Guru Gobind Singh Indraprastha Vishwavidyalaya 2007 B.E Mechanical Engineering MACHINE DESIGN - 1 - Question Paper
END TERM exam
FIFTH SEMESTER [B.TECH] – DEC - 2007
MACHINE DESIGN - 1
(Please write your Exam Roll No.) Exam Roll No.
|
End-Term Examination Fifth Semester [B.Tech.]- December-2007 | ||||||
|
Q.1 Choose the correct answei. - (1x11)
(a) Ball bearings are usually made of
(i) Low. carbon ;,teel (ii) High speed steel
(iii) chrome steel (iv) High carbon steel
(b) The centre to cenue distance between two consecutive rivets in a row is called.
(i) margin (ii) pitch
(iii) back pitch (iv) diagonal pitch
(c) For determining endurance limit a specimen is subject to (i) dynamic load (ii) static load
(iii) bending toad (iv) completely reversed load
(d) Stress concentration factor is a function of
(i) geometry of he component
(ii) material of the component
(iii) geometry a; -d material of the component
(iv) none of the above
(e) Endurance limit of a material
(i) depends on surface finish
(ii) does not depend on surface finish
(f) If the diameter of a solid shaft is doubled, its torque transmitting capacity will be (i) two times (ii) four times
(iii) eight times (ivj sixteen times
(g) The strength of a j 'veted joint is equal to
(i) the pull required to shear off the rivet
(ii) the pull required to crush the rivet
(iii) the pull required to tear off the plate
(iv) the minimum of the above three values
(v) maximum of the above three values
(h) Cotter joint is used to connect two coaxial rods which are subjected to
(i) bending (ii) twisting
(iii) axial loading (iv) all of the above
(i) Residual compressive stress introduced by shot peening in a machine member subjected to cyclic ioading
(i) improves t\:e load carrying capacity
(ii) degrades marginally the load carrying capacity
(iii) degrades drastically the load carrying capacity
(iv). is insensitive to load carrying capacity (j) Fullering is used in
i) welded joint (ii) riveted joint
(iii) threaded joint (iv) spigot and socket joint
(k) Lewis equation is jsed in the design of
(i) springs (ii) spur gears
(iii) pressure vessels (iv) screwed fastenings
Define the following: - (1x6)
toj (I) Factor of safety I(m) Pressure angle it (n) Tolerance p (o) Allowance (p) Notch sensitivity (q) Toughness
Fill in the blanks: - (*nv -f
(r) The helix angle of square-threaded screw of 70 mm mean diameter and 10 mm pitch js___
(s) The rocker arms d internal combustion engines are of_type of levers.
(t) The radial distance from the pitch circle to the bottom a gear tooth is known as
(u) The type of fli obtained from the combination of H6 hole and J5 shaft is a __fit.
(v) At a point in a sitessed body the principal stresses are 30 MPa tensile, 20 MPa
compressive ano 0 MPa. The maximum shear stress at that point is_
MPa.
(w) If a helical coil spring of stiffness K is cut into two identical half coil springs, the
stiffness of each of these spring will be_.
(x) The diameter of Ivet hole is usually__ than the nominal diameter of the
rivet.
(y) A thin cylinder of diameter d and thickness t is subjected to an internal pressure p. The circumie. ;ntial or hoop stress developed is_.
UNIT-1
Q.2 (a) What is meant L/ stress concentration? How does take into consideration a case of a component subjected to dynamic loading? Illustrate how the stress concentration in component can be reduced. (6.5)
(b) What are common engineering materials suitable for forging? State and illustrate important rule forged component design. Name some components which are forged. Why ar-2 they not cast? (6)
Q.3 (a) What is mean oy Endurance Strength' of a material? How do the size and surface finish affect the endurance strength? Differentiate clearly between Endurance Strength' and Endurance Limit'. (6)
(b) Select the inoof commonly used materials for the following applications along
with brief justification. (6.5)
| ||||||||||||||||||
|
UNIT-11 | ||||||||||||||||||
Q.4 (a) Design a coiler joint to connect two mild steel rods of equal diameter transmitting an axial force of 25 KN which is subjected to slow reversals of direction. Tensile stress in the-motoria! is limited to 50 MPa. The shear stress has the value 4/5 of the permissible lo-nsible stress. The crushing stress is limited to 60 Mpa. (7)
(b) Two pieces of /IS flat plates 200 mm x 12 mm are to be joined together by means of a lap riveted joint, using only four rivets. The plates are subjected to tension along their axes. Determine the size of the rivets and their arrangement to give strongest joint. Take permissible stress as at = 80 N/mm2, t = 60 N/mm2 and cc = 120 N/rnm2. What is the efficiency of this joint. (5.5)
Q.5 (a) A low carbon steel plate of 0.7 m width welded to a structure of same material by means of two parallel fillet welds of 0.112 m length (each) is subjected to an eccentric load oi A KN the line of action of which has a distance of 1.5 m from the e.g. of the we'd group. Find the required thickness of the plate when the allowable stress of the weld metal is 60 MN/m2 and that of the plate is 40 MN/m2. (6)
(b) A Cylinder head is fastened to the cylinder of compressor using 8 number of M 16 bolts. Beit material is C20 for which ay = 420 MPa and aen = 200 MPa. The maximum pressure is 3.5 MPa cylinder diameter is 80 mm. A soft gs.sket ( k = 1)
|
Attachment: |
| Earning: Approval pending. |
