Systematic Design Process

Systematic Design Process

Chiradeep Sen PhD Student 136 Fluor Daniel EIB [email protected] http://aid.ces.clemson.edu/Chiradeep_Sen http://www.ces.clemson.edu/~gmocko/people/csen.html Advisors: Dr. Joshua D. Summers Dr. Gregory M. Mocko Dr. Georges M. Fadel

What is Design 

Design is: –

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the systematic systematic and creative application of scientific and mathematical principles to practical ends such as the design, manufacture, and operation of efficient and economical structures, machines, processes, processes, and systems (www.doe.mass.edu/frameworks/scitech/2001/resources/glossary.html ) is the creative, iterative and often open-ended process of conceiving and developing components, systems and processes. Design requires the integration of engineering, basic and mathematical sciences. A designer works under constraints, taking tak ing into account economic, health and safety, social and environmental environmental factors, codes of practice and applicable laws. www.ee.wits.ac.za/~ecsa/gen/g-04.htm

Design is an activity: – – – – –

Affects all areas of life Uses laws and insights Builds on exper experience ience Is a prereq prereq for the realization realization of ideas ideas into reality reality Is a SOCIAL activity

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Engineering Design   

To design is to imagine things that don’t do n’t exist and bring them into the world These things are tangible Design is regarded as an art rather than science – –

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Science: proceeds by laws (sometimes mathematical) Art: proceeds by rules of thumb, intuition, feeling; but adheres to constraints and laws of nature

Engineering design is a systematic intelligent generation and evaluation of specifications for artifacts whose form and function achieve stated objectives and satisfy satisfy specified specified constraints constraints (Dym (Dym and Little) Little)

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Engineering Design 

Bigger part of the product realization process –

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Includes sales, marketing, marketing, industrial design, manufacturing, manufacturing, etc

Must work together with other disciplines Engineering design is the set of decision-making processes and activities used to determine the form of an object given the functions desired by the customer (Eggert)

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Engineering Analysis 

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Predict the behavior or function of an object using analytical equations or experimental methods Formulating – – –

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Solving – –

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Determine unknowns of the equations Solve and label with units

Checking –

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Understand and plan solution Gathering information Rough plan on how to solve

Does it make sense

Essential, but not only component to design

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Problems with Understanding Design 

Some common and dangerous thoughts –

Design Cannot be taught

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In order to design you must build stuff!

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Design is easy to demonstrate and not easy to articulate

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Mathematics provides a formal language to articulate behavior –

Such mathematical models do not exist to describe design

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What we know about design 

Open ended problems

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Ill structured

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There are several acceptable solutions

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Design solutions cannot be simply found by using mathematical formulae and algorithms

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Motivation to Understand Design

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Decisions made during a product’s design phase generally establish the majority of manufacturing costs The National Research Council has determined that nearly 70% of a product’s cost is determined in the first 5% of the design process

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Systematic Design: Some Requirements 

Requirements for a systematic design methodology: –

be applicable to every type of design activity

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foster inventiveness and understanding

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be compatible with other disciplines

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not rely on chance

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facilitate the application of known solutions

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be compatible with electronic data processing

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be easily taught and learned

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reflect the findings of psychology and ergonomics

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emphasize the objective evaluation of results

P&B: 10-11. [email protected]

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My View of Design …

A controlled broadening and narrowing of scope to generate information about the product …

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ASME Design Theory and Methodology 

Topics of interest include, but are not limited to: – – – – – – – – – – – – –

Advances in Design Theory, Representations, Methods, and Formalisms Creativity and Innovation in Design Design Behavior Study and Cognitive Modeling Validating and Verifying Design Theories and Methods Making Better Decisions in Engineering Design Risk Based Design Designing in Collaborative and Distributed Environments Product Architecture Design Methods Theory and Methods for Sustainable Product Development Widely Applicable Techniques for Improving Design Practice in Industry Advanced Design Education and Design Curricula Artificial Intelligence in Engineering Design The impact of design theory and methodology research in the last 20 years

