R05220103-strength-of-materials-ii

Set No. 1

Code No: R05220103

II B.Tech Supplimentary Examinations, Aug/Sep 2008 STRENGTH OF MATERIALS-II (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Using max. strain energy theory, estimate the safe dia. for a mild steel rod to carry an axial pull of 10 kN together with a transverse shear 5 kN and the factor of safety 3. Take the Poisson?s ratio as 0.3. [16] 2. (a) What is the difference between a closely coiled and open coiled helical springs? (b) Derive the formula to find the deflection of a closely coiled helical spring subjected to an axial load. [6+10] 3. An R.S.Tee-section, 150mm wide × 75mm deep, thickness of flange 9mm, thickness of web 8.4mm, is used as a strut, 3 metre 4 long, ends hinged.Calculate the safe axial load by Rankines formula, using a factor of safety of 3. Rankines constants, f c = 315N/mm2 ; a = 1/ 7500. [16] 4. A horizontal strut 3m long is of-hollow circular section 16cm external dia. And internal dia. 14cm. It carries an end thrust of 300kN along with a u.d.l of 5kN/m. Assuming the ends as hinged and taking the self weight also into account, calculate the max. stress induced in the section (Density = 78.5kN/m3 ). [16] 5. A short hollow cylindrical column having an outside of 300mm and inside dia of 200mm was cast in a factor. On inspection it was found that the Bore is eccentric in such a way that the thickness varies from 30mm at one end to 70mm at the other. Calculate the extreme stress intensities if it carries a load of 800kN along the axis of bore. Sketch the stress distribution. [16] 6. A cantilever consists of a 60 mm × 60 mm ×10 mm angle with the top face AB horizontal. It carries a load of 1 kN at 1 m from the fixed end, the line of action of the load passing through the centroid of the section and inclined at 300 to the vertical. Determine the stresses at A, B and C and also the position of the neutral axis. As shown in the Figure6 [16]

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Set No. 1

Code No: R05220103

Figure 6 7. A semi circular beam is supported on three equally spaced columns. Derive expressions for max.B.M. and max. Twisting moment by first obtaining the general expressions. [16] 8. Find the forces in all the a member of the simply-support N-girder as shown in figure 8 by the method of joints. [16]

Figure 8 ⋆⋆⋆⋆⋆

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Set No. 2

Code No: R05220103

II B.Tech Supplimentary Examinations, Aug/Sep 2008 STRENGTH OF MATERIALS-II (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Using max. principal stress theory, calculate the dia of a mild steel bar subjected to an axial pull of 10 kN and a transverse shear of 5 kN. Take the elastic limit in simple tension as 240N/mm2 and factor of safety 3. [16] 2. A circular shaft transmits 80 H.P. at 120 R.P.M. It is supported on bearings 3m apart. At 1m from the left bearing a pulley is attached which exerts a transverse load of 40 kN on the shaft. Determine a suitable dia. of the shaft if (a) the max. direct stress is not to exceed 100N/mm2 and (b) max. shear stress is not to exceed 50N/mm2 .

[8+8]

3. An R.S.Tee-section, 150mm wide × 75mm deep, thickness of flange 9mm, thickness of web 8.4mm, is used as a strut, 3 metre 4 long, ends hinged.Calculate the safe axial load by Rankines formula, using a factor of safety of 3. Rankines constants, f c = 315N/mm2 ; a = 1/ 7500. [16] 4. (a) What do you understand by “Beam-columns”? (b) A horizontal strut of length L, having hinged ends, carries an axial compressive load P, and central vertical load W. Derive expression for max values of deflection, B.M. and stress. [4+12] 5. A masonry wall, 2.4 metres long, trapezoidal in section with one side vertical, is 6 metres high, 1.2 metres wide at the top and 3.6 metres at the bottom. A thrust of 173.2 KN is transmitted at the top, on the vertical side, in the middle of the length, at an angle of 30o to the horizontal. If masonry weights 21KN/m3 calculate the extreme stress - intensities on the base. [16] 6. A simply supported beam of rectangular section (150 × 200mm) is of span 6m. It carries two point loads of 5KN each at third points. The plane of the load makes an angle of 300 with the vertical plane of symmetry. Find the direction of netural axis and the bending stresses at the top two corners. [16] 7. A semi circular beam is supported on three equally spaced columns. Derive expressions for max.B.M. and max. Twisting moment by first obtaining the general expressions. [16] 8. Using the method of sections, find the magnitude and nature of forces in all the members of the pin-jointed, simply-supported, plane frame shown in figure 8. Make the forces in the frame. [16] 1 of 2

