Degree cad 6_th sem

K.J.INSTITUTE OF ENGINEERING AND TECHNOLOGY
MECHANICAL DEPARTMENT
COMPUTER AIDED DESGN (2161903)
IMPORTANT QUESTIONS
Prepared by: Pradip Darji and Sandip Dave, Mechanical Department, KJIT Page 1 of 10
CHAPTER-1 INTRODUCTION ( 10-12 MARKS)
1. What is graphic standard? Explain different CAD standards.
2. Determine following for an 8-plane raster display with resolution of 1280 x 1024 and
a refresh rate of 60Hz (non-interlaced):
i. The size of graphical memory (refresh buffer memory).
ii. The time required to display a scan line & a pixel.
iii. The active display area of the screen if the resolution is 78 dpi (dots per inch).
3. Write Bresenham’s line algorithm. Determine intermediate pixels for line
starting from (1,1) to (8,5).
4. Discuss the reasons for implementing CAD. Also draw a diagram showing product
cycle with the implementation of CAD.
5. Write Bresenham’s algorithm for generation of line also indicate which raster
locations would be chosen by Bresenham’s algorithm when scan converting a line
from screen co-ordinate (1,0) to (10,3).
6. Describe the structure of an IGES file and compare IGES and PDES.
7. What do you mean by Computer Aided Design (CAD)? Discuss reasons for
implementing CAD in industry.
8. Give your Comments on the need for standardisation in Computer Graphics. Briefly
discuss about various graphics standards available.
9. Explain DDA algorithm for generation of line.
10. Explain Bresenham’s algorithm for generation of line.
11. Define computer aided design. Compare computer aided design and conventional
design with a neat sketch/block diagram. State the different applications of CAD in an
engineering field. Justify the need of CAD in engineering area.
12. Describe a standard graphics workstation in detail along with neat sketch.
13. What are different software package used in CAD. Give specification of CAD work
station.
14. What are the advantages of CAD in design? Explain application of Computers to the
design process.
15. List and explain the important parameters to be considered while selecting CAD
systems. List the different application of CAD in mechanical engineering.
16. State the different CAD software commercial available and explain the features of
CAD software in detail. (any two software.)
17. Describe the structure of an IGES file and compare IGES and PDES.
18. Explain different types of coordinate systems available in CAD softwares.
19. State different commercial CAD software available and explain the features of any
two CAD software in detail.
20. State the various stages for a design process, in which various CAD tools can be used
to improve productivity.
CHAPTER-2 CURVES AND SURFACES (14 TO 16 MARKS)
1. With the help of neat sketches explain various types of surfaces.

IMPORTANT QUESTIONS
2. Derive general parametric equation for Hermitz cubic spline curve in matrix form.
3. Two Bezier curve sections A and B have order of 3 and 4 respectively. Derive the
condition for 1st order (C1) continuity between these two sections.
4. Explain Hermite cubic spine curve with neat sketch also write its characteristics and
obtain the parametric equation for the same.
5. Briefly discuss about B-spline curve and Bezier curve with its advantage.
6. With neat sketch explain the characteristics of Bezier curve and mention its
advantages.
7. Explain the following surfaces
1. Patch 2. Ruled 3. Coons
8. Explain analytic curves and synthetic curves with example.
9. What is parametric representation? A line having length 20 unit, passes through the
point P1 (1,2) . It make an angle 60 degree with x axis. Determine parametric
equation of line.
10. A Bezier curve is to be constructed using control points P0 (35,30), P1 (25,0), P2
(15,25), P3 (5,10). The Bezier curve is anchored at P0 and P3. Find the equation of
the Bezier curve and plot the curve for u=0, 0.2, 0.4, 0.6, 0.8, and 1.
11. Explain different types of surfaces with respect to modeling.
12. Develop vector equation of line in parametric form.
13. Derive equation of Bezier’s curve with 5 control points. State the order of the curve
generated by these control points. What do you mean by ‘Convex hull’ property?
CHAPTER-3 MATHEMETICAL REPRESENTATION OF SOLIDS
(7-8 MARKS)
1. Explain constructive solid geometry (CSG).
2. Write limitations of a wire frame model.
3. What are different types of geometric technique available? Describe the common
facilities available in a solid modeling package.
4. Write short note on CSG and B-rep.
5. List various approaches used for creating solid models. Discuss about Constructive
solid modelling (C-Rep) and Boundary representation (B-Rep) approaches.
6. What is feature based modelling? Discuss various steps involved in creation of
models using features.
7. What do you mean by 2D and 3D wireframe modeling? Differentiate between
wireframe modeling and solid modeling technique for CAD. OR Explain wireframe
modeling in detail. Compare it with solid modeling
8. What is geometric modeling? Explain its importance in CAD / CAM applications.
States the different types of geometric modeling in mechanical engineering field.
9. Explain B-rep and C-rep approach of solid modeling in detail.
10. Explain solid modeling in detail.
11. Derive from fundamentals the parametric equation for the Hermite Cubic spline.
Represent the equation in matrix form.
12. What do you understand by 2 ½ D model ? Clearly distinguish it from 3D model.

