L length, m inn speed, rpm revolutions per minute coefficient of end condition n0 speed, rps revolutions per second l, m, n direction cosines also with subscripts Q first moment of the cros
Trang 11 Datsko, J., Material Properties and Manufacturing Process, John Wiley and Sons, New York, 1966.
2 Datsko, J Material in Design and Manufacturing, Malloy, Ann Arbor, Michigan, 1977
3 ASM Metals Handbook, American Society for Metals, Metals Park, Ohio, 1988
4 Machine Design, 1981 Materials Reference Issue, Penton/IPC, Cleveland, Ohio, Vol 53, No 6, March 19,1981
5 Lingaiah, K., Machine Design Data Handbook, Vol II (SI and Customary Metric Units), Suma Publishers,Bangalore, India, 1986
6 Lingaiah, K., and B R Narayana Iyengar, Machine Design Data Handbook, Vol I (SI and Customary MetricUnits), Suma Publishers, Bangalore, India, 1986
7 Technical Editor Speaks, the International Nickel Company, New York, 1943
8 Shigley, J E., Mechanical Engineering Design, Metric Edition, McGraw-Hill Book Company, New York,1986
9 Deutschman, A D., W J Michels, and C E Wilson, Machine Design—Theory and Practice, Macmillan lishing Company, New York, 1975
Pub-10 Juvinall, R C., Fundaments of Machine Components Design, John Wiley and Sons, New York, 1983
11 Lingaiah, K., and B R Narayana Iyengar, Machine Design Data Handbook, Engineering College tive Society, Bangalore, India, 1962
Co-opera-12 Lingaiah, K., Machine Design Data Handbook, Vol II (SI and Customary Metric Units), Suma Publishers,Bangalore, India, 1981 and 1984
13 Lingaiah, K., and B R Narayana Iyengar, Machine Design Data Handbook, Vol I (SI and Customary MetricUnits), Suma Publishers, Bangalore, India, 1983
14 SAE Handbook, 1981
15 Lessels, J M., Strength and Resistance of Metals, John Wiley and Sons, New York, 1954
16 Siegel, M J., V L Maleev, and J B Hartman, Mechanical Design of Machines, 4th edition, InternationalTextbook Company, Scranton, Pennsylvania, 1965
17 Black, P H., and O Eugene Adams, Jr., Machine Design, McGraw-Hill Book Company, New York, 1963
18 Niemann, G., Maschinenelemente, Springer-Verlag, Berlin, Erster Band, 1963
19 Faires, V M., Design of Machine Elements, 4th edition, Macmillan Company, New York, 1965
20 Nortman, C A., E S Ault, and I F Zarobsky, Fundamentals of Machine Design, Macmillan Company, NewYork, 1951
21 Spotts, M F., Design of Machine Elements, 5th edition, Prentice-Hall of India Private Ltd., New Delhi, 1978
22 Vallance, A., and V L Doughtie, Design of Machine Members, McGraw-Hill Book Company, New York,1951
23 Decker, K.-H., Maschinenelemente, Gestalting und Bereching, Carl Hanser Verlag, Munich, Germany, 1971
24 Decker, K.-H., and Kabus, B K., Maschinenelemente-Aufgaben, Carl Hanser Verlag, Munich, Germany,1970
25 ISO and BIS standards
26 Metals Handbook, Desk Edition, ASM International, Materials Park, Ohio, 1985 (formerly the AmericanSociety for Metals, Metals Park, Ohio, 1985)
27 Edwards, Jr., K S., and R B McKee, Fundamentals of Mechanical Components Design, McGraw-Hill BookCompany, New York, 1991
28 Shigley, J E., and C R Mischke, Standard Handbook of Machine Design, 2nd edition, McGraw-Hill BookCompany, New York, 1996
29 Structural Alloys Handbook, Metals and Ceramics Information Center, Battelle Memorial Institute, bus, Ohio, 1985
Colum-30 Wood Handbook and U S Forest Products Laboratory
31 SAE J1099, Technical Report of Fatigue Properties
32 Ashton, J C.,I Halpin, and P H Petit, Primer on Composite Materials-Analysis, Technomic Publishing Co.,Inc., 750 Summer Street, Stanford, Conn 06901, 1969
33 Baumeister, T., E A Avallone, and T Baumeister III, Mark’s Standard Handbook for Mechanical Engineers,8th edition, McGraw-Hill Book Company, New York, 1978
34 Norton, Refractories, 3rd edition, Green and Stewart, ASTM Standards on Refractory Materials Handbook(Committee C-8)
Trang 2Black, P H., and O Eugene Adams, Jr., Machine Design, McGraw-Hill Book Company, New York, 1983.Decker, K.-H., Maschinenelemente, Gestalting und Bereching, Carl Hanser Verlag, Munich, Germany, 1971.Decker, K.-H., and Kabus, B K., Maschinenelemente-Aufgaben, Carl Hanser Verlag, Munich, Germany, 1970.Deutschman, A D., W J Michels, and C E Wilson, Machine Design—Theory and Practice, Macmillan Publish-ing Company, New York, 1975.