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The P&B Systematic Approach

Product Planning & Clarification of Task

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Customer

Phase 0 - Start

Task

Clarify the task Elaborate the specification

Specification

Specification

Conceptual Design

Concept

Embodiment Design

Preliminary Layout

Definitive Layout

e v o r p m I d n a e d a r g p U

Identify essential problems Establish function structures Search for solution principles Combine and firm up into concept variants Evaluate against technical and economic criteria

Concept

Develop preliminary layouts and form designs Select best preliminary layouts Refine and evaluate against techincal and economic criteria

Preliminary Layout

Optimize and complete form designs Check for errors and cost effectiveness Prepare the preliminary parts list and production documents

Definitive Layout

Finalize details Complete detail drawings and production documents Check all documents

Documentation

Detail Design

Solution

Documentation [email protected]

Solution

Figure 3.3. P&B: 66.

Phase 1 – Product Planning PP/CT

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Developing and formulating a promising product idea… Task

Product Planning

Analyze market / company Find and select product ideas Formulate a product proposal

Product Proposal

Clarifying the Task

Clarify the task Elaborate a requirements list

Specification

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P h a s e 1

Overview of Product Planning PP/CT

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Successful product planning takes into account market, company, and economy

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Market – – – –

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Other sources – – –

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technical and economic position of product changes in market requirements suggestions and complaints of customers technical and economic superiority of other products economic and political changes … oil prices … regulations … limitations … culture new technologies environmental and recycling issues

Within the company – – – –

company R&D product evolution … new functions to satisfy new market needs process evolution … new ways of doing / making things rationalization of product line

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Activities in Product Planning PP/CT

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Take into account the goals, strengths and weaknesses of the company, market niches and needs Search fields Search for new functions, working principles or geometries based on existing or extended energy, material signal flows Products Ideas

Select product ideas –

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Analyze the situation of the company and products using knowledge of market and other sources Situation Analysis

Find product ideas –

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Formulate search strategies –

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Analyze the situation –

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Using selection procedure that takes into account goals, strengths, and market Idea

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A Product

Define products –

Elaborate and evaluate product ideas. Results in a Product Proposal

Technology push vs. customer pull: Do you think that customers wanted to watch videos on their IPODS?

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Case Study PP/CT

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Kittyhawk drive –

HP introduced in 1992

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1.3" Kittyhawk microdrive

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20 and 40 megabytes of storage

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Tiny motion sensor that would park the heads if it detected the device being dropped. How not to bring a technology to market

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DD

Phase 1 - Clarification of Task PP/CT

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Product Proposal

ED

• •

Clarify the task Elaborate a requirements list

• •

DD

Define the goals Clarify boundary conditions Dispel prejudice Make decisions

Specification

“Fixed solution ideas or concrete indications implicit in the task formulation often have an adverse effect on the final outcome.” PB: p130.

What objectives must the intended solution satisfy? What properties must it have? What properties must it not have? P&B: Chapter 5.

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Clarifying the Task PP/CT

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DD

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What is the essence or crux of the problem?

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What implicit wishes and expectations are involved?

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Do the specified constraints actually exist?

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What paths are open for development?

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What are the objectives?

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What are essential properties?

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Avoid: –

fixed solution ideas / solution-specific considerations

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fictional constraints and concrete implications

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Requirements List PP/CT

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The requirements list is a document that contains: –

the name of the group(s) / individual(s) responsible for specific requirements

Modifications / Date ... 

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an indication of requirements that must be satisfied versus those that are less “critical”

Group or Individual Responsible … 

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the project identifier (e.g., project number and name) and the date the requirements list was generated

Demands / Wishes ... 

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Summary of the the crux of the problem

Project ID / Issue Date ... 

