Basic steps in the design and synthesis process: identification of need, problem definition, collection of relevant information and functional requirements, concept development, evaluation of design alternatives, design communication, feedback from manufacturers and users
Communicating the design: engineering drawings and CAD, graphs and charts
Material Selection for Design (2 hours)
Materials properties
Economics of materials
Evaluation criteria for materials selection
Cost versus performance relations
Cost and value analysis
New Product Design (2 hours)
Feasibility studies and assessment
Preliminary design development
Detailed design and engineering analysis
Planning for manufacturing, distribution and product usage
Planning for product retirement and end-of-life handling
Problem Solving and Decision Making (2 hours)
Problem-solving process and techniques
Invention and ideation methods
Brainstorming
Problem definition: needs, goals, constraints, compromises, conditions and evaluation criteria
Problem-solving stages: preparation, incubation, inspiration and verification
Decision matrix method and decision tree analysis
Design of Shafts (12 hours)
Shafts and fatigue failure
Stress-life method and the S-N diagram
Design for static loads
Endurance limit and modifying factors
Stress concentration and notch sensitivity
Characterizing fluctuating stresses: completely reversed stress, fluctuating stress between unequal values, fluctuating stress in the same sign
Combination of loading modes (axial, bending and torsion)
Failure criterion (Gerber, Soderberg and Goodman)
Rolling Contact Bearings (6 hours)
Bearing types and their classification
Bearing life, load-life relationship and reliability-life relationship using the Weibull distribution
Combined radial and thrust loading in bearings
Bearings under variable loading conditions
Selection of ball and cylindrical roller bearings
Selection of tapered roller bearings
Lubrication and Journal Bearings (4 hours)
Types of lubrication, viscosity and viscosity charts
Petroff's law and stable lubrication (thick film lubrication)
Hydrodynamic lubrication theory
Design considerations for journal bearings
Minimum film thickness, coefficient of friction, lubricant flow, film pressure and temperature rise
Design of Flexible Mechanical Elements (10 hours)
Flat belts
V-belts
Timing belts
Chain and sprocket drive
Wire rope
Force Analysis of Gears (5 hours)
Basic concepts of gears: types, nomenclature, involute properties, conjugate action, contact ratio, interference, gear tooth formation, tooth systems and gear trains
Force analysis
Spur gearing
Helical gearing
Bevel gearing
Worm gearing
Practicals
Problems related to the design of shafts (iterative design problems), covering shaft layout using computational tools
Problems related to the design of rolling contact bearings (iterative design problems) using computational tools
Problems related to the design of journal bearings (iterative problems concerned with temperature rise) using computational tools
Problems related to the design of flexible mechanical elements (multi-options design problem) using computational tools
Problem on a simple power transmission system design comprising shafts, bearings and flexible mechanical elements
Evaluation
Final exam questions cover all chapters. Approximate marks distribution (total 60 marks over 45 hours):
Introduction and Material Selection for Design: 6 marks
New Product Design and Problem Solving and Decision Making: 6 marks
