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- Strength Of Materials - SOM
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**Anna university - ACEW**- Civil Engineering
- B.Tech
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Visit : Civildatas.blogspot.in PART-B 1. An alloy circular bar ABCD is 3m long is subjected to a tensile force of 50kN as shown in fig. If the stress in the middle portion BC is not to exceed 150Mpa, then what would be its diameter? Also find the length of the middle portion, if the total extension of the bar should not exceed by (Nov/Dec 2010) sp ot. in 3mm. Take E=100GPa. (12 Marks) 2. Find the stresses in each section of the bar shown in fig and also find the total extension of the bar. E = 2.1x105N/mm2 (16 Marks) s.b log (Nov/Dec 2006) ata 3. Find the value of P and the change in length of each component and the total change in length Ci vil d of the bar shown in fig. 2 Visit : Civildatas.blogspot.in

Visit : Civildatas.blogspot.in 4. A steel rod of 25mm diameter is placed inside a copper tube of 30mm internal diameter and 5mm thickness and the ends are rigidly connected. The assembly is subjected to a compressive load of 250kN. Determine the stresses induced in the steel rod and copper tube. Take the modulus of elasticity of steel and copper as 200GPa and 80GPa respectively. (10 Marks). sp ot. in (NOV/DEC 2006). 5. An aluminum cylinder of diameter 60mm located inside a steel cylinder of internal diameter 60mm and wall thickness 15mm. The assembly is subjected to a compressive force of 200kN. What are the forces carried and stresses developed in steel and aluminum? Take modulus of elasticity for steel as 200GPa and aluminum as 50GPa. (8 Marks) (Nov/Dec 2008) 6. A reinforced concrete column 500 mm x 500 mm in section is reinforced with 4 steel bars of 25 mm diameter; one in each corner, the column is carrying a load of 1000 kN. Find the stresses in the concrete and steel bars. Take Esteel = 210x103N/mm2 and ECon = 14x103N/mm2. (Nov/Dec log 2007) 7. A reinforced concrete circular column of 400 mm diameter has 4 steel bars of 20mm diameter embedded in it. Find the maximum load which the column can carry, if the stresses in steel and 18 times that of concrete. s.b concrete are not to exceed 120MPa and 5MPa respectively. Take modulus of elasticity of steel as 8. A steel tube of 20mm internal diameter and 30mm external diameter encases a copper rod of 15mm diameter to which it is rigidly joined at each end. If the temperature of the assembly is ata raised by 80 C. Calculate the stresses produced in the tube. ES=2x105N/mm2, EC=1x105N/mm2, Co-efficient of linear expansion of steel and copper are 11x10-6 per C and 18x10-6 per C. (MAY/JUNE 2009). vil d 9. A steel tube 30mm external diameter and 25mm internal diameter encloses a gun metal rod 20mm diameter to which it is rigidly joined at each end. The temperature of the whole assembly is raised to 150 C. Find the intensity of stress in the rod when the common temperature has fallen to 20 C. The value of the young’s modulus for steel and gun metal are 2.1x105N/mm2 and Ci 1x105N/mm2 respectively. The co-efficient of linear expansion for steel is 12x10-6/ C and for gun metal 20x10-6/ C. (MAY/JUNE 2009). 10. The composite bar shown in fig is rigidly fixed at the ends. An axial pull of P=15kN is applied at B at 20 C. Find the stresses in each material at 80 C. Take αs=11x10-6/ C, αa=24x106 / C, Es= 210kN/mm2, Ea= 70kN/mm2. 3 Visit : Civildatas.blogspot.in

Visit : Civildatas.blogspot.in 11. A bar of 30mm in diameter was subjected to a tensile load of 54kN and measured extension on 300mm gauge length was 0.112 mm and change in diameter was 0.00366 mm. Calculate the Poisson’s ratio and the values of three elastic modulii. (MAY/JUNE 2009). 12. A steal rod 5mm long and 25 mm in diameter is subjected to an axial tensile load of 50kN. sp ot. in Determine the change in length, diameter and volume of the rod. Take E=2x105N/mm2 and 1/m=0.30 (MAY/JUNE2007) 13. A 25mm diameter bar is subjected to an axial tensile load of 100 kN. Under the action of this load a 200mm gauge length is found to extend 0.19 mm.Determine the modulus of elasticity of the material. If in order to reduce the weight whilst keeping the external diameter constant, the bar is bored axially to produce a hollow cylinder of uniform thickness, what is the maximum diameter of bore possible given that the maximum allowable stress is 240MPa? The load can be assumed to remain constant at 100kN. What will be the change in the outer diameter of the bar log under the above load? Taking 1/m=0.3, also calculate the bulk modulus and the shear modulus of the material. (APL/MAY 2010) 2 14. The modulus of rigidity of a material is 38 kN/mm . A 10mm diameter rod of the material is subjected to an axial tensile force of 5kN and the change in its diameter is observed to be s.b 0.002mm. Calculate the Poisson’s ratio, modulus of elasticity and bulk modulus of the material. 15. In an experiment, a bar of 30mm diameter is subjected to a pull of 60kN. The measured extension on gauge length of 200mm is 0.09mm and the change in diameter is 0.0039 mm. ata Calculate the Poisson’s ratio and the values of the three moduli. 16. For a given material, Young’s modulus is 120 GPa and modulus of rigidity is 40 GPa. Find the bulk modulus and lateral contraction of a round bar of 50mm diameter and 2.5m long, when vil d stretched 2.5 mm, Take 1/m as 0.25. 17. A steel plate 300mm long, 60mm wide and 30mm deep is acted upon by the forces shown in fig. Determine the change in volume. Take E=200 kN/mm2 and Poisson’s ratio=0.3. 18. A metallic bar 250mm x 50mm is loaded as shown in fig. Find the change in volume. Take Ci E=2x105 N/mm2 and 1/m =0.25. Also find the change that would be made in the 4MN load, in order that there should be no change in the volume of the bar. (NON/DEC 2008) 19. The maximum extension produced by an unknown falling weight through a height of 40mm in a vertical bar of length 3m and cross-sectional area of 500mm2 is 2.1mm. Determine the 4 Visit : Civildatas.blogspot.in

Visit : Civildatas.blogspot.in instantaneous stress induced in the vertical bar and the value of unknown weight. Take E=2x105N/mm2 (8) (NON/DEC 2008) sp ot. in 20. A reinforced concrete column 500 mm × 500 mm in section is reinforced with 4 steel bars of 25 mm diameter; one in each corner, the column is carrying a load of 1000 kN. Find the stresses in the concrete and steel bars. Take E for steel =210 ×103 N/mm2 and E for concrete =14 ×103 N/mm2. (MAY/JUNE 2013) Ci vil d ata s.b log 21. A solid circular bar of diameter 20 mm when subjected to an axial tensile load of 40 kN, The reduction in diameter of the rod was observed as 6.4 × 10-3 mm. The bulk modulus of the material of the bar 67 GPa. Determining the following: (i) Young’s Modulus (ii) Poisson’s ratio (iii) Modulus of rigidity (iv) Change in length per meter (v) Change in volume of the bar per metre length (MAY/JUNE 2013) 5 Visit : Civildatas.blogspot.in

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