IMPORTANT QUESTIONS
13. With example clearly define the term topology as used in modeling
CHAPTER-4 GEOMETRIC TRANSFORMATIONS (7-8 MARKS)
1. A triangle PQR has its vertices at P(0,0), Q(4,0) and R(2,3). It is to be translated by 4
units in X direction, and 2 units in Y direction, then it is to be rotated in anticlockwise
direction about the new position of point R through 90o. Find the final position of the
triangle.
2. A triangle ABC has vertices as A(2,4), B(4,6) and C(2,6). It is desired to reflect
through an arbitrary line L whose equation is y 0.5x 2. Calculate the new vertices
of triangle and show the result graphically.
3. Evaluate the shape functions N1, N2 and N3 at the interior point P(3.85,4.8) for the
triangular element shown in figure-3. Also determine Jacobian of the transformation J
for the element.
4. Reflect the diamond shape polygon whose vertices are A(-2,0), B(0,-1), C(2,0),
D(0,1) about an arbitrary line L which is represented by equations y=0.5x+1.

IMPORTANT QUESTIONS
6. A triangle ABC with vertices A(0,0), B(4,0) and C(2,3). Perform the following
operations for it. (i) Translation through 4 and 2 units along X and Y directions
respectively. (ii) Rotation through 900 in counter clockwise direction about the new
position of point C.
7. What is a geometric transformations? Define and explain the following With respect
to 2-D transformations (any three) : (i) Translation (ii) rotation (iii) scaling (iv)
reflection
8. A rectangle formed by four points PQRS whose coordinates are
P(50,50),Q(100,50),R(100,80),S(50,80).Find the new coordinates of the rectangle in
reduced size using scaling factors SX = 0.5 and SY = 0.6
9. Explain 3-D geometric transformations (any three) in detail.
10. The coordinates of the triangle are P(50,20),Q(110,20) and R(80,60).Determine the
coordinates of the vertices for the new reflected triangle, if it is to be reflected about :
11. (i) X-axis and (ii) line y=x
12. Derive the transformation matrix for the Rotation. Further give the transformation
matrix for scaling,reflection and shear.
13. A triangle ABC with vertices A(30,20), B(90,20) and C(30,80) is to be scaled by
factor 0.5 about a point X(50,40). Determine (i) the composition matrix and (ii) the
coordinates of the vertices for a scaled triangle.
14. Explain the following 2D geometric transformation with suitable examples: -
translation and rotation.
15. A rectangle ABCD has vertices A(1,1), B(2,1) ,C(2,3) and D(1,3) . It has to be rotated
by 300 CCW about point P (3,2). Determine (i) the composite transformations of
matrix and (ii) the new coordinates of rectangle.
16. Reflect the diamond shape polygon whose vertices are A(-3,0), B(0,-2), C(3,0),
D(0,2) about an arbitrary line L which is represented by equations y=0.5x+1.

IMPORTANT QUESTIONS
17. A triangle ABC with vertices A(0,0), B(4,0) and C(2,3) is Translated through 4 and 2
units along X and Y directions respectively and then Rotated through 90o in
counterclockwise direction about the new position of point C. Find:
(1) The concatenated transformation matrix and
(2) The new position of triangle.
18. Explain orthographic and oblique projections in details with suitable sketch.
19. Explain window to view port transformations.
20. What are homogeneous coordinate systems? Write the matrix transformation in
homogeneous form for clockwise rotation about origin.
CHAPTER-5 FINITE ELEMENT METHOD (28-32 MARKS)
1. Explain general procedure for doing Finite Element Analysis. Give stiffness
matrix for structural analysis.
2. Explain Penalty approach and Elimination approach for FEA.
3. What are the different types of Elements? OR Explain 2-D and 3-D elements used in
finite element analysis.
4. What is shape function? Derive linear shape functions for 1-dimensional bar element
in terms of natural coordinate. Also plot variation of shape functions within this
element.
5. With the help of suitable examples explain condition of plane stress and plane strain.
6. Write element stiffness matrix and element load vectors for a beam element.
7. List properties of global stiffness matrix [K].
8. Write short note on automatic mesh generation with an example.
9. Discuss the different steps used in finite element analysis in detail. State the suitable
examples of FEA in engineering.
10. Explain the concept of finite element method. Discuss about various steps involved in
finite element analysis.
11. State and describe the various types of elements used in the finite element analysis.
12. Explain plain stress and plain strains with figure.
13. List various engineering application of FEA.
14. Derive equation of global stiffness matrix for 1D linear element considering thermal
effect.
15. Explain CST element defects.
16. Explain potential energy equation, used in FEA.
17. Consider the bar shown in figure- An axial load F=35 kN is applied as shown. Using
Elimination approach for handling boundary conditions, determine nodal
displacements and support reactions. Take E=200 GPa for all elements. Length of
each element is in mm.

