A Critical Approach To TRIZ Methodology Applied To A Case Study

Proceedings of the TMCE 2008, April 21–25, 2008, Izmir, Turkey, Edited by I. Horváth and Z. Rusák
© Organizing Committee of TMCE 2008, ISBN ----
1
A CRITICAL APPROACH TO TRIZ METHODOLOGY APPLIED TO A CASE
STUDY
Edoardo Rovida
Department of Mechanical Engineering
Politecnico di Milano
edoardo.rovida@polimi.it
Marco Bertoni
Marina Carulli
Umberto Giraudo
Department of Mechanical Engineering
Politecnico di Milano
{marco.bertoni, marina.carulli, umberto.giraudo}@polimi.it
ABSTRACT
The kernel we intend to address to with the present
work is a critical investigation of the effectiveness of
the implementation of TRIZ based concepts within
the product development process. Main objective of
this paper is, therefore, to investigate benefits and
drawbacks of the TRIZ method and to propose a new
approach to streamline the design process.
The new methodology aims to support the design
team in dealing with the complexity of product
design, integrating TRIZ and Quality Function
Deployment matrixes (QFD). TRIZ, in fact, is still far
to be a panacea for all kind of design related
problems. Although TRIZ is characterized by a
highly innovative imprinting, at procedural level it is
quite complex and, sometimes, quite dispersive.
Moreover, it can be difficult, especially for
beginners, to understand how to apply TRIZ
principles in a specific field of study. The use of QFD
in the early step of concept development can help in
identifying more clearly the boundaries of the
problem domain by translating the voice of the
consumer into engineering parameters and by
enhancing stakeholders’ involvement in product
design.
The methodology presented in this paper has been
then applied in a real industrial study case to
develop new tools and devices able to solve the
problem of “traction on slippery surfaces”.
KEYWORDS
TRIZ, QFD, Conceptual Design, Anti-slippery
devices.
1. INTRODUCTION
The increasing complexity of global markets and the
introduction of new IT communication technologies
force industry in extremely increasing their
competitiveness and, therefore, in introducing better
and cheaper products faster on the market. In this
sense, to cope with the demanding market
requirements, innovation is becoming a hot topic.
Innovation is an extremely wide issue with different
levels of description and different application areas.
Some authors (Krishnan, V. and Ulrich, K.T., 2001)
have reported that the measure on which a product
becomes a commercial success largely depends on
the underlying concept; still it is not so immediate to
achieve the “right” concept and to develop it in
defined time and quality constraints. By some
researchers it has been reported that it is required to
have at least 3000 ideas to achieve a single
commercial success (Stevens, G., Burley, J., 1997).
Therefore, to develop a large amount of ideas, a large
amount of time is required which consequently leads
to uncertainty about the efficacy of the final results
within well defined economic parameters.
2. SURVEY
In the past twenty years a number of different
methodologies have been proposed to tackle the
problem of concept development. Most of these
methodologies are based on group discussions like
Brain Storming (Osborn, A.F., 2001) or Six Hats
(DeBono, E., 1996), on a procedural basis as the
Concept-Knowledge (C-K) Theory (Hatchuel, A. et
al, 2002) or basing on concept expansion methods as
Synectic Thinking (Roukes, N., 1988). All these
methods have great advantages over the conceptual

2 Edoardo Rovida, Marco Bertoni,
Marina Carulli, Umberto Giraudo
phase, enabling the enrichment of the ideas
production. Still none of them, on the other side, is
effectively targeted to product development or is able
to solve the process uncertainty factors. However,
since a couple of decades a new theory has started to
spread out, the Theory of Inventive Problem Solving,
known as TRIZ theory (Altshuller, G., 1996). The
kernel of this theory states that all problems,
transposed to a higher level of abstraction, have a
common root of solution which is based on already
invented solutions. Altshuller, the theory founder,
basing on the research of more than a million patents,
found out the evidence of forty “inventive
principles”, applicable to any design field.
In this way TRIZ reduces the randomness of idea
finding process, in favor of a more oriented solution
searching process. Traditional problem solving
approaches, in fact, just suggest what the problem is,
not how the problem should be solved (Kang, Y. J.,
2004). In most cases inventors tell the solution of a
problem has been found by a lot of trial and error
steps or accidents. These methods were understood
by Altshuller as a slow thinking process. TRIZ,
instead, suggests that invention is systematic and it
has an algorithmic structure (Figure 1).
