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SystemsEngineering1.pdf

SystemsEngineering1.pdf

Systems Engineering & Voice of the Customer

US Automotive RecallsVehicle Sold

(Millions) Vehicles Recalled

2011 2012 2013 2011 2012 2013

Toyota 1.6 1.7 2.2 219% 312% 241%

Honda 1.2 1.4 1.5 325% 243% 187%

BMW 0.2 0.3 0.3 150% 200% 300%

Hyundai 1.1 1.3 1.3 109% 138% 169%

Chrysler 1.4 1.4 1.8 57% 76% 261%

Ford 2.1 2.2 2.5 157% 64% 48%

Nissan 1.0 1.0 0.9 30% 100% 133%

GM 2.5 2.6 2.8 68% 58% 54%

Slide 2

System understanding

HoQ1→Boundary→HoQ2→P-diagram→DFMEA→PFMEA→SCIF→Control plan

HoQ1→Boundary→HoQ2→P-diagram→DFMEA→PFMEA→SCIF→Control plan

HoQ1→Boundary→HoQ2→P-diagram→DFMEA→PFMEA→SCIF→Control plan

HoQ1→Boundary→HoQ2→P-diagram→DFMEA→PFMEA→SCIF→Control plan

System validation plan

System verification plan

Sub-system verification plan

Component verification plan

Time line

System

Sub-system

Component

System

Sub-system

Requirements Flow Down Example

We Must Know the Mathematical Relationship to Flow Down Requirements• What are the options if the engineering is not

known?• Safety factor

• Pass responsibility to customer

• Refuse the business

• Increase price to compensate for the additional risk

• Use experiments to create empirical models

• Basic research

Never accept a known risk for safety or compliance with government regulations

Slide 6

Relationships

Boundarydiagram

Parameter diagram

DesignFMEA

R&Rmatrix

HoQ #1

ProcessFMEA

Critical characteristicsidentificationform

Manufacturingcontrol plan

Field performance

Project goals Knowledge storage & re-use is

critical

Our Influence Over Risk

Start

up

RISK MANAGEMENT PROCESS

(APQP)

ABILITY TOINFLUENCE RISK

Design &

Develop

Product

Design &

Develop

Process

Product &

Process

Validation

RISK

Start

up

RISK MANAGEMENT PROCESS

(APQP)

ABILITY TOINFLUENCE RISK

Design &

Develop

Product

Design &

Develop

Process

Product &

Process

Validation

RISK

TimeStart

up

RISK MANAGEMENT PROCESS

(APQP)

ABILITY TOINFLUENCE RISK

Design &

Develop

Product

Design &

Develop

Process

Product &

Process

Validation

RISK

Start

up

RISK MANAGEMENT PROCESS

(APQP)

ABILITY TOINFLUENCE RISK

Design &

Develop

Product

Design &

Develop

Process

Product &

Process

Validation

RISK

Time

DEFINE IT RIGHT

House of Quality (HoQ)• Features:

• Inputs from customer

• Measurable functional requirements to test against

• Targets and limits set by customer

• We will use rooms 1 and 3 to assist in creating the FMEA

• May be:• Used as an aid when completing a CSCM or

• Not used if the CSCM is sufficient in define customer needs

7

3

5

4

6

2

8

Direction of improvement

Calculated importance

Competitive comparison of

customer ratings

Conflicts

Correlations

Competitive benchmarks

Targetsand limits

Functional requirements

1

Cu

sto

me

r e

xp

ect

ati

on

s

Fast Car Example

91 3 9

Types of Requirements• Functional Requirements

• Define what functions need to be done to accomplish the mission objectives• Example

• The Thrust Vector Controller (TVC) shall provide vehicle control about the pitch and yaw axes.

• This statement describes a high level function that the TVC must perform.

• Statement has form of Actor – Action Verb – object acted on

• Performance Requirements (Specification)• Define how well the system needs to perform the functions• Example: The TVC shall gimbal the engine a maximum of 9 degrees, +/- 0.1 degree

• Constraints• Requirements that cannot be traded off with respect to cost, schedule or performance• Example: The TVC shall weigh less than 120 lbs.

