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Design and Optimization (MCL742) George E. Dieter, Linda C. Schmidt, Dr. Harish Hirani, Fellow ASME Engineering Design, McGraw-Hill, 2013 Professor (HAG), Department of Mechanical Engineering Norton, Robert L. "Machine...

Design and Optimization (MCL742) George E. Dieter, Linda C. Schmidt, Dr. Harish Hirani, Fellow ASME Engineering Design, McGraw-Hill, 2013 Professor (HAG), Department of Mechanical Engineering Norton, Robert L. "Machine design: an integrated approach”, 2000. IIT Delhi, Hauz Khas, New Delhi-16 Messac, Achille. Optimization in practice with MATLAB®: for engineering students and professionals. Cambridge University Press, 2015. ❑ Design problems within context of mechanical engineering ➔ complicated ➔ Understanding of technical requirements, constraints, and broader contextual environment. ❑ Course explores significance of defining design problems, methodologies employed, and contextual factors influencing mechanical engineering solutions. 1  Course Policy Minor (25) Major (30) Lab (26) Attendance (%) ≥75 4 Marks < 50 0 Marks Project → 15 Linear variation (0–4) for attendance ranging 50% Attendance → 4 to 75%. 2% is awarded for each lab (a total of 13 classes). No compensation or extra lab sessions. Project presentations will be held at different stages (2+4+9). Project includes design and optimization of a gearbox (components and assembly) for SOME APPLICATION. Lab classes use MATLAB coding and Design & Analysis with SolidWorks.  Audit Pass criterion Marks>40  Environmental impact of Car Tire using Life Cycle Impact Assessment *Piotrowska, K et al."Assessment of the Scope of life cycle assessment environmental impact of a car tire throughout its lifecycle using the LCA method." Materials 12, no. 24 (2019). Inputs Raw material acquisition Outputs Atmospheric Raw materials Production emissions Overall tire Use Waterborne weight ~ Energy 10 kg. emissions End of life (recycling) Size P205/55/R16. Use Eco-indicator 99, Solid waste https://www.michelin.in/auto/ty cumulative energy demand (CED) & Storage res/michelin-primacy-suv Intergovernmental Panel on Climate Change Other releases (IPCC) techniques to conduct LCA. Distribution Composition: Synthetic rubber (24.17% of tire mass), natural rubber (18.21), Carbon black (19), coated steel wires (11.4), precipitated silica Disposal (9.65), oil (6.12), textiles (4.7), zinc oxide (1.58), sulphur (1.28), stearic acid (0.96), recycled rubber (0.5) and other. "Eco Indicator 99" refers to method for assessing sustainability. Based on life cycle assessment (LCA) principles, Eco-indicator 99 seeks to quantify potential environmental impacts (categories, such as resource depletion, climate change, ozone depletion, human toxicity, …) of product/service throughout its entire life cycle. It combines the impacts into single score: "eco-points," to compare products or procedures. Cumulative Energy Demand (CED) metric evaluates total quantity of energy needed throughout entire life cycle of product/process/service. Comprehensive evaluation of energy inputs at various phases, including extraction of raw materials, production, transportation, use & disposal. CED considers both direct and indirect energy consumption, including electricity, fossil fuels & renewable energy sources. It facilitates identifying energy-intensive stages. Energy inputs are typically expressed in megajoules (MJ) or kilowatt-hours (kWh) with appropriate-transparent documentation of assumptions, data sources, and calculation procedures. International Panel on Climate Change (IPCC), established in 1988, plays crucial role in providing scientific assessments/reports on climate change, its effects, possible mitigation & adaptation strategies. Primary objective of IPCC is to appraise and synthesise most recent scientific, technical, socio-economic data on climate change, ensuring a thorough & objective evaluation of current state of knowledge. These reports are based on exhaustive reviews of scientific literature and opinions of several thousands of experts from around the globe.  According to manufacturer data, manufacturing process generates ~ 0.5 kg of trash. 3,000 liters of fuel are required for a car travelling 50,000 km. Each tire consumes 750 liters. Collected between 16-17 litre/km 2015 and 2016. “A travelled distance of 50,000 km“, “5-year life” Eco-index for manufacture, usage, and recycling of automobile tire over its whole life cycle was determined to be 153 Pt, with standard deviation of 37.2 Pt. To lessen environmental impact of automobile tires: Use more efficient recycling systems and reduce energy consumption in manufacturing operations. Efforts should also be made to increase fuel economy.  Customer Driven Innovation Lecture 1 Defining Design Problems in Context of Mechanical Engineering ❑Four contextual Factors: 1. Technological Context: Advances in materials, manufacturing techniques, and computing constantly change mechanical design. Using new developments in design is essential for optimum solution. 2. Growing awareness of environmental impact and sustainability requires design problems to consider energy efficiency, recyclability, and a minimal ecological footprint. 3. Regulatory and safety standards are constantly updated. These standards set the rules for designs, making sure products are safe, reliable, and meet legal requirements. 