Utf8''2-The Design Process

8/13/2019 Utf8''2-The Design Process

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DESIGN PROCESS AND

MATERIAL SELECTIONDr. Alexey Sverdlin

Mechanical Engineering DepartmentMarquette University


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I dont design clothes,I design dreamsRalph Lauren, NY Times, 19 April 1986.


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The process of translating an idea or need

for a device into the detailed information(drawings, bill of materials, etc.) from

which the device or product can be made.


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Technical design Industrial design

Product design


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Technical design includes the aspects ofdesign that bear on the proper technical

functioning of the product. Industrial design includes the aspects of

design that bear on the satisfaction affordedby the product.

Product design means the synthesis oftechnical and industrial design to createsuccessful products.


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ObservationPerception


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The design of a device or product for Carrying loads

Transmitting power Conducting heat Resisting wear Etc.


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The product itself is called a technical system:

Subassemblies

Components

The design converts the inputs into the

outputs.


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The design proceeds by developing conceptsto perform the functions in the function

structure, each based on a working principle. The designer considers alternative concepts

and the ways in which these might beseparatedor combined.


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Original Design

Design of something totally new

Adaptive or Developmental DesignDesign resulting in an incremental advance in a

device

Variant Design

Scaling up or scaling down a design


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Hubble Telescope Mars Rover


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New designs can spur the development ofnew materials to meet the need.

Example: Gas turbine design spurred thedevelopment of single crystal nickel based alloy

turbine blade alloys.

New materials can spur new designs

Example: Carbon fiber composite spurred thedesign of stealth aircraft.


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Wood Aluminum Carbon Fiber

Tennis Rackets


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3.5 HP

Briggs and Stratton Engines

10 HP


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Functional Design

Design from a systems (input/output) point of view.

(Materials selection is usually not considered here.)

Assembly or Component Design

Design of individual components and assemblies of

technical systems. (Materials selection is usually

considered here.)


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Fuel

Air

Control

Signals

Electrical

Power

Internal Combustion Engine

Fuel

InjectionSystem

Electrical

System

Motor

(Block, crank,

pistons, etc.

Cooling

System

Inputs

Rotational

Mechanical

Energy

Control

Signals

Exhaust

Gases

Heat

Outputs


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InternalCombustion

Engine

Motor

FuelInjection

System

Cooling

System

Electrical

System

Engine Block

Crank Shaft

Pistons

Fuel Injectors

Intake Manifold

Radiator

Water Pump

Alternator

Spark Plugs

Note: Materials selection made at the component level


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Originaldesign involves a new idea orworking principle:

The ballpoint pen The compact disc


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Almost all design is adaptiveor developmental. Adaptive design takes an existing concept and

seeks an incremental advance performance, toreduce cost, or to adapt it to changing marketconditions.


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Variant design involves a change of scale ordimension or detailing without a change of

function or the method of achieving it. Boilers

Boats

Cars


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Prototype

Testing

and

Failure

Analysis


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Ashby, p.17

Increasing

sophistication

in design toolsand accuracy

of calculations

Increasing

specificity in

materialsselection and

material

properties

Screening

Selection of

specific

materials


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Main basis for selectinga material for a

function is its

properties.

Available shape of a

material affects

selection. Ability to process

material affects

selection.

Function, material, shape and process must

all be taken into account in selection.


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Utf8''2-The Design Process

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