Pemilihan Konsep
Dr. Eng. Rakhmad Arief Siregar
3
Model Empat Tahap Proses
Berpikir Kreatif & Pemecahan Masalah
Persiapan (tahap1):
Unsur-unsur masalah diperiksa dan keterkaitannya dipelajari.
Inkubasi (tahap 2):
Anda "tidur pada masalah". Tidur melepaskan pikiran sadar Anda,
memungkinkan pikiran bawah sadar untuk mengerjakan suatu masalah dengan bebas.
Inspirasi (tahap 3):
Sebuah solusi atau jalan menuju solusi muncul.
Verifikasi (tahap 4):
Solusi yang diilhami diperiksa terhadap hasil yang diinginkan.
Improving Creativity
• Meningkatkan kreativitas adalah upaya yang populer.
• Pencarian Google di bawah Metode Kreatif menghasilkan lebih dari 12 juta klik!
• Metode berikut ditujukan untuk meningkatkan karakteristik pemecah masalah berikut:
• Sensitivitas: Kemampuan untuk mengenali bahwa ada masalah.
• Kefasihan: Kemampuan untuk menghasilkan sejumlah besar solusi alternatif.
• Fleksibilitas: Kemampuan untuk mengembangkan berbagai pendekatan terhadap suatu masalah.
• Orisinalitas: Kemampuan untuk menghasilkan solusi asli untuk suatu masalah.
Brainstorming
• Brainstorming adalah metode yang paling umum digunakan oleh tim desain untuk menghasilkan ide.
• Kata brainstorming telah menjadi penggunaan umum dalam bahasa untuk menunjukkan segala jenis generasi ide.
• Brainstorming adalah proses yang diatur dengan hati-hati.
• Sesi brainstorming yang dilakukan dengan baik adalah sesi antusias
dari ide-ide yang mengalir bebas dan cepat.
Idea Generating Techniques
• Enam Pertanyaan Kunci:
• WHO? Apa? Kapan? Di mana? Mengapa? Bagaimana?
• Lima Mengapa:
• Mengapa mesin berhenti?
• – Sekering putus karena kipas kelebihan beban.Mengapa terjadi kelebihan beban?
• – Pelumasan bantalan yang tidak memadai.Mengapa tidak ada cukup pelumasan?
• – Pompa berhenti bekerja.Mengapa pompa tidak bekerja?
• – Getaran poros pompa disebabkan oleh keausan abrasi.Mengapa terjadi abrasi?
• – Tidak ada filter pada pompa pelumas, memungkinkan kotoran masuk ke system
• Daftar periksaFantasi atau angan-angan
Checklist
Desain Biomimetik
• Sumber analogi langsung yang sangat menarik adalah analogi yang diilhami oleh sistem biologis.
• Biomimetik adalah meniru sistem biologis seperti:Penemuan pengencang Velcro.
• Tantangan bagi desainer ada dua:perancang teknik tidak terlatih
dalam berbagai macam sistem biologis kata-kata yang digunakan para
insinyur untuk mengekspresikan perilaku tidak selalu cocok dengan
kata-kata yang digunakan untuk menggambarkan sistem biologis.
Invensi Velcro
• Burdock burr (biji) yang terus menempel di baju dan bulu anjingnya
Peta Konsep untuk Daur Ulang
Logam
Physical Decomposition of a Bicycle
12
Functional Representation:
Standard Flow Classes & Member Flow
13 R. E. Stone, “Functional Basis”, Design Engineering Lab Webpage, designengineeringlab.org/FunctionCAD/FB.htm, accessed November 10, 2011.
Components Abstracted into Function Blocks
14
Function Structure Black Box for a Basketball Ball Return
15
Function Structure for a Mechanical Pencil
16
Metode Morfologi
• Analisis morfologi adalah metode untuk merepresentasikan dan mengeksplorasi semua hubungan dalam masalah multidimensi.
• Kata morfologi berarti ilmu yang mempelajari tentang bentuk dan rupa.
• Analisis morfologi adalah cara untuk menciptakan bentuk-bentuk baru.
• Metode morfologi telah dicatat dalam sains sebagai cara untuk
menghitung dan menyelidiki alternatif solusi sejauh tahun 1700-an.
• Zwicky meresmikan proses penerapan metode morfologi untuk desain
pada pertengahan 1960-an dengan penerbitan teks yang diterjemahkan ke
dalam bahasa Inggris pada tahun 1969.
