part c4 simple stresses for students
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stress analysisTRANSCRIPT
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29-Sep-10 SJEC4SimpleStresses ١
Engineering MechanicsIII
(Stress Analysis)
MANF231
Simple Stresses
Part C4
29-Sep-10 SJEC4SimpleStresses ٢
Exercise C15
The steel tie bar shown is tobe designed to carry atensile force P=120kN whenbolted between doublebrackets at A and B. The barwill be fabricated from a20mm thick plate. For steel,the maximum allowablestresses are σ=175MPa,shear stress=100MPa andσb=175MPa. Find thediameter d of the bolt, thedimension b at each end ofthe bar and the dimension hof the bar.
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Exercise C15Diameter of Bolt
Shear Stress
Bearing Stress
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Exercise C15
Dimension b
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Exercise C15
Dimension h
29-Sep-10 SJEC4SimpleStresses ٦
Exercise C16
Two forces are applied to the bracket
BCD as shown.1. Knowing that the control rod AB is
to be made of a steel having an
ultimate normal stress of 600MPa,
determine the diameter of the rod
for which the factor of safety withrespect to failure will be 3.3.
2. The pin at C is to be made of a steel
having an ultimate shearing stress
of 350MPa. Determine the diameter
of the pin C for which the factor ofsafety with respect to shear will
also be 3.3.
3. Determine the required thickness of
the bracket supports at C knowing
that the allowable bearing stress ofthe steel used is 300MPa.
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29-Sep-10 SJEC4SimpleStresses ٧
Exercise C16
Free body diagram
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Exercise C16
Control rod AB
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Exercise C16
Shear in pin C
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Exercise C16
Bearing at C
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Exercise C17
The rigid beam BCD is attached bybolts to a control rod at B, to ahydraulic cylinder at C and to a fixedsupport at D. The diameters of thebolts used are dB=dD=10mm,dC=12mm. Each bolt acts in doubleshear and is made from a steel forwhich the ultimate shearing stress=280MPa. The control rod AB has adiameter dA=11mm and is made of asteel for which the ultimate tensilestress =420MPa. If the minimumfactor of safety is to be 3 for theentire unit, determine the largestupward force which may be appliedby the hydraulic cylinder at C.
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Exercise C17
Free body diagram
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Exercise C17
Control rod AB
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Exercise C17
Bolt at B
Bolt at D
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Exercise C17
Bolt at C
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The horizontal link BC is 6 mm thick and is made of a
steel with a 450 MPa
ultimate strength in
tension.
What should be the width w of the link if the
structure shown is to be
designed to support a
load P = 32 kN with a
factor of safety = 3 ?
Exercise C18