Anjuman-i-Islam’s

M.H.SABOO SIDDIK COLLEGE OF ENGINEERINGByculla, Mumbai-400 008.

Department Of Automobile Engineering

Machine Design-I

Prof.Shaikh Ibrahim.I.

Assignment No 05Date: 08/04/2019

Q.01) What is stress concentration?What are the causes of stress concentration?What are the methods of reducing stress concentration?

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Q.02) With the help of a stress–time curve ,explain fluctuating stress ,repeated stress and reversed stress.

Q.03) (a) What is S–N curve? Explain endurance limit and fatigue life. (b) What is notch sensitivity? What is notch sensitivity factor?

Q.04) What is the difference between the Gerber curve and Soderberg and Goodman lines?Explain.

Q.05) A shaft carrying a load of 5 kN midway between two bearings is shown in Fig.01. Determine the maximum bending stress at the fi llet section. Assume the shaft material to be brittle

Q.06) A circular rod is subjected to 700kN tensile to 300kN compressive varying axial load. Find the diameter of the rod using soderberg criteria and assuimg following data.Endurance limit = 280Mpa , Tensile yield strength = 350Mpa, FOS = 2 correction factor for loading= 0.7 , surface factor = 0.8

Q.07) A machine component is subjected to fl uctuating stress that varies from 60 to 110 N/mm2. The corrected endurance limit stress for the machine component is 300 N/mm2. The ultimate tensile strength and yield strength of the material are 610 and 460 N/mm2 respectively. Find the factorof safety using i) Gerber theory ii) Soderberg line (iii) Goodman line Also, find the factor of safety against static failure.size factor = 0.854 and stress concentration factor= 1.

Date of sub: 15/04/2019

Q.08) A Helical comression spring is subjected to the load vasry from 500n to 1100N having spring index of 6. free length is to be between 100 mm to 150 mm. the maximum compression under the variation of load is 30 mm. Assuming shear stresses for spring material design the spring completely.

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Q.08) An automotive engine develops maximum torque at a speed of 1000 rpm At this speed, the power developed by the engine is 25 kW. The engine is equipped with a single plate clutch having two pairs of friction surfaces. The mean diameter of the friction disk is 190 mm and the coeffi cient of friction is 0.35. Six springs, with a spring index of 6, provide the necessary axial force. The springs are made of patented and cold-drawn steel wires of Grade 2 (G = 81 370 N/mm2). The permissible shear stress can be taken as 50% of the ultimate tensile strength. Design the spring and calculatei wire diameter ii mean coil diameter iii number of active coils iv total number of coilsv solid length vi free length

Q.09)A semi-elliptic leaf spring consists of two extra full-length leaves and eight graduatedlength leaves, including the master leaf. The entre-to-centre distance between the two eyes of the spring is 1 m. The maximum force acting on the spring is 10 kN and the width of each leaf is 50 mm. The springis initially pre-loaded in such a way that when the load is maximum, the stresses induced in all the leaves are equal to 350 N/mm2. The modulus of elasticity of the leaf material is 207 000 N/mm2. Determine:

Q.10) what is nip of leaf spring. what is the objective of nipping of leaf spring .

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om i) The thickness of the leaves ; ii) The deflection of spring at maximum load; andiii) initial nip.