Konsep Morfologi
Concept Generation and Evaluation
19
Shot Buddy Concept Generation
20 Adapted from J. Davis, J. Decker, J. Maresco, S. McBee, S. Phillips, and R. Quinn, “JSR Design Final Report: Shot-Buddy,” unpublished, ENME 472, University of Maryland, May 2010.
Sketch of Key Model Building Factors
21 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
FEA in Machine Design
22
Pugh Chart
• A particularly useful method for identifying the most
promising design concepts among the alternatives generated at is the Pugh chart.
• Pugh’s method compares each concept relative to a reference or datum concept and for each criterion determines whether the concept in question is better than, poorer than, or about the same as the reference concept.
• Pugh Chart is a relative comparison technique.
23
Steps of Building the Pugh Chart
1) Choose the criteria by which the concepts will be evaluated 2) Formulate the decision matrix
3) Clarify the design concepts 4) Choose the datum concept 5) Complete the matrix entries 6) Evaluate the ratings
7) Establish a new datum and rerun the matrix
8) Examine the selected concept for improvement opportunities
24
Pugh Chart 1 for Shot-Buddy Example
25
Pugh Chart 2 for Shot-Buddy Example
26
Weighted Decision Matrix
• A decision matrix is a method of evaluating competing
concepts by ranking the design criteria with weighting factors and scoring the degree to which each design concept meets the criterion.
• To do this it is necessary to convert the values obtained for different design criteria into a consistent set of values.
• The simplest way of dealing with design criteria expressed in a variety of ways is to use a point scale.
27
Evaluation Scheme for Design Alternatives or Objectives
28
Systematic Methods for Determining Weighted Factors
• Direct Assignment:
• This method is only recommended for design teams where there are many years of experience designing the same product line.
• Objective Tree:
• This method relies on some experience with the importance of the criteria in the design process.
• Analytic Hierarchy Process (AHP):
• This method is the least arbitrary method for determining weighting factors.
29
Objective Tree: Design of a Crane Hook
30 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
Weighted Decision Matrix:
Steel Crane Hook
31 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
Analytic Hierarchy Process (AHP)
• The Analytic Hierarchy Process (AHP) is a problem-solving methodology for making a choice from among a set of
alternatives when the selection criteria represent multiple objectives, have a natural hierarchical structure, or consist of qualitative and quantitative measurements.
• AHP was developed by Saaty.
• AHP is a decision analysis tool that is used throughout a number of fields in which the selection criteria used for evaluating competing solutions that do not have exact, calculable outcomes.
32
AHP’s Ratings for Pairwise Comparison of Selection Criteria
33 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
The ratings of even numbers (2, 4, 6, 8) are used when the decision maker needs to compromise between two positions in the table.
Example: Design of Crane Hook
34 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
AHP Process for Determining Criteria Weights
• The process is:
1) Complete criteria comparison matrix [C] using 1–9 ratings described in Table 7.8.
2) Normalize the matrix [C] to give [NormC].
3) Average row values. This is the criteria weight vector {W}.
4) Perform a consistency check on [C] as described in Table 7.10.
35
Consistency Check Process for AHP Comparison Matrix( C )
• Calculate weighted sum vector, {Ws} = [C] × {W}
• Calculate consistency vector, {Cons} = {Ws}/{W}
• Estimate λ as the average of values in {Cons}
• Evaluate consistency index, CI = (λ − n)/(n − 1)
• Calculate consistency ratio, CR = CI/RI
• If CR < 0.1 the {W} is considered to be valid; otherwise adjust [C] entries and repeat.
36
RI Values are given in Table 7.11.
Consistency Check for {W} for Crane Hook
37 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
AHP’s Ratings for Pairwise Comparison of Design Alternatives
38 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
Determining Ratings for Design Alternatives with Respect to a Criterion
• The process is summarized as:
1) Complete comparison matrix [C] using 1–9 ratings of Table 7.12 to evaluate pairs of competing design alternatives.
2) Normalize the matrix [NormC].
3) Average row values—This is the vector priority {Pi} of design alternative ratings.
4) Perform a consistency check on [C].
39 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
Determine the Best of Design Alternatives
• The process is summarized as:
• Compose Final Rating Matrix [FRating].
• Calculate [FRating]{W}
={Alternative Value} by first taking the transpose of [FRating].
• Select the alternative with the highest rating relative to others.
40 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
Design Alternative Ratings for Material Cost
41 Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
Final Rating Matrix
42
The best solution is the riveted plate design option.
Dieter/Schmidt, Engineering Design 5e.
©2013. The McGraw-Hill Companies
