Concept Eval Morpho Table

More concept generation methods: TRIZ , and Morphological Table and basics of concept evaluation Main TRIZ assumption A creative-design technical problem is defined by contradictions. That is, if there are no contradictions, there is no creative-design problem (it maybe instead a standard, handbook calculation problem). A bit of history… The “inventor” of TRIZ method was the Russian engineer Genrikh Saulovich Altshuller. TRIZ is the Russia acronym for “Theory of Inventive Problem Solving”. “Original design occurs by overcoming a contradiction” Can overcome contradiction by use of one of the 40 “Inventive Principles” EXAMPLE: 1. Segmentation Divide an object into independent parts. - Replace mainframe computer by personal computers. - Replace a large truck by a truck and trailer. - Use a work breakdown structure for a large project. Make an object easy to disassemble. - Modular furniture - Quick disconnect joints in plumbing Increase the degree of fragmentation or segmentation. - Replace solid shades with Venetian blinds. - Use powdered welding metal instead of foil or rod to get better penetration of the joint. "Technical" and "Physical" Contradictions Technical contradictions are the classical engineering "trade-offs“: when something gets better, something else gets worse. They are easier to identify. Classical examples include: The product gets stronger (good) but the weight increases (bad) The bandwidth increases (good) but it requires more power (bad) More "Technical“ Contradictions Automotive examples are easy to construct: The vehicle has higher horsepower, but uses more fuel The vehicle has high acceleration but uses more fuel The ride feels smoother, but the handling is difficult on high speed curves A pick-up truck has high load capacity (stiff rear suspension) but the ride is rough. Putting controls on stalks increases driver convenience, but makes assembly of the steering column more complex. Electric vehicles can go long distances between recharging, but the battery weight gets too high to move at all! Physical Contradictions :where one object has contradictory, opposite requirements. Everyday examples: When pouring hot filling into chocolate candy shells, the filling should be hot to pour fast, but it should be cold to prevent melting the chocolate. Aircraft should be streamlined to fly fast, but they should have protrusions (landing gear) to maneuver on the ground. Aircraft should fly fast but should fly slowly (for minimum velocity on landing.) Surveillance aircraft should fly fast ( to get to the destination) but should fly slowly to collect data directly over the target for long time periods. Software should be easy to use, but should have many complex features and options. Physical Contradictions : Automotive industry examples : Braking should be instantaneous to avoid road hazards but braking should be gradual for control. Refueling should be sealed but should be open. Upholstery should be luxurious but be easy to maintain. The frame should be heavy (for structural safety) but the frame should be light (for cost and ease of assembly.) Manufacturing should be done in small lots for flexibility but manufacturing should be done in large lots for low cost. NOTE: many problems can be stated as both physical and technical contradictions. TRIZ has 4 classical ways to resolve physical contradictions 1.Separation in time 2.Separation in space 3.Phase transition : Solid - liquid - gas – plasma, Paramagnetic –Ferromagnetic, others-ferroelectric, superconducting, crystal structure, … 4.Move to the super-system or the subsystem. Case study: Air bag contradictions Examples are found in system and subsystems: The deployment threshold should be high and low. The air bag should be aggressive and de-powered. The air bag should protect everyone and harm no one. The gas should be generated quickly and slowly. The sensor should be complex and simple. The air bag should exist and should not exist. Air bag technical contradictions: If the threshold for deployment is set low, protecting belted occupants, more unbelted small people in the passenger seat are injured. But if it is set high, unbelted passengers are protected from air bagcaused injury, but belted passengers suffer more injury from the collision. High power ("aggressive") deployment saves lives of average-sized drivers, but increases injuries to unbelted or small passengers. Adding more sensors (and data processing) to customize the deployment to the circumstances, and thereby save lives of small and unbelted people, increases the complexity of the system but also decreases the reliability of the system. “The deployment threshold should be high but it should be low” The deployment threshold is the “deceleration” (maybe change of acceleration) of the car that is required for the air bag to fire. Since this is a contradiction, the answer will not be a number-that would be the non-TRIZ way of doing a trade-off. Applying the 4 methods for resolving a physical contradiction will cause us to deal with the cause of the problem (air bags cause injuries) and not just with the short-term solution (changing the speed of deployment.) Separate the requirements in space: Idea 1: using a low deployment threshold for a belted, average driver, and a high deployment threshold for a small driver or unbelted