Figure 1: A comparison between Brainstorming and TRIZ
method
3. PURPOSE
It is widely recognized that TRIZ is a powerful
problem solving method, but several problems arise
when trying to apply this technique in a real study
case. Although TRIZ is characterized by a highly
innovative imprinting, at procedural level it is quite
complex and, sometimes, quite dispersive, since it is
formed by a number of different applicable
approaches, specifically directed to increase the
description of the problem at hand.
the product development process. Main objective of
this paper is, therefore, to investigate benefits and
drawbacks of the TRIZ method and to propose a new
approach to support the design team during concept
generation based on the integrated use of TRIZ and
of Quality Function Deployment (QFD) method.
The methodology here described has been applied in
a real industrial study case, with the aim to develop
innovative anti-slippery devices for the car industry.
Thanks to the study case selected it was possible to
test “on the field” and to underline benefits and
drawbacks of the proposed approach.
4. ASSUMPTIONS
TRIZ is not a panacea for all kinds of design-related
issues. Some authors, like Mann, D. (2002), showed
in the past that some of TRIZ tools are often
inadequate to represent certain types of problem,
finding out that the success rate of this method is
only 48%. Although TRIZ comprises plenty of
creativity tools, it can be difficult in a lot of
situations even to locate a specific design variable in
the 39 engineering parameters of the TRIZ
Contradiction Matrix.
Moreover, one of the main problems related to the
application of the TRIZ is the lack of instruments
which links high level design targets (set by mainly
by customers and main product stakeholders) with
the technicalities of the problem domain.
For these reasons, a lot of work has been spent in the
past to integrate TRIZ with different problem-solving
tools. Hua, Z. et al. (2006) analyzed TRIZ integration
into other creativity methods and philosophies using
a literature review of publications from 1995 to 2006.
The analysis showed that, although it is true that
TRIZ is gaining the hearts of the engineers, it
remains evident that its original form is insufficient.
From the survey it emerged that plenty of authors
indicates QFD to be the most suitable tool to be
combined with TRIZ. Plenty of different
methodologies integrating these two design
techniques, in fact, can be found in literature
(Verduyn and Wu, 1995; Terninko, 1997; Domb and
Corbin, 1998; Jugulum and Sefik, 1998; Kunst, 1999;
Clarke, 2000; Eversheim et al., 2001; Schlueter,
2001; Tan and Dieter, 2002; Yamashina et al., 2002;
Zhao and Yang, 2002; Novacek, 2003; Park, 2003;
Tsai et al., 2004; Hipple, 2005; Lai et al., 2005;
Wang et al., 2005). Most of these works propose to

A CRITICAL APPROACH TO TRIZ METHODOLOGY APPLIED TO A CASE STUDY 3
use QFD to correctly identify the boundaries of the
problem’s domain before applying TRIZ inventive
principles to a specific technical issue. QFD can help,
in fact, in identifying the specific nature of a problem
by translating the voice of the consumer into
engineering parameters and to enhance, thanks to its
simple and intutive approach, product stakeholders’
involvement in the product design. Although various
applications complemented this integration, the
methods proposed seem sometimes questionable,
because too complex and overaddicted with different
tools. Main aim of this paper is, therefore, to propose
a different use of the QFD matrixes and TRIZ in the
design process. The methodology aims to solve
common drawbacks of TRIZ promoting at the same
time an easy and intuitive use of both techniques.
5. THE INTEGRATED METHODOLOGY
The methodology foresees several steps, as described
in Figure 2. Main result of the design activity is the
identification of a new product concept able to meet
initial high level targets.
QFD
QFD
TRIZ
De fine high le ve l
targets
De fine syste m’s
Func tional
Require ments
QFD
matrix
QFD
matrix
State of the Art and
patent analisys
Define evaluation
me tric s
Ide ntify possible
areas of
inte rve ntion
Ide ntify spec ific
proble ms
QFD
matrix
QFD
matrix
QFD
matrix
QFD
matrix
Ide ntify ge ne ric
proble ms
Ide ntify the
ge ne ric solution
Contradic tion ma trix
Identify the
ge ne ric solution
T
re nds of e volution
Elaborate and
e valuate spec ific
solutions
Find the be st
solution
QFD
matrix
QFD
matrix
Figure 2: Proposal for a product development
methodology integrating TRIZ and QFD
QFD has been used in the first steps of the product
development process in order to derive system’s
Functional Requirements (FRs) from initial design
targets and to define, always starting from FRs, the
metrics indicators to be applied during the concepts’
evaluation activity.