4. Additionally, engineering solutions must be cost effective.  Lecture 2 Design Problems ?? Dr. Harish Hirani, Fellow ASME Professor (HAG), Department of Mechanical Engineering IIT Delhi, Hauz Khas, New Delhi-16  “DESIGN” Process of finding best solution using creativity & science, and effectively communicating that plan to others (group activity). Defining goal thinking process producing something NEW - at least partly Seed plantation Seedbed Agricultural Challenges preparation Tillage: Major operation for seedbed preparation Tillage ➔ Mechanical manipulation of soil to create optimal environment for seed germination & plant growth. 1.Tillage improves soil aeration by breaking up compacted soil, bury crop residues, and control weeds, which is essential for root breathing, creating environment for root penetration and water infiltration and water retention. Maintaining an appropriate balance of air & water in soil to promote seed germination and early plant development. 2.By exposing soil to air, tillage can help in warming up seedbed ➔ Providing a more favorable temperature range for seeds to germinate. 3. Tillage ensures that nutrients are evenly distributed. https://pib.gov.in/Pressreleaseshare.aspx?PRID=1740858 Tillage to Spading (machine) Spading machine loosens soil instead of slicing it, creating a porous and permeable bed that enables soil to breathe and absorb water. Spading turns over soil in chunks in a way that minimizes disruption to soil layers and maintains soil health. 30 JUL 2021  Design needs Creativity to unlock imagination. Company X, decided to design air-circulators for paint shops. Length of 2-m and diameter of 0.6-m was designed for rotor of air-circulator. Company X wanted to design suitable bearings to reduce power consumption on 2/3. On studying air-circulator problem, it was found that rotor length could be reduced from 2-m to 1.4-m by relocating drive- motor. Reduction in length of rotor itself fulfilled the requirements. Two components vs Single component Bridge Base- plate  Avoid/induce stress Better Material Produce a compressive residual stress layer and modify mechanical properties of metals. Design of a pizza box provides convenience for handling 15  Corrugated cardboard design of Pizza boxes help to retain heat, keeping pizza warm during transportation. to provides good insulation. to protect pizza from damage during transit by providing strength and durability. Withstand stacking, movement, and other physical stresses without collapsing or deforming, ensuring that pizza inside remains intact and uncrushed. The design includes ventilation holes or slits to allow steam to escape. This prevents the pizza from becoming soggy by reducing condensation inside the box. Proper ventilation ensures that the crust stays crispy while still maintaining the overall warmth of the pizza. Pizza boxes are designed with sustainability in mind. They are often made from recycled materials and are themselves recyclable.  Where is Problem? Both the quantity & quality of human needs, increase with time……… Problems can be identified from What was once considered Luxury becomes necessity. reactions to: New needs emerge as humans strive for improved living standards and well-being. Advancements in Technology Changes in social structures In early human societies, needs were Shifts in cultural norms primarily centered around survival: food, water, shelter, and safety. Creative mind observes how people react to these changes.. Transportation Voice of customers is often used to: Discover mismatch between society’s product needs and capabilities offered by existing product solutions. Digital connectivity ?? How to identify need ????? Patterns of Design Evolution Evolution of engineering systems isn't arbitrary; it adheres to specific patterns, with design changes following certain established trends. Industrial Revolution ➔ Shift from handcrafted to machine-made products➔ Increase production efficiency, New materials, New manufacturing processes. Present trend (cultural differences) ➔ Emphasis on sustainability and eco-friendliness ➔ Renewable energy-efficient processes. Virtual prototype, 3D printing. Advancements in artificial intelligence and machine learning are enabling development of adaptive and intelligent designs that can respond to user needs in real-time.  Lecture 3 Patterns of Design Evolution?? Dr. Harish Hirani, Fellow ASME Professor (HAG), Department of Mechanical Engineering IIT Delhi, Hauz Khas, New Delhi-16  Patterns of Design Evolution As a new system evolves, development continues…. Evolution Towards Decreased Human Involvement Multifunctionality Animal driven Segmentation Increase in Single bogy Motor-driven comfort Multi-bogy 4. Comfort Pattern of design evolution ➔ Effective tool to develop a new design with (quantum) improvement over current product.  Gear Design Gear design has evolved significantly over time, driven by advancements in materials, manufacturing processes and learnings from failure analysis. Early gears were made from WOOD First hand lever-driven pinion and gear with winch drum to lift water from below ground level to first floor in a castle in Poland (built around 15th century).  