Faires, V M., Design of Machine Elements, 4th edition, McGraw-Hill Book Company, New York, 1965.Honger, O S (ed.), (ASME) Handbook for Metals Properties, McGraw-Hill Book Company, New York, 1954.ISO standards
Juvinall, R C., Fundaments of Machine Components Design, John Wiley and Sons, New York, 1983
Lessels, J M., Strength and Resistance of Metals, John Wiley and Sons, New York, 1954
Lingaiah, K., and B R Narayana Iyengar, Machine Design Data Handbook, Engineering College Co-operativeSociety, Bangalore, India, 1962
Mark’s Standard Handbook for Mechanical Engineers, 8th edition, McGraw-Hill Book Company, New York,1978
Niemann, G., Maschinenelemente, Springer-Verlag, Berlin, Erster Band, 1963
Norman, C A., E S Ault, and I E Zarobsky, Fundamentals of Machine Design, McGraw-Hill Book Company,New York, 1951
SAE Handbook, 1981
Shigley, J E., Mechanical Engineering Design, Metric Edition, McGraw-Hill Book Company, New York, 1986.Siegel, M J., V L Maleev, and J B Hartman, Mechanical Design of Machines, 4th edition, International Text-book Company, Scranton, Pennsylvania, 1965
Spotts, M F., Design of Machine Elements, 5th edition, Prentice-Hall of India Private Ltd., New Delhi, 1978.Vallance, A., and V L Doughtie, Design of Machine Members, McGraw-Hill Book Company, New York, 1951
Trang 3A area of cross section, m2(in2)
Aw area of web, m2(in2)
a constant in Rankine’s formula
b radius of area of contact, m (in)
bandwidth of contact, m (in)
width of beam, m (in)
c distance from neutral surface to extreme fiber, m (in)
D diameter of shaft, m (in)
C1 constant in straight-line formula
e deformation, total, m (in)
eccentricity, as of force equilibrium, m (in)
unit volume change or volumetric strain
et thermal expansion, m (in)
E modulus of elasticity, direct (tension or compression), GPa
(Mpsi)
Ec combined or equivalent modulus of elasticity in case of
composite bars, GPa (Mpsi)
G modulus of rigidity, GPa (Mpsi)
Mb bending moment, N m (lbf ft)
Mt torque, torsional moment, N m (lbf ft)
I moment of inertia, area, m4or cm4(in4)
mass moment of inertia, N s2m (lbf s2ft)
Ixx, Iyy moment of inertia of cross-sectional area around the respective
principal axes, m4or cm4(in4)
J moment of inertia, polar, m4or cm4(in4)
k radius of gyration, m (in)
k0 polar radius of gyration, m (in)
kt torsional spring constant, J/rad or N m/rad (lbf in/rad)
Trang 4L length, m (in)
n speed, rpm (revolutions per minute)
coefficient of end condition
n0 speed, rps (revolutions per second)
l, m, n direction cosines (also with subscripts)
Q first moment of the cross-sectional area outside the section at
which the shear flow is required
v velocity, m/s (ft/min or fpm)
V volume, m3(in3)
shear force, kN (lbf)
V volume change, m3(in3)
Z section modulus, m3(in3)
deformation of contact surfaces, m (in)
coefficient of linear expansion, m/m/K or m/m/8C ðin=in=8F)