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Problem Statement … 

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the date and type of modification made to requirements

Requirements ... 

particular characteristics of the intended solution, quantified (if possible) and clearly arranged

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Requirements List Document PP/CT ME 6170 ME870

Problem Statement

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Requirements List for Yoke Design

Issued on:

Problem Statement:

October 16, 1998

Redesign a yoke component to fit in the existing switch assembly, attach to and hold the necessary components, provide required structural support, and dissipate a known amount of heat to ensure safe operation. Further, as much as possible, the design must facilitate standardization with respect to design reusability and manufacturing process for the four existing products addressed.

h Interfaces

w

Changes

Demands / Wishes

D W D D D W D D

Requirements 1. Devices on the yoke: (If necessary suggestions for changes possible) clearance for machanical signals (switches: main,dimmer,cut-off; led's; contacts) hold button and faceplate allow for ground (according to UL 1472, 4.5 & 5.8 / UL 486B) possibility to adjust dimmer in misaligned box screw holes and possibilities to assemble parts of the dimmer interface with back housing

2. Geometric constraints: D interface with standard wall box (according to UL 1472, 4.4 / UL 514) D installation directly next to other dimmers must be possible 3. Heat transfer: D temperature must be less then 90 dgr. C at the contact areas with the fiberboard wall according to UL 1472, 5.5 & table 10) W determine best material properties (trade-off with temperature)

Modifications / Date Fri, Oct-23

Fri, Oct-23 Fri, Oct-23

W W D D W W D

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Project ID / Issue Date

Resp. Marc, Tord & Christ. for all points

Group or Individual Responsible

4. Manufacturing determine most cost effective design easy to manufacture use same manufacturing line must be stamped single piece easy to assemble maximum press force: P = 0.7(UTS)(t)(L) ; P max = 1.5 tons

UTS = ultimate tensile strength (Al or Cu) t = thickness L = perimeter (including interior holes 2 D maximum bending force: P = (1/W)*K(UTS)LT ; Pmax = 1.5 tons K = 1.25; L,T,W see page 392,404 Manufacturing processes for ME W determine best material properties (trade-off with stamping force) 5. Electrical safety D yoke cannot extend past face plate (prevent contact with user) 6. Quality/Cost Goal W consolidate as many yokes as possible

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Requirements

Categories of Requirements PP/CT

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Geometry –

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physical and chemical properties of the initial and final product, auxiliary materials, prescribed materials (food regulations, etc.)

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Ergonomics ... –

quietness, wear, destination/environment, special uses, market

Maintenance ... –

service, inspection, repair, painting, cleaning

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Recycling ...

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Costs ... –

direct safety principles, protective systems, operator and environmental safety

lifting, clearance, transportation

Operation ...

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inputs and outputs, form, display, control equipment

special regulations, installation, siting, foundations

Transport ...

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possibilities of testing and measuring, application of special regulations and standards

Assembly …

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output, efficiency, loss, friction, ventilation, state, pressure, temperature, heating, cooling, supply, storage, capacity, conversion

factory limitations, maximum possible dimensions, preferred production methods, means of production, achievable quality and tolerances

Quality Control ...

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Safety ... –

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direction and magnitude of force, frequency, weight, load, deformation, stiffness, elasticity, stability, resonance

Signals … –

Production ...

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Material –

DD

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type of motion, direction of motion, velocity, acceleration

Energy –

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size, height, breadth, length, diameter, space requirement, number, arrangement, connection

Forces –

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Kinematics –

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reuse, reprocessing, waste disposal, storage maximum permissible manufacturing costs, investment, depreciation

Schedules ... –

man-machine relationship, type of operation, clearness of layout, lighting, aesthetics

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end date of development, project planning and control, delivery date

Outcome of Phase 1 

Deliverables:

PP/CT

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Detailed Product Proposal

–

Requirements List

CD

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Make a decision to proceed to Phase 2

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Answer the following questions: –

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DD

Has the task been clarified sufficiently to allow for development of a solution in the form of a design? Must further information be acquired?

