Engineering Design Lecture 1 PDF

Engineering Design ET ZC413 Lecture - 1 BITS Pilani Dr. Glynn John Pilani Campus Mechanical Engineering Engineering Design Definition & Concept of design Engineering Design Process...

Engineering Design ET ZC413 Lecture - 1 BITS Pilani Dr. Glynn John Pilani Campus Mechanical Engineering Engineering Design Definition & Concept of design Engineering Design Process Consideration of good design Summary 27 July 2024 2 27 July 2024 ENGINEERING DESIGN 3 What is design? Some common definitions To design is to create something that has never been. To design is to pull together something new or to arrange existing things in a new way to satisfy a recognized need of society. Design establishes and defines solutions to and pertinent structures for problems not solved before, or new solutions to problems which have previously been solved in a different way.” The design process is the organization and management of people and the information they develop in the evolution of a product. The ability to design is both a science and an art. The science can be learned through techniques and methods, but the art is best learned by doing design. 27 July 2024 4 Analysis and synthesis Good design requires both analysis and synthesis. We approach complex problems like design by decomposing the problem into manageable parts. Because we need to understand how the part will perform in service, we must be able to calculate as much about the part’s expected behavior as possible before it exists in physical form by using the appropriate disciplines of science and engineering science and the necessary computational tools. This is called analysis. It usually involves the simplification of the real world through models. Synthesis involves the identification of the design elements that will comprise the product, its decomposition into parts, and the combination of the part solutions into a total workable system. 27 July 2024 5 The four C’s of desgin Creativity Requires creation of something that has not existed before or has not existed in the designer’s mind before Complexity Requires decisions on many variables and parameters Choice Requires making choices between many possible solutions at all levels, from basic concepts to the smallest detail of shape Compromise Requires balancing multiple and sometimes conflicting requirements 27 July 2024 6 Engineering Design Process The engineering design process can be used to achieve several different outcomes. One is the design of products Another is a complex engineered system Examples: Examples: refrigerators Electrical power generating station power tools petrochemical plant DVD players building missile system bridge. jet transport plane 27 July 2024 7 Importance of the Design Process Decisions made in the design process cost very little in terms of the overall product cost but have a major effect on the cost of the product. 27 July 2024 8 Importance of the Design Process This shows that only a small fraction of the cost to produce a product (5 percent) is involved with the design process, while the other 95 percent of cost is consumed by the materials, capital, and labor to manufacture the product. The design process consists of the accumulation of many decisions that result in design commitments that affect about 70 to 80 percent of the manufactured cost of the product. In other words, the decisions made beyond the design phase can influence only about 25 percent of the total cost. If the design proves to be faulty just before the product goes to market, it will cost a great deal of money to correct the problem. 27 July 2024 9  Importance of the Design Process Decisions made in the design process cost very little in terms of the overall product cost but have a major effect on the cost of the product. Source: https://www.fabbricaagile.it/en/shadow-of-costs-in-product- development-part-1/ 27 July 2024 10 Importance of the Design Process The decisions made beyond the design phase can influence only about 25 percent of the total cost. The second major impact of design is on product quality, today we realize that true quality is designed into the product. The third area where engineering design determines product competitiveness is product cycle time. Cycle time refers to the development time required to bring a new product to market. Decisions made in the design process cost very little in terms of the overall product cost but have a major effect on the cost of the product. You cannot compensate in manufacturing for defects introduced in the design phase. The design process should be conducted so as to develop quality, cost- competitive products in the shortest time possible. 27 July 2024 11 Importance of the Design Process You cannot compensate in manufacturing for defects introduced in the design phase. 