shearing strain, rad/rad
xy,yz,zx shearing strain components in xyz coordinates, rad/rad
deformation or elongation, m (in)
" strain,mm/m (min/in)
"T thermal strain,mm/m (min/in)
"x,"y,"z strains in x, y, and z directions,mm/m (min/in)
angular distortion, rad
angle, deg
angular twist, rad (deg)
angle made by normal to plane nn with the x axis, deg
bulk modulus of elasticity, GPa (Mpsi)
radius of curvature, m (in)
stress, direct or normal, tensile or compressive (also with
subscripts), MPa (psi)
b bearing pressure, MPa (psi)
bending stress, MPa (psi)
c compressive stress (also with subscripts), MPa (psi)
hydrostatic pressure, MPa (psi)
sc compressive strength, MPa (psi)
cr stress at crushing load, MPa (psi)
e elastic limit, MPa (psi)
s strength, MPa (psi)
t tensile stress, MPa (psi)
st tensile strength, MPa (psi)
x, y, z stress in x, y, and z directions, MPa (psi)
1, 2, 3 principal stresses, MPa (psi)
y yield stress, MPa (psi)
sy yield strength, MPa (psi)
u ultimate stress, MPa (psi)
su ultimate strength, MPa (psi)
0 principal direct stress, MPa (psi)
00 normal stress which will produce the maximum strain, MPa (psi)
Trang 5s shear strength, MPa (psi)
xy,yz,zx shear stresses in xy, yz, and zx planes, respectively, MPa (psi)
shear stress on the plane at any angle with x axis, MPa (psi)
Other factors in performance or in special aspects are included from time to
time in this chapter and, being applicable only in their immediate context,
are not given at this stage
(Note: and with initial subscript s designates strength properties of material
used in the design which will be used and observed throughout this Machine
Design Data Handbook.)
SIMPLE STRESS AND STRAIN
The stress in simple tension or compression (Fig 2-1a,
Trang 6FIGURE 2-2
Young’s modulus or modulus of elasticity
The shear stress (Fig 2-1c)
Shear deformation due to torsion (Fig 2-18)
Shear strain (Fig 2-2c)
The shear modulus or modulus of rigidity from Eq
(2-7)
Poisson’s ratio
Poisson’s ratio may be computed with sufficient
accuracy from the relation
The shear or torsional modulus or modulus of rigidity
is also obtained from Eq (2-10)
The bearing stress (Fig 2-3c)
STRESSES
Unidirectional stress (Fig 2-4)
The normal stress on the plane at any angle with x
Trang 7FIGURE 2-3 Knuckle joint for round rods.
FIGURE 2-4 A bar in uniaxial tension.3;4
The shear stress on the plane at any angle with x axis
Principal stresses
Angles at which principal stresses act
Maximum shear stress
Angles at which maximum shear stresses act
Trang 8The normal stress on the plane at an angle
PURE SHEAR (FIG 2-5)
The normal stress on the plane at any angle
The shear stress on the plane at any angle
The principal stress
Angles at which principal stresses act
Maximum shear stresses
Angles at which maximum shear stress act
FIGURE 2-5 An element in pure shear.