passenger, but it introduces problems of sensor and logic complexity. The popular solutions: put children in the back seat and have drivers sit as far as possible from the steering column. Note: separate them in space from the air bag. Could the shape of the airbag be changed so that it is fully deployed when the short person reaches it? And still protect the average and large person? Separation in time Suggests examining the sequence of events in an accident to see if different kinds of accidents require different deployments, rather than using the velocity as the triggering factor. Note: This is also an idea of solving the problem at the super-system level, since it changes the problem from one of how to set the threshold, to examination of whether the threshold is the right parameter to use at all. Phase transition appears unlikely in this case, but… One form of injury is caused when short drivers sit close to the steering column. The bag is still accelerating when the person strikes it, instead of fully inflated as it would be for average height drivers. Could the acceleration that harms people be moderated by using some other material? a foam bag? Or a liquid barrier? Or any other barrier? Change the problem: use the supersystem or the subsystem. Use the subsystem: by using lower power inflation, so that the acceleration of the air bag will be lower, causing less injury to the person who strikes it, while still inflating with enough power to protect the person from injury. Use the super-system: the ultimate supersystem approach is to prevent accidents and eliminate the need for the air bag. There is a fifth way to “resolve” a physical contradiction: convert it to a technical contradiction. Ask "WHY?" Why must it be high? To avoid deployment in lowspeed accidents and prevent air bag-caused injuries Why must it be low? To protect people in accidents at any speed This leads us to the technical contradiction: as speed of the car increases, injuries to occupants become worse This is not just circular logic: it focuses us on the root cause of the problem, deployment threshold is only a "band-aid" solution. Now let’s use the TRIZ principles Principle 21. Skipping. Conduct a process at high speed:Inflate the air bag faster, so that it is fully inflated when the small person impacts it. Principle 39. Inert atmosphere. Or add neutral parts, or inert additives to an object. What does the damage is the encounter between the person and the air bag: the bag acts "hard" because of its motion. Something that would "soften" the surface would be the equivalent of an "inert" material-it does not prevent the original purpose. How can this be implemented? Change the structure of the bag-make it corrugated, or make it of filaments, or use multiple crushable layers. Change the "hardness" without changing the structure (this is the 2-stage inflation that has already been proposed.) Principle 16. Partial or excessive actions: using 'slightly less' or 'slightly more' of the same method. The de-powered air bag has been proposed as a solution of this type. By using less power, the acceleration of the bag is less, and injuries will be reduced. Conversely, smaller bags with higher power would reach full inflation sooner, so that the passenger would be protected from the accident and not injured by the air bag. Now let’s use the TRIZ principles + MATRIX Principle 22. "Blessing in disguise" or "Turn Lemons into Lemonade" Use the relative motion of the person and the vehicle as part of the protection: Design other parts of the system (seat, dash, side panels) to redirect the moving person to be properly placed for best air-bag protection. Eliminate the primary harmful action by adding it to another harmful action to resolve the problem. This again suggests inflating the air bag faster, so that it is no longer harmful by the time the person reaches it. Once a contradiction is expressed in the technical contradiction form (the trade-off) the next step is to locate the features in the Contradiction Matrix. See web reference for the complete matrix, and see following figure for an extract. http://www.triz40.com/ THE MORPHOLOGICAL METHOD (or TABLE) A technique of the morphological method is the “Morphological Table”, which is good to generate combination of alternatives for subsystems. First a list of needed functions is developed Then a list of concepts for each function is brainstormed Finally, they are combined in a “Morphological Table” CONCEPT EVALUATION The purpose of concept evaluation is to choose a few (usually one) concept alternatives to develop them further, but the decision must be made under little knowledge. (1) By “feasibility evaluation”, each concept get one of three possible “gut feeling” outcomes: - It is NOT feasible - It is conditional - It is worth considering CONCEPT EVALUATION (2) (2) For new technology, feasibility must be proved by answering six “metrics” about technology maturity: (a)Are the critical parameters identified? (b)Is the sensitivity of parameters known? (c) Have the failure modes been identified? (d)Can the technology be manufactured with a known process? (e)Does hardware exist that proves (a) to (d)? (f) Is the technology controllable (reliable) throughout the product life cycle? Example: Example(2) Another method: Simple Numerical Evaluation (Example: leaf collection system)