professor seung-hwan chang [email protected] school of...

Structural design with advanced composite materials

Professor Seung-Hwan Chang

[email protected]

School of Mechanical EngineeringSchool of Mechanical Engineering

Chung-Ang University

System design with advanced composites lab.

Introduction

1. 수강대상: 수강대상• 기계공학부 3학년및공학인증대상학생• 공학인증제편입대상자

2. 교재/부교재• 복합재료(장승환외 5명 홍릉과학출판사 2007)• 복합재료(장승환외 5명, 홍릉과학출판사, 2007)• System design with advanced composites (SH Chang, CAU)

3. 학습성과및반영률• 요구된필요조건에맞추어시스템, 요소, 공정을설계할수 있는능력복합학제적팀의한구성원의역할을해낼수있는능력• 복합학제적팀의한구성원의역할을해낼수있는능력

• 공학문제들을인식하며, 이를 해결할수있는능력

4. 수업운영방식:• 강의를통한복합재료역학의이해• Project 수행을위한 Team Project 운영

5. 평가방식• 중간/기말고사/term project• Team project의경우 Team별평가를원칙으로함Team project의경우 Team별평가를원칙으로함


Presentation evaluation

평가항목

과제의완성도배점

점수

공학적이해도배점

점수

발표기술배점

점수

재료특성 현상의

세부

재료특성활용도 10 현상의

공학적설명 20 발표시간 10

모형제작여부 10 논리적연관성 10 자료의간결성/정확성 5

부항목

정확성

결과의완성도 10 전문성 10 청중의호응도 5

전문용어사용 5

발표자세 5

총계 30 40 30


Information and Queries http://cau.ac.kr/~phigs


Any Questions?y Q


System Design

Materials

“Fully interconnected”

Function

Shape

ProcessProcess


Materials

Materials

Material attributes;

• Physicaly

• Mechanical

• Thermal

• Electrical

• Environmental

• Economic• Economic

• Etc.


Functions

FunctionFunction of System:

• Transmit Loads & Heat

• Contain Pressure

• Store Energy

• Etc.

@ Minimum mass

@ Minimum cost@ Minimum cost

@ Minimum environmental impact


Shape

Shape Factor:

• Bendingg

• Twisting

• Compression

Shape

• Etc.

@ I-beam

@ Sandwich structures@ Sandwich structures

@ Shell types


Processes

Manufacturing:

• Primary forming

• Material removal process

• Finishing

• Joining

Process

• Joining

@ Materials

@ Processing cost Process


General Design Process

Aim: Development of a methodology for selecting materials and processes

1) The starting point is a market needs1) The starting point is a market needs

① Need statement (required performances)

② Solution-neutral (to avoid limited thinking)

2) Conceptual design stage

① Define specification

② D t i f ti t t② Determine function structure

③ Seek working principles

④ Evaluate and select concepts④ Evaluate and select concepts

3) Embodiment design stage

① Develop layout, scale, form

② Model and analysis assemblies

③ Optimise the functions

④ E l t d l t l t④ Evaluate and select layout


General Design Process

4) Detailed design stage

① Anal se components in detail① Analyse components in detail

② Select processing route

③ Optimise performance and cost③ p p

④ Prepare detailed drawings

5) The end point is the full specification of a product (embodiment of idea)

Analysis methods for system design

• System decomposition

: useful way to analyse the existing system

• Function structure or function decomposition• Function structure or function decomposition

: Transformation of energy, materials and information

⇒ advantageous to the synthesis of new idea

systematic way of evaluating design options System design with advanced composites lab.

Market NeedsGeneral Design Process

Market Needs

① Define specification

② Determine function structure

ConceptConcept

② Determine function structure

③ Seek working principles

④ Evaluate and select concepts

EmbodimentEmbodiment

① Develop layout, scale, form

② Model and analysis assemblies

③ Optimise the functions③ Optimise the functions

④ Evaluate and select layout

① Analyse components in detailDetailDetail

① y p

② Select processing route

③ Optimise performance and cost

④ P epa e detailed d a ings

Product Specification IterateIterate

④ Prepare detailed drawings

Product Specification


Types of design

• New materials ⇒ New unique combinations of properties ⇒ Original design• New materials ⇒ New, unique combinations of properties ⇒ Original design

e.g. high purity silicon: transistor

high purity glass: optical fibre

• New materials ⇔ New products

e.g. space technology: lightweight composites

• Variant design: changing scales or dimensions with the same function• Variant design: changing scales or dimensions with the same function