BIAXIAL STRESSES (FIG 2-6)
The normal stress on the plane at any angle
The shear stress on the plane at any angle
The shear stressat ¼ 0
The shear stressat ¼ 458
0¼ xcos2
þ2
cos
þ2
Trang 9BIAXIAL STRESSES COMBINED WITH
SHEAR (FIG 2-7)
The normal stress on the plane at any angle
The shear stress in the plane at any angle
The maximum principal stress
The minimum principal stress
Angles at which principal stresses act
Maximum shear stress
Angles at which maximum shear stress acts
The equation for the inclination of the principal
planes in terms of the principal stress (Fig 2-8)
FIGURE 2-7 An element in plane state of stress.
2
þ 2 xy
2
þ 2 xy
Trang 10MOHR’S CIRCLE
Biaxial field combined with shear (Fig 2-9)
Maximum principal stress 1
Minimum principal stress 2
Maximum shear stressmax
FIGURE 2-9 Mohr’s circle for biaxial state of stress.
TRIAXIAL STRESS (Figs 2-10 and 2-11)
The normal stress on a plane nn, whose direction
cosines are l, m, n
The shear stress on a plane normal nn, whose
direc-tion cosines are l, m, n
The principal stresses
The cubic equation for general state of stress in three
dimensions from the theory of elasticity
The maximum shear stresses on planes parallel to x, y,
and z which are designated as
1is the abscissa of point F
2is the abscissa of point G
maxis the ordinate of point H
Trang 11MOHR’S CIRCLE
Triaxial field (Figs 2-10 and 2-11)
Normal stress at point (Fig 2-11b) on one octahedral
plane
Shear stress at point T (Fig 2-11b) on an octahedral
plane
FIGURE 2-10 An element in triaxial state of stress.
FIGURE 2-11 Mohr’s circle for triaxial octahedral stress state.
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
½ð 1 2Þ2þ ð 2 3Þ2þ ð 3 1Þ2q
ortis the ordinate of point T
Trang 12STRESS-STRAIN RELATIONS
Uniaxial field
Strain in principal direction 1
The principal stress
The unit volume change in uniaxial stress
Biaxial field
Strain in principal direction 1
Strain in principal direction 2
Strain in principal direction 3
The principal stresses in terms of principal strains in a
biaxial stress field
The unit volume change in biaxial stress
Triaxial field
Strain in principal direction 1
Strain in principal direction 2
Strain in principal direction 3
The principal stresses in terms of principal strains in
triaxial stress field
Trang 13The unit volume change or volumetric strain in terms
of principal stresses for the general case of triaxial
stress (Fig 2-12)
FIGURE 2-12 Uniform hydrostatic pressure.
The volumetric strain due to uniform hydrostatic
pressure cacting on an element (Fig 2-12)
The bulk modulus of elasticity
The relationship between E, G and K
STATISTICALLY INDETERMINATE
MEMBERS (Fig 2-13)
The reactions at supports of a constant cross-section
bar due to load F acting on it as shown in Fig 2-13
The elongation of left portion Laof the bar
Trang 14The shortening of right portion Lbof the bar
FIGURE 2-13
THERMAL STRESS AND STRAIN
The normal strain due to free expansion of a bar or
machine member when it is heated
The free linear deformation due to temperature change
The compressive force Fcbdeveloped in the bar fixed
at both ends due to increase in temperature (Fig 2-14)
The compressive stress induced in the member due to
thermal expansion (Fig 2-14)
The relation between the extension of one member to
the compression of another member in case of rigidly
joined compound bars of the same length L made of
different materials subjected to same temperature
(Fig 2-15)
The forces acting on each member due to temperature
change in the compound bar
The relation between compression of the tube to the
extension of the threaded member due to tightening
of the nut on the threaded member (Fig 2-16)
The forces acting on tube and threaded member due
to tightening of the nut
Trang 15FIGURE 2-15
COMPOUND BARS
The total load in the case of compound bars or
col-umns or wires consisting of i members, each having
different length and area of cross section and each
made of different material subjected to an external
load as shown in Fig 2-17
An expression for common compression of each bar
Trang 16The load on first bar (Fig 2-17)
The load on ith bar (Fig 2-17)
EQUIVALENT OR COMBINED MODULUS
OF ELASTICITY OF COMPOUND BARS
The equivalent or combined modulus of elasticity of a
compound bar consisting of i members, each having a
different length and area of cross section and each
being made of different material
The stress in the equivalent bar due to external load F
The strain in the equivalent bar due to external load F
The common extension or compression due to
Trang 17Another expression for power in terms of force F
acting at velocity v
TORSION (FIG 2-18)
The general equation for torsion (Fig 2-18)
Torque
The maximum shear stress at the maximum radius r
of the solid shaft (Fig 2-18) subjected to torque Mt
The torsional spring constant
FIGURE 2-18 Cylindrical bar subjected to torque.
