machine design-1 qpaper nov-dec 2010 nit raipur mech 5th sem

8/8/2019 Machine Design-1 Qpaper Nov-Dec 2010 Nit Raipur Mech 5th Sem

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lr :ea, I osnCSVTU Course Code:ME

B.Tech.( Fifth Semester) Examination, Nov. - Dec. 2o1o

Subject: Machine Design-IBranch: Mechanical Engineering

Time: Four hours ' MaxMarks:8oMin. Pass Marks: eB

Note: All questions are compulsory. Assume suitable data wherever necessary with justification.

Use of pSG data book and data sheets are allowed. Drawings to the scale are to be prepared on

separate sheets to be attached with answer sheet. All dimensions are in mm in the figures ifotherwise not specified

by 1 t<N. Ascertain the saf,ety factor based on

theory.

(8,8)MPa yield steel and loaded

the maximum shear stress

(b) Determine the safety factor using Maximum Shear Stress theory and

distortion enerry theory, for the state of stress ox = 1O MPa; oy = -rO MPa;Tr,y = o, applied to pure aluminum, Sb = 3o MPa. Draw Mohr's stress circle

to show the stress state.

. l.c)Acantilever beam made of steel Fe54o ( So,

= S4oN/mmz and Sr1 = $2o

v N/mms) and subjected to a completely reversed load P of 5 kN is shown inFig.r(c). The shaft is machined and the reliability is go%2. The factor ofsafety is z. and the notch sensitivity factor is o.9. Calculate the diameter dfor infinite life.

Qu.z. Solve the following: (4rtz)(a) Determine the key dimensions for fixing a gear on,a thut of z5mm

diameter. rSkW power atZz,a r?m is transmitted from the shaft to the gear.

The key material is steel SoC4.O) Desrgn a cotter or lmuckle joint to connect two steel rods of eqgal

diameter subjected to an axial tensile force of 5okl'{. Select the material for

the joint as plain carbon steel of grade 3oC8. Df?rw the sectional elevation ofthe joint to a suitable scale showing all the dimensions.

Qu,g. Solve any one part of the following: (16)(a) Design the various components of screw jack, Fi8.3(a) for lifting the

machine parts on the shop floor ( Screw- steel3oCS, nut - Phosphorbronze grade r, handle - steel goCS and frame - FGzoO ) with a load

carrying capacity of roo kN and maximum lifting height of o.5m. The jack is

to be manually operated. The load applied at the end of the lever will be 5ooN.

(b) Solve the following (8'8)

(i) A steel plate subjected to a foree of 5kN and fixed to a channgl by me-ansof three identical bolts, Fig.B(b-i). The bolts are made of plain carbon

steel 45CS(Syt = 38o N/mmz) and the factor of safety is 3. Speciff thesize ofbolts.

(ii) Using the maximum shear stress theory speciS the size oJ the bolts(plain carbon steel 4SC8 Syt = 38o N/m*z) for the following

biacket, Fig.S&-ii), P = z5k\[, e = 1oo mm' lr = l5offih, I" = 25mmand factor of safety 2.5.

Qu.1. Solve anytwo part of the folloyrrng: i

@)The torque wrench,rFig.r(a) is niade from a 35o



Qu.4. Solve any one part of the following: (16)

bl A8o kN load is transmitted from a weld fitting into a 2oo mm steel channel\'/as shown in Fig.4(a). Estimate the maximum stress in the weld.

(b) Solve the following: (8,8)

(i)Find the distance b for the

riveted joint,Fig.4(b-i)' if

the maximum

shearing stress on the most heavily loaded rivet is to be r3r5oo psi.(ii) Find the permissible load P for the riveted joint, Fig. 4(b-ii), if the

resultant shearing stress for the most highly stressed rivet is r5ooopsi.Rivets are t in in diameter.

Qu.S. Solve any one part of the following: (r6)

(a) Design a rigid type of flange coupling to connect two shafu. The input

shaft transmits B7.SkW power at 18o rpm to the output shaft through

the coupling. The service factor for the application (torque) is r.5. Select

suitable material for various parts (shaft, key, bolts, flange) of the

coupling, design the coupling and specifr the dimensions of the

components. Draw the sectional view of the coupling.(b)The horizontal shaft ABCD is mounted in bearings at B and D as shown,/ Fis. sG). A belt passes around the z5o mm diameter pulley fixed to the

shaft at A, and a gear pinion of r5o mm pitch diameter is mounted on theshaft at C. Shaft diameters and axial disposition of the cornponents are as

sketched. The belt strand tensions are hqUzqntat and i-n the ratioF/Fz * 4, while the vertical rea";i@, acts taiffiid$ tothe pinion's pitch circle. Ascertain the shaft{s safety factor when

transferring 2tl kW from belt to pinion at a steady 7.5 flz,, taking theyield strength of the ductile shaft material to be 5oo MPa. Fatigue and

stress concentration are neglected.



Fig.r(a)

Fig.4(a)

{t} tF rur flr}

Fig.4(h-i)

s'*J

Fig.E&)



,&nnl;*nr ffiH,*f *9"*l.t# f,rs{*

't;,"^-o+.ry, {t*lJt

#!r'r' fi*t tf,ffiffit

IB-e*artr:p,crl n*q,|,

.t

Fig.3(a)

{n}

*

FiS.3(b-i)

)

Ftf.--\'ilp"ffi,

S KFT

1 2 *,@----€----s

sr}[ ?$ 15, I go *ffi,;- -'l -

r-- -r'qr- -*.

Fig.3(b-ii)

machine design-1 qpaper nov-dec 2010 nit raipur mech 5th sem

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