• Interface Requirements• Example: The TVC shall interface with the J-2X per conditions specified in the CxP 72262

Ares I US J-2X Interface Control Document, Section 3.4.3.

• Environmental requirements• Example: The TVC shall use the vibroacoustic and shock [loads] defined in CxP 72169, Ares 1

Systems Vibroacoustic and Shock Environments Data Book in all design, analysis and testing activities.

• Other -illities requirement types including availability, reliability, maintainability, etc.

Attributes of Acceptable Requirements• A complete sentence with a single “shall” per numbered

statement

• Characteristics for Each Requirement Statement:• Clear and consistent – readily understandable

• Correct – does not contain error of fact

• Feasible – can be satisfied within natural physical constraints, state of the art technologies, and other project constraints

• Flexibility – Not stated as to how it is to be satisfied

• Without ambiguity – only one interpretation

• Singular – One actor-verb-object requirement

• Verify – can be proved at the level of the architecture applicable

• Characteristics for pairs and sets of Requirement Statements: • Absence of redundancy – each requirement specified only once

• Consistency – terms used consistent

• Completeness – usable to form a set of “design-to” requirements

• Absence of conflicts – not in conflict with other requirements or itself

• Clarified with boundary and P-diagrams

• NASA Systems Engineering Handbook for Reference

Requirements Definitions Mistakes• Writing implementations (How) instead of

requirements (What)• Forces the design

• Implies the requirement is covered

• Using incorrect terms• Use “shall” for requirements

• Avoid• “support”

• “but not limited to”

• “etc”

• “and/or”

• Using incorrect sentence structure or bad grammar

• Writing unverifiable requirements• E.g., minimize, maximize, rapid, user-friendly, easy,

sufficient, adequate, quick

• Requirements only written for “first use”

Did any Changes or Improvements Have a Negative Impact on Another Function?

Potato Cannon Exercise• Customer wants to win the potato cannon contest

• Fire a potatoes into squares• Square are 20 meters long on each side

• Center of square is 150 meters away

150 meters

10 meters

Potato Cannon• How it works

• Potato is pushed into the sharpened barrel which cuts potato to size

• Hair spray (propane – C3H8) is added at the back end

• Spark creates explosion

• Demonstration

• Components• Loading rod

• Combustion Chamber, end cap, end cap connector and igniter

• Barrel & reducer

• Teams of 3 or 4

• Use “TBD” if exact valuescannot be determined

• Additional Links• Search for potato cannon fails

• Fire

Barrel

Combustion

Chamber

Igniter

Reducer

End Cap ConnectorEnd Cap

Igniter

Seal

Scoping and Definition of Responsibility• The customer needs a solution and is looking to SKF to deliver some functions

• To deliver the functions, we need clear definition of the functions, and detail regarding the conditions our product is expected to work under• The CSCM provides the function definitions

• The boundary diagram contains these functions and• the operating conditions

• responsibility for each component

Our Solution

System Part 1 System Part 2

System Part 3

Condition 1

Condition 2

Condition n

Function 1

Function 2

Function p

Las Vegas High Roller

Las Vegas High Roller• Multiple companies designing simultaneously

• Used the boundary diagram to:• Understand the tolerances of all interfaces

and non-interfacing parts that potentially impact the bearing

• Define loading• Wind loads• Seismic events

• Define bearing handling and installation

• This was challenging• Strengthened hub design• Changed spindle design• Given responsibility for installation procedure

and equipment design• Automatic lubrication • Automatic Condition monitoring

Las Vegas High Roller Boundary Diagram

Spindle

Tapered

sleeve

Housing

Grease

Support

Legs

Brace

Leg

CablesRim

Mounting

ringCabin

Drive

system

Spherical

roller

bearing

Inputs

•Loads (Cable, wind, passengers)

•Contamination (dust, water)Desired Outputs

•Fatigue life

•Wheel rotation

•Accommodate heat growth

Undesired Outputs

•Friction

•Vibration

Operating conditions analyzed:

– Service case 1

– Service case 2

– Service case 3

– Service case 4

DESIGN IT RIGHT

What Could Go Wrong?• Now the boundary of our solution is clearly defined, we should

question what could cause the functions not to be delivered.

