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3. (a) What are the effects contributing to the generation of elastohydrodynamic films? 10 points (b) The valve train of an internal combustion engine is shown below. The load interacted between the cam and the follower may be determined by multiplying the stiffness of a valve spring (not shown in the figure) and the total compressive displacement of the spring. If the spring stiffness is 20 kN/m, determine: (a) size of the contact area between the cam and the follower (the contact width is 10 mm) (b) The film thickness of the lubricant between the cam and the follower (d) Comment on the effectiveness of the lubrication. 25 points The other parameters are: (1) Spring initial compression = 8 mm (ii) Cam maximum lift = 30 mm (iii) Lubricant absolute viscosity n = 0.06 Pas (iv) Pressure viscosity coefficient C = 2.2 x 10" Pa! (v) Young's modulus of cam and follower material = 207 GPa (vi) Poisson's ratio of cam and follower material - 0.3 (vii) RMS-Surface finish of surfaces, Rea = Rab = 0.3 uum (viii) Linear speed between the cam and the follower = 2.5 m/s