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Phase 2 - Conceptual Design PP/CT

CD

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DD

Specification Abstract to identify essential problems

Remove false functions Eliminate functions that do not have bearing on the product

Establish function structures

Search for working principles

Combine working principles into working structures

Start in the function domain -What must the product do? NOT - What must the product look like •

Select suitable combinations

• •

Firm up into principle solution variants

Evaluate against technical and economic criteria

• • •

Concept

P&B: Chapter 6.

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Define the goals Clarify boundary conditions Dispel prejudice Search for variants Evaluate Make decisions

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Overview of Conceptual Design PP/CT 

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The main goals in conceptual design: – – –

by the identification of the essential problems through abstraction, by the establishment of function structures, and by the search for appropriate working principles and their combination,

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The basic solution path is laid down through the elaboration of a solution principle Concepts are developed from the solution principle

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The difference between

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What and how Principle and principal

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Abstracting to Identify Essential Problems PP/CT

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What is Abstraction?

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DD

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Ignoring what is particular or incidental and emphasizing what is general

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Identifying fictitious constraints and eliminating all but genuine restrictions

Why is Abstraction Necessary? – –

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To establish the crux or essence of the design task Essential constraints become clear without prejudicing the choice of a particular solution. To overcome prejudices, or conventions which, coupled with risk aversion, may lead to solution fixation

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Abstracting Essential Requirements PP/CT

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Abstracting the requirements list 1.

Eliminate personal preferences from the requirements list

2.

Consider only requirements that affect function and essential constraints

3.

Transform quantitative into qualitative data, reducing them to essential ideas

4.

Broaden essential ideas systematically (generalize)

5.

Formulate the design problem in solution-neutral terms

*** Identification of essential requirements ***

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Establishing Function Structures PP/CT

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What is a function?

A function specifies the relationship between inputs and outputs.

P&B: Fig. 2.3

Why function structures?

Express relationships between inputs and outputs independently of the solution. Facilitate the subsequent search for solutions. Where do I start? Use abstraction to identify the crux or essence of the problem. This becomes the overall function.

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Hair Dryer Function Structure PP/CT

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DD

???

Heat signal Input signal

Flow signal

Interface energy

Provide Interface

Human

Interface energy

Human

Provide Airflow

Electrical energy

Air @ v1 , T 1

Wasted flow energy

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Air @ v2 , T 1

Heat Air

Wasted heat energy

Air @ v2 , T 2

Hair Dryer Function Structure (cont.) PP/CT

Electrical energy

CD

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DD

Electrical energy

Supply Electricity

Heat energy

Electrical energy

Heat signal

Control Temperature

Convert electric to Heat

Air @ v 2 , T 2

Air @ v 2 , T 2 Transfer Heat to Air

Convey Flow

Air @ v 1, T 1 Supply Air

Air @ v 1, T 1

Support flow generation

Air @ v 1, T 1

Electrical energy Provide Electricity

Electrical energy Control flow

Electrical energy

Convert electricity to rotational

Flow signal

Convert rotational to flow

Air @ v 2 , T 1

Mechanical Energy

Interface signal energy Interface energy

Provide Controls

Human signal Interface holding energy

Human

Wasted heat energy

Interface signal energy

Wasted noise energy

Provide handle

Unharmed Human Protect User Wasted heat energy

Interface holding energy + Interface signal energy Harmful {material, signal, energy}

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Wasted Air @ v’, T 2

Search for Solution Principles PP/CT

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DD

Search for solution (working) principles to fulfill all leaf-functions. –

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Working principles represent a physical effect and preliminary embodiment (e.g., “cartoon” sketch). Use ideation techniques, searches, and analysis of known or existing systems to determine as many working (solution) principles as possible Catalog the solution principles for all of the sub-functions

P&B: Fig. 6.13.