• Our solution will work and be used in some uncontrolled

conditions. These external factors are called noise factors.

• The standards define 5 types of noise factors:

• Piece to piece variation (tolerance stack-ups)

• Degradation over time

• Environment

• Customer use and abuse

• System interaction

• Listing these potential noise factors is key, as these noise factor will

become the potential causes of failure.

Unintended Functions• Unintended Failures

• Electric car burns down garage (Alleged)

• “Toyota announced it was recalling 7.4 million vehicles to repair power-window switches that can break down and pose a fire risk”

• Sooner or later everything will fail• 100 year old car

• Modified car (Pimp my Ride)

• How is a car’s brake system designed to fail safe?

• The DFMEA should be used to• Anticipate failures and ensure failures are as benign as possible

• Limp home mode in a vehicle

• Assure no injuries

• Boeing considered encapsulating dreamliner batteries in fire proof container

• Explore and eliminate unintended failure modes

• Other unintended failures• Scully

• McDonnel Douglas

Foreseeable Use & Abuse

Potential Causes• Potential causes of failure are taken from the P-

diagram

• The engineer is NEVER the failure cause; examples• Wrong bolt plating specified

• Lower plating thickness is incorrect

• In identifying potential causes of failure, use concise descriptions of the specific causes of failures• Bolt plating allows rusting from exposure to humidity

• Potential cause of failure is defined as an indication of how the design or process could allow the failure to occur, described in terms of • Something that can be corrected or can be controlled

• Something remedial action can be aimed at

• Something that can be identified as a root cause

• The system allowed or even facilitated the failure cause – the system must be changed

Failure Modes• How can the function not be

delivered?

• There are 4 potential failure modes:• No function at all

• Intermittent function

• Degradation of performance

• Unintended function

Identification of Potentially Special Characteristics• Utilize two stages of special characteristics

• Potential• Confirmed

• Potential special characteristics are identified by• Design – as a rule-of-thumb 80% of all variation

• Cannon animation• Reservoir example

• ISO or other standard• Customer• Supplier

• Potential special characteristics are identified on the drawing and SCIF• Manufacturing (or the supplier) confirms if special controls are needed

for these characteristics based on capability (including special causes)• There is no set capability limit• Maintain flexibility based on severity and industry

• The SCIF records the confirmation decision and reasoning• The decision is reviewed as part of the ECM process

Solution Space for Projectile Distance• Solution 1

• Angle 70°± 1°

• Velocity 316.5 ± 1 ft/sec

• Solution 2

• Angle 70°± 0.8°

• Velocity 316.5 ± 2.5 ft/sec

• Solution 3

• Angle 45°± 1°

• Velocity 253.8± 6.2 ft/sec

• Solution 4

• Angle 45°± 2°

• Velocity 253.8± 6.0 ft/sec

• Solution 5

• Angle 45°± 5°

• Velocity 253.8± 4.5 ft/sec

2100 ft

1900 ft

2000 ft

Gearbox Example

Only one special

characteristic

Airbus Super Puma Crash• What items should be added to the

P-diagram?• Customer use & abuse (Dropped

gearbox)• This has been moved to the boundary

diagram

• Piece-to-piece (worst case roller & raceway profiles)

• What is the failure cause?• Worst case roller & raceway profiles &

max shock load

• The accident could have been prevented if there was a warning• Detection of a metal particle• Vibration

Video

Failure Effect• The effects should always be stated in terms of the

specific project, system, product or process analyzed​

• Remember that a hierarchical relationship exists between the component, sub-system, and system levels. For example, a part could fracture, which may cause the assembly to vibrate, resulting in an intermittent system operation.