Trang 18BENDING (FIG 2-19)
The general formula for bending (Fig 2-19)
FIGURE 2-19 Bending of beam.
The maximum values of tensile and compressive
bending stresses
The shear stresses developed in bending of a beam
(Fig 2-20)
The shear flow
FIGURE 2-20 Beam subjected to shear stress.
Trang 19The first moment of the cross-sectional area outside
the section at which the shear flow is required
The maximum shear stress for a rectangular section
For a hollow circular section beam, the expression for
maximum shear stress
An appropriate expression for max for structural
beams, columns and joists used in structural
indus-tries
ECCENTRIC LOADING
The maximum and minimum stresses which are
induced at points of outer fibers on either side of a
machine member loaded eccentrically (Figs 2-22
and 2-23)
The resultant stress at any point of the cross section of
an eccentrically loaded member (Fig 2-24)
COLUMN FORMULAS (Fig 2-25)
Euler’s formula (Fig 2-26) for critical load
Trang 20FIGURE 2-22 Eccentric loading.
FIGURE 2-23 Eccentrically loaded machine member FIGURE 2-24
FIGURE 2-25 Column-end conditions (i) One end is fixed and other is free (ii) Both ends are rounded and guided or hinged (iii) One end is fixed and other is rounded and guided or hinged (iv) Fixed ends.
Trang 21Johnson’s parabolic formula (Fig 2-26) for critical
load
FIGURE 2-26 Variation of critical stress with slenderness
ratio.
Straight-line formula for critical load
Straight-line formula for short column of brittle
material for critical load
Ritter’s formula for induced stress
Ritter’s formula for eccentrically loaded column (Fig
2-23) for combined induced stress
Rankine’s formula for induced stress
The critical unit load from secant formula for a
round-ended column
Fcr¼ A y 1 y
2E
lk
lk
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
ðFcr=4AEÞ
Trang 22HERTZ CONTACT STRESS
Contact of spherical surfaces
Sphere on a sphere (Fig 2-27a)
The radius of circular area of contact
FIGURE 2-27 Hertz contact stress.
The maximum compressive stress
Combined deformation of both bodies in contact
along the axis of load
Spherical surface in contact with a spherical socket
(Fig 2-27b)
The radius of circular area of contact
The maximum compressive stress
377
1=3
ð2-109Þ
cðmaxÞ¼ 0:918 F
1
377
377
377
1=3
ð2-112Þ
cðmaxÞ¼ 0:918 F
1
377
1=3
ð2-113Þ
Trang 23Combined deformation of both bodies in contact
along axis of load
Distribution of pressure over band of width of contact
and stresses in contact zone along the line of
sym-metry of spheres
Sphere on a flat surface (Fig 2-27c)
The radius of circular area of contact
The maximum compressive stress
Contact of cylindrical surfaces
Cylindrical surface on cylindrical surface, axis parallel
(Fig 2-27a and Fig 2-28b)
The width of band of contact
The maximum compressive stress
Cylindrical surface in contact with a circular groove
(Fig 2-27b)
The width of band of contact
The maximum compressive stress
Distribution of pressure over band of width of contact
and stresses in contact zone along the line of
377
37
377
377
377
377
1=2
ð2-120Þ
Refer to Fig 2-28b
Trang 24Cylindrical surface in contact with a flat surface
(Fig 2-27c):
The width of band of contact
The maximum compressive stress
Deformation of cylinder between two plates
The maximum shear stress occurs below contact
surface for ductile materials
37
1=2
ð2-122Þ
where d ¼ d1(Fig 2-27c)
d1¼4FL
Trang 25DESIGN OF MACHINE ELEMENTS AND
STRUCTURES MADE OF COMPOSITE
Honeycomb composite
For the components of composite materials which
give high strength–weight ratio combined with
rigidity
For sandwich construction of honeycomb structure
FIGURE 2-29 Sandwich fabricated panel.