1997 Mercedes A-Class De Havilland Comet with square during a moose test windows 27 July 2024 12 Importance of the Design Process 27 July 2024 13 Quality by design 27 July 2024 14 Types of Designs Original design Adaptive design Redesign Selection design Industrial design 27 July 2024 15 Types of Designs Original design, also called innovative design. This form of design is at the top of the hierarchy. It employs an original, innovative concept to achieve a need. Sometimes, but rarely, the need itself may be original. A truly original design involves invention. Adaptive design: This form of design occurs when the design team adapts a known solution to satisfy a different need to produce a novel application. Redesign: The task may be to redesign a component in a product that is failing in service, or to redesign a component so as to reduce its cost of manufacture. Often redesign is accomplished without any change in the working principle or concept of the original design. When redesign is achieved by changing some of the design parameters, it is often called variant design. Selection design. in this case the design task consists of selecting the components with the needed performance, quality, and cost from the catalogs of potential vendors. Industrial design. This form of design deals with improving the appeal of a product to the human senses, especially its visual appeal. While this type of design is more artistic than engineering 27 July 2024 ENGINEERING DESIGN 16  Original Design A completely new design which didn’t exist before. Scooters based on aircraft design. 1946 Vespa Source: Vespa.com BITS Pilani, Pilani Campus  Adaptive Design Application of a known solution to satisfy a different need to produce a novel application CNC Milling 3D Printing/ Additive Printer Manufacturing BITS Pilani, Pilani Campus  Redesign Honda CB 500 – 1976 Honda CB 500 – 2020 498 cc (30.4 cu in), air-cooled, 8-valve, 471cc, liquid-cooled, parallel-twin SOHC, transverse inline-four BITS Pilani, Pilani Campus Variant Design Material:Metal, Color:Multicolour Head : 6 - 26 m. Head : 6 to 41 meters Capacity : 1980 to 360 LPH Capacity : 2160 to 450 lph Power rating : 0.37 kw / 0.5 hp, voltage Power rating : 0.75kw, 1hp range : 180 to 240 volts (1phase) Voltage range : 180 to 240 volts BITS Pilani, Pilani Campus Selection Design Products selected from a manufacturer’s catalogue. 27 July 2024 21 Industrial design Products designed for their visual appeal 27 July 2024 22 Key to world-competitive products The real key to world-competitive products lies in high-quality product design. 27 July 2024 23 THE ENGINEERING DESIGN PROCESS A Simplified Iteration Model ▪ exploring the alternative concepts that could satisfy the specified need ▪ formulating a mathematical model of the best system concept ▪ specifying specific parts to construct a subsystem ▪ selecting a material from which to manufacture a part. Design Method Versus Scientific Method A Problem-Solving Methodology – Definition of the problem – Gathering of information – Generation of alternative solutions – Evaluation of alternatives and decision making – Communication of the results 27 July 2024 24 A Simplified Iteration Model Exploring the alternative concepts that could satisfy the specified need Formulating a mathematical model of the best system concept Specifying specific parts to construct a subsystem Selecting a material from which to manufacture a part. 27 July 2024 ENGINEERING DESIGN 25 Design Method Versus Scientific Method science is based on studies of the observed, while design is based on artificial concepts characterized in terms of functions, goals, and adaptation. 27 July 2024 ENGINEERING DESIGN 26 A Problem-Solving Methodology Definition of the problem Gathering of information Generation of alternative solutions Evaluation of alternatives and decision making Communication of the results 27 July 2024 ENGINEERING DESIGN 27 Definition of the Problem The most critical step in the solution of a problem is the problem definition or formulation. The final design can differ greatly depending upon how the problem is defined. The formulation of the problem should start by writing down a problem statement. It should include objectives and goals, the current state of affairs and the desired state, any constraints placed on solution of the problem, and the definition of any special technical terms. Problem definition often is called needs analysis 27 July 2024 ENGINEERING DESIGN 28 Definition of the Problem 27 July 2024 ENGINEERING DESIGN 29 Thank You References: ▪ George E. Dieter, Linda C. Schmidt, "Engineering Design", 6/e (Indian Edition), McGraw Hill Education (India) Pvt. Ltd., New Delhi, 2021. ▪ David G. Ullman, “The Mechanical Design Process”, McGraw-Hill Inc., Singapore, 1992 ▪ Kevin Otto and Kristin Wood, “Product Design: Techniques in Reverse Engineering and New Product Development”, 1/e, Pearson Education, New Delhi, 2004. ▪ N. J. M. Roozenburg, J. Eekels, Roozenburg N. F. M., “Product Design: Fundamentals and Methods”, John Wiley and Sons, 1995 27 July 2024 30