⇒ requires change of materials

e.g. small boats: fibreglass ⇔ large ones: steel


Design tools and Material data

• Design tools• Design tools

; Modelling and optimisation of a design

- Function modeller: viable function structure

- Geometric and 3-D solid modelling package

: visualization and creation of files for forming processes

-Optimisation, DFM (Design for Manufacture), DFA (Design for Assembly),

cost-estimation software: for details

- Finite element packages:Finite element packages:

precise mechanical and thermal analysis for complex geometry


Example of FEA

: AC induction motor for high speed application

Rotor body Squirrel cage rotor Induction rotor and shafty q g Induction rotor and shaft

Various materials for the rotor and the shaft

• Silicon steel

• Magnetic powder containing epoxy resin

Iron powder• Iron powder

• Ferrite powder

• Stainless steelMagnetic density analysis

• Fibre reinforced composite materialsSystem design with advanced composites lab.

Design process w.r.t. Precision and Complexity

• Progression in the use of the tools

① Approximate analysis and modelling (conceptual stage): widest possible① Approximate analysis and modelling (conceptual stage): widest possible

range of materials

② Sophisticated modelling and optimisation (embodiment stage): higher ② p g p ( g ) g

level of precision and detail, subset of materials

③ Precise analysis (detailed design stage): one or a very few materials with

higher level precision and detail including the manufacturer of the materials and

special properties


Materials in Design

; Process of translating a new idea into detailed information

• Material selection for design depends on;

① Experience

② Systematic Procedure

1) Beginning stage of design; All materials must be considered

2) Focused design; Selection criteria/shortlist of materials

⇒ more accurate data different way of analysing the choice are needed⇒ more accurate data, different way of analysing the choice are needed

3)Final stage of design; Precise data (Based on final design calculations)

Choice of Materials


• Choice of material should consider;

① Cost

② Aesthetic aspect② Aesthetic aspect

③ Process

④ Properties

⑤ ( ll ibili i )⑤ Etc. (All possibilities)

★ Strategy for material development;

⇒ Fibre reinforced composite materials, Sandwich panels

FoamComposites


Kingdom of Materials


System Design Force

F

STEP 1

b

b

Area

A

F

Define the design requirements:

Function: what does the component do?p

Objective: what is to be maximised or minimised?

Constraints: essential requirements which must be met

(stiffness, strength, corrosion resistance, forming characteristics…)

Design variables: sensitivity check, free/fixed

STEP 2

Develop an equation for the objective in terms of the functional requirements,

the geometry and the material properties (Variables).

ρlAm =System design with advanced composites lab.

STEP 3

Identify the free (unspecified) variables.

EICFSTEP 4

Develop equations for the constraints (no yield; no fracture; no buckling, etc.)

31

lEICFS ≥=

δ

STEP 5 ⎟⎠⎞

⎜⎝⎛

⎟⎟⎠

⎞⎜⎜⎝

⎛≥ 2/1

32/1

1 El

lCS12m ρ

12A

12bI

24

==

Substitute for the free variables from the constraint equations into the objective function.

STEP 6

Find the extremum of the objective function according to the constraints.


System Design-Summary

Function Has a Function Has a Function Has a

FUNCTIONTie

Each combination of ObjectiveConstraintFree variable

characterising material index

FUNCTIONTie





Minimum cost

OBJECTIVE

CONSTRAINTS

e

BeamMinimum cost

OBJECTIVE

CONSTRAINTS

e

Beam

Minimumweight

Maximum energy

INDEX Shaft

C l

Stiffnessspecified

⎥⎤

⎢⎡ ρ

=M

Minimumweight

Maximum energy

INDEX Shaft

C l

Stiffnessspecified

⎥⎤

⎢⎡ ρ

=MMaximum energy storage

Minimum environ impact

Column

M h i l

Strengthspecified

Fatigue limit

⎥⎦⎢⎣= 2/1E

MMaximum energy storage

Minimum environ impact

Column

M h i l

Strengthspecified

Fatigue limit

⎥⎦⎢⎣= 2/1E

M

environ. impactMechanical,Thermal,

Electrical...

Fatigue limit

Geometryspecified

Minimise this!

environ. impactMechanical,Thermal,

Electrical...

Fatigue limit

Geometryspecified

Minimise this!

Minimise this!


professor seung-hwan chang [email protected] school of...

Documents