General principles of design , Engineering design , General studies , UPSC ESE

•  It is the process of applying basic science , mathematics and engineering science in order to shape out the available resources to develop an useful product that satisfies customer need or requirements. e.g. refrigerator , missile system , etc.

• A design process involves 4 C's 

1. Creativity : it requires creation of something that has not exist before . eg : internet , microprocessor , android , engines.
2. Complexity : it requires right decision on many variables and parametres. eg : engines - torque , displacement , fuel efficiency , power.
3. Choice : making right choice from available solution. eg : depending on the position of engine chasis - conventional chasis , semi forward chasis , centre engine chasis , rear engine chasis.
4. Compromise : balancing the solution and sometimes conflucting situation. eg : car - fuel effieciency , speed.

Types of engineering design :

1. Original or innovative design : it requires invention which occurs rarely and it exist it destroys ongoing market . eg : aeroplane , microprocessor , internet.
2. Adaptive design : it requires adaptation of existing design with minor modification . eg : honda city : 2016 , 2017 , 2018 and so on.
3. Redesign : enhancing the existing design . eg : manual gear box , convention TV
4. Selection design : it requires selection of certain designing solution based upon its cost , performance and quality . eg : spark plug , battery.
5. Industrial design : 

a) Aesthatic design : design that appeal human sense . eg : taj mahal , pyramid , etc.

• Aesthtic design is performed on golden ratio.
• Two numbers are in golden ratio if the ratio of two numbers is same as their sum to the largest of the numbers then the number are in golden ratio.

b) Ergonomic design: design pertaining to human machine interaction . eg : adjustable seats in  car.

c) Evolutionary design : it consist of 

1. Benchmarking : comparing and evaluating one's company design against best in market eg : delhi metro , made easy.
2. Reverse engineering : it is not a savory process. it requires decomposing the design in to components to understand how it works.

Steps to engineering design:

1. 
   
2. 

Problem definition and information gathering:

Problem definition means defining the problem according to the customer requirements and information can be gathered through various channels like:

• Customer interview : design team interview each customer
• Focus groups : moderate discussion with 6 to 12 targeted members
• Customer service : providing customer service centre will gave a fair idea about the product
• Warranty data : providing warranty data with product customer ensures the quality of product
• Customer survey : questionaire in the form of telephonic , written , email to know about product from customer.

Once the customer requirement (CRs) is understand the design team will not evaluate its implemented feature against CRs using kano diagram.

According to kano diagram there are four types of customers :

Kano diagram:

1. Expectors : the basic feature of a customer would expect to be in the product . eg braking system , suspensions.
2. Spokens : the customer speaks about the feature required in the product . eg mounted control on steering , projector lamp.
3. Unspokens :customer does not speak about the product hence its become challenging for design team to know it . eg safety feature , bluetooth feature.
4. Exciters (delighters) : the feature that is unique and distinguish from its compitetor. eg self driven cars , wifi cars.

• Once the CRs is known against implemented feature the design team makes PDs (product design specification)
• PDs is a dynamic or living document written in list format and is implemented before the execution of design process.
• Example : CRs (what) : fuel efficiency , safety feature , comfort. 
• Engineerign characteristics ECs : how : weight decrease , air bags , length increase.

House of quality

Generate multiple solution:

• A person must be creative so that he /she can process the thought i generate solution to the problem at hand.
• Psycologist have developed several model as how a brain or mind develops thought process to generate solution.

Brain dominance theory (Roger Sperry)

Sigmund Freud's level of mind:

• Concious mind : short term memory / working memory
• Pre concious mind : long lasting memory
• Sub concious mind : it is not under current focal awareness.

Four step process to creativity:

1. Prepration : percepating problem at hand correctly
2. Incubation : sleep on problem
3. Illumination : solution to problem emerges
4. Verification : verify the solution against problem

Concept generation methods:

1. Brainstorming : it is a group activity in which every individual discuss about problem and tries to find its solution.

Guidelines:

• Focus on quantity rather than quality
• With hold criticism and encourage wild ideas
• Record ideas
• Stay focused on the topic

2. Beyond brainstorming:

a) Scamper checklist 

• s = substitute
• c = combine
• a = adapt
• m = modify
• p = put to other use
• e = eliminate
• r = rearrange

b) 6 key questions

• Who is benefitted
• What if it fails/succeed
• When X occurs
• Where to use 
• Why it occured
• How to use it

c) Five why: it gives root cause of problem

d) Random input techniques:

eg: 

e) Symetics : reasoning by analogy

1. Direct analogy: eg
2. Personal analogy : placing self at the place of actual problem.
3. Symbolic analogy : assosciating with natural world. eg aeroplane - bird , water flow - reverse
4. Fantasy analogy : idealistic concept eg medical treatment without disecting the body like removal of stones , removal of pendix.

Barriers to creative thinking:

1. Perceptual block : inability to percept problem at hand .

a) Stereotyping : not thinking out of box i.e. thinking conventionally or in formulaic way.

b) Fixation : not thinking problem in fresh perspective

c) Information overload : delvin too much in unnecessary details of problem

2. Intellectual block: 

a) Sufficient knowledge base 

b) Memory block

c) Poor choice of problem representation

3. Emotional block : 

a) Fear of taking risk

b) Lack of motivation

c) Unease with chaos : unable to balance oneself in chaotic environment.

4.Cultural  block:

People tend to develop certain traits due to culture in which he / she is broughtup.

5. Environmental block:

a) Physical environment 

b) Criticism

Analyse and select solution:

Before selecting the solution we must analyse each and every solution.

1. Decision tree

Which ever is larger amongst x,y, z we will select solution corresponding to that.

2. Evaluation method

a) Pugh's chart (datum method)

Solution is analyse with respect to certain refrence and datum, eg:

b) Evad (design evalution) method

eg mouse trap

c) Weighted decision matrix:

• Direct assessment : eg kowsik - car , honda - comfortable , fuel efficient , low maintenancy 

• Objective tree :
• 
• 
  

a)Weight of material cost = 1x0.6x0.3=0.18

b)Weight of manufacturing cost = 1x0.6x0.5=0.3

c)Weight of repairability of cost = 1x0.6x0.2=0.12

• AHP (analytical hierarchy process)

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Embodiment design:

Design concept developed and processed so far is now can entered to physical form known as embodiment design.

It is 3 step process:

1. Product architecture: eg arranging physical components to carry out desired functions. it can be realised in two ways .
2. Configuaraion design : approximate dimension is selected , selection of material and manufacturing
3. Parametric design : exact dimension and tolerance

Prototyping:

• It is  a physical working model needed to be tested against design solution using CAD tools before mass manufacturing .
• The physical component is manufactured parallely known as concurrent engineering and it is implemented long before project execution.
• After prototyping the design concept testing is conducted.