• Do not list effect beyond your area of responsibility​

• Brake tube designer cannot have “No Brakes” as effect​

• The effect is “Loss of Brake Pressure”​

• State clearly if the failure mode could impact safety, non-compliance to regulations

Severity• Severity is defined as how serious the effects of a failure

would be should they occur

• It is important to realize that each failure mode may have more than one effect, and each effect can have a different level of severity

• It is the effect which is being rated and not the failure, therefore each effect should be assigned its own severity ranking

• A scaling system from 1 to 10 should be used, with 10 being reserved for the most severe failure modes

• You may have to defer to the customer• Build to print PFMEA with no access to DFMEA

Is the Product Designed Right?

• Green specifications – provide the customer’s functions

• Blue specifications – artificially tight providing a safety factor• Improperly built parts may deliver the customer’s functions

• Red specifications – the design is not correct• Properly produced parts will not always deliver the

customer’s functions

What Happens if You Drive Off with the Gas Pump Nozzle Still in the Car?

• This should be on the P-diagram• Customer use (and mis-use)

• What was the severity of this incident in 1950?

• What is the severity of this incident today?• The hose that attaches the nozzle to the gas pump is designed to break into two

pieces when a certain amount of force is applied to it

• Next time you’re at the gas station, check the hose for a metal coupling

• That’s the break-away point

• Once the hose is broken and you’re off on your merry way, check valves in the hose keep fuel from leaking out and creating a hazard

• Severity can only be improved by a design change• Failure mode designed out

• This is the design control

• It is important to keep this information in the DFMEA so future designs don’t repeat the mistake• Remove the coupling for cost save

• Remove check valves for cost save

What Happens if You Drive Off with the Gas Pump Nozzle Still in the Car?

Controls• There are two types of design controls to consider

• Prevention controls• Aim to eliminate or prevent the cause of the failure mechanism or the failure mode from

occurring

• Aim to reduce rate of occurrence

• The preferred approach is to use prevention controls• Gives a more robust product or process

• Initial occurrence rankings will be affected by the prevention controls

• Prevention controls• Predict performance based on scientific knowledge or

• Ensures performance based on historical experience

• Design out failure mode

• Examples of prevention controls• Fail-safe designs (if two wheel speed sensors disagree, the ABS system is disabled)

• Follow proven design and material standards (internal and external)

• Calculation & Simulation studies (computing the maximum deflection by computing deflection for every possible combination of tolerances)

• Use of components proven under less stressful conditions

• Error-proofing (using non-symmetrical parts to make it impossible to install a component backwards)

Controls• Detection controls

• Aims to identify the existence of a cause that results in a mechanism of failure

• The detection ranking is associated with the best detection control listed in the current design control detection column

• Should include identification of those activities which detect the failure mode as well as those that detect the cause, and could include:• Prototype testing

• Validation testing

• Design of experiments including reliability testing

• Mock-up using similar parts

• A suggested approach to current design control detection is to assume the failure has occurred and then assess the capabilities of the current design controls to detect this failure mode

• Warning • Often the detection method is assumed to be good because no parts with

the failure mode have passed through the detection method

How Much Confidence Do You Have?• Compare this to a design change, or

a choice between two materials• Is George Bush equivalent to the

university player?

• They are both one-for-one (the same performance)

• What should be considered for a DV test• Choose parts and loads that target the

highest risk areas• Minimum thickness

• Highest wavieness

• Maximum preload

• Highest load, etc

Occurrence Rating

• The occurrence ranking is solely a function of prevention controls

• No prevention control gives a ranking of 10

• Ranking of 1• DFMEA: perfect knowledge of engineering with calculations at worst

case

• PFMEA: perfect error proofing or PPM less than 1

• This forces a separation of the prevention and detection controls and strengthens the thinking of prevention over detection

