Engineering Design and Material Selection Lecture 2 PDF

Engineering Design and Material Selection Lecture 2 — Introducing Engineering Design Prof. Dr. Kristina Shea Prof. Kristina Shea 1  Course Schedule Week/ Topic Case...

Engineering Design and Material Selection Lecture 2 — Introducing Engineering Design Prof. Dr. Kristina Shea Prof. Kristina Shea 1  Course Schedule Week/ Topic Case study Quiz Lecturer Dates 1 Introduction and Sketching 2 Introducing Engineering Design Health Prof. Dr. Kristina Shea 3 Technical Drawing: Projections and Cuts 4 CAD: Introduction and Modeling Operations 5 CAD: Features and Parametric Modeling Future Mobility 6 CAD: Freeform Modeling Dr. Tino Stankovic 7 CAD: Assemblies and Standard Mechanical Parts X (45 min) 8 Technical Drawing: Dimensioning Health 9 Sustainability in Engineering Design 10 Materials and their Properties 11 Manufacturing Processes with Focus on Additive Manufacturing Sustainable Materials Prof. Dr. Kristina Shea 12 Material Selection 13 Review and Q+A X (75 min) Prof. Kristina Shea Engineering Design + Computing Laboratory 2  Learning Objectives – Lecture 2 ▪ Learn a creative and systematic concept development approach ▪ Understand the importance of well-defined design requirements ▪ Generate concepts, evaluate and select them. ▪ Reflect on human bias in the process. Prof. Kristina Shea Engineering Design + Computing Laboratory 3  Overview of Key Elements in Engineering Design User Process Organization Product Models Methods Prof. Kristina Shea Engineering Design + Computing Laboratory 4  A Product Development Process Phase 1: Phase 2: Phase 4: Phase 5: Concept System-Level Phase 3: Testing & Production Phase 0: Planning Detail Design Development Design Refinement Ramp-Up Prof. Kristina Shea Engineering Design + Computing Laboratory 5  Phase 1: Concept Development Phase 1: Phase 2: Phase 4: Phase 5: Phase 3: Phase 0: Planning Concept System-Level Testing & Production Detail Design Development Design Refinement Ramp-Up Purpose: Tasks include: Define product requirements Identify lead users Generate promising concepts and Identify competitive products select one for further development Collect user needs and testing Define product requirements Develop alternative design concepts Evaluate the design concepts and select one Build and test concept prototypes Prof. Kristina Shea Engineering Design + Computing Laboratory 6  Product Development – An Interdisciplinary Process Engineers rarely work alone in product development Product development teams include: Need for effective communication: ▪ Engineers of different disciplines ▪ Be aware of discipline specific knowledge ▪ Industrial designers and standards: ▪ Market researchers ▪ ‘Do I express myself clearly?’ ▪ Field experts (e.g. Medicine, ▪ ‘Do I explicitly state requirements Biology, Chemistry,...) instead of assuming them as given?’ ▪ Define system interfaces explicitly ▪ Perspectives and priorities can differ immensely ▪ Communication is the key to get on the same page Prof. Kristina Shea Engineering Design + Computing Laboratory 7  Requirement Definition What are the requirements? Why do we need well-defined requirements? To effectively communicate and define goals, Needs the product is supposed to fulfil priorities, and interfaces for the product Explicit descriptions of the desired form and To capture user expectations in a binding functionality of the product contract To ensure the fitness of the product for its Solution-independent intended use Prof. Kristina Shea Engineering Design + Computing Laboratory 8  Which Device Fits Your Requirements? “I need a charging device...” A B C Prof. Kristina Shea Engineering Design + Computing Laboratory 9  Which Device Fits Your Requirements? “I need a charging device...” “...that can deliver at least 50 W...” Prof. Kristina Shea Engineering Design + Computing Laboratory 10  Which Device Fits Your Requirements? “I need a charging device...” “...that can deliver at least 50 W...” “...through an USB-C interface.” Prof. Kristina Shea Engineering Design + Computing Laboratory 11  Challenges of Understanding User Needs ▪ Not all user needs are obvious or