QFD matrixes have been also applied to compare and
rank existing anti-slippery methods and tools, with
the aim to outline possible areas of interventions for
the application of TRIZ. Commonly in use devices
together with up-to-date patents have been, in fact,
analyzed and ranked on the basis of the FRs
previously expressed by product’s stakeholders.
Once those systems representing the best trade off
between FRs have been outlined, they have been
optimized making use of the Inventive Problem
Solving Theory.
For each system, a set of specific trade-offs has been
formulated. Then, these specific issues have been
translated into more generic statements, in form of
physical and technical contradictions. On one side,
the 40-principles matrix suggested, for each
contradiction, a list of useful inventive principles
which helped the design team in elaborating a list of
possible solution alternatives. In parallel with the
application of the Contradiction Matrix, the authors
analyzed the position of each device in the Pattern of
Evolution diagram of TRIZ to identify new directions
for improvements. The resulting set of alternatives
has been then evaluated making use of QFD on the
basis of the metrics indicators collaboratively defined
by product stakeholders, to find out which of the
concepts generated with TRIZ was the one really
able to satisfy initial requirements.
6. APPLICATION
In this paper we also intend to report the application
of the Integrated Methodology to a practical problem,
defined at higher level of abstraction as the problem
of “car traction on slippery surfaces”. The authors
selected this specific issue for several reasons. First,
the problems is particularly challenging, since, up to
date, no really effective solutions have been found to
solve the problem of cars’ motion on snow and mud.
Secondly, it can be tackled at different levels of
granularity and can be related to different parts of the
system under analysis (i.e. concentrating on the
wheel, on the tire or on the floor surface).
To reach the analysis scopes we made use of two of
the main TRIZ softwares actually available on the
market, as CreaTRIZTM
by CREAX

(http://www.creax.com) and TechOptimizerTM
by
Invention Machine (http://www.invention-
machine.com), plus typical bibliographical support.
6.1. Find the targets
Designing a new product is not just a technological
issue, but has to take into consideration a large
numbers of different aspects, mainly related to a
business dimension.
Initial High Level Objectives (HLOs) are particularly
important along all the design process since they
guide the decision making activity in all the
following design steps. However, in the 40-principles
matrix of TRIZ, no business-contradictions can be
formulated. Although cost effectiveness is one of the
primary requirements of a product, all the conflicting
features are mostly related to dimensions, physical
attributes and so on, not apparently related to the
issue of cost. Many authors like Domb E. (2005)
indicated that beginners’ attempts to apply TRIZ to
cost problems often fail as they view the problem
only at the system level of the original presentation
of the problem.
Business-related contradictions cannot be directly
solved making use of TRIZ. For this reason, they
need to be carefully defined and translated in more
technical terms during the preliminary phases of
concept design.
In the study case presented in this paper, 5 different
high level targets have been identified (Table 1) and
used as a reference point to develop innovative anti-
slippery devices for the car industry.
Table 1: High level targets related to the development of
innovative anti-slippery devices
Low price
Low installation-related costs
Low usage-related costs
High safety & performances
Low environment-related costs
A new device, method or tool able to solve the
problem of traction on slippery surfaces is first asked
to be competitive in monetary terms with actually in
use technologies. It is required to be relatively cheap
for consumers to purchase to maintain and with low
installation-related costs. Improving passengers’
safety is another important aspect of the new
solution. It should be able to improve car
performances on the snow and to make driving on
the slippery surfaces as easy as driving in normal
road conditions. Last but not least, also environment-
related costs have to be taken deep into
consideration. The new solution is asked not to
produce damages on the car, on the infrastructures
and on the natural environment in general.
A set of parameters at a more technical level, named
Functional Requirements (FRs) have been then
derived from these high level targets in order to help
the design teams in identify the right direction for
improvements. Cascading down business issues into
Functional Requirements helps in identifying
correctly the set of trade-offs which really need to be
solved when applying the inventive principles in a
specific problem area.