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Working Structures PP/CT

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DD

Combine solution (working) principles into working structures. Use a morphological chart to help identify combinations (i.e., working structures) Each combination of working principles should fulfill the overall function (i.e., assure both physical and geometric compatibility and a smooth flow of Energies, Materials, and Signals)

P&B: Figure 4.18. [email protected]

Working Principles to Concept Variants PP/CT

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DD

Are the combinations of working principles likely to meet budgetary and other requirements?

Firm up into concept variants –

Qualitative to Quantitative Transition     

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ED

Selecting suitable combinations of working principles –

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CD

Simplified calculations Geometrical sketches and studies Experiments on essential properties, model building Simulations Market, literature or patent search

Evaluate concept variants against technical and economic criteria

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Outcome of Phase 2 PP/CT 

CD

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DD

Deliverables: –

Abstract Requirements List

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Function Structure

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Morphological Matrix

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Solution Selection and Evaluation

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Make a decision to proceed to Phase 3

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Answer the following questions: –

Have sets of working principles (i.e. viable concepts) been identified to satisfy the requirements of the design

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Have I properly abstracted and searched broadly for working principles

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Am I design fixated and have I put added constraints to the design space?

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Phase 3 - Embodiment Design PP/CT

CD

ED

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DD

Concept 

Develop preliminary layouts and form designs Select best preliminary layouts Refine and evaluate against technical and economic criteria

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Begins with a concept and ends with a definitive layout: –

Working structure  Concept

–

Technical details are added

Fleshing out a selected concept –

Start with embodiment-determining requirements and their function carriers or working principles

–

Proceed with requirements having less impact on embodiment

Preliminary Layout Eliminate weak spots Check for errors & cost effectiveness

Prepare preliminary parts list and production documents Definitive Layout

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Phase 3 - Overview of Embodiment Design PP/CT

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DD

Concept 

General steps of embodiment design: – – –

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Preliminary layout and form design Definitive layout and form design Completion of checks & optimization (Only after checks, can you move on to detail design!)

Characteristics of embodiment design: – –

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Complexity!! Many simultaneous, interdependent activities! Analysis and synthesis alternate and complement each other! Optimization and error ID + solution search and evaluation. Some steps must be repeated at a higher info level. Proceed from qualitative to quantitative, from abstract to concrete, from rough to detailed, with provisions for checks and corrections (I.e., iterations!).

Develop preliminary layouts and form designs Select best preliminary layouts Refine and evaluate against technical and economic criteria Preliminary Layout Eliminate weak spots Check for errors & cost effectiveness

Prepare preliminary parts list and production documents Definitive Layout

Details: P&B Fig. 7.1. 201. [email protected]

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Steps of Embodiment Design PP/CT

1.

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DD

Concept

Steps 1 - 4 Develop preliminary layouts and form designs

Step 5: Select best preliminary layouts

Steps 6-10: Refine and evaluate against technical and economic criteria

Top-down assembly modeling versus bottom-up modeling

Establish rough layout (based on concepts) which emphasizes the embodiment-determining main function carriers, that is, the assemblies and components fulfilling the main functions. 

4.

size determining requirements such as output, through-put, size of connectors, etc. arrangement determining requirements such as direction of flow, motion, position, etc. material determining requirements such as resistance to corrosion, service life, specified materials, etc.

Produce scale drawings of the spatial constraints determining or restricting the embodiment design (e.g., clearances, installation requirements, etc.) 

3.

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Identify requirements that have a crucial bearing on the embodiment of the design 

2.

CD

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Which main functions and function carriers determine the size, arrangement and component shapes of the overall layout? What main functions must be fulfilled by which function carriers jointly or separately?

Determine preliminary layouts and form designs for the embodiment-determining main function carriers.

Preliminary Layout

Step 12: Eliminate weak spots

Step 13: Check for errors & cost effectiveness

Steps 14-15: Prepare preliminary parts list and production documents

Definitive Layout


Steps of Embodiment Design, contd. PP/CT

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6.

