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    Plane StressLoading

    1

    x

    Therefore, the state

    of stress at a pointcan be defined by

    the three

    independent

    stresses:x; y; and xy

    x

    y x

    y

    A

    A

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    REFERENCES:

    http://en.wikipedia.org/wiki/

    Principal_stress#Overview

    http://www.learnengineering.

    org/2013/01/principal-stress-

    plane-mohr-circle.html#

    www.enduratec.com

    http://en.wikipedia.org/wiki/Principal_stresshttp://en.wikipedia.org/wiki/Principal_stresshttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://www.learnengineering.org/2013/01/principal-stress-plane-mohr-circle.htmlhttp://en.wikipedia.org/wiki/Principal_stresshttp://en.wikipedia.org/wiki/Principal_stress
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    IntroductionStress at a point is resolved into normal

    and shear components

    When there is no shear stresses acting on

    the planes giving the maximum normal

    stress acting on the planes.

    These planes are called the principal

    planes, and stresses normal to these planes

    are the principal stresses 1, 2 and 3 whichin general do not coincide with the cartesiancoordinate

    axes x, y, z.

    When a material is deformed by an external loading,

    work done during elastic deformation is stored as

    elastic energy and will be recovered when the load is

    released.

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    Objective

    4

    A

    x

    y State ofStress at A

    whatwould be

    x, y,

    and xy?

    x

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    opyright

    001

    Transformation

    5

    x

    y

    x

    A

    State of

    Stress at A

    x

    y x

    y xyx=

    ?

    xy=?

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    Transformation

    6

    2sin2cos22

    ' xyyxyxx

    2os2in2

    ' cs xyyxxy

    Solving equilibrium

    equations for the wedge

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    Principal Planes & Principal

    Stresses

    7

    PrincipalPlanes

    ~ are the two planes where the

    normal stress () is themaximum or minimum

    ~ the orientations of the

    planes (p) are given by:

    yx

    xy

    p

    2tan2

    1 1

    gives two values

    ~ there are no shear stresses on

    principal planes

    ~ these two planes are mutuallyperpendicular

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    Principal Planes &

    Principal Stresses

    8

    x

    p

    1

    p

    2

    90

    Orientation ofPrincipal Planes

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    Principal Planes & Principal

    Stresses

    9

    PrincipalStresses

    ~ are the normal stresses () actingon the principal planes

    Ryx

    21max

    Ryx

    2

    2min

    2

    2

    2xy

    yx

    R

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    Maximum Shear(max)

    10

    ~ maximum shear stress occurs on

    two mutually perpendicular

    planes

    xy

    yxs

    2

    tan2

    11

    gives two values

    (s1 and s2)

    ~ orientations of the two planes

    (s) are given by:

    max = R2

    2

    2xy

    yx

    R

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    Maximum Shear

    11

    x

    s

    1

    s

    2

    90

    Orientation of MaximumShear Planes

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    Principal Planes & Maximum

    Shear Planes

    12

    x

    Principal

    plane

    Maximum

    shear plane

    p = s45

    45

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    Plane Strain Loading

    13

    x

    ~ where all elements

    of the body aresubjected to normal

    and shearstrains

    acting along a plane

    (x-y); noneperpendicular to the

    plane (z-direction)

    z

    = 0; xz

    =

    0; zy = 0

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    Plane Strain

    Transformation

    14

    Similar to previous

    derivations. Just replace by ,and by/2

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    Plane Strain

    Transformation

    15

    SignConvention:

    Shear strain ( ): decreasingangle positive

    e.g

    .,

    Normal strains (x and y):extension positive

    x

    y

    bef

    ore

    x

    y

    afte

    r

    xpositi

    veynegativepositi

    ve

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    Plane Strain

    Transformation

    16

    2sin2

    2cos22

    ' xyyxyxx

    2os2

    2in22

    'cs xyyxxy

    Same format as

    the stress

    transformatione uations

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    Principal Strains

    17

    yx

    xy

    p

    1tan

    2

    1Gives two values

    (p1 and p2)

    ~ maximum (1) and minimum (2)principal strains

    ~ occur along two mutuallyperpendicular directions, given by:

    Ryx

    21

    Ryx

    21

    22

    22

    xyyxR

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    Maximum Shear Strain

    (max)

    18

    max/2

    = R22

    22

    xyyxR

    p = s45

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    References: http://www.google.co.in/url?sa=t&rct=j&q=ignition%

    20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http%3A%2F%2Fwww.ignou.ac.i

    n%2Fupload%2Funit%25204.pdf&ei=N7wTUufENsi

    XrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS

    2Fh88vIQ&bvm=bv.50952593,d.bmk

    http://en.wikipedia.org/wiki/Ignition_system#Modern_

    ignition_systems

    I.C Engines By V.Ganesan ,TMH Punlication.

    http://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://en.wikipedia.org/wiki/Ignition_systemhttp://en.wikipedia.org/wiki/Ignition_systemhttp://en.wikipedia.org/wiki/Ignition_systemhttp://en.wikipedia.org/wiki/Ignition_systemhttp://en.wikipedia.org/wiki/Ignition_systemhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmkhttp://www.google.co.in/url?sa=t&rct=j&q=ignition%20system%20pdf&source=web&cd=1&cad=rja&ved=0CCkQFjAA&url=http://www.ignou.ac.in/upload/unit%204.pdf&ei=N7wTUufENsiXrAfn24EQ&usg=AFQjCNEqTMr1qLrKhrtETcfCqS2Fh88vIQ&bvm=bv.50952593,d.bmk