Mechanical System Design 2012

MBB4034

MECHANICAL SYSTEMS DESIGN

Associate Professor Dr Fakhruldin Mohd Hashim

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Imagine

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Learning Outcome

At the end of the course, you should be able to:1. Apply formal design techniques for energy/

automotive / manufacturing systems.2. Design energy/ automotive/ manufacturing systems

by applying standards and industrial practices, involving model formulation, design calculation, simulation, material and process selection, preparation of system configuration/ assembly designs and bills of materials.

3. Develop cost estimate of the project covering both the CAPEX and OPEX.

4. Produce technical and cost reports and present the reports orally.

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Assessment

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Progress Report – 20%Seminar / Tests – 20%Poster – 5%Final Report – 40%Oral Presentations & Viva-voce – 15%

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References

George E. Dieter, “Engineering Design - A Materials & Processing Approach”, 3rd edition, McGraw-Hill, 2000.

David G. Ullman, “The Mechanical Design Process”, 3rd edition, McGraw-Hill, 2003.

Karl T. Ulrich & Steven D. Eppinger, “Product Design & Development”, 3rd edition, McGraw-Hill, 2003.

Stuart Pugh, “Total Design”, Addison-Wesley, 1991.

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The Design Process

Descriptive models: “solution-focused” nature of

design thinking repeated evaluation cycle heuristic process

Prescriptive models: “problem-focused” nature of

design thinking more analytical work algorithmic process

Design is considered as a process of transforming perceived needs into a product or collection of products that meet these needs. Models of the design process can be categorized as either descriptive or prescriptive. More importantly it involves both analysis & synthesis activities.

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The Design Process Model

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FOCUSSED CHAPTERS

5

6

7

14

PROJECTENDS

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Terminologies

CONC-D is the process by which the design is initiated, carried to the point of creating a number of possible solutions, and narrowed down to a single best concept.

EMBO-D is the phase where a structured development of the chosen design concept takes place. Decisions pertaining to strength, material selection, size, shape and spatial compatibility are made in this phase.

CONF-D is the phase where the shape and general dimensions of components are established. Subsequently assembly, sub-assembly and parts are formalized.

DETAIL-D is the phase where the design is brought to a stage of a complete engineering description of a tested and producible product. Information pertaining to form, dimensions, tolerances, surface properties, materials, and manufacturing processes for each part & components are added. Detailed engineering drawings suitable for prototyping or manufacturing are prepared.

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Design Concept Generation

Creative MethodsMethods which are intended to help stimulate creative thinking. Such methods include: brainstorming synectics transformation counter-planning

Rational MethodsTechniques which encourage a systematic approach to design and incorporate methods which are relevant to certain stage(s) of the design process. Examples: morphology chart evaluation matrix

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Brainstorming

The Rules of Brainstorming Generate as many solutions as

possible – quantity counts Wild ideas are encouraged No criticism is allowed – defer

judgment till later

Brainstorming Methods Verbal

Speak out the ideas and list them down. Long explanation not allowed. Time limit: 30 min.

Written (“brainwriting”) Pin card method Method 6-3-5 Delphi method Mind mapping

Interactive Combined verbal & written Morphology chart Storyboard Synectics

Imagination is more important than knowledge, for knowledge is limited,

while imagination embraces the entire world

Albert Einstein

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Morphology Chart

A structured approach to the search for the solution to a complex or vague problem. It generates a large number of relationships

between related factors and elements of the problem, thus coming up with plausible solution ideas.

FEATURES MEANS (HOW)

POWER SOURCE Solar Hydrogen Natural gas

ENGINE TYPE Hybrid Linear Generator Electric

SUSPENSION Active Semi-active

Design of a futuristic car

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Evaluation Methods

Pugh EvaluationMatrix

Weighted ScoreMatrix

Benchmarking

Uses (+) ( - ) (S) scale

Weighted Rankx

Rating Score

Comparative studyagainst best-in-class

EUREKA!

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PUGH Evaluation MatrixAn approach to effectively evaluate concepts based on an agreed

set of criteria. The criteria are deduced from the design specificationand the analysis of needs. The evaluation is done based on the

comparison with a datum.

CRITERIA C1 C2 C3

SPEED PERFORMANCE D + + +

EASE OF MANUFACTURE A s + -

RELIABILITY T _ s +

Sum of ‘+’ U 1 2 2

Sum of ‘-’ M 1 0 1

Sum of ‘s’ 1 1 0

The winning concept is the one that has the highest difference between the ‘+’ and ‘- ‘. If there is a tie, then the one with the lowest ‘s’ is the winner

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Weighted Score Matrix

Also known as Decision Matrix: a decision-support tool allowing decision makers to solve their problem

by evaluating, rating, and comparing different alternatives on multiple criteria

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ALTERNATIVES

Option A Option B Option C

CRITERIA Weight Rating Score(1) Rating Score(1) Rating Score(1)

Criterion C1 1 3 3 3 3 3 3

Criterion C2 2 2 4 1 2 2 4

Criterion C3 3 1 3 3 9 2 6

Total 10 14 13

Scenario #1(1) Score = Rating * Weight

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Prototyping

A prototype is a scaled working model of the design, technically and visually complete. The purpose of the prototype is to confirm that the design satisfies all customer requirements and performance criteria. Prototype testing will give information about the reliability and robustness of the design, and also to verify whether environmental, safety and other requirement have been met.

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Dare to Innovate ?

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