ProblemSet3MDpart2
問題一覧
1
In a specification schedule is used when the pipe specified as "schedule 80", the pipe corresponds to the
allowable stress
2
The modulus of elasticity for ordinary steel usually falls between _____ million pounds per square inch.
28 to 31
3
The modulus of elasticity is a measure of
stiffness
4
The modulus of elasticity for most metals in compression is usually taken as that in
tension
5
The ratio of moment and stress is called
section modulus
6
For a symmetrical cross-section beam the flexural stress is ____when the vertical shear is maximum.
zero
7
When tested in compression, ductile materials usually exhibit characteristics up to the yield strength as they do when tested in tension.
approximately the same
8
It has been said that 80% of the failures of machine parts have been
fatigue failures
9
Cazand quotes values for steel showing Sn/Su ratios, often called endurance ratio, from
0.23 to 0.65
10
The discontinuity or change of section, such as scratches, holes, bends, or grooves is a
stress raiser
11
The degree of stress concentration is usually indicated by a
stress concentration factor
12
In a part at uniform temperature and not acted upon by an external load, any internal stresses that exist.
Residual stress
13
The stress or load induced by the tightening operation.
Initial stress
14
A type of failure due to instability is known as
buckling
15
The ratio of the length of the column and the radius of gyration of the cross-sectional area about a centroidal axis.
Slenderness ratio
16
Formula that applies to a very slender column is called:
Euler's formula
17
If two principal stress is zero, the state stress is
uniaxial
18
If one principal stress is zero, the state stress is
biaxial
19
If all the principal stresses have finite values, the system is
triaxial
20
Under theories of failure for static loading of ductile material, the design stress is the
yield stress/factor of safety
21
Under theories of failure, the value of shear stress that of tensile stress.
half
22
The theory of mechanics of materials shows that the results from the octahedral shear stress theory and those from the maximum distortion energy theory are.
the same
23
A kind of stress that is caused by forces acting along or parallel to the area.
Shearing stress
24
Obtained by dividing the differential load dF by the dA over which it acts.
Stress
25
The highest ordinate in the stress strain diagram or curve is called
ultimate strength
26
A pair of forces equal in magnitude opposite in direction, and not in the same line.
Couple
27
Framework composed of members joined at their ends to form a rigid structure is known as
truss
28
The ratio of the tensile stress to the tensile strain is called
Young modulus
29
The ratio of the volume stress to the volume strain is called the coefficient of volume elasticity or
bulk modulus
30
The action of a force is characterized by
its magnitude
31
At highest or lowest point on the moment diagram
shear is zero
32
The built-in or fixed support is capable of supporting
an axial load
33
The modulus of elasticity in shear is commonly called
modulus of rigidity
34
The stress beyond which the material will not return to its original shape when unloaded, but will retain a permanent deformation.
Elastic limit
35
Refers to the actual stress the material has when under load is known as
working stress
36
The safe soil bearing pressure of diesel engine is about
4890 kg per sq. cm
37
The machine foundation must have a factor of safety of
5
38
The load acts over smaller area, and the ______ continues to increase unit failure.
actual stress
39
In the stress-strain diagram where there is a large increase in strain with little or no increase in stress.
Yield strength
40
A member that carries loads transverse to its axis.
Beam
41
Which type of load that is applied slowly and is never removed?
Static load
42
When varying loads are applied that are not regular in their amplitude, the loading is called
Random loading
43
A measure of the relative safety of a load-carrying component is termed as
design factor
44
The condition, which causes actual stresses in machine members to be higher than nominal values predicted by the elementary direct and combined stress equations.
Stress concentration
45
The stress value, which is used, in the mathematical determination of the required size of the machine member.
Design stress
46
Typical values for Poisson's ratio of cast iron is in the range of
0.25 to 0.27
47
Typical values for Poisson's ratio of steel is in the range of
0.27 to 0.30
48
Typical values for Poisson's ratio of aluminum and titanium is in the range of
0.30 to 0.33
49
The angle of inclination of the planes on which the principal stresses act is called
principal plane
50
It provides a very accurate prediction of failure of ductile materials under static loads or completely reversed normal, shear or combined stresses.