Various Applications This chariot features gear-mechanism always pointing to south, regardless of Differential gear mechanism also first found chariot's direction, making it one of the in Chinese developed south-pointing earliest methods to gauge key directions chariot. without using magnets. Most South-Pointing Chariots used rotation of road wheels to https://en.wikipedia.org/wiki/South-pointing_chariot operate geared mechanism that kept pointer aimed south, requiring manual alignment of pointer southward at the start of journey. Mechanism Process ➔ prone to cumulative rotated pointer to errors & uncertainties. counteract turns, Stronger materials (steel) maintaining improved gear durability & constant southern load-bearing capacity direction, Precise manufacturing (hobbing, gear shaping), ➔ more accurate and South-Pointing Chariot➔ two-wheeled vehicle equipped reliable gears with a movable pointer, typically represented by figure with outstretched arm, that indicate south.  History of Toothed Gear Invention and Development: With the introduction of the differential gear mechanism, the concept of bevel gear is also developed. Straight Bevel Herringbone Bevel (1927) 90o Crossed Worm & Helical Gear Spiral Bevel Worm Wheel Hypoid Bevel Emergence of form cutters and gear hobbing machines allowed ➔ mass-production, Refinement in form and performance. In 1897, Herman Pfauter invented a machine capable of cutting both traditional "spur" gears & helical gears. Now full 6-axis machines perfected the design, cutting, and manufacturing of gears. Design Evolution in Gear Geometry: Development of various gear types for specific applications. Helical gear drive Spur gear drive Bevel gear drive with straight teeth Cylindrical teeth Worm gear drive Helix (right- handed or left- handed) angle ➔ Herringbone gear 10° to 45°. Gears come in various tooth configurations tailored for specific applications. Combination of rolling and sliding motion. Design of helical (less noise & vibration), bevel, and worm gears is more complex than simple spur gears. American Gear Manufacturers Association (AGMA) offers detailed data and algorithms for calculations. CROSSED HELICAL GEARS: gears are mounted on shafts that are neither parallel nor intersecting. connect shafts that are at an angle to each other, typically between 45 and 90 degrees. Used in light-load applications, such as in distributor, speedometer drives of automobiles. less efficient than parallel helical gears Additive manufacturing, 3D printing technology ➔ Production of complex gear geometries. Future trends ➔ Integration of sensors and IoT technology into gears for real-time monitoring and predictive maintenance ➔ to reduce ecological impact of gear production. Development of new coatings to enhance gear performance in extreme environments such as space and deep-sea applications.  Meshing errors In the gear contact sense, mesh misalignment implies the axial shifting of the position of the meshing surfaces due to either deflections or errors in the manufacture of the gears and their housings. The occurrence of any of these actions typically alters the location of contact on the tooth flank and may lead to large stresses and increased noise of a gear pair. Mesh misalignment may be divided into three categories: 1. Parallel misalignment (centre distance change) 2. Radial misalignment 3. Angular misalignment  k >1 “long addendum gear”… High Contact Ratio Internally meshing spur gears  Plastic Gears Plastic gears offer numerous advantages, such as low noise, corrosion resistance, lightweight, low inertia, and cost-effectiveness. – No breakage of gear or gear teeth Bending and contact stresses < Allowable – Precise geometry Precise manufacturing Plastic forming process during manufacturing often leads to low-precision due to shrinkage, resulting in non-standard tooth profiles, greater pitch and tooth profile errors, poor tooth surface, and inadequate tooth contact properties. Precision defects in injection molding due to plastic shrinkage become more prominent. To address minimum tip thickness problem in small gears three main aspects are considered: 1. Relationship between plastic gear tooth root modification and rack tool tip modification 2. Relationship between plastic gear tooth tip modification and rack tool root modification 3. Controllable coating … No residual tensile stresses or thermal distortion.  Coefficient of Friction Example: Performance of Nylon/Steel gear pair will be better than the Nylon/Nylon pair “Industrial Gear Lubrication” (AGMA 9005-D94) Four types of gear lubricants in standard: 1.Rust and oxidation-inhibited oils 2.Compounded gear oils 3.EP gear oils 4.Synthetic gear oils  Applications that demand complex motion and a high degree of flexibility, making it particularly suitable for robotics, aerospace mechanisms, and advanced machinery where traditional drives fall short in movement capabilities. https://doi.org/10.1139/tcsme-2018-0265 Spherical Gears Materials Manufacturing Design (Dimension, Shape)  5. Evolution towards Micro-nano Level Transition from solid structures to fragmented (Segmentation??) or finely dispersed media. – Magneto-rheological Finishing to achieve sub-nanometer polishing (Ref: http://www.lle.rochester.edu/pub/review/ v96/96Polishing06.pdf MEMS & NEMS MRF "polishing tool" never dulls or changes. MRF "polishing tool " adapts to complex shapes because it is a compliant fluid. MRF removal rates are very high resulting in short processing times.