| \ | |
|-----b------| \V |
|---c----------| \ |
| \V
(A) wo wo
q(x)=---x－ ---<x-a>^1－wo<x-a>^0－P<x-b>^-1－M<x-c>^-2
a a
(B) wo 2wo
q(x)=---x－ ---<x-a>^1－P<x-b>^-1－M<x-c>^-2
a a
(C) wo wo
q(x)=---x－ ---<x-a>^1－wo<x-a>^0＋P<x-b>^-1＋M<x-c>^-2
a a
(D) wo wo
q(x)=---x－ ---<x-a>^1－wo<x-a>^0＋P<x-b>^-1－M<x-c>^-2
a a
(E)
wo 2wo
q(x)=---x－ ---<x-a>^1－P<x-b>^-1+M<x-c>^-2
a a
6.Beams with different supports are loaded at their center with a concentrated
force P.Which one has a nonzero curvature at the right end?
(A)
|\ P
|/| |
| |
|_______________v___________________
△ △
|-------L/2-----|
|----------------L-------------------|
(B)
P
|
|
_______________v___________________
△ △
|-------L/2-----|
|----------------L-------------------|
(C)
P
|
| | |
| |______________v_________________
| | △
|￣------L/2-----|
|----------------L-------------------|
(D)
P
|
| | | | |
| |______________v________________| |
| | | |
|￣------L/2-----| ￣
|----------------L-------------------|
(E)
P
|
| | |
| |______________v_________________
| |
| |
| ------L/2-----|
|----------------L-------------------|
先PO選擇題好了 我快累死了.....
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※ 編輯: jamesemaj 來自: 140.112.245.221 (07/02 20:03)