6.2. Define Functional Requirements
The list of business issues defined at the beginning of
the concept generation activity needs to be cascaded
down in order to define at a more technical and
practical level features and characteristics of the new
solution. Moving from these specific FRs it is
possible to express specific trade-offs that will be
then used to elaborate for each design alternative a
list of technical and physical contradictions. These
requirements have been defined and prioritized
collaboratively by the design team and they have
been used, moreover, as a basis for the definition of
metrics indicators to be applied in the final
evaluation steps.
QFD matrixes support engineers and design experts
in this cascading activity. It was decided to make use
of the QFD method since it represents one of the best
and intuitive way to integrate customer requirements
into the product design (Akao, Y.; 2004) and to
develop interoperability among all the different
design department collaborating for system’s
development.
In order to better evaluate the impact of a FRs on a
specific HLO, it was decided to avoid the simple
binary check approach (0-1) of QFD and to slightly
modify the Analytic Hierarchy Process method, or
AHP (Saaty, T.L., 1990) based on 0-1-3-9 or 0-1-5-9
scale, by adopting a 0-1-3-5 scale to denote weak,
medium and strong relationships between pairs of
business and technical design requirements (Table 2).

Table 2: Example of application of the QFD matrix to
derive the FRs of the new product
Price
Installation
Usage
Safety
&
Perf.
Environment
Final price in the stores 3
Price/Km 5
Time to install 5
Time to disassemble 3
Cost to install 3
Cost to disassemble 3
Manual intervention 1
Maintenence cost/Km 3
Space needed for storage 3
Comfort 5
Versatility/flexibility of the device 5
Maximum acceleration 3
Maximum speed on snow 3
Maximum speed without snow 1
Lateral grip 5
Braking performances 5
Time needed to act 5
Pollution produced 5
Damages to infrastructures 5
Recycling 3
6.3. Identify problems and tradeoffs
As said before, TRIZ is a powerful tool to help in
improving innovation by solving contradictions.
However, before applying the innovative principles
of TRIZ a clear and wide vision of the problem is
needed, since it is not an easy task identifying the
level of abstraction in which the specific problem has
to be faced and contradictions should be formulated.
A complex technical system can be characterized by
plenty of contradictions, formulated at different
detail extents. Understanding which of these
contradictions really address initial expectations it’s
not an easy an intuitive task. On one side, a generic
formulation of a problem is associated with a wide
solution space. This formalization suggests changes
that may potentially influence the whole industry. A
few constraints can help creativity, but sometimes
too open questions can be disorienting, since it could
be difficult for the design team to understand the core
of the problem and to converge to an optimal
solution. On the other side, narrowing the analysis to
a single components or sub-components would limit
too much the space of possible for interventions,
limiting creativity and, substantially, hiding
innovation. That is, to formulate the right problem,
we should know the solution. But, to get the solution,
it is very important to state the right problem. Behind
the popular phrase “a problem well stated is half
solved” lies the assumption that one can state the
problem well. However, this assumption is often
wrong, as stated by Rantanen, K. and Domb, E.,
(2002).
Similar conditions can be found in the background of
the study case presented in this paper. Different
strategies have been followed in the past to develop
innovative methods and tools to cope with the
problem of traction on slippery surfaces. Due to the
inner complexity of the problem domain and to time
and resource constraints, it is very important to
understand quickly the core of the problem (in terms
of most promising directions for improvement) in the
preliminary steps of product design (Liu, C.C. et al.,
2006). It would be impossible, in fact, to formalize
technical and physical contradictions for all possible
and single components and sub-components of the
system.
Define the boundaries of the problem domain: a
framework for problem classification
As experienced by the authors, it can be difficult,
sometimes, making use of TRIZ, to identify correctly
the boundaries of a problem domain and to detect
most promising areas of interventions for a specific
system under analysis. A more structured approach is
needed, therefore, to manage complexity and to
guide the design team in the application of the
Inventive Problem Solving Theory.
Since the problem of traction on slippery surfaces
can be undertaken from different perspectives, the
methodology here presented proposes to make use of
a framework to structure the problem domain at three
different detail extents. This framework has been
elaborated starting from the 9 windows’ matrix
(Figure 3) used in the TRIZ methodology as a
reference for the Resources and Constraints analysis.
The TRIZ matrixes make a distinction between parts,
features and elements at System, Sub-System and
Super-System level. In the same way, the problem of
traction on snow has been approached from System,
Sub-system and Super-system dimensions.

