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# AICTE Mechanical Engineering UG Model Question Papers : All India Council for Technical Education

Name of the Instution : All India Council for Technical Education
Class : Undergraduate Programs – UG
Document Type : Model Question Papers
Paper : Mechanical Engineering
Year : 2018
Website : https://www.aicte-india.org/education/model-syllabus

## AICTE Mechanical Engineering UG Model Question Papers

Download Mechanical Engineering Model Question Papers For Undergraduate Program from the All India Council for Technical Education website. The model question papers are suggestive blueprints.

Related : AICTE Electronics & Communications Engineering UG Model Question Papers : www.pdfquestion.in/33542.html

The primary aim of these question papers is to bring clarity about the process of connecting questions to performance indicators and hence to course outcomes.

## Introduction to Finite Element Methods

1a) Differentiate between FEM, FDM, FVM and BEM. Explain which method is suited for analysis of polymer composite crack propagation along with software tool and justify.

1b) Using Rayleigh-Ritz method determine the expressions for deflection in a simply supported beam subjected to uniformly distributed load over entire span. Also calculate the percentage of error when RR method values arecompared with analytical values.

2a) Consider a thin (steel) plate as shown in figure 2a. The plate has a uniform thickness t=1in, Youngs modulus E = 30x106psi, and weight density 0.2836lb/in3. In addition to its self-weight, the plate is subjected to a point load p = 100lb at its midpoint.
a) Model the plate with two finite element points
b) Write down the element stiffness matrices and element body force vectors.
c) Assemble the structural stiffness matrix K and global load factor F.
d) Using the elimination approach, solve for the global displacement vector Q.
e) Evaluate the stresses in each element.

2b) Explain Different types of elements in FEM. Explain H type and P type method with the help of suitable example.

3a) Using Galerkin’s method, establish an expression of the maximum deflection for a cantilever beam having length L, moment of inertia I and young’s modulus E, subjected to point load P at the end. Also calculate the percentage of error when Galerkin’s method values are compared with analytical values.

b) Explain different mesh quality parameters. Discuss any five of them. 10 CO3 L2 2.4.1

4a) For a given problem how a FEA engineer has to decide the following
i) Element size ii) Element Type iii) Type of analysis to carry out iv) Linear or Non linear analysis v) How results are compared with real time scenario?

4b) An axial load P=200x103N is applied on a bar as shown in Fig. 4b. Using the penalty approach for handling boundary conditions, determine nodal displacements, stress in each material and reaction forces.

## Design of Thermal Systems

1 a Name the specific heat exchanger construction type that may be used in each of the following application and justify your selection.
a. Milk pasteurizing
b. Power condenser
d. Marine oil cooler
e. Air cooled condenser

b A two shell pass and two tube pass shell & tube heat exchanger is used to heat process fluid (water) from 30°C to 80°C. The mass flow rate of the process fluid is 8000kg/hr and that of the service fluid is 6000kg/hr, which is available at a temperature of 200°C. The overall heat transfer coefficient is 1500W/ m2K. Find out the outlet temperature of service fluid, and the area required for the heat transfer. After a long time of operation of the heat exchanger, it is found that the outlet temperature of the process fluid is only 70°C. Find the fouling resistance developed during this period. Cp of the service fluid = 2.8kJ/Kg K Cp of the process fluid =4.2kJ/Kg K

2. a What are the different kinds of spiral plate heat exchangers and what are their limitations?
b. A counter flow shell and tube heat exchanger is used to cool engine oil flowing through the tube at 0.25kg/s, the specificheat of oil is 2.2kJ/kg K. This oil is cooled by the water, which flows at 0.3kg/s. The oil enters at 560K and leaves at 340K. The cooling water enters at 298K. Find the lengthof the tube if the heat transfer coefficient from oil to tube surface is 2340W/m2K, and from tube surface to water is6215W/m2K. The mean diameter of the tube is 18mm.

## Manufacturing Processes

1a Manufacturing processes are classified as,
i) Processing operations and
ii) Assembly operations
Mention sub-classifications under these two categories with suitable examples.

1b A broken railway track needs welding on-site. Recommend a suitable process & outline its working principle.
1c Differentiate between Brazing, Soldering and Welding with the following aspects,
i) Temperature
ii) Type of material to be joined
iii) Surface finish and
iv) Strength

2a Discuss the criteria for selection of manufacturing processes. 6 CO1 L2 1.4.1
2b A precision foundry needs to produce IC engine pistons. Suggest suitable process and explain the procedure with neat sketch.
2c Explain the post processes of casting, fettling-cleaning and finishing of castings.
3a Enumerate the steps involved in sand casting.
3b A pattern shop has received order to make a wooden pattern for making sand castings. Discuss various pattern allowances to be considered by him to produce the required pattern.
3c With neat sketch, discuss the working principle of investment casting process and list the advantages & limitations of it.

4a Draw Merchant’s force diagram. State the assumptions made in the development of such a diagram.

