51. Which one of the following is the most conservation fatigue failure criterion?

1. 1. Soderberg

   
   
   

   2. Modified Goodman

   
   
   

   3. ASME Elliptic

   
   
   

   4. Gerber

   
   
   

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1. View Hint View Answer Discuss in Forum

   Soderberg

   Correct Option: A

   Soderberg

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52. A static load is mounted at the centre of a shaft rotating at uniform angular velocity. This shaft will be designed for

1. 1. the maximum compressive stress (static)

   
   
   

   2. the maximum tensile stress (static)

   
   
   

   3. the maximum bending moment (static)

   
   
   

   4. fatigue loading

   
   
   

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   Shaft will be designed for fatigue loading.

   Correct Option: D

   Shaft will be designed for fatigue loading.

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53. For the given fluctuating fatigue load, the values of stress amplitude and stress ratio are respectively
    

1. 1. 100MPa and 5

   
   
   

   2. 250 MPa and 5

   
   
   

   3. 100 MPa and 0.20

   
   
   

   4. 250 MPa and 0.20

   
   
   

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1. View Hint View Answer Discuss in Forum

   Stress amplitude =	σmax - σmin
   	2

   
   

   =	250 - 50	= 100 MPa
   	2

   
   

   Stress ratio =	σmax	=	50	= 0.2
   	σmin		250

   Correct Option: C

   Stress amplitude =	σmax - σmin
   	2

   
   

   =	250 - 50	= 100 MPa
   	2

   
   

   Stress ratio =	σmax	=	50	= 0.2
   	σmin		250

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54. In a structure subjected to fatigue loading, the minimum and maximum stresses developed in a cycle are 200 MPa and 400 MPa respectively. The value of stress amplitude (in MPa) is _____.

1. 1. 110

   
   
   

   2. 120

   
   
   

   3. 100

   
   
   

   4. 200

   
   
   

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   σ_min = 200 MPa
   σ_max = 400 MPa
   

   σa =	σmax - σmin
   	2

   
   

   =	400 - 200
   	2

   
   = 100 MPa

   Correct Option: C

   σ_min = 200 MPa
   σ_max = 400 MPa
   

   σa =	σmax - σmin
   	2

   
   

   =	400 - 200
   	2

   
   = 100 MPa

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55. A rotating steel shaft is supported at the ends. It is subjected to a point load at the center. The maximum bending stress developed is 100 MPa. If the yield, ultimate and corrected endurance strength of the shaft material are 300 MPa, 500 MPa and 200 MPa, respectively, then the factor of safety for the shaft is ______.

1. 1. 2

   
   
   

   2. 4

   
   
   

   3. 5

   
   
   

   4. 6

   
   
   

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1. View Hint View Answer Discuss in Forum

   σ =	(Syt,Sut,Se)
   	FOS

   
   

   FOS =	200	= 2.
   	100

   Correct Option: A

   σ =	(Syt,Sut,Se)
   	FOS

   
   

   FOS =	200	= 2.
   	100

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