Unit 1
Introduction to the design process – factors influencing machine design, selection of materials based on mechanical properties – Preferred numbers, Limits, fits and tolerances. Types of loading, Direct, Bending and torsional stress equations – Impact and shock loading – calculation of principle stresses for various load combinations, eccentric loading Factor of Safety, Factor influencing the selection of Factor of Safety, Working stress, theories of failure – Design based on strength and stiffness
Design for variable loading: Fatigue load stress cycle, Fluctuating load, reversed and repeated load, Endurance limit, Endurance strength, Endurance limit, S-N curves, Modifying factors: Size, surface finish, Stress concentration factors, Goodman and Soderberg relationship, Stress due to combined loading