IMPORTANT QUESTIONS
18. Consider the bar as shown in figure. Determine the nodal displacements and element
stresses, if the temperature rises from 20 degree C to 60 degree C. Take P=300kN,
E1=70GPa, A1=900 mm2,Coefficient of thermal expansion, α1=23 x 10-6 per degree
C ; E2=200GPa, A2=1200 mm2, Coefficient of thermal expansion, α2=11.7 x 10-6
per degree C.
19. A four bar truss is as shown in figure. Assuming that for each element, the cross-
sectional area is 400 mm2 and modulus of elasticity is 200 GPa, determine the nodal
displacements. Length of each element is in mm.
20. Axial load P = 300 KN is applied at 20° C to the rod as shown in fig. The temperature
is then raised to 60° C. The coefficient of thermal expansion for Aluminium is 23x10-
6 per °C and Steel is 11.7x10-6 per °C. AAl = 900 mm2, ASteel = 1200 mm2, EAl =
70 x 109 N/m2, ESteel = 200 x 109 N/m2. Using FEM, (1) Determine the nodal
displacement and element stresses. (2) The reaction forces at the supports.

IMPORTANT QUESTIONS
21. Consider the stepped bar shown in fig. A load P=200 KN is applied as shown.
Determine the nodal displacements, element stresses, and support reactions. use
elimination approach for boundary conditions. Take E= 2x105 N/mm2.
22. A stepped bimetallic bar made of Aluminium (E= 70x103 N/mm2) and steel (E=
200x103 N/mm2) is subjected to an axial load of 200 KN, as shown in the fig. Using
finite element method, determine (i) the nodal displacements (ii) the stresses in each
material and (iii) the reaction forces at the supports.
23. Figure shows the compound section fixed at both ends. Estimate the reaction forces at
the supports and the stresses in each material when a force of 200 kN is applied at the
change of cross section.

IMPORTANT QUESTIONS
24. An axial stepped bar as shown in figure is subjected to an axial pull of 50 KN. If the
material of the bar is uniform and has a modulus of elasticity as 200 GPa. Determine
the displacement and stresses of each of the section. Also find the reaction.
25. Figure below shows the bar with dimensions and loads. Determine the nodal
displacements, element stresses and reacting if the temperature rises by 600 degree C.
Assume the modules of elasticity for the complete bar as 200 GPa and coefficient
thermal expansion as 12 x 10 per degree C.
21. A system of a rigid cart connected by three linear springs as shown in Fig.. The force
of 60 N is acting on cart as shown in figure. Determine the following:
(1) Use finite element concept to assemble the elemental stiffness matrices of three
linear springs into global stiffness matrix.
(2) Write global load vector.
(3) Find Nodal solution.

IMPORTANT QUESTIONS
26. Formulate the finite element model using 1D-bar element for the system shown in
figure-2 below. Area at the junction shown below is AJ =250 mm2, at the left end is
equal to AL=750 mm2 and at the right end is equal to AR=500 mm2. Length up to
junction from any end is 200 mm. Load P=500kN is acting at the junction. Young’s
modulus of elasticity E= 200 Gpa. The temperature of the system is raised by 40°C.
Co-efficient of thermal expansion is 11×10-6 per °C. Assemble the stiffness matrix &
force vector.
27. A thin plate as shown in figure-4 has a uniform thickness of 10 mm and modulus of
elasticity is 200 Gpa. The plate is subjected to a point load P = 500 N as shown in
figure. Model the problem with two elements and find stresses in each element.
28. For the one dimensional fluid flow problem as shown in figure 5 with velocity known
at right end, determine velocities at nodes 1 and 2. Let Kxx=2cm/s
29. Modeled the tapered bar shown in figure 2 by considering it is made of 2 elements
and determine deflection at both end and in middle of the bar. Assume modulus of
elasticity as 200 Gpa.

IMPORTANT QUESTIONS
30. Determine the temperature at x = 40 mm (Figure 1), if the temperature at nodes Ti =
120 °C, Tj = 80 °C and xi = 10 mm and xj = 60 mm. Consider linear shape function.
31. List various engineering application of FEA.
32. Derive equation of global stiffness matrix for 1D linear element considering thermal
effect.
33. Explain CST element defects.
34. Explain potential energy equation, used in FEA.

Degree cad 6_th sem

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