explicitly mentioned by users ▪ Interview techniques are used to find what are called “latent” needs, or non- obvious ones. ▪ Standards, norms and regulatory bodies. Goal: Develop a user understanding that will justify your task definition and target scenario as well as future product specifications. Oakland, John S. Tot al quality managem ent and operati onal excellence: text with cases. Routl edge, 2014. Prof. Kristina Shea Engineering Design + Computing Laboratory 12  Types of User Needs Unfulfilled ▪ Easy for the customer to express ▪ Known to be difficult to address ▪ Generally not fulfilled Explicit Latent ▪ Easy for the user to express ▪ Hard for customers to express ▪ Widely known and understood ▪ Not yet widely understood ▪ Likely to be already fulfilled in ▪ Currently unaddressed existing products Prof. Kristina Shea Engineering Design + Computing Laboratory 13  Product Specifications: Motivation Translate needs into precise targets. Agree on what Resolve trade-offs. constitutes success. Develop confidence that the product will gain significant market share. Prof. Kristina Shea Engineering Design + Computing Laboratory 14  Product Specifications: What are they? ▪ Precise, measurable quantities of “what” the product will do. Improved buildability and compactness ▪ They do NOT say “how” to do it!, i.e. no solutions! ▪ Specifications are as specific as possible – quantitative ▪ Continuously refined over the initial stages of product The ventilator must be smaller than l x w x h development. w w l w l h h h l ht tps:/ /upload. wikimedia. org/wikipedia/ com mons/ 3/31/ Servo_I_V entilat or.jpg Prof. Kristina Shea Engineering Design + Computing Laboratory 16  Product Goal Product Specifications: Bicycle Example Identify User Needs Establish product specifications Generate, Select and Test Product Concepts Adapted from:Ulrich, K. T., Eppinger, S. D., & Yang, M. C. (2008). Product design and development (Vol. 4, pp. 1-3). Boston: Finalized Specifications McGraw-Hill higher education. Prof. Kristina Shea Engineering Design + Computing Laboratory 17  Establishing Product Specifications Translating User Needs ▪ It is necessary to translate user needs to a set of precise, measurable specifications ▪ If these specifications are met, the underlying user needs will be satisfied as well ▪ Based also on competitive benchmarking, norms and regulations ▪ Example user need: Reduce vibration felt in the user’s hands; tests available are: Maximum value from known benchmark test “Monster” – units [g] Minimum descent time on test track – units [s] Adapted from:Ulrich, K. T., Eppinger, S. D., & Yang, M. C. (2008). Product design and development (Vol. 4, pp. 1-3). Boston: McGraw-Hill higher education. Prof. Kristina Shea Engineering Design + Computing Laboratory 18  Establishing Product Specifications Ideal and Marginal Values Example: Bicycle suspension system ▪ Ideal value – best value the team could hope for ▪ Marginal value – value that would just make the product commercially viable ▪ Five ways to define: 1. a ≥ X 2. a ≤ X 3. X ≤ a ≤ Y 4. a = X 5. a = {X; Y; Z} Adapted from:Ulrich, K. T., Eppinger, S. D., & Yang, M. C. (2008). Product design and development (Vol. 4, pp. 1-3). Boston: McGraw-Hill higher education. Prof. Kristina Shea Engineering Design + Computing Laboratory 19  Mechanical Ventilator: Product Goals ▪ Low-cost and high quality ▪ Meets regulatory requirements ▪ Multiple ventilation modes ▪ Improved buildabilty and compactness ▪ Robust ▪ Easy to maintain ▪ Easy to learn and use Prof. Kristina Shea Engineering Design + Computing Laboratory 20  Technical Specifications The breathe ventilator is an emergency and transport ventilator that is built to ventilate critically-ill patients (adult and pediatrics) in any emergency situation. It is specifically designed for low- resourced settings and enables fast and reliant patient treatment through its first-of-its-kind bag- based solution and its ease of use, portability and long battery run-times. Improving emergency care in low-resource settings Technical specifications: Patient range : Pediatrics to adults (from 5 kg) Ventilation modes: CMV-VC, CMV-PC, CPAP, SIMV