Download GTU (Gujarat Technological University Ahmedabad) B.Tech/BE (Bachelor of Technology/ Bachelor of Engineering) 2020 Summer 6th Sem 2161903 Computer Aided Design Previous Question Paper

Enrolment No.___________

**GUJARAT TECHNOLOGICAL UNIVERSITY**

**BE - SEMESTER? VI EXAMINATION ? SUMMER 2020**

**Subject Code: 2161903**

**Date:02/11/2020**

**Subject Name: COMPUTER AIDED DESIGN**

**Time: 10:30 AM TO 01:00 PM**

**Total Marks: 70**

**Instructions:**

**1. Attempt all questions.**

**2. Make suitable assumptions wherever necessary.**

**3. Figures to the right indicate full marks.**

**MARKS**

**Q.1 (a)**Why CAD is widely used in modern manufacturing industries?

**03**

**(b)**Determine raster locations of a line joining two points from A(12, 12) to B(4,

**04**

2) using DDA line drawing algorithm.

**(c)**Determine generalized parametric form of a line passing through two points

**07**

using neat sketch. Find Parametric equation of line through points A(3,-6,7)

and B(5,1,-4).

**Q.2 (a)**Why Bresenham's algorithm is superior to DDA algorithm?

**03**

**(b)**Answer the following:

**04**

(i) Compare Analytic and Synthetic curves

(ii) Why Homogeneous coordinate transformations are used in CAD?

**(c)**Prove that the transformation matrix for reflection about the line = - is

**07**

equivalent to clockwise rotation by 45? followed by reflection relative to Y

axis and finally counter clockwise rotation by 45?.

**OR**

**(c)**Find concatenated matrix if the operations are performed as per the following

**07**

sequence:

a) Rotation through 45? counterclockwise.

b) Translation through 5 and -8 units along the X and Y directions.

c) Rotations through 60? clockwise.

**Q.3 (a)**Discuss any three properties of solid models. (Don't enlist properties only).

**03**

**(b)**Explain following surfaces:

**04**

(i) Revolved surface (ii) Bezier Surface

**(c)**A Bezier curve is to be constructed using control points P0 (35, 30), P1 (25,

**07**

0), P2 (15, 25) and 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.

**OR**

**Q.3 (a)**Explain Constructive Solid Geometry (CSG) with sketch.

**03**

**(b)**Enlist various types of surfaces. Explain ruled surface.

**04**

**(c)**Derive equation of a Hermite's cubic spline curve with two end points P0

**07**

and P1 and their tangent vectors are

0 and 1 .

**Q.4 (a)**What are the properties of the Stiffness matrix?

**03**

**(b)**What is shape function? Draw a sketch for a linear shape function used in

**04**

FEM.

**(c)**How many elements to be considered in the problem of figure 1? Determine

**07**

Global stiffness matrix bar elements used in the system below:

1

Figure1

**OR**

**Q.4 (a)**What do you mean by `Discretization'? State precautions required during

**03**

discretization.

**(b)**What do you mean by `Iso-Parametric formulation' of problems in FEM.

**04**

**(c)**How many elements to be considered in the problem of figure 2? Determine

**07**

Global stiffness matrix bar elements used in the system below:

Figure 2

**Q.5 (a)**List applications areas of Finite Element Analysis (FEA).

**03**

**(b)**Enlist steps to be followed for solution of Structural problems using FEM.

**04**

**(c)**For one dimensional element shown in Figure 3, temperature at node 1 is

**07**

100? C and at node 2 is 40? C. Evaluate shape function associated with node

1 and node 2. Calculate temperature at point P. Assume linear shape function

Figure 3

**OR**

**Q.5 (a)**What are the types of loading acting on the structure? Give suitable

**03**

examples.

**(b)**Define total potential energy. State the principle of minimum potential energy.

**04**

**(c)**Analyze the two-members truss shown in Figure 4. Assume EA to be

**07**

constant for all members. The length of each member is 5m. Area A=0.01

m2 and E=210GPa. Compute nodal displacements and reactions forces.

Determine stresses in each member.

Figure 4

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2

This post was last modified on 04 March 2021