4b Interpret the program syntax.
N10 G28 U0 W0;
N20 T0101;
N30 G00 X35 Z2;
N40 G00 X30 M03 S1500;
N50 G01 Z64 M08 F0.1;

Machines & Mechanisms
1a) Draw the kinematic diagram for the mechanisms shown in the Fig.Q1a (i to iv). Compute the mobility.
1b) For the mechanisms shown in the Fig. Q1b i) and ii), locate all the instantaneous centers. Fig Q1b.i) Self-locking brace Fig Q1b.ii) Landing gear

2a) Three links in a kinematic chain move relatively to each other. Prove that they have three instantaneous centers and lie in a straight line

2b) The gearbox shaft and propeller shaft of an automobile are connected by a universal joint. Obtain the expression for ratio of output shaft speed to input shaft speed. analyze the conditions when propeller shaft will have i) maximum speed ii) minimum speed and iii) both shafts have equal speeds.

3a) Describe with neat sketch the mechanism used in the automobile steering system and obtain the expression for condition of correct steering.

3b) The mechanism shown in the Fig. Q3b) is used to feed cartons to a labeling machine and, at the same time, to prevent the stored cartons from moving down. At full speed, the driveshaft rotates clockwise with an angular velocity of 200 rpm. At the instant shown, determine the acceleration of the rocker arm that rotates and lowers the arts.

4a) A shaft has 3 disturbing masses in the single plane with radii of rotation r1, r2 and r3 and angular positions ?1, ?2 and ?3. Discuss how the system will be balanced by adding another balancing mass in the same plane.

4b) Determine the required input torque on the crank AB of the reciprocating engine mechanism for the static equilibrium when applied piston load is 1000 N. The lengths of crank AB and connecting rod BC are 100 mm and 300 mm respectively and crank has turned through 60° from I.D.C.

## Mechanical Vibrations

1 a) An inverted pendulum as shown in Fig. Q 1(a) is pivoted at point O. Assume small oscillations and neglect the mass of the rod. Obtain the condition for the system to vibrate. Develop 1 and 2 dof mathematical model of a car
1 b) A gun barrel shown in Fig. Q 1(b) having mass 560 kg is designed with the following data. Initial recoil velocity of 36 m/s and recoil distance on firing 1.5m. Determine i) Spring constant ii) Critical damping coefficient of the dashpot which is engaged at the end of the recoil stoke. iii) Time required for the barrel to return to a position of 0.12 m from its initial position.

2 a) A cylinder of mass ‘m’ and radius ‘r’ rolls without slipping on a cylindrical surface of radius R as shown in Fig. Q 2(a). Find the natural frequency for small vibrations. Fig.
2 b) A rotor of mass 4 kg is mounted midway between bearings which may be assumed to be simple supports. The bearing span is 480 mm. The shaft is of 9 mm diameter and is horizontal. The center of gravity of the disc is displaced 3 mm away from the geometric center of rotor. The equivalent viscous damping at the center of the disc and shaft may be assumed as 49 N-S/m. The shaft rotates at 760 rpm. Take E= 2x1011N/m2. Determine i) The critical speed of the shaft ii) Deflection of the shaft iii) Dynamic load on the bearings iv) The maximum stress in the shaft. v) Identify the parameters to reduce the stress in the shaft. Use any one parameter and reduce the stress to its 50%.

3 a) Explain any four instruments used for measuring, assessing and analyzing the noise output of machines.
3 b) A railroad car of mass 2,000 kg traveling at a velocity 10 m/s is stopped at the end of the tracks by a spring-damper system, as shown in Fig. Q3(b). The stiffness of each spring (K/2) is 40 N/mm and the damping constant is 20N-s/mm. Determine i) Undamped and damped natural frequency ii) Damping factor iii) The maximum displacement of the car after engaging the springs and damper.

## Mechanics of Materials

1a Two solid cylindrical rods (1) and (2) are joined together at flange B and loaded, as shown in Figure Q.1a. The diameter of rod (1) is 1.75in. and the diameter of rod (2) is 2.50 in. Determine the normal stresses in rods (1) and (2)

1b The five-bolt connection shown in Figure Q.1b must support an applied load of P = 265 kN. If the average shear stress in the bolts must be limited to 120 MPa, determine the minimum bolt diameter thatmay be used for this connection.

1c State the Hook’s law. Neatly draw the Stress-strain diagram for Steel indicating all silent points and zones on it.

2a At an axial load of 22 kN, a 45-mm-wide × 15-mm-thick polyimide polymer bar elongates 3.0 mm while the bar width contracts 0.25 mm. The bar is 200 mm long. At the 22-kN load, the stress in the polymer bar is less than its proportional limit. Determine: (a) the modulus of elasticity, (b) Poisson’s ratio, (c) the change in the bar thickness

2b A solid circular rod with a diameter of d = 16 mm is shown in Figure Q.2b. The rod is made of an aluminum alloy that has an elastic modulus of E = 72 GPa and Poisson’s ratio of = 0.33. When subjected to the axial load P, the diameter of the rod decreases by 0.024 mm. Determine the magnitude of load P

3a With standard notations derive the expression for deformation of axially loaded bars of uniform cross-section

3b Aluminum [E = 70 GPa] member ABC supports a load of 28 kN, as shown in Figure Q.3b. Determine:
(a) the value of load P such that the deflection of joint C is zero.
(b) the corresponding deflection of joint B.