Super-System
System
Sub-System
Super-System
present
Super-System
past
Super-System
future
System
present
System
past
System
future
Sub-System
present
Sub-System
past
Sub-System
future
Level of
abstraction
Time
Figure 3: Graphical representation of the framework
elaborated on the basis on the TRIZ 9-windows
matrix
Acting at Super-System level. On one side it’s
possible to try to remove the bad action caused by the
snow trying to remove the snow itself. The authors
started, therefore, tackling the problem of the
disturbing element at first, investigating the solution
area inherent to the snow itself and working with the
ideal model of “snow not present when the car runs/
present in other conditions”. This strategy is common
to a lot of already in use systems and methods. A
typical example is represented by the use of salt on
the road as a melting agent to remove ice from the
ground.
Acting at System level. Our work focalized then on
the wheel. At this level the innovative principles of
TRIZ have been used to improve wheel’s
performances without acting on the “external
environment”, that is on the road or on the snow.
Devices like spiders, snow chains or snow tires to
belong to this second category.
Acting at Sub-System level. In a third step, we
analyzed at a physical level the dynamic of the
traction itself, spotlighting the interaction between
tire and snow. All the methods and tools operating
both on the snow and on the tire have been classified
inside this cluster.
Using the framework, TRIZ principles can be applied
three times within the same problem area and a wider
comprehension of the specific issue can be reached.
The framework can be use as a mental schema to
improve design team’s understanding of the
problems under analysis to achieve a higher number
of design solution alternatives at the end of the
creative process.
State of the Art and patent analisys
The development of the high level specifications of
the new solution has been lead in parallel with a deep
State of the Art survey. Main scope of this activity
was to point out main benefits and drawbacks related
to commonly used techniques, to have a wider
picture of possible intervention areas and not to re-
invent the wheel during concept development. In
order to anticipate future trends and to enlarge the
problem perception, a deep patent survey has been
conducted in parallel with the SoA analysis.
The SoA and patent analysis represent a preliminary
empirical attempt to empirically sketch the problem
boundaries and to spotlight how trade-offs can be
solved at different levels of abstraction. The work
done in this phase brought to the identification of a
huge amount of tools, devices and methods actually
in use to solve the problem of car traction on the
snow. SoA and Patent analysis have not been limited
to the car domain. Observations have been made also
outside the automotive field in order to encourage
cross-fertilization and creativity. At the end of this
survey, the design team could count on a solid
knowledge base which has been used in the
subsequent step of product development to define
from a qualitative perspective a new set of possible
design alternatives.
All the system coming out from the SoA analysis
have been compared and ranked, on the basis of the
design team priorities, making use of QFD. Methods
and tools with the highest rating in each of the three
categories (System, Sub-System and Super-System)
have been then analyzed deeply in detail to outline
their inner specific tradeoffs and to formalize
contradictions.
An example of the classification used is reported in
Table 3. The QFD matrix has been used to compare 6
different anti-slippery devices belonging to the
System layer. The overall rating obtained by these
devices expresses their capability to satisfy
previously elaborated FRs.

Table 3: Example of application of the QFD matrix to
evaluate anti-slippery devices
Spiders
Snow
Tyres
Autosocks
SnowClaws
Put&Go
Snow
Chains
Final priceinthestores 3 1 1 3 3 5 1
Price/Km 5 3 5 1 3 3 3
Timetoinstall 5 3 3 3 3 3 1
Timetodisassemble 3 3 3 3 3 3 3
Cost toinstall 3 3 1 5 5 5 5
Cost todisassemble 3 3 3 5 5 5 5
Manual intervention 1 3 5 1 1 1 1
Maintenancecost/Km 3
Spaceneededfor storage 3 3 1 5 5 5 3
Comfort 5 1 5 5 3 3 1
Versatility/flexibilityof thedevice 5 1 5 1 3 3 1
Maximumacceleration 3 3 3 3 1 1 3
Maximumspeedonsnow 3 3 3 1 1 1 1
Maximumspeedwithout snow 1 1 5 1 3 3 1
Lateral grip 5 1 3 1 3 1 5
Brakingperformances 5 5 3 3 3 1 5
Timeneededtoact 5
Pollutionproduced 5
Damagestoinfrastructures 5 1 5 5 5 5 1
Recycling 3 3 1 3 3 3 3
145 203 181 197 183 159
Total
Best-in-class solutions (snow tires and SnowClaws),
the ones with the highest score, combines a good
versatility with a good comfort and affordable costs.