• Ideally, prevention=1 and detection=10

• Weaker prevention mandates stronger detection

Detection Rating• The detection rating is determined by how well a test

can discover the failure mode or effect

• The rating is dependent on:• The correlation of the test to real world conditions

• The parts tested• If parts built very close to nominal are tested, the detection test

provides little value

• The best test utilizes parts built close to the worst case condition that aggravates the failure mode or effected targeted

Priorities• Severity is the primary driver

• Action Priority (AP)• Low, Medium or high based on a combination of severity, occurrence

and detection

• Risk Priority Number (RPN) • This is calculated by multiplying the 3 rankings recorded for severity,

occurrence and detectionRPN = Severity (S) * Occurrence (O) * Detection (D)

• RPN can range between 1 and 1000

• The use of an RPN threshold is NOT a recommended practice for determining the need for actions• Establishing such thresholds may promote wrong behavior (trying to justify

a lower occurrence or detection ranking value to reduce the RPN)

• This type of behavior avoids addressing the real problem that underlies the cause of the failure mode and merely keeps the RPN below the threshold

• IF customers require actions based on thresholds, we shall follow the customer requirements

AP

Recommended Actions

• The intent of recommended actions is to improve the design

• Identifying these actions should consider reducing rankings in the following order:• Severity

• Occurrence

• Detection

• Be sure to include any actions that may be the responsibility of the customer

• Never list a recommended action without a completion date and responsibility for actions related to safety or adherence to government regulation

Robust Design ExampleCost was

reduced by

32% while

the process

capability

was

increased by

132%

BUILD IT RIGHT

The Transition from the DFMEA to the PFMEA• The drawing has so many characteristics … how do I control them all?

• When creating the DFMEA, the characteristics with the biggest impact and severity on the functions to be delivered were identified as potentially special characteristics

• Other characteristics must also be controlled, but the consequences of the non-special characteristics does not warrant the level of oversight that must be taken with special characteristics

• Special characteristics are only potential at the design phase; manufacturing may have error proofing or outstanding capability, that eliminates any need for special controls

The Transition from the DFMEA to the PFMEA

• The Special Characteristics Information Form (SCIF) lists all the potentially special characteristics from the DFMEA, eliminating the possibility of overlooking a potentially special characteristic

• The SCIF also records the origin of the characteristic• Was the characteristic determined from an engineering calculation?

• Was the characteristic flowed down by our customer?

• Was the characteristic flowed up by a supplier?

• Is the characteristic required by a standard?

• The SCIF also records why each characteristic was confirmed or not, and what controls are in place for those characteristics confirmed

Transition to the PFMEA with the SCIF• Forms the bridge from the DFMEA to the PFMEA

• Prevents Special Characteristics from being misses

Internal

PFMEA• What do we have now :

• The specifications for all characteristics

• Potentially special

• Not potentially special

• Now we have to determine how to build the product to specification

• We have the requirements for the final part

• What are the requirements for the intermediate steps?

• What are the requirements for purchased material?

• How do we ensure purchased material conforms to our specifications?

Product Flow

• Just like functions are flowed down from the end customer to sub-systems and eventually components, the manufacturing characteristics needed to deliver these functions are flowed back from the final assembly to previous manufacturing steps and eventually purchased materials

• The inputs for each step are the required outputs for the previous step

What Could Go Wrong?• Now the boundary for each manufacturing step is clearly defined, we should question what could

cause the characteristics not to be achieved.

• There are only 4 potential failure modes:• No characteristic (part not hardened)• Characteristic not achieved for the entire part (roughness is OK for 90% of the raceway, but

not the remaining 10%)• Degradation of performance (part is hardened, but not to specification)• Unintended function (part is scratched)

• There is variability in manufacturing. This variability is defined by noise factors.

• The standards define 5 types of noise factors:• Man• Machine• Material• Measurement• Environment

• Listing these potential noise factors is key, as these noise factor will become the potential causes of failure.