Distortion energy theory
51
Torsional deflection is a significant consideration in the design of shaft and the limit should be in the range of ____ degrees/foot of length.
0.08 to 1
52
For a universal joint shaft angle should be _____ degrees maximum and much less if in high rotational speed.
15
53
It is a good design practice for steel line shafting to consider a limit to the linear deflection ____ of inch/foot length maximum.
0.010
54
It is a rotating machine member that transmits power.
Shaft
55
A stationary member carrying pulleys, wheels and etc. that transmit power.
Axle
56
A line shaft is also known as
main shaft
57
Which of the following shaft intermediate between a line shaft and a driven shaft?
All of the above
58
Short shafts on machines are called
spindles
59
For shafts, the shear due to bending is a maximum at the neutral plane where the normal stress is
zero
60
Criteria for the limiting torsional deflection vary from 0.08 per foot of length for machinery shafts to ____per foot
1°
61
For transmission shafts the allowable deflection is one degree in a length of ________diameters.
20
62
An old rule of thumb for transmission shafting is that the deflection should not exceed _____ of length between supports.
0.01 in. per foot
63
In general for machinery shafts, the permissible deflection may be closer to
0.002 in/ft
64
The speed at which the center of mass will equal the deflecting forces on the shaft with its attached bodies will then vibrate violently, since the centrifugal force changes its direction as the shaft turns.
Critical speed
65
For shaft, the minimum value of numerical combined shock and fatigue factor to be applied in every case to the computed bending moment is
1.5
66
It is suggested that the design factor on the yield strength be about 1.5 for the smooth load, about 2 to 2.25 for minor shock loads, and _____ when the loading reverses during operation.
4.5
67
A column is called short column when
the length is less than 8 times the diameter
68
For a circular shaft subjected to torque the value of shear stress
is zero at the axis and linearly increases to a maximum value at the surface of the shaft
69
The compression members tend to buckle in the direction of
least radius of gyration
70
A reinforced concrete beam is considered to be made up of
heterogeneous material
71
The column splice is used for increasing
length of the column
72
A simply supported beam has a uniformly distributed load on it, the bending moment is
parabola
73
The power obtained by piston reaches flywheel through the
crank shaft
74
There are two types of crankshafts
single piece and built up
75
Engine valves get open by means of
cam shaft
76
The ____ value of allowable stresses are generally used in practice for main transmitting shafts.
282 kg/cm²
77
The value of allowable stresses are generally, used in practice for line shafts carrying pulleys.
423 kg/cm²
78
The ____ value of allowable stresses are generally used in practice for small, short shafts, countershafts.
599 kg/cm²
79
Torsional deformation in transmission shafts should be limited to____ in 20 diameters.
1°
80
Lateral deflection caused by bending should not exceed
0.01 in. per foot of length
81
Front axle should be live and
dead
82
The steering is coupled to the two front wheels by means of a
tie rod
83
In the overdrive transmission system the rotation speed____ rest higher than that of engine's speed.
propeller shaft
84
A slip joint the length of propeller shaft.
keeps appropriate
85
The transmission system incorporates clutch, gear box, and propeller shaft and
differential
86
The lay shaft moves _____ the primary shaft.
in the gear ratio
87
The main shaft is lifted ____the lay shaft.
parallel to
88
In the top gear, the rotational speeds of _____ remain the same.
primary and main shafts
89
The primary and lay shafts rotate in ____ direction
reverse
90
It is an integral part of the machine
Machine shaft
91
Stresses in shafts are analyzed through
all of these
92
Standard stock length is
all of the above
93
Centrifugal separators that operate at ____ speeds also employ these flexible shafts.
20,000 to 50,000 rpm
94
Which of the following material is used for shafting?
AISI 3240
95
The process of redistributing the mass attached to a rotating body in order to reduce arising from a centrifugal force
Shaft balancing
96
In many cases the ___ of the shaft is an import design feature.
rigidity
97
Commercial shafting is made of
low carbon steel
98
The most common material for shafting is
A.
B.