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Select one or more suitable preliminary layouts. Develop preliminary layouts and form designs for remaining function carriers. Determine which essential auxiliary functions are needed. – –

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Exploit known solutions if available (e.g., catalogues). Search for special solutions.

Develop detailed layouts and form designs for main function carriers in accordance with embodiment design rules and guidelines. – –

Consider compatibility with auxiliary functions Divide into assemblies or areas to be elaborated individually if necessary.

DD

Concept




Preliminary Layout




Definitive Layout


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CD

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DD Concept

9.

Develop detailed layouts and form designs for auxiliary function carriers – –

10.

Evaluate layouts against technical and economic criteria – –

11. 12.

Use standard parts, if possible. Combine all function carriers into overall layouts

Make sure all designs are at the same level of embodiment, BUT don’t go beyond the level of detail required by evaluation. You may need only a preliminary layout, or you may need more details to choose among alternative layouts.

Fix preliminary overall layout Optimize and complete form designs for the selected layout. – –

Eliminate weak points. Adopt suitable solutions from less favored variants.




Preliminary Layout




Definitive Layout



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DD

Concept

13.

Check layout design for errors –

–

14.

Prepare preliminary documentation. – – –

15.

in function, spatial compatibility, etc. achievement of objectives with respect to cost and quality

parts lists production documents assembly documents




Preliminary Layout


Fix definitive layout design and pass on to detail design phase



Definitive Layout


Considerations in Embodiment Design PP/CT

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fulfillment of the technical function and economic feasibility Durability, deformation, stability, expansion, ergonomics, aesthetics, ease of assembly Value of a concept is not absolute Establish objectives from:  

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Designer determines the value of solutions wrt specific objective(s). –

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DD

General considerations for evaluating alternatives –

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Basic rules of clarity, simplicity, and safety are derived from general objectives, –

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CD

requirements list technical properties (e.g., Fig 7.3)

All embodiment designs must have same degree of correctness and information content Production costs must be determined to the extent possible Evaluation should include a search for weak spots. Look for opportunities to combine strong aspects of different alternatives.

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Outcome of Phase 3 

Deliverables: –

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The requirements related to the layout of the design The general layout of the product solution neutral format A systematic method to evaluate the more detailed design

Preliminary Diagram 

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DD

Solution Evaluation 

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ED

Preliminary Layouts 

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CD

General Layout Requirements 

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PP/CT

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The general layout of the final design with minimal knowledge about the details of the final product

A definitive layout for which production documents can be prepared with minimal detail design. Before proceeding to Phase 4, ask yourself: –

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Am I satisfied that this definitive layout satisfies all relevant and appropriate requirements (function, layout, assembly, costs, maintenance, etc.)? Am I ready to prepare final production documents for this design (tolerances, assembly processes, materials, tooling, etc.) without delay?

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Detail Design (Section 7.8) PP/CT

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CD

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Begins with a definitive layout and ends with product documentation –

The use of Computer-aided design tools

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Final design specifications 

Form

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Dimensions

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Surface quality

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Properties

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DD

Definitive Layout

Steps 1-2: Finalize details Step 3: Complete all documents

Step 4: Check all documents Documentation

Final chance to identify and correct mistakes

Solution


Steps in Detail Design PP/CT

1.

– –

–

– – –

4.

Steps 1-2: Finalize details

include assembly drawings Parts lists (BOM)

Complete production documents –

– – –

Step 3: Complete all documents

Step 4: Check all documents

manufacturing assembly transport operating instructions

Documentation

Check all documents, especially detail drawings and parts lists for: –

DD

Definitive Layout

Detailed drawings of components Detailed optimization of shapes, Materials, surfaces, tolerances and fits

Integrate individual components into assemblies and assemblies into overall product –

3.

ED

Finalize the definitive layout –

2.

CD

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Solution

observation of general and in-house standards accuracy of dimensions and tolerances other essential production data ease of acquisition, e.g., availability of standard parts


Systematic Design Process

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