Dimensions: 35 cm x 36 cm x 32 cm Weight: 6.8 kg Redundancy: Removable integrated resuscitator bag Battery: Internal/external charging, exchangeable, run-time up to 10 hours Quick settings: Ideal body weight of 20 kg, 40 kg, 60 kg, 80 kg Gas supply: Room air (compression via bag on the inside) Low flow oxygen up to 15 L/min (from oxygen concentrator / oxygen bottle or wall outlet) The breathe ventilator is an emergency and transport ventilator that is built to ventilate critically-ill patients (adult and pediatrics) in any emergency situation. It is specifically designed for low- resourced settings and enables fast and reliant patient treatment through its first-of-its-kind bag- based solution and its ease of use, portability and long battery run-times. Prof. Kristina Shea Engineering Design + Computing Laboratory 21  Requirements can be very specific, i.e. to follow a curve Pressure Flow Volume Oxford Textbook of Critical Care (2 ed., April 2016) Prof. Kristina Shea Engineering Design + Computing Laboratory 22  https://breathe.ethz.ch Prof. Kristina Shea Engineering Design + Computing Laboratory 23  Challenges of Requirements – Why Prototyping Is Needed Objectives of paddle design: Use of prototyping to determine the paddle-shape ▪ Maximize compression of the bag ▪ Compatibility with different bag sizes Compression of a soft bag ▪ Relation between paddle profile and performance not intuitive ▪ Difficult to simulate and optimize Prof. Kristina Shea Engineering Design + Computing Laboratory 24  In the exercise you will formulate two requirements for the ventilator and develop four further ones on your own: ▪ Maximize the tidal volume, which is the volume of air delivered for each compression of the resuscitator bag. You must have a range of at least 300–450ml. ▪ The device must be compact since the use case is emergency situations and the transport of patients. Prof. Kristina Shea Engineering Design + Computing Laboratory 25  Which of the requirements for the ventilator gear box are well formulated? (multiple answers possible) ▪ A. The axes should be supported by ISO15 ball bearings with an inner diameter of 10mm. ▪ B. The gear box housing must be made of cast aluminum. ▪ C. The gear box should weigh less than 4kg. ▪ D. The gears must be protected against dust. Prof. Kristina Shea Engineering Design + Computing Laboratory 26  Concept Generation and Selection Design task Concept Solutions Concept Generation Requirements and Selection Prof. Kristina Shea Engineering Design + Computing Laboratory 27  Concept Generation and Selection Design task Concept Solutions Concept Generation Requirements and Selection Prof. Kristina Shea Engineering Design + Computing Laboratory 28  Concept Generation and Selection – A Systematic Approach Concept Development Design task Problem Clarification External Search Internal Search Concept Solutions Requirements Systematic Exploration Reflection Concept Selection Prof. Kristina Shea Engineering Design + Computing Laboratory 29  Concept Generation and Selection – Theory vs. Practice Concept Development Design task Problem Clarification External Search Internal Search Concept Solutions Requirements Systematic Exploration Reflection Concept Selection ▪ Design processes do not strictly move in one direction ▪ Jumps between stages can be useful and necessary ▪ Avoid infinite loops and carefully consider revising a design decision. Prof. Kristina Shea Engineering Design + Computing Laboratory 30  Clarify the Problem – Main Function and Functional Decomposition Central Question The formulation of the main function ▪ Should be solution-independent What is the underlying problem I am trying to solve? ▪ Influences the explored space for concept solutions Main Function energy flows airflow Main Function Create airflow energy air material Critical Subfunction signal energy energy airflow airflow Sub-Functions Accept/store energy Accelerate air Guide airflow air Prof. Kristina Shea Engineering Design + Computing Laboratory 31  External Search – Look for Existing Concepts Search Patents ▪ Determine the State-of-Art ▪ Search published literature Benchmark related products ht