C.
mild steel
99
Gold drawing produces a ____ shaft ----- but with higher residual stresses
stronger
100
Allowable stresses in shear equal to _____ with common in design of a shaft
5000 to 8000 psi
問題一覧
1
In a specification schedule is used when the pipe specified as "schedule 80", the pipe corresponds to the
allowable stress
2
The modulus of elasticity for ordinary steel usually falls between _____ million pounds per square inch.
28 to 31
3
The modulus of elasticity is a measure of
stiffness
4
The modulus of elasticity for most metals in compression is usually taken as that in
tension
5
The ratio of moment and stress is called
section modulus
6
For a symmetrical cross-section beam the flexural stress is ____when the vertical shear is maximum.
zero
7
When tested in compression, ductile materials usually exhibit characteristics up to the yield strength as they do when tested in tension.
approximately the same
8
It has been said that 80% of the failures of machine parts have been
fatigue failures
9
Cazand quotes values for steel showing Sn/Su ratios, often called endurance ratio, from
0.23 to 0.65
10
The discontinuity or change of section, such as scratches, holes, bends, or grooves is a
stress raiser
11
The degree of stress concentration is usually indicated by a
stress concentration factor
12
In a part at uniform temperature and not acted upon by an external load, any internal stresses that exist.
Residual stress
13
The stress or load induced by the tightening operation.
Initial stress
14
A type of failure due to instability is known as
buckling
15
The ratio of the length of the column and the radius of gyration of the cross-sectional area about a centroidal axis.
Slenderness ratio
16
Formula that applies to a very slender column is called:
Euler's formula
17
If two principal stress is zero, the state stress is
uniaxial
18
If one principal stress is zero, the state stress is
biaxial
19
If all the principal stresses have finite values, the system is
triaxial
20
Under theories of failure for static loading of ductile material, the design stress is the
yield stress/factor of safety
21
Under theories of failure, the value of shear stress that of tensile stress.
half
22
The theory of mechanics of materials shows that the results from the octahedral shear stress theory and those from the maximum distortion energy theory are.
the same
23
A kind of stress that is caused by forces acting along or parallel to the area.
Shearing stress
24
Obtained by dividing the differential load dF by the dA over which it acts.
Stress
25
The highest ordinate in the stress strain diagram or curve is called
ultimate strength
26
A pair of forces equal in magnitude opposite in direction, and not in the same line.
Couple
27
Framework composed of members joined at their ends to form a rigid structure is known as
truss
28
The ratio of the tensile stress to the tensile strain is called
Young modulus
29
The ratio of the volume stress to the volume strain is called the coefficient of volume elasticity or
bulk modulus
30
The action of a force is characterized by
its magnitude
31
At highest or lowest point on the moment diagram
shear is zero
32
The built-in or fixed support is capable of supporting
an axial load
33
The modulus of elasticity in shear is commonly called
modulus of rigidity
34
The stress beyond which the material will not return to its original shape when unloaded, but will retain a permanent deformation.
Elastic limit
35
Refers to the actual stress the material has when under load is known as
working stress
36
The safe soil bearing pressure of diesel engine is about
4890 kg per sq. cm
37
The machine foundation must have a factor of safety of
5
38
The load acts over smaller area, and the ______ continues to increase unit failure.
actual stress
39
In the stress-strain diagram where there is a large increase in strain with little or no increase in stress.
Yield strength
40
A member that carries loads transverse to its axis.
Beam
41
Which type of load that is applied slowly and is never removed?
Static load
42
When varying loads are applied that are not regular in their amplitude, the loading is called
Random loading
43
A measure of the relative safety of a load-carrying component is termed as
design factor
44
The condition, which causes actual stresses in machine members to be higher than nominal values predicted by the elementary direct and combined stress equations.
Stress concentration
45
The stress value, which is used, in the mathematical determination of the required size of the machine member.
Design stress
46
Typical values for Poisson's ratio of cast iron is in the range of
0.25 to 0.27
47
Typical values for Poisson's ratio of steel is in the range of
0.27 to 0.30
48
Typical values for Poisson's ratio of aluminum and titanium is in the range of
0.30 to 0.33
49
The angle of inclination of the planes on which the principal stresses act is called
principal plane
50
It provides a very accurate prediction of failure of ductile materials under static loads or completely reversed normal, shear or combined stresses.