Set No. 2

Code No: R05220103

Figure 8 ⋆⋆⋆⋆⋆

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Set No. 3

Code No: R05220103

II B.Tech Supplimentary Examinations, Aug/Sep 2008 STRENGTH OF MATERIALS-II (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. (a) Briefly illustrate the shear strain energy theory. (b) Using the above theory estimate the factor of safety for a certain type of steel whose proportional limit is 280 MPa. The principal stresses were found to be 100 MPa (tensile), 60 MPa (tensile) and 30 MPa (compressive). [6+10] 2. The internal dia. of a hallow shaft is 2/3 of its external dia. compare its resistance to torsion with that of a solid shaft of the same weight and material. [16] 3. An R.S.Tee-section, 150mm wide × 75mm deep, thickness of flange 9mm, thickness of web 8.4mm, is used as a strut, 3 metre 4 long, ends hinged.Calculate the safe axial load by Rankines formula, using a factor of safety of 3. Rankines constants, f c = 315N/mm2 ; a = 1/ 7500. [16] 4. A horizontal strut 3m long is of-hollow circular section 16cm external dia. And internal dia. 14cm. It carries an end thrust of 300kN along with a u.d.l of 5kN/m. Assuming the ends as hinged and taking the self weight also into account, calculate the max. stress induced in the section (Density = 78.5kN/m3 ). [16] 5. A trapezoidal masonry dam having 4m top width, 8m bottom width and 12m height retains water up to a depth of 9m on the vertical side. The density of masonry is 20kN/m3 . The co efficient of friction between the dam and soil is 0.55. The allowable compressive stress is 345kN/m2 . Check the stability of dam, stating the conditions. [16] 6. Determine the principal moments of inertia for an unequal angle section 200×150× 10mm analytically or graphically. [16] 7. A semi circular beam of radius R, is supported on 3 equally spaced columns. If W is the load per unit length of the beam, derive expressions for B.M and twisting moments at any point P. and hence at supports. [16] 8. (a) Illustrate the types of trusses with the help of sketches. (b) Find the forces in all the members of the cantilever truss loaded as shown in figure 8b. by the method of sections. [6+10]

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Set No. 3

Code No: R05220103

Figure 8b ⋆⋆⋆⋆⋆

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Set No. 4

Code No: R05220103

II B.Tech Supplimentary Examinations, Aug/Sep 2008 STRENGTH OF MATERIALS-II (Civil Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ⋆⋆⋆⋆⋆ 1. Based on shear strain energy theory, suggest a safe dia. for a steel rod subjected to an axial pull of 9 kN and a transverse shear of 5 kN. Take the elastic limit as 240 MPa and factor of safety 3, Poisson’s ratio = 0.3. [16] 2. A circular shaft transmits 80 H.P. at 120 R.P.M. It is supported on bearings 3m apart. At 1m from the left bearing a pulley is attached which exerts a transverse load of 40 kN on the shaft. Determine a suitable dia. of the shaft if (a) the max. direct stress is not to exceed 100N/mm2 and (b) max. shear stress is not to exceed 50N/mm2 .

[8+8]

3. An R.S.Tee-section, 150mm wide × 75mm deep, thickness of flange 9mm, thickness of web 8.4mm, is used as a strut, 3 metre 4 long, ends hinged.Calculate the safe axial load by Rankines formula, using a factor of safety of 3. Rankines constants, f c = 315N/mm2 ; a = 1/ 7500. [16] 4. A horizontal strut 3m long is of-hollow circular section 16cm external dia. And internal dia. 14cm. It carries an end thrust of 300kN along with a u.d.l of 5kN/m. Assuming the ends as hinged and taking the self weight also into account, calculate the max. stress induced in the section (Density = 78.5kN/m3 ). [16] 5. A masonry retaining wall of trapezoidal section is 6m height and retains earth up to the top. On the vertical side. If the top width is 1m, find the bottom width so that no tension in inclined at the base? The density of masonry is 23kN/m3 . The density of earth is 160kN/m3 . The angle of repose is 30o . [16] 6. What do you understand by circle of inertia? Using the same obtain graphically the principal moments of inertia for an unequal angle section 60 × 40 × 6mm .[16] 7. A semi circular beam is supported on three equally spaced columns. Derive expressions for max.B.M. and max. Twisting moment by first obtaining the general expressions. [16] 8. Using the method of section find out the forces in all the members of the simplysupported pin-jointed plane truss loaded as shown in figure 8. [16]

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Set No. 4

Code No: R05220103

Figure 8 ⋆⋆⋆⋆⋆

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