Evaluation

Question 1

What is the rule of ten?

Answer 1

cost for change increases significantly with time (factor 10 per development phase)

Question 2

What are possible consequences of failures during product use?

Answer 2

▪ Compensation claims
▪ Damage to company or product image
▪ Penal steps
→ This motivates preventive measures to ensure goal achievement, and reduce or eliminate risk or failures

Question 3

What is the purpose of the FMEA procedure?

Answer 3

▪ Systematic analysis of possible failures and associated risks
▪ Derivation of preventive actions

Question 4

What are some questions that are addressed by FMEA?

Answer 4

▪ Which failures may occur?
▪ What are the causes?
▪ What is the probability of failure?
▪ What is the probability of detection of the failure?
▪ What is the severity, if the failure occurs?
▪ What are the recommended actions to reduce/avoid the risk?

Question 5

What does FMEA stand for?

Answer 5

Failure Mode and Effects Analysis

Question 6

What are some resources to support the generation of a system structure (or product structure)? Name 2.

Answer 6

▪ Documentation of your product
▪ Lists of parts
▪ Engineering sketches, drawings
▪ CAD models

Question 7

How do you identify failure candidates in FMEA?

Answer 7

▪ Negate functions and check if this is a trigger or cause for a failure chain
▪ Also analyze
− Quality assurance reports, list of deficiencies
− Customer complaints, customer surveys
− Test reports

Question 8

How are failure chains documented in FMEA?

Answer 8

In three columns: first (failure cause), last (failure consequence) and one representative in the middle (failure)

Question 9

How is the Risk Priority Number (RPN) calculated?

Answer 9

severity * occurrence probability rating * detection probability rating (each measured on a scale of 1-10, 1 being good, 10 being bad)

Question 10

What are some possibilities for actions in step 5 of the FMEA?

Answer 10

▪ Possibility 1: Actions to avoid failures
− Optimize the component considered
− Reduce the Index of occurrence (O)
▪ Possibility 2: Actions to reduce the effects
− Reduce severity (S)
▪ Possibility 3: Actions to detect a failure
− Increase the chances of detection (D)
− Detect causes (e.g., by sensors)

Question 11

What is the right situation to use FMEA?

Answer 11

▪Many interacting components → high complexity
▪New or changed product, technology, material, or process
▪Risk needs to be minimized (e.g., for safety-related products)

Question 12

What is the input for FMEA?

Answer 12

▪ Information related to system structure and functions
▪ Information to assess severity/occurrence/detection
▪Optional: Risk factor maps

Question 13

What is the output for FMEA?

Answer 13

▪Documentation of estimated possible failure chains with associated risk priority number (only single-factor cause view)
▪List of action items for improvement

Question 14

What is the procedure for FMEA?

Answer 14

1.Establish system structure
2.Assign functions
3. Identify failure candidates
4.Assess risks (by severity (S), occurrence (O), Detection (D), RPN = SOD )
5.Define actions

Question 15

What are the benefits of FMEA?

Answer 15

▪ Systematic approach to identify potential failures or failure modes
▪ Generally applicable
▪ Accepted as measure to avoid failure

Question 16

What are the limitations of FMEA?

Answer 16

▪ Subjective → no guarantee to identify all possible failures
▪ Subjective → assessment may be inappropriate
▪ Basic FMEA only considers failures that occur due to single-factor causes (remember: a cause is a combination of INUS conditions).
▪ Time consuming

Question 17

Pareto optimal - definition

Answer 17

A design (or alternative) is Pareto optimal if no Pareto improvement is possible.

Question 18

Pareto improvement - definition

Answer 18

A Pareto improvement is an improvement of at least one attribute without making another worse.

Question 19

Pareto-dominated - definition

Answer 19

Non-Pareto-optimal alternatives are called Pareto-dominated.

Question 20

Utility - definition

Answer 20

Utility is a measure of the (individual) degree of satisfaction of needs

Question 21

utility function - definition

Answer 21

A utility function expresses utility as a function of quantities of interest

Question 22

What is the right situation to use Basic Utility Evaluation?

Answer 22

▪Need to choose from several alternatives
▪Several assessment criteria relevant

Question 23

What is the input for Basic Utility Evaluation?

Answer 23

▪Solution alternatives
▪Criteria / requirements / preferences

Question 24

What is the output for Basic Utility Evaluation?

Answer 24

▪Ranking of solution alternatives according to their utility value
▪Documentation of decision made

Question 25

What is the right situation to use Extended Utility Evaluation?

Answer 25

▪Need to choose from several alternatives ▪Several assessment criteria relevant ▪Detailed justification necessary ▪Progessive/ digressive effects

Question 26

What is the procedure for Basic Utility Evaluation?

Answer 26

1.Establish assessment criteria 𝐶𝑗 (e.g., quantities of interest from requirement list). 2.Determine weighting factors 𝑤𝑗 . 3.Determine all rating values 𝑦𝑖,𝑗. Rating may be objectified by rating criteria. 4.Compute utility values 𝜑𝑖 and rank by 𝜑𝑖.

Question 27

What is the input for Extended Utility Evaluation?

Answer 27

▪Solution alternatives ▪Criteria / requirements / preferences ▪ Information to establish rating functions

Question 28

What is the output for Extended Utility Evaluation?

Answer 28

▪Ranking of solution alternatives according to their utility value ▪Documentation of decision made

Question 29

What is the procedure for Extended Utility Evaluation?

Answer 29

1.Establish assessment criteria 𝐶𝑗 (e.g., quantities of interest from requirement list). 2.Determine weighting factors 𝑤𝑗 by hierarchical weighting. 3.Determine all rating values 𝑦𝑖,𝑗 by using rating functions. 4.Compute utility values 𝜑𝑖 and rank by 𝜑𝑖.

Question 30

What is the procedure for the Hierarchical Weighting System of the Extended Utility Evaluation?

Answer 30

1. Define (sub-)QoIs (QoI = quantities of interest) 2. Evaluate relative weights of (sub-)QoI (sQoI): ∑𝑠𝑄𝑜𝐼 𝑤ℎ = 1 3. Repeat 1. and 2. until desired level of detail is reached. 4. Multiply each branch to get the all-over weights

Question 31

What is the purpose of rating functions in Extended Utility Evaluation?

Answer 31

Used to transform assessment values into rating values

Question 32

What is the purpose of utility evaluation?

Answer 32

−Rationalizing your decision by organizing the important aspects that your decision is based on, and −Communication, i.e., making your preferences transparent

Question 33

How can subjective ratings be supported?

Answer 33

- by rating criteria (basic utility evaluation) - by hierarchical weighting and/or rating functions (extended utility evaluation)

Question 34

What is a good decision characterized by?

Answer 34

− Intuitive view = rational view − Your view = other stakeholder’s view