tps:/ /comm ons.wikimedi a.org/wiki/ File: Am bu_Bag_valve_mask.jpg ▪ Interview lead users ▪ Consult experts ventilation profile ht tps:/ /upload. wikimedia. org/wikipedia/ com mons/ 3/31/ Servo_I_V entilat or.jpg volume-controlled energy energy airflow airflow airflow Accept/store energy Accelerate air Guide airflow Control airflow air Additional subfunction based on external search Prof. Kristina Shea Engineering Design + Computing Laboratory 32  External Search – Results for the Ventilator Accept/store energy Accelerate air Control airflow Prof. Kristina Shea Engineering Design + Computing Laboratory 33  Internal Search – Development of New Concepts ▪ Concept development is a process that can be learned Creativity Methods ▪ Creativity methods ▪ Support the development process Make analogies ▪ Can help to overcome human bias and fixation Wish and wonder Guidelines 1. Suspend judgement Stimuli 2. Generate a lot of ideas Set quantitative goals 3. Welcome ideas that seem infeasible 4. Make plenty of sketches 5. Build sketch models Prof. Kristina Shea Engineering Design + Computing Laboratory 34  Related Stimuli Hand pumping of bag. Tip: Search for videos on different techniques for ventilating a patient manually. Prof. Kristina Shea Engineering Design + Computing Laboratory 35  Unrelated Stimuli Prof. Kristina Shea Engineering Design + Computing Laboratory 36  Creativity Methods – Brainwriting Brainwriting is a team ideation method similar to brainstorming People generate ideas in a group and pass them around for the others to work on. Often used in the 6-3-5 format: 6 people 3 initial ideas (per person) 5 minutes per round working on the ideas Other formats are possible e.g. 4-3-5 P hoto by f auxels Prof. Kristina Shea Engineering Design + Computing Laboratory 37  Internal Search – Results for the Ventilator Accept/store energy Accelerate air Control airflow Prof. Kristina Shea Engineering Design + Computing Laboratory 38  Explore Systematically – Concept Classification Tree Accept/store energy Electrical Mechanical Pneumatic Thermal ? Benefits 1. Elimination of less promising branches 2. Identification of independent approaches to the problem 3. Exposure of fixation on certain branches 4. Refinement of the problem decomposition for a particular branch Prof. Kristina Shea Engineering Design + Computing Laboratory 39  Explore Systematically – Concept Classification Tree Accept/store energy Electrical Mechanical Pneumatic Thermal Benefits 1. Elimination of less promising branches 2. Identification of independent approaches to the problem 3. Exposure of fixation on certain branches 4. Refinement of the problem decomposition for a particular branch Prof. Kristina Shea Engineering Design + Computing Laboratory 40  Concept Classification Tree – Results for the Ventilator Accept/store energy Accelerate air Control airflow Prof. Kristina Shea Engineering Design + Computing Laboratory 41  Explore Systematically – Concept Combination Table ▪ Combine different partial solutions to solution concepts Subfunction 1 Subfunction 2 Subfunction 3 ▪ Think about the physical and geometric interfaces among Concept 1-1 Concept 2-1 Concept 3-1 partial solutions Concept 1-2 Concept 2-2 Concept 3-2 ▪ Refinement of partial solutions might be needed to derive a solution concept Concept 1-3 Concept 3-3 Concept 3-4 Prof. Kristina Shea Engineering Design + Computing Laboratory 42  Concept Combination Table – Concept Combination A Accept/store energy Accelerate air Control volume flow Prof. Kristina Shea Engineering Design + Computing Laboratory 43  Concept Combination Table – Concept Combination B Accept/store energy Accelerate air Control volume flow Prof. Kristina Shea Engineering Design + Computing Laboratory 44  Based on what you have learned so far: How would you approach the concept generation phase? (multiple answers possible) ▪ A. Focus on known functional principles to ensure the developed concept will work. ▪ B. Develop the most promising concepts to a high level of detail. ▪ C. Generate a variety of concepts without immediately judging them. ▪ D. Utilize creativity and classification methods to fill gaps in the