People are not the Problem• The system is always at fault

• Do not blame the operator

• Do not blame the engineer

• Root cause is found by determining how the system allowed a defect to be created and escape

• Example• The label is placed in an incorrect position on a box

• 8D corrective action – the operator was sent to training

• Noooooooooooooo!

• Why did the system allow the operator to incorrectly place the label?• No orientating fixture?

• Poor light?

• What can be done to prevent an operator from locating the label incorrectly?

What Happens if the Characteristics are not Delivered

• If a special characteristic is produced outside the green specification, it does not matter if design determined the specification wrong, or if the part was produced wrong, the result is the same

• This must be reflected in the PFMEA; the severity and the effect in the PFMEA must be the same as in the DFMEA

• The PFMEA also includes an internal severity ranking• Is there a possibility of injury?

• What is the severity of finding a defect at the final production step as opposed to immediately detecting the defect?

DFMEA & PFMEA

• If the failure mode, severity or effect is updated in the DFMEA, the PFMEA must also be updated

Can we Build the Part to Specification

• How strong is our manufacturing knowledge?• Can I predict the process outputs from inputs

(machine settings)?

• Is my SOP reliable given the input conditions specified on the boundary diagram?

• Are error proofing methods in use, and how effective are they?

• This ability to predict function performance provides a probability of the failure to produce the part to specification, and is assessed with the Occurrence rating

Why Occurrence Does Not Come From Defect Data

• Green specifications – provide the customer’s functions

• Blue specifications – artificially tight providing a safety factor• Improperly built parts may deliver the customer’s

functions

• Red specifications – the design is not correct• Properly produced parts will not always deliver the

customer’s functions

• Case 1• Red specifications, but Cpk

is very good, and all production is within the blue lines

• DFMEA occurrence should be high, and PFMEA Occurrence should be low

• Case 2• Blue specifications, and

Cpk is poor resulting production between Green and Blue

• DFMEA occurrence should be low, and PFMEA Occurrence should be high

Can We Build the Part to Specification?

• How strong is our assessment program?• Are all characteristics measured?

• Are characteristics measures at a rate of 100% of sampled?

• How much measurement error is present?

• Has gage R&r been removed from the specifications?

• How often are known good and known bad parts measured?

• Are statistical process control or trend charts used?

• This ability to measure characteristics provides a probability of our ability to detect the failure of our manufacturing process to deliver the required characteristics, and is assessed with the Detectionrating

Purchased Material

• Receiving is a process

• What are the requirements?

• What are the controls?• Prevention

• Supplier certification

• Supplier audits

• Require supplier to send data with each shipment

• Electronic access to supplier data

• Detection• Incoming inspection

Manufacturing Control Plan• The controls in the PFMEA become the Manufacturing Control Plan• Additional information in the control plan

• Measurement assurance activities• Reaction plans

• Following the Manufacturing Control Plan does not ensure zero defects• The occurrence and detection rankings determine the effectiveness of

the manufacturing controls• The effectiveness of the manufacturing controls combined with the

severity ranking highlights internal and external quality risks• Highlighting these risks is a key part of business and technical gate

reviews• The recommended actions portion of the PFMEA provides options for

mitigating these risks

What do I Verify & Validate?

Slide 63

Pool is 50 metres long

500 metres

System boundary diagram

Slide 64

AngleMechanism

VelocityMechanism

Support

Barrel

Distance(475 – 525 m)

Angle43o – 47o

Velocity (m/s)75.5 – 79.2

GravitationalAcceleration(m/sec2)9.81 – 9.82

Sound(100 – 120 dB)

Height(> 90 m)

SoundMechanism

Pool

Side ShowBob

( ) g

2sinvd

=( )2g

sinvh

22θ

=

Velocity mechanism boundary diagram

Slide 65

SupportInner Barrel

Wall

Spring Constant

Weight

FrictionCoefficient

DistanceCompressed

v = f(spring constant,friction coefficient,weight, distancecompressed)