At the same time, the matrix outlines some important
week points, mainly related to the capability of these
tools to grab snow and to transmit power.
QFD matrixes have been applied to evaluate devices
belonging to the other two dimensions of the
framework too. At the end of this preliminary
evaluation process it was possible to identify a set of
solutions which represents the best anti-slippery
technology currently in used for the set of Functional
Requirements selected.
6.4. Problem Solving with TRIZ
Once a set of specific trade-offs for each of the
devices selected has been formulated the classical
TRIZ problem solving approach (Figure 4) has been
applied to elaborate a list of high-level contradictions
and generic solutions to the problem.
Figure 4: TRIZ problem solving methodology
As said before, TRIZ consists of several different
modules and tools and there is no fixed order which
must be followed in the problem solving process.
Main aim of the methodology is, therefore, to suggest
how to apply TRIZ tools when dealing with complex
and multifaceted problems as the one faced in the
study case. One of the main drawbacks of the
classical TRIZ method is related to the fact that, very
often, it is just the TRIZ users’ knowledge and
experience which suggest the tools to be used in
connection with a particular problem. This lack of
constraints and procedures can be disorienting,
especially for beginners and for people which are not
expert in this design techniques.
The use of contradictions to explicit the generic
problem
After selecting the set of devices to be used as a
starting point for the application of TRIZ, a list of
more generic physical and technical contradictions
have been formulated for each method and tool of
interest. The Contradictions analisys is, in fact, one
of the most powerful problem solving tools in the
frame of the TRIZ method. In Altshuller view, in
fact, an engineering problem, characterized by one or
more trade-offs, can be solved eliminating the inner
contradictions between contrasting design
parameters. At this purpose, two different types of
contradictions can be formulated:
Technical Contradiction: It is very common to have
a system characterized by two properties, A and B. A
technical contradiction is present in a system when
improving A, B get worse. For example, when
improving the thickness of the steel frame of a car to
make it safer, the weight of car increases. Technical
contradiction is that more than two requirements are
related to each other. It makes impossible to solve
problem because one situation get worse when
improving another.

Physical Contradiction: In case of Physical
contradictions, two properties, A and B, are
controlled by the same parameter C. For instance,
airplanes need wheels during landing, but don't need
them when flying.
In order to correctly formalize a contradiction,
improving and worsening parameters have to be
synthesized in one of the standard 39 characteristics
which form the axis of the contradiction matrix. By
matching these features, the solution of problem is
found in some of the 40 inventive principles which
populate the cells of the table. For each cell the
contradiction matrix usually recommends 1 to 5
principles. After selecting the inventive principles of
interest, they can be applied on the specific problem
to develop a new concept.
An example of contradictions formalized trying to
optimize Snow Claws and snow tires at System Level
is reported in Table 4.
Table 4: Example of physical and technical contradictions
related to the study case
Device present when the car
runs on snow
Device not present in other
conditions
Improving feature Worsening feature
Power Device complexity
Adaptability and versatility Force
Volume of moving objects Weight of moving objects
Area of moving objects Weight of moving objects
Pysical contraddiction
Technical contraddictions
From a physical point of view, the contradiction has
been expressed in terms of: “Device present when
car runs on snow/ not present in other conditions”
From a technical perspective, three contradictions
can be taken as example of how the TRIZ
methodology has been applied in order to solve the
problem at System level.
On one side, increasing the adaptability and
versatility of the device, like in the case of the snow
tires and Snow Claws, the force transmitted by the
wheel to the snow decrease proportionally.
Moreover, trying to increase the power transmitted
by the car to the road means adding new tools and
components to the wheel and so increasing the device
complexity.
Finally, since at system level the problem is focalized
just on the wheel, improving the device complexity
results in improving the area and the volume of
moving objects, increasing at the same time the total
weight and inertia of the wheel, reducing at the same
time performances, comfort and safety of the car.
The use of the 40 principles matrix to obtain a
generic solution
In the case of the Physical contradiction, 5 different
suitable inventive principles have been suggested by
the contradictions matrix (Figure 5). They are
Parameter Change, Composite, Hole, Enrich, and
Mechanics Substitution.
Figure 5: Inventive principles suggested by the matrix to
solve the physical contradiction
In the case of the first technical contradiction 4
general inventive principles have been suggested, as
shown in Figure 6: Continuity of Useful Action,
Periodic Action, Thin and Flexible and Discard and
Recover.
