Design of Machine Members

Course Objectives:

To impart the knowledge of the design procedures and principles so as to enable the student, understand and design basic mechanical elementals that are subjected to various loads.

Objective: To learn various factors to be considered in designing an element and to understand different theories of failures.

UNIT – I 

INTRODUCTION: General considerations in the design of Engineering Materials and their properties – Manufacturing consideration in design. Tolerances and fits –BIS codes of steels.

STRESSES IN MACHINE MEMBERS: Simple stresses – Combined stresses – Torsional and bending stresses – Various theories of failure – factors of safety – Design for strength and rigidity – preferred numbers. Static strength design based on fracture toughness.

STRENGTH OF MACHINE ELEMENTS : Stress concentration –Fatigue stress concentration factor-notch sensitivity – Design for fluctuating stresses – Endurance limit – Estimation of Endurance strength – Goodman’s line – Soderberg’s line – Modified goodman’s line.

UNIT – II: 

The students are to be exposed to the design of riveted, welded joints and bolted joints. Rivited and welded joints – Design of joints with initial stresses Bolted joints – Design of bolts with pre-stresses – both of uniform strength.

UNIT – III : 

To learn various factors to be considered in designing shafts subjected to different loads. Further, design aspects of rigid and flexible couplings. Shafts, keys and cotters:

SHAFTS : Design of solid and hollow shafts for strength and rigidity – Design of shafts for combined bending and axial loads – Shaft sizes – BIS code. Design of Keys-stresses in keys-cottered joints-spigot and socket, sleeve and cotter.

COUPLINGS: Design of Rigid couplings: Muff, Split muff and Flange couplings‖-Flexible couplings.

UNIT – IV : 

The students are to be exposed to learn various factors to be considered in designing different types of springs.

Mechanical Springs: Stresses and deflections of helical springs – Extension and DMM – I compression springs – Springs for fatigue loading – natural frequency of helical springs – Energy storage capacity – helical torsion springs – Co-axial springs, leaf springs.

UNIT – V : 

The objective is to make the students learn fundamentals of lubrication, various bearings and estimation of bearing life.

BEARINGS : Types of Journal bearings – Lubrication – Bearing Modulus – Full and partial bearings – Clearance ratio – Heat dissipation of bearings, bearing materials – journal bearing design – Ball and roller bearings – Static loading of ball & roller bearings, Bearing life.

UNIT – VI : 

The objective is to make the students use the design concepts to design various engine components.

ENGINE PARTS: Connecting Rod: Thrust in connecting rod – stress due to whipping action on connecting rod ends – Cranks and Crank shafts, strength and proportions of over hung and center cranks – Crank pins, Crank shafts. Pistons, Forces acting on piston – Construction Design and proportions of piston, Cylinder timers.

Course outcomes: The students completing the course will be able to understand the concepts of various theories of failure, factors of safety, Design for strength and rigidity. Further the same will be used to design mechanical parts such as joints, shafts couplings, springs, bearings and other engine components.