Universiti I J Malaysia V PAHANG

Engineering Technology Creativity

FACULTY OF MANUFACTURING ENGINEERING

FINAL EXAMINATION

COURSE : MECHANICS OF MATERIALS

COURSE CODE : BFF1133/BHM1123

LECTURER : DR. AKM ASIF IQBAL

I DATE : 16 JUNE 2015

I DURATION 3 HOURS

SESSION/SEMESTER : SESSION 2014/2015 SEMESTER II

I PROGRAMME CODE : BFF/BHM

INSTRUCTIONS TO CANDIDATE:

a) This question paper consists of FOUR (4) questions. Answer ALL questions. b) All answers to a new question should start on a new page. c) All calculations and assumptions must be clearly stated. d) Candidates are not allowed to bring any material other than those allowed by the

invigilator into the examination room.

EXAMINATION REQUIREMENTS:

1. Appendix A— Average Mechanical Properties of Materials

DO NOT TURN THIS PAGE UNTIL YOU ARE TOLD TO DO SO

This examination paper consists of SIX (6) printed pages including front page.

A.

1

mm /iDflhi ft002

400

CONFIDENTIAL BFF/BHM/1 4 1511IBFF1 133IBHM1 123

QUESTION 1 [25 MARKS]

a) Determine the average shear stress developed in pin A of the truss as shown in Figure la.

A horizontal force of P = 40 kN is applied to joint C. Each pin has a diameter of 25 mm

and is subjected to double shear. (12 Marks)

C D

2iii

Figure la

b) The elastic portion of the stress-strain diagram for a steel alloy is shown in Figure lb.

The specimen from which it was obtained had an original diameter of 13 mm and a gauge

length of 50 mm. If a load of = 20 kN is applied to the specimen, determine its diameter

and gauge length. Take v = 0.4.

(13 Marks)

TMPa)

Figure lb

2

2 Fri

CONFIDENTIAL BFFIBIIIMJ1415IIIBFF1 I 33/BRiM 1123

QUESTION 2 [25 MARKS]

a) The plate is deformed due to the loading into the dashed shape shown in Figure 2a.

Determine:

(a) the average normal strain along the side AB

(b) the average shear strain in the plate at A relative to the x and axes.

(10 Marks)

V

3 m;n'

B I___ 2mrn

I 25'lJ mm

A l . - IC

Figure 2a

b) The three suspender bars are made of A-36 steel and have equal cross-sectional areas of

450 mm2 Determine the average normal stress in each bar if the rigid beam is subjected to

the loading shown in Figure 2b

(15 Marks)

[-1 tiF-F---i IflTi — . f---i cii—j

Figure 2b

3

CONFIDENTIAL

BFFLBHMJ1415I1'BFF1 133/BHM1 123

QUESTION 3 [25 MARKS]

a) Gear B supplies 15 kW of power, while gears A, C, and D withdraw 6 kW, 4 kW, and 5

kW, respectively as shown in Figure 3a. If the shaft is made of steel with the allowable

shear stress of Tallow = 75 MPa, and the relative angle of twist between any two gears

cannot exceed 0.05 rad, determine the required minimum diameter d of the shaft to the

nearest millimeter. The shaft is rotating at 600 rpm.

(15 Marks)

Figure 3a

b) Draw the shear and moment diagrams for the beam shown in Figure 3b. (10 Marks)

15.kN

Figure 3b

4

a

'm

TD Section a - a

CONFIDENTIAL BFF/BHM/1415I11BFF1133[BHMI 123

QUESTION 4 [25 MARKS]

a) If the beam is subjected to a shear of V = 15 kN as shown in Figure 4a, determine the

web's shear stress at A and B. (10 Marks)

200 nun /

1 4 30 rnii

i -25 mm

B

30 mmT̂i2 mm

Figure 4a

b) If the load has a weight of 2700 N, determine the maximum normal stress developed on

the cross section of the supporting member at section a—a, shown in Figure 4b. Also, plot

the normal stress distribution over the cross-section.

(15 Marks)

Figure 4b

END OF EXAMINATION PAPER

5

C/D

c4

(f

C.)

C.)

z

AyrageMechanicai Pr-opertis of Typical Eginee.ring Materia]s

(Si Uns)

Maienals Dtnity p (M/m)

NI Moduusoto4uJu of

E1isbc& E Thgdty 0

(GFa) (Cra)

Yicla Strengb (Ma)

Tent Comp.b Sha

lfltwate Strength (J%1P)

Teos Comp Shear -S

% E'ongation u Onmccnucrt

Poon s Rato '

(1o,t ofTbei-m a

(Q') C

--..--- -S-S.-'--.--.---.-.-------..- --S

Alumimim- 2,79 73.1 27 414 418 172 469 469 290 10 035 23

A2c)rs 231 68.9 26 1 255 255 231 290 190 1&5 12 035 24

Cs jtou - Or3y kT' 20 7 67.0 21 - - 179 669 0.6 Q,i 12

L MaUeb 1 eASTM A 197 1.

223 172 68 - - 276 .72 - 5 028 12

Copp"r Red Bm% =400 874 102 37 70.0 70,0 - 241 241 35 0.35 1-8

Mloys L BtozCS6i00 5.83 103 38 545 545 655 655 - 20 034 17

r 1)4T6LJ 183 .4 7 iS 1-52 152 - 276 27 52 1. 0 26

StruetuT9 A36 7.85 790 75 250 250 - 400 400 - 30 032 12 Stool

- —$taitloss304 "AlIOYS736 19.3 75 207 207 517 537 40 0.27 17

Tool L2 6.16 20 75 703 703 800 800 -. o 12

Thu 924 924 - 1,000 ,000 -' 16 036 94 All

w5tn1 238 22.2 - 12 - - 015 31

St.zgth

1,33 0.15 it

PitcKUa49 1 S 131 1 -- 117 483 203 28 034 I

Rxfoced L 30% G1ts 145 72' - - - - 0 13 - - 034 -

Se1ct rUCtUl047 2.111 24' 621 - 1291

0rad '-'VtcSpntct 3.60 05