Figure 6: Inventive principles suggested by the matrix to
solve the first technical contradiction

The second, the third and the fourth technical
contradiction have been inserted in the matrix in the
same way in order to derive a general solution to the
proposed problem. Once the design team, on the
basis of its experience, has determined which of
these principles are suitable for a specific problem,
further work is needed in order to implement by
analogy the standard solution identified into a
specific tool or system.
Patterns of evolutions
Sometimes, formulating contradictions, mapping
resources and defining the ideal final result of a
system may be not enough in order to obtain a really
innovative solution. The authors decided, therefore,
to make use of the Patterns (also Trends) of
Evolution module of TRIZ to solve the technical and
physical contradictions identified in the previous
phase with the aim to make the system more ideal.
These patterns consist in a set of soft, non rigorous
and not mathematical formulas and laws which
represent important regularities in the development
of a system. After defining the evolutionary position
of a current product, the Patterns of Evolution
module of TRIZ simulates future developments of
technical systems, suggesting engineers and
designers which should be the way to be followed to
evolve a system in order to reach an higher degree of
ideality. The theoretical basis for this analysis is the
classical S-curve model (Rogers E., M., 2003).
Knowing these patterns helps to go from the features
of the ideal final result to concrete solutions. Back to
the case study, snow tires and SnowClaws have been
analyzed in order to obtain the current status of the
system and to point out the evolution trends.
Two patterns have been considered of special interest
for the development of snow tires. In terms of Space
Segmentation, this device belongs to the second
evolution step of Figure 7, which means system with
a single cavity. Next evolution step foresees,
therefore, a multi tube tire, intended as a system with
multiple cavities.
Figure 7: Space Segmentation evolution pattern followed
by a practical example (Tech OptimizerTM
)
Analyzing snow tires under the lens of the Surface
Segmentation trend, they can be classified at the third
evolution step of Figure 8. They are characterized, in
fact, by a rough surface with small treads. The
evolution pattern suggests moving towards the design
of an adhering wheel characterized by active pores
able to act on the snow to improve wheel’s
performances.
Figure 8: Surface segmentation evolution pattern followed
by a practical example (Tech OptimizerTM
)
Snow claws have been analyzed from two different
viewpoints too. First, the attention has been oriented
towards the analysis of the Dynamization trend
(Figure 9). In these terms, SnowClaws, which can be
classified as a nearly completely flexible device,
have to be considered the natural evolution of the
traditional snow chains, which are a typical multiple-
joints system. The natural evolution of the system
foresees the substitution of this mechanical device
with a liquid, a gas or a field.
Figure 9: Dynamization evolution pattern (CreaTRIZTM
)
Then the analysis focused on the possibility to reduce
human involvement, in order to make easier and
faster the installation of the device. To install Snow
Claws on the car wheels, a manual intervention of the
driver is needed. The Decrease Human Involvement
trend (Figure 10) suggests investigating the
possibility to develop a powered or semi-automated
tool in order to reduce the drivers’ intervention
during the installation.

Figure 10:Decrease Human Involvement evolution
pattern (CreaTRIZTM
)
The analysis of the common patterns of technological
developments brought to the identification of several
possible directions for improvements. Applying these
standard problem solving principles to the specific
problem of “traction on slippery surfaces” it was then
possible to determine a set of possible solution
alternatives, with different features. This list of
alternatives has been then evaluated making use of
QFD in order to identify which of these innovative
solution best meet initial requirements.
6.5. Define evaluation metrics
One of the most striking results from the authors’
experience in applying TRIZ tools is that
recognizing, appreciating and evaluating solutions
may be more difficult that finding them. It can seem
trivial, but having good ideas is useless if they are
rejected.
The huge amount of ideas defined during concept
development has to be carefully analyzed in order to
identify which of these design alternatives really
satisfy initial requirements. Starting from the
Business and Functional Requirements lists defined
in the early development steps, a set of metrics
indicators have been elaborated to perform a
preliminary and quantitative evaluation of the
systems and methods developed.
To determine if a solution can be good or bad, a set
of qualitative and quantitative parameters has been
defined moving from the initial high level targets,
taking care of the following assumptions:
• In the final system, all (or at least most) of the
harmful features have to disappear.
• In the final system, all useful features are retained
an new benefits appear.
• In the final system, new harmful features do not
appear.