The moment of inertia of sandwich panel, Fig 2-30
Simplified Eq (2-124) after neglecting powers of h
The flexural rigidity
The flexural rigidity of sandwich plate/panel
The flexural rigidity of sandwich construction for
þ 2Bh
Hcþ h2
F ¼ force over a support span Lc
Trang 26The shear modulus G of isotropic material if the
modulus of elasticity E is available
The modulus of elasticity of the core material (Fig
2-31)
FIGURE 2-31 A unit cube foam subject to a tensile load.
The deflection for a beam panel according to
Casti-gliano’s theorem
FIGURE 2-32 Phantom load.
The deflection at midspan (Fig 2-32)
, Ef ¼ modulus of elasticity offoam, GPa (psi), Em¼ modulus of elasticity
of basic solid material, GPa (psi) Subscript
f stands for foam/filament, m stands formatrix, and c stands for composite
¼@U@F ¼@F@
ð
Mb2dx2EI þ
ð
V2dx2GA
ð
V2dx2GA
W ¼ 0
ð2-133aÞ
¼ 5FL3349EIþ FL
where W is the phantom load (Fig 2-32)
Trang 27The deflection per unit width for a sandwich panel at
midspan (Fig 2-32) under quarter-point loading
The deflection per unit width for a sandwich panel at
quarter panel (Fig 2-32) under quarter-point loading
The deflection/unit width for a sandwich panel at
center loading (Fig 2-33)
The maximum normal stress (Fig 2-32)
The minimum normal stress
The average stress often used in the composite panel
design
The maximum shear stress in the core
The core shear strain
FILAMENT REINFORCED STRUCTURES
(Fig 2-34)
The strain in the filament is same as the strain in the
matrix of composite material if it has to have strain
compatibility
L=2¼ 5FL3349DBþ FL
8DcB
where Dc¼ Gcore
HðH þ HcÞ2Hc
ð2-134Þ
L=4¼ FL396DBþ FL
2L4
BhHcðh þ Hc=2ÞH=2
¼ FL8BhHc
ð2-137Þ min¼ FL
core¼ max
FIGURE 2-34
Trang 28The relation between stress in matrix and stress in
filament
For equilibrium
The stress in the filament
The stress in the matrix
The Young’s modulus of composite
The Young’s modulus of chopped-up glass filaments
in resin matrix but still oriented longitudinally with
respect to load as proposed by Outerwater
The relation between mand f, which has to satisfy
Eq (2-142) at any location on the curves, Fig 2-35
From Eq (2-144), the expression for c
For structure with all filament, Am¼ 0
For structure with no filament, Af ¼ 0
4
yf
where ¼ applied tensile stress, MPa (psi)
yf ¼ the strength of the fiber, MPa (psi)
Df ¼ diameter of fiber, mm (in)
pc¼ uniform distance of one fiber fromanother on circumference, mm (in)
L ¼ length of fiber, mm (in)Subscript chpd-f stands for chopped-up fiber m
Trang 29FIGURE 2-35 Stress-strain data for system shown in
The force carried by a helical filament wound on a
shell of width w subjected to internal pressure p in
the-direction
The force in helical filament wound on a shell of width
wsubjected to internal pressure p in the hoop
direc-tion
The hoop stress in the vessel wall due to the pressure p
The stress in the vessel wall in the
longitudinal/axial-direction
From Eq (2-154) to (2-159) the optimum winding
angle for closed end cylinders
The optimum winding angle for open end cylinders
FIGURE 2-36 Filament wound cylindrical pressure vessel.
