Intro Dscm

8/11/2019 Intro Dscm

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DESIGN, SELECTION & CHARACTERISATION OF

ENGINEERING MATERIALS (MY-407)FALL TERM: 2014

BOOKS TO BE CONSULT:

ASM Handbook volume 20: Materials Selection and Design.

ASM Handbook volume 10: Materials Characterisation

EVALUATION:

1. Popup Quizzes (approx. 4):10 Marks

2. Test & VIVA: 10 Marks

3. Assignment: 10 Marks

SYNOPSIS OF COURSE:

The specific objectives for the course are:

1. Describe, both conceptually and analytically, how system components work using

scientific engineering principles.

2. To gain experience in the selection of materials and optimization of behavior by

using a systematic methodology which combines materials properties with the

engineering function of the process or product design.

3. To acquire knowledge about different Characterization techniques.

REMEMBER!!!!

Thetrue art of memory is the art of attention

Samuel Johnson!


2/13

WHAT QUALITIES IN A GOOD ENGINEER?

A sharp mind.

Refined knowledge

Superb observational

capabilities Great listening power

Reflexivity

Attitude

Communication Skills

MINIMUM COMPUTER SKILLS?

BASIC COMPUTER OPERATIONS

MS OFFICE

WORD

POWER POINT

EXCEL

PUBLISHER

AUTOCAD, PRO-E

PREZI

FEA, SOLID CAST etc.MS PROJECT , MATLAB

C++ Language

JOB TITLE(s):

Design Engineer (Metallurgy),

Trainee Design Engineer.

The ENGINEERis the key figure in the material progress of the world.

It is his engineering that makes a reality of the potential value of science

by translating scientific knowledge into tools, resources, energy and labor

to bring them into the service of man ... To make contributions of this kind

the engineer requires the IMAGINATIONto visualize the needs of society

and to appreciate what is possible as well as the technological and broad

social age understanding to bring his vision to reality

Sir Eric Ashby!

Positive point


3/13

Formaldefinition

of

design:

Design

establishesand

definessolutionstoand

pertinentstructuresfor

problems

not

solved

before,ornewsolutions

toproblemswhichhave

previouslybeensolved

inadifferentway.

Adesignmayormay

notinvolveinvention.

The

professional

practiceofengineering

is

largely

concerned

withdesign;itisoften

saidthatdesignisthe

essenceofengineering.

Theactionorfactof

carefullychoosingsomeo

ne

orsomethingasbeingthe

bestormostSuitable.

Theselectionofmaterials

isacriticalstageinprodu

ct

developmentand

manufacturingofEngg.

Component.Vastmateria

ls

processesavailableand

enormousvarietiesofdes

ign

requirementshavebeen

identifiedastherootofth

e

problemsinmaterials

selectionthatchallenges

engineer.

Fromthemanufacturing

perspective,thesequence

throughwhichthe

componentismanufactur

ed

isconsideredmorecritica

l

thandesignrequirement.

Therefore,

theselection

processisnotonly

determinedbyitsfunction

andshape,butalsobythe

manufacturingprocess

MaterialsChara

cterization

referstotheuseof

externaltechniqu

esto

probeintotheinternal

structure&Propertiesofa

material.

Basedonthe

informationrequ

ired,

the

characterizationof

materialsmaybe

divided

intothefollowin

ggroups:

Microscopi

cAnalysis

ChemicalA

nalysis

ThermalAnalysis

MechanicalAnalysis

NDTAnaly

sis

DESIGN,SELE

CTION&CHARACTERISATIONOF

ENGINEERINGM

ATERIALS

Thetangiblesubstance

thatgoesintothemakeupof

aphysicalo

bject.

Eng

ineer

ing

Ma

teria

ls:

Materialsfo

rEngineering

applications

.

Metals

Polym

ers

Composites

Ceram

ics

Glass

esetc.

SELECTION

DESIGN

CHARACTERISATION

ENGINEERINGMATERIALS


4/13

THE FOUR CsOF DESIGN

1.CREATIVITY Requires creation of something that has not existed before or has not existed in

the designers mind before

2.

COMPLEXITY

Requires decisions on many variables and parameters3.CHOICE

Requires making choices between many possible solutions at all levels, from

basic concepts to the smallest detail of shape

4.COMPROMISE Requires balancing multiple and sometimes conflicting requirements

COMPARISON BETWEEN THE SCIENTIFIC METHOD

AND THE DESIGN METHOD


5/13

WAYS TO THINK ABOUT THE ENGINEERING DESIGN PROCESS:

1-A SIMPLIFIED ITERATION MODEL

2-A PROBLEM-SOLVING METHODOLOGY

1-A SIMPLIFIED ITERATION MODEL

ITERATIONis the process of doing something again and again, usually to improve it. OR Anamount that you get when you use a mathematical rule several times.