Rollers Plunger Spring

CompressionLever

CompressionGauge

Side ShowBob

Velocity (m/s)75.5 – 79.2

Spring boundary diagram

Slide 66

Spring Constant

Wire Diameter

Free Length

Number of Active Windings

Young’s Modulus

Force =f(Young’s modulus, wire diameter, free length, number of active windings, Poisson ratio, outer diameter)

Poisson Ratio

Outer Diameter

System P-diagram

Slide 67

AngleMechanism

VelocityMechanism

Support

Barrel

Distance(475 – 525 m)

Angle43o – 47o

Velocity (m/s)75.5 – 79.2

GravitationalAcceleration(m/sec2)9.81 – 9.82

Sound(100 – 120 dB)

Height(> 90 m)

SoundMechanism

Pool

Side ShowBob

Noise1.Piece to Piece

– Angle– Velocity– Gravitational Acceleration

2.Degradation– Barrel surface finish– Velocity– Angle variability

3.Environment– Temperature impact on velocity– Temperature impact on barrel flex– Elevation impact on g– Latitude impact on g– Contaminants

▪ Dust▪ Food▪ Spider webs▪ Water▪ Ice▪ Snow▪ Lightening

4.Customer Use– Is it moved (vibration)– Frequency of use

▪ Launched warm▪ Launched cold

5.System Interaction– Slope between pool & cannon– Stiffness of support (angle)

Velocity mechanism P-diagram

Slide 68

SupportInner Barrel

Wall

Spring Constant

Weight

FrictionCoefficient

DistanceCompressed

v = f(spring constant,friction coefficient,weight, distancecompressed)

Rollers Plunger Spring

CompressionLever

CompressionGauge

Side ShowBob

Velocity (m/s)75.5 – 79.2

Noise1.Piece to Piece

– Spring Constant– Weight– Friction Coefficient– Distance Compressed

2.Degradation– Spring Constant

3.Environment– Temperature impact on spring– Temperature impact on friction– Contaminants

▪ Dust▪ Food▪ Spider webs▪ Water▪ Ice▪ Snow▪ Wasp nest

4.Customer Use– Frequency of use

▪ Launched warm▪ Launched cold

5.System Interaction– Barrel & rollers– Weight– Support firmness (Recoil)– Barrel surface finish– Barrel surface contamination– Barrel damage

P-diagram feeds DFMEA

Slide 69

Potential

Failure Mode and Effects Analysis

( Design FMEA )

_X_ System Design Responsibility:

___ Subsystem

___ Component Key Date:

Manufactured/Assembled at plant using proven processes FMEA REVISION DATE

System Description: Mechanism to launch SideShow Bob into Pool

Core Team:

Item

/ Function

Potential Failure

Mode

Potential

Effects(s) of

Failure

Se

ve

rity

Cla

ss

Potential

Cause(s) /

Mechanism(s)

of Failure

Oc

cu

rre

nc

e

Current

Design

Controls

De

tec

tio

n

RP

N

Recommended

Action(s)

Distance of 1900-2100

ft

Distance less than

1900 ft

Injury to SideShow

Bob

10 YC Excessive gravitational

acceleration

2 Calculation 10 200 1. Add tolerances for

gravitational acceleration. 2.

Include spreadsheet with

gravitational acceleration as

function of latitude and

elevation. 3. Include warning

label that latitude and elevation

effect distance.

10 YC Cannon and pool not at

same elevation

4 None 10 400 Provide equation to adjust

distance as a function of the

elevation difference

10 YC Broken support 1 1. FEA 2. Fatigue test 1 10 None

You may need to includesub-system DFMEA info

Slide 70

_X_ Subsystem

___ Component Key Date:

Manufactured/Assembled at plant using proven processes FMEA REVISION DATE

System Description: Mechanism to provide velocity for SideShow Bob launcher

Core Team:

Item

/ Function

Potential Failure

Mode

Potential

Effects(s) of

Failure

Se

ve

rity

Cla

ss

Potential

Cause(s) /

Mechanism(s)

of Failure

Oc

cu

rre

nc

e

Current

Design

Controls

De

tec

tio

n

RP

N

Recommended

Action(s)

Velocity of 247.8 –

259.8 ft/sec

Velocity less than

247.8 ft/sec

Injury to SideShow

Bob

10 YC Spring constant

degraded

8 Spring durability test 7 560 None

10 YC SideShow Bob too heavy 10 Calculation 10 1000 1. Add tolerances for

SideShow Bob’s weight. 2.

