SMAR²T - Systematic Method for Axiomatic Robust Reliability-Testing

Abstract

SMAR²T is based on established methods (Axiomatic Design and the Taguchi Method) and applies VDI2221 as a chronology. Hence, SMAR²T refers to already successfully applied methods and experiences. Compared to the known and established methods, SMAR²T goes even further by adapting and combining these methods to a holistic approach with adaptive entry possibilities. Additionally, several limitations of the Taguchi Method are improved. Another major impact is the forecast of the reliability and advice of a possible test strategy.

Full text

CONTACT:
Dipl.-Ing. Stefan Kemmler
Research Assistant at the Institute of Machine Components (IMA), University of Stuttgart
Research Assistant at the Technologie-Transfer-Initiative (TTI) GmbH
Pfaffenwaldring 9, 70569 Stuttgart, Germany
Phone +49 711 685-66 696
Telefax +49 711 685-66 319
stefan.kemmler@ima.uni-stuttgart.de
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SMAR2T – Systematic Method for Axiomatic Robust Reliability-Testing
- Holistic Robust Design method for the design of robust and reliable products -
MOTIVATION:
 Structured process and combining different Robust Design methods not available
 Chronological Classification of Taguchi in the early stages of the Product
Development Process
 Integration of Reliability in Robust Design
OBJECTIVE:
 Creation of a holistic Robust Design and Reliability method with
 Adaptive entry points into the method and
 Iterative improvement of the product
Dipl.-Ing. Stefan Kemmler, Prof. Dr.-Ing. Bernd Bertsche
Institute of Machine Components (IMA) – Reliability Engineering – University of Stuttgart
CONCLUSIONS:
SMAR2T is based on established methods (Axiomatic Design and the Taguchi Method) and applies VDI2221 as a chronology. Hence, SMAR2T refers to already successfully applied
methods and experiences. Compared to the known and established methods, SMAR2T goes even further by adapting and combining these methods to a holistic approach with adaptive
entry possibilities. Additionally, several limitations of the Taguchi Method are improved. Another major impact is the forecast of the reliability and advice of a possible test strategy.
Is the
information
satisfactory?
Set up of the
transfer
matrix [A]
Redefining
the Design
Parameter
Comparison
on the basis
of the
information
axiom
Application
of the
information
axiom
Introduction
of new draft
levels
Defining the
functional
requirements
and design
parameters
from the
customer
requirements
determined
Is the draft
already
available?
Is the
transfer
matrix
satisfactory?
Application
of the
independence
axiom
Reorganization
of the transfer
matrix
Design of
Experiment
Carrying out
the experiment
Analysing the
experiment
Axiomatic Design
to disclose any
draft errors that
may have
occurred, and to
remedy them
Setting up the
P-diagram
Determination
of the predicted
reliability Was the
confirmation
experiment
successful?
Optimization
possible?
Carrying out the
confirmation
experiment
Was the
confirmation
experiment
successful?
Are the optimum
nominal values
for the
Design
parameter known?
Starting the
contemplation
of the system
Is the
reorganization
possible?
Optimizing
the draft on
the basis of
the results
Are there
several drafts
Tolerance
synthesis
based
Technical
feasibility
possible?
Analysis using
statistical
methods
Optimization
of tolerance
costs using
weighting
factors
Set up
Quality Loss
Function
Robustness
criteria
satisfies?
Best possible
costs?
Limit sample
test Determining
the reliability
Recommending
the steps of
action
Variance
decomposition
Design of
Experiment
Tolerance
analysis
customer
requirements
functional
tolerances
Technical
Feasibility
possible?
on the
planned process
capability
that remove
the couplings
Main workflow
1. Loop
2. Loop
Yes
No
(for draft part
concerned)
and thus
transfer
Matrices
available?
FR1
FR2
FR3
DP1DP2DP3
x 0
x
x
0
x x
xx x
x x
0
0
0
0 0
0 0
0 0
DP4DP5
FR4
FR5
0
0
x x
FR1
FR5
FR2
DP1DP5DP2
x 0
x
x
0
x x
x
x x
x x
0
0
0
0
00
0
0
0
DP4DP3
FR4
FR3
0
0
x x
FRi
System Range (SRi)
Bias
Probability
density
function f(FRi)
Target
Design Range
(DRi)
Common Range (CRi)
FR1
FR2
FR3
DP1DP2DP3
x 0
x
x
0
00
0 0
FR1
FR2
FR3
DP1DP2DP3
x 0
x
x
0
0x
x x
FR1
FR2
FR3
DP1DP2DP3
x 0
x
x
x
0x
x x
Uncoupled
Design Decoupled
Design Coupled Design
Strength
Stress
Stress-
Strength
Probability
Failures ?
Target
USL
LSL
µ µ+σ µ-σ 2σ3σ4σ5σ6σ-2σ-3σ-4σ-5σ-6σ
68 %
95 %
99 %
Loss
y
System Range (SRi)
L(y)
€
Target
τ τ + Δ0
τ - Δ0
L(y)
Noise
Factors
P-Diagram
(Product / Process)
Control
Factor
Signal
Factos
Error
States
Response
1
2
3
1 2 3
1 1
1 1
2
2 1
1
21
4 5
4
5
6
7
8
6 7
2
2
1
2
2
2
1 1
1 2
1
2 1
2
22
2
1
2
1
1
2
1 1
2 2
2
2 1
1
12
1
2
2
1
2
1
1
2
2
2
1
1
1
2
Experim
ent No.
Time (Durability characteristic)
Test object No.
Failure
Test object is intact
after removal
Durability (t-t0) 106 LC
Failure Probability F(t)
Shape parameter b
Design Parameter
Customer
domain Functional
domain Physical
domain
How How How
Customer
needs Functional
requirements
What What