explored solution space. Prof. Kristina Shea Engineering Design + Computing Laboratory 45  Concept Selection – Approaches Concept selection takes place explicitly and implicitly ▪ Explicit: Decision processes, discussion ▪ Implicit: Bias in formulation of requirements and task descriptions, favouring of established solutions, dominance of group members Concept selection methods support a conscious selection P hoto by RODNA E Producti ons process based on explicitly developed criteria. Prof. Kristina Shea Engineering Design + Computing Laboratory 46  Concept Selection Method – Pugh Concept Screening Matrix Example: Reuseable insulin syringe for ▪ Simple and quick concept selection method outpatient injections ▪ Definition of selection criteria ▪ Basic evaluation of the generated concept solutions/variants next to each other (Plus + / Same 0 / Minus -) ▪ Ranking of concepts based on evaluation score ▪ The highest ranking concepts are then selected for further development. Prof. Kristina Shea Engineering Design + Computing Laboratory Source: https://www.novonordisk.com/our-products/pens-and-needles/novopen-4.html 47  What are pitfalls of concept selection methods? (multiple answers possible) ▪ A. Prefer solutions that are already implemented in existing products. ▪ B. Using a selection tool to justify a personal or team favorite. ▪ C. Invest time into the consideration of unrealistic concepts. ▪ D. A decision is made too early. Prof. Kristina Shea Engineering Design + Computing Laboratory 48  Concept Testing and Prototyping User Interviews Prototyping ▪ Present the developed concept to users and ▪ Can be used in different stages of the design evaluate their reaction process ▪ Measure user interest to estimate the potential ▪ For concept development: Build a physical market share version of your concept to evaluate the proposed functional principle and user interaction Photo by Sora Shimazaki Photo by Senne Hoekman Prof. Kristina Shea Engineering Design + Computing Laboratory 49  Mechanical Ventilator: Usability Study ▪ 5 anesthesiologists in Zurich ▪ 3 have experience working in low-income countries ▪ Experience in ICU, shock room, OR and ambulance ▪ Findings: ▪ Easy to use for the first time and felt confident using it. ▪ Easy for participants to teach someone how to use it. ▪ A smaller size would be better for transport and emergency use case. ▪ All participants said that their overall experience with it was either good or very good. Prof. Kristina Shea Engineering Design + Computing Laboratory 50  Concept Generation and Selection – Wrap Up Well-defined requirements guide the design process Concept development can be approached systematically Design methods can help in the concept development process (functional decomposition, creativity methods, selection matrices,...) Prototyping helps to validate concepts, carry out usability studies and identify additional requirements An explicit concept selection process can help to overcome bias and fixation Prof. Kristina Shea Engineering Design + Computing Laboratory 51  Exercise 2: Design and Concept Generation Can you and your colleagues come up with a better design for the ventilator? Prof. Kristina Shea Engineering Design + Computing Laboratory 52  Exercise 2: Design and Concept Generation Tips for Teamwork Tips for a Creative Mood ▪ To reduce potential misunderstanding, it is ▪ A creative mood is sometimes seen as an ability good practice to be as explicit as possible to play with ideas and explore them, with no in your communication. What you say immediate practical purpose. might be heard and perceived differently ▪ Accept all ideas irrespectively of their feasibility. than intended. Use a sketch! Defer judgment to not hinder the creative mood. ▪ Give constructive feedback on both ▪ Explore all ideas fully. See where it takes you! positive and negative aspects: Start by pointing out something good about the ▪ Do not interrupt someone explaining their idea. Try to build on others’ ideas constructively. idea of your colleague. ▪ Treat everyone with the same respect. ▪ Be kind to each other. Prof. Kristina Shea Engineering Design + Computing Laboratory 53