¼
cos2sin2¼ cot
2 or ¼ 908 ð2-161Þ
Trang 30The stress in the hoop/circumferential direction for
the filament wound cylinder/vessel consisting
wind-ings in longitudinal, hoop and helical directions to
satisfy equilibrium condition
The longitudinal stress for the case of winding under
Eq (2-162)
From Eqs (2-159) and (2-158)
From Eqs (2-154) and (2-155)
The sum of stresses and a
For the ideal vessel
ha, h and h are the thicknesses in the preceding
layers of filament windings
a¼ 0ah0aþ ah
where ¼
soh
Trang 31The structural efficiency of the wound vessel/cylinder
FILAMENT-OVERLAY COMPOSITE
The stress in the wire which is wound on thin walled
shell/cylinder with a wire of the same material
(Fig 2-37)
Under equilibrium condition over the length of shell
L, the hoop stress
The tension in the wound wire on the shell under
internal pressure
The tension in the shell under the above same
condi-tion
The yielding of shell due to internal pressure, i.e., due
to plastic flow of material of the shell
For the above same winding material under the
ten-sion equal to compresten-sion yield limits, the stress in
the wire
If the vessel material is different from the winding
material then stress in the wire and vessel
Venpi
ð2-169Þwhere W ¼ weight of the vessel, kN (lbf)
Ven¼ enclosed volume, m3(in3)
pi¼ internal pressure, MPa (psi)
ð2-175Þ
Trang 32For uniform distribution of stress in the cylinder/shell
and in the wire, strains are proportional to the mean
radii
From Eq (2-177), the stress in the cylinder and the
wire
The total load on the cylinder and the winding
From Eq (2-179), the stress in the cylinder ( cy) and
For advanced theory using Theory of elasticity and
Plasticity construction on composite structures and
materials
For representative properties for fiber reinforcement
FORMULAS AND DATA FOR VARIOUS
CROSS SECTIONS OF MACHINE
ELEMENTS
For further data on static stresses, properties and
torsion of shafts of various cross-sections: shear,
moments, and deflections of beams, strain rosettes,
and singularity functions
For summary of stress and strain formulas under
various types of loads
com-Refer to Table 2-1
Refer to Tables 2-2 to 2-12
Refer to Table 2-13
Trang 34Polar section
modulus,
Angular deflection, Cross section Z 0 ¼ J=c Polar radius of gyration, k 0 In terms of torsional moment, M t In terms of maximum stress,
G
at outer circumference B
G
G
at center of side
Trang 35Shear stress at a distance y from neutral axis,
, MPa (psi) Maximum shear stress, max , MPa (psi)
3F 2bh
1
2y h
3 2 ¼ 1:33F
A ðfor y ¼ 0Þ
F ffiffiffi 2 p
b 2
1 þy
ffiffiffi 2 p
b 4
y b
2
1 :591FA
for y ¼4c
3F 4a
bc2 ðb aÞd 2
bc 3 ðb aÞd 3
ðfor y ¼ 0Þ
TABLE 2-4
The values of constantsa in Eq (2-107)
Yield stress in compression, yc Value ofa for various end-fixity coefficients
One end fixed and the other end free 0.25
Both ends rounded and guided or hinged 1
One end fixed, and the other end rounded and
guided or hinged
2
TABLE 2-6End-fixity coefficients for cast iron column to be used in
Trang 36Section Area, A Moment of inertia, I
Distance
to farthest point, c Section modulus,Z ¼ I=c Radius of gyration,k ¼pffiffiffiffiffiffiffiffiffiI=A
2b þ b 0
3
32
D 4
¼
ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi
R 2 þ R 2
q 2
3
64
a 2
2
32
a 4
Trang 40Type of load General energy equation Energy equation General deflection equation
GJ þsin2EI
where R ¼D2¼ mean radius of coil
¼ helix angle of spring
i ¼ number of coils or turns