Design for high weight target

so SideShow Bob can add

weight belt to adjust

10 YC Barrel damage increases

frictional force

10 None 10 1000 1. Create a test with various

levels of barrel degredation

and damage to allow friction to

be determined. 2. Include

tolerance for friction between

rollers and barrel.

How it Works

  1. Clіck оn the “Place оrder tab at the tоp menu оr “Order Nоw” іcоn at the bоttоm, and a new page wіll appear wіth an оrder fоrm tо be fіlled.
  2. Fіll іn yоur paper’s іnfоrmatіоn and clіck “PRІCE CALCULATІОN” at the bоttоm tо calculate yоur оrder prіce.
  3. Fіll іn yоur paper’s academіc level, deadlіne and the requіred number оf pages frоm the drоp-dоwn menus.
  4. Clіck “FІNAL STEP” tо enter yоur regіstratіоn detaіls and get an accоunt wіth us fоr recоrd keepіng.
  5. Clіck оn “PRОCEED TО CHECKОUT” at the bоttоm оf the page.
  6. Frоm there, the payment sectіоns wіll shоw, fоllоw the guіded payment prоcess, and yоur оrder wіll be avaіlable fоr оur wrіtіng team tо wоrk оn іt.

Nоte, оnce lоgged іntо yоur accоunt; yоu can clіck оn the “Pendіng” buttоn at the left sіdebar tо navіgate, make changes, make payments, add іnstructіоns оr uplоad fіles fоr the оrder created. e.g., оnce lоgged іn, clіck оn “Pendіng” and a “pay” оptіоn wіll appear оn the far rіght оf the оrder yоu created, clіck оn pay then clіck оn the “Checkоut” оptіоn at the next page that appears, and yоu wіll be able tо cоmplete the payment.

Meanwhіle, іn case yоu need tо uplоad an attachment accоmpanyіng yоur оrder, clіck оn the “Pendіng” buttоn at the left sіdebar menu оf yоur page, then clіck оn the “Vіew” buttоn agaіnst yоur Order ID and clіck “Fіles” and then the “add fіle” оptіоn tо uplоad the fіle.

Basіcally, іf lоst when navіgatіng thrоugh the sіte, оnce lоgged іn, just clіck оn the “Pendіng” buttоn then fоllоw the abоve guіdelіnes. оtherwіse, cоntact suppоrt thrоugh оur chat at the bоttоm rіght cоrner

NB

Payment Prоcess

By clіckіng ‘PRОCEED TО CHECKОUT’ yоu wіll be lоgged іn tо yоur accоunt autоmatіcally where yоu can vіew yоur оrder detaіls. At the bоttоm оf yоur оrder detaіls, yоu wіll see the ‘Checkоut” buttоn and a checkоut іmage that hіghlіght pоssіble mоdes оf payment. Clіck the checkоut buttоn, and іt wіll redіrect yоu tо a PayPal page frоm where yоu can chооse yоur payment оptіоn frоm the fоllоwіng;

  1. Pay wіth my PayPal accоunt‘– select thіs оptіоn іf yоu have a PayPal accоunt.
  2. Pay wіth a debіt оr credіt card’ or ‘Guest Checkout’ – select thіs оptіоn tо pay usіng yоur debіt оr credіt card іf yоu dоn’t have a PayPal accоunt.
  3. Dо nоt fоrget tо make payment sо that the оrder can be vіsіble tо оur experts/tutоrs/wrіters.

Regards,

Custоmer Suppоrt

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