Different writers or designers have outlined the design process in as few as five steps or as

many as 25. One of the first to write about design was Morris Asimow.

He viewed the heart of

the design process as consisting of the elements shown in Fig.

As portrayed in fig, design is a sequential process consisting of many design operations.

Examples of the operations might be

(1) Exploring the alternative concepts that could satisfy the specified need.

(2) Formulating a mathematical model of the best system concept.

(3) Specifying specific parts to construct a subsystem. And

(4) Selecting a material from which to manufacture a part.

Each operation requires information (General, technical and business information

expected from the trained professional).

Acquisition of information is a vital and often very difficult step in the design process,

but fortunately it is a step that usually becomes easier with time. (We call this process

EXPERIENCE.)


6/13

2-A PROBLEM-SOLVING METHODOLOGY

Designing can be approached as a problem to be solved. A problem-solving methodology that is

useful in design consists of the following steps.

Definition of the problem

Gathering of informationGeneration of alternative solutions

Evaluation of alternatives & decision making

Fig: Note how the design depends on the viewpoint of the individual who defines the

problem, illustrates how the final design can differ greatly depending upon how the

problem is defined.

Problem definition often

called needs analysis.

It is the nature of t

design process that ne

needs are established

the design proce

proceeds because ne

problems arise as t

design evolves

Design is proble

solving only when needs and potential issu

with alternatives a

known.

If these additional nee

require reworking tho

parts of the design th

have been completed, thpenalties are incurred

terms of cost and proje

schedule.

Experience is one of t

best remedies for th

aspect of designing, b

modern computer-basdesign tools he

ameliorate the effects

inexperience.


7/13

While many consider that the engineering design process ends with detail design, there are

many issues that must be resolved before a product can be shipped to the customer. These

additional phases of design are often folded into what is called the product development

process.

Phase IV:Planning for manufacturedesign of tooling and fixtures, designing the process

sheet and the production line, planning the work schedules, the quality assurance system, and

the system of information flow.

Phase V:Planning for distributionplanning for packaging, shipping, warehousing, and

distribution of the product to the customer.

Phase VI:Planning for useThe decisions made in phases I through III will determine such

important factors as ease of use, ease of maintenance, reliability, product safety, aesthetic

appeal, economy of operation, and product durability.

Phase VII:Planning for product retirementAgain, decisions made in phases I through III

must provide for safe disposal of the product when it reaches its useful life, or recycling of its

materials or reuse or remanufacture.

(Phase I)

(Phase III)(Phase II)

STEPS IN THE DESIGN PROCESS


8/13

Fig. The design paradox between design knowledge and design freedom.


9/13

The goal of design:

To create products that perform their function effectively, safely, at

acceptable cost.. What do we need to know about materials to do this?

More than just test data.


10/13

INTERACTION B/W MATERIAL, ITS FUNCTION, SHAPE,

AND PROCESS

The selection of material is tied in with process and shape.

To make a shape, the material is subjected to processes that, collectively,are called manufacture: these include primary forming processes (e.g.,

casting and forging), material removal processes (machining, drilling),

joining processes (e.g., welding) and finishing processes (e.g., painting or

electroplating).

Function influences material choice.

Material choice influences processes through the materials ability to becast or molded or welded or heat-treated.

Process determines shape, size, precision and cost.

These interactions are two-way: specification of shape restricts the

choice of material and process; but equally the specification of process

limits the material choice and the accessible shapes. The more

sophisticated the design, the tighter the specifications and the greater the

interactions.

The interaction between function, material, shape, and process lies at the

heart of the MATERIAL SELECTION PROCESS


11/13

MATERIALS SELECTION METHODOLOGY

Translate the design

requirements into materials

specifications. It should takeinto consideration the design

objectives, constraints and

free variables.

Screening out of materials

that fail the design

constraints.

Ranking the materials by

their ability to meet the

objectives. (Material

Indices).

Search for supporting

information for the material

candidates.

MATERIAL ATTRIBUTES


12/13

CHOOSING A MATERIAL:Design requirements are first expressed as constraints and

objectives. The constraints are used for screening. The survivors are ranked by the

objective, expressed as a material index.


13/13

DEFINING THE DESIGN REQUIREMENTS

Free variables: What is the designer free to change?* It is sometimes useful to distinguish between hard and soft constraints. Stiffness and

strength might be absolute requirements (hard constraints); cost might be negotiable (soft

constraint).

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Intro Dscm