Machine Design Miscellaneous

Machine Design Miscellaneous

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Machine Design

Machine Design Miscellaneous
  1. Two identical ball bearings Pand Q are operating at loads 30 kN and 45 kN respectively. The ratio of the life of bearing P to the life of bearing Q is








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    For ball bearing
    P.(L)1/3 = C
    Given: PP = 30 kN
    P2 = 45 kN

    LP
    		 =
    P2
    		³
    L2PP

    45
    		³ =
    3
    		³ =
    27
    3028

    Correct Option: B

    For ball bearing
    P.(L)1/3 = C
    Given: PP = 30 kN
    P2 = 45 kN

    LP
    		 =
    P2
    		³
    L2PP

    45
    		³ =
    3
    		³ =
    27
    3028

  1. Weldments in fabricated steel beams are designed for








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    NA

    Correct Option: C

    NA

Direction: A single riveted lap Joint of two similar plates as shown in the figure below has the following geometrical and material details.

width of the plate ω = 200 mm, thickness of the plate t = 5 mm, number of rivets n = 3, diameter of the rivet dr = 10 mm, diameter of the rivet hole dr= 11 M mm, allowable tensile stress of the plate σp = 200 MPa, allowable shear stress of the rivet σs = 100 MPa and allowable bearing stress of the rivet σc = 150 MPa.

  1. If the plates are to be designed to avoid tearing failure, the maximum permissible load P in kN is








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    For plates,

    σ
    P
    A

    ⇒ 200 =
    P
    (W - 3dh)t

    P = 167kN

    Correct Option: C

    For plates,

    σ
    P
    A

    ⇒ 200 =
    P
    (W - 3dh)t

    P = 167kN

  1. A bracket (shown in figure) is rigidly mounted on wall using four rivets. Each rivet is 6 mm in diameter and has an effective length of 12 mm.

    Direct shear stress (in MPa) in the most heavily loaded rivet is








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    Given: Number of rivets = 4,
    Diameter of each rivet, d = 6 × 10–3m
    Direct load on the bracket = 1000 N
    since there is no eccentricity

    ∴ Load on each rivet =
    1000
    		 = 250N
    4

    ∴ Shear stress =
    P
    		 =
    250
    		 = 8.8 MPa
    Aπ/4 (6)²

    Correct Option: B

    Given: Number of rivets = 4,
    Diameter of each rivet, d = 6 × 10–3m
    Direct load on the bracket = 1000 N
    since there is no eccentricity

    ∴ Load on each rivet =
    1000
    		 = 250N
    4

    ∴ Shear stress =
    P
    		 =
    250
    		 = 8.8 MPa
    Aπ/4 (6)²

  1. In the design of shafts made of ductile materials subjected to twisting moment and bending moment, the recommended theory of failure is








  1. View Hint View Answer Discuss in Forum

    NA

    Correct Option: C

    NA