Distortion energy theory
51
Torsional deflection is a significant consideration in the design of shaft and the limit should be in the range of ____ degrees/foot of length.
0.08 to 1
52
For a universal joint shaft angle should be _____ degrees maximum and much less if in high rotational speed.
15
53
It is a good design practice for steel line shafting to consider a limit to the linear deflection ____ of inch/foot length maximum.
0.010
54
It is a rotating machine member that transmits power.
Shaft
55
A stationary member carrying pulleys, wheels and etc. that transmit power.
Axle
56
A line shaft is also known as
main shaft
57
Which of the following shaft intermediate between a line shaft and a driven shaft?
All of the above
58
Short shafts on machines are called
spindles
59
For shafts, the shear due to bending is a maximum at the neutral plane where the normal stress is
zero
60
Criteria for the limiting torsional deflection vary from 0.08 per foot of length for machinery shafts to ____per foot
1°
61
For transmission shafts the allowable deflection is one degree in a length of ________diameters.
20
62
An old rule of thumb for transmission shafting is that the deflection should not exceed _____ of length between supports.
0.01 in. per foot
63
In general for machinery shafts, the permissible deflection may be closer to
0.002 in/ft
64
The speed at which the center of mass will equal the deflecting forces on the shaft with its attached bodies will then vibrate violently, since the centrifugal force changes its direction as the shaft turns.
Critical speed
65
For shaft, the minimum value of numerical combined shock and fatigue factor to be applied in every case to the computed bending moment is
1.5
66
It is suggested that the design factor on the yield strength be about 1.5 for the smooth load, about 2 to 2.25 for minor shock loads, and _____ when the loading reverses during operation.
4.5
67
A column is called short column when
the length is less than 8 times the diameter
68
For a circular shaft subjected to torque the value of shear stress
is zero at the axis and linearly increases to a maximum value at the surface of the shaft
69
The compression members tend to buckle in the direction of
least radius of gyration
70
A reinforced concrete beam is considered to be made up of
heterogeneous material
71
The column splice is used for increasing
length of the column
72
A simply supported beam has a uniformly distributed load on it, the bending moment is
parabola
73
The power obtained by piston reaches flywheel through the
crank shaft
74
There are two types of crankshafts
single piece and built up
75
Engine valves get open by means of
cam shaft
76
The ____ value of allowable stresses are generally used in practice for main transmitting shafts.
282 kg/cm²
77
The value of allowable stresses are generally, used in practice for line shafts carrying pulleys.
423 kg/cm²
78
The ____ value of allowable stresses are generally used in practice for small, short shafts, countershafts.
599 kg/cm²
79
Torsional deformation in transmission shafts should be limited to____ in 20 diameters.
1°
80
Lateral deflection caused by bending should not exceed
0.01 in. per foot of length
81
Front axle should be live and
dead
82
The steering is coupled to the two front wheels by means of a
tie rod
83
In the overdrive transmission system the rotation speed____ rest higher than that of engine's speed.
propeller shaft
84
A slip joint the length of propeller shaft.
keeps appropriate
85
The transmission system incorporates clutch, gear box, and propeller shaft and
differential
86
The lay shaft moves _____ the primary shaft.
in the gear ratio
87
The main shaft is lifted ____the lay shaft.
parallel to
88
In the top gear, the rotational speeds of _____ remain the same.
primary and main shafts
89
The primary and lay shafts rotate in ____ direction
reverse
90
It is an integral part of the machine
Machine shaft
91
Stresses in shafts are analyzed through
all of these
92
Standard stock length is
all of the above
93
Centrifugal separators that operate at ____ speeds also employ these flexible shafts.
20,000 to 50,000 rpm
94
Which of the following material is used for shafting?
AISI 3240
95
The process of redistributing the mass attached to a rotating body in order to reduce arising from a centrifugal force
Shaft balancing
96
In many cases the ___ of the shaft is an import design feature.
rigidity
97
Commercial shafting is made of
low carbon steel
98
The most common material for shafting is
A.
B.
C.
mild steel
99
Gold drawing produces a ____ shaft ----- but with higher residual stresses
stronger
100
Allowable stresses in shear equal to _____ with common in design of a shaft
5000 to 8000 psi