• The final system does not get more complex.
• In the final system all the inherent, primary and
most important contradictions of the problem are
removed.
The evaluation metrics focus both on technical
(product performances, reliability, safety, etc.) and
business aspects (production costs, expected
incomes, profits, expected break-even point, etc.).
These set of indicators have been defined and ranked
collaboratively by all the product’s stakeholders
participating the concept development process.
6.6. Find the optimal solution
At the end of the conceptual design process, 10
different innovative design alternatives have been
generated making use of TRIZ to solve the problem
of traction on slippery surfaces. Two of these
solutions have been defined at Super System level,
three of them belong to the Sub System dimension,
while 5 refer to the System layer.
Once the metrics have been defined, all the ideas
have been deeply investigated and ranked making
use of QFD. Also in this case the evaluation process
has been performed avoiding the simple binary check
approach (0-1) and adopting a 0-1-3-5 scale.
7. RESULTS
The design alternative selected after several iteration
steps belong to the System dimension. Briefly stated,
it is intended as a sort of flexible rubber tire cover to
be installed on wheels in order to improve traction
when needed. This choice reflects the need to
develop a cheap and easy to use device, extremely
flexible, able to solve some of the drawbacks
affecting commonly in use anti-slippery tools.
Snow tires, on one side, behave perfectly on compact
and very cold snow, but they show some problems on
ice and fresh snow. Snow chains, instead, very
effective on mud and snow, can not be used on
normal roads (intended as roads free from snow) as
well as spiders, SnowClaws or Autosocks.
The idea is, therefore, to develop a special tire cover
(Figure 11) which presents a peculiar footprint,
combining small tire treads, very efficient on ice and
compact snow, with large treads to improve traction
on fresh snow.
In order to decrease weight and volume of the device
and to make easier storing and packing, it was
decided to improve the total amount of vertical
surfaces grabbing the snow not adding new

protrusions but, instead, making holes on the cover
surfaces. This solution allows, moreover, to reduce
vibrations and to rubber consumption, especially
when using on thick ice and asphalt. The particular
rubber compound chosen provides, in fact, a good
traction in all the driving situations and it does not
wear away too quickly when driving on normal
roads.
Figure 11:Example of the design alternative selected with
the QFD
The device can be also equipped with small spikes in
order to improve efficiency on icy roads. However,
this design alternative, although more efficient, has
been rejected because much less flexible. One of the
main advantages of the device is strictly linked to the
possibility to avoid uninstalling as soon the snow
melts.
This rubber-made device increases comfort of
passengers, reduce noise and decrease the risk to
damage car in case of improper use, since the weight
of the device is strongly reduced compared to snow
chains. Moreover, its impact on the external
environment is very low and doesn’t cause any
damages to the infrastructures.
It can be installed and uninstalled easily, although
manually. In order not to increase too much the cost
for installation, the device is not conceived to be
installed in a semi automatic way making use of
special tools.
Figure 12:Front view and Left view of the design
alternative selected with the QFD
The inner part of the device is filled with special
foam (Figure 12) to ensure it adheres perfectly to the
wheel. To prevent leakage it is ensured on the tire
with two lateral locks too.
On of the main advantages associated to the design
alternative chosen is also related to the fact that, due
to the high flexibility of rubber, it can fit perfectly on
tires of different sizes. The same tool can be used, in
fact on different wheels and different cars. It means
that producers can develop important economies of
scale, decreasing per unit cost as output increases.
Rubber, moreover, it’s cheap to purchase, to shape,
to store and to transport. Once installed, it requires
very little maintenance and it can be easily and safely
stored inside the car.
8. CONCLUSIONS
the product development process Main aim of this
paper is, at the end, to propose a new methodology
based on the integrated use of TRIZ and of Quality
Function Deployment (QFD) method to support the
design team during concept development.
The methodology aims to support the design teams in
cascading down initial high level design targets into
the technical details of a new product. In order to
ensure that the results of the design process will be
able to reflect initial targets, it proposes to make an
integrated use of Quality Function Deployment
matrixes and of the TRIZ theory. The integrated use
of QFD and TRIZ allows solving, in fact, some of the
main drawbacks related to these techniques, reducing
complexity, improving traceability of initial targets
and enhancing the management of product
alternatives.
Holes
Small
treads
Lateral
lock
Locking
system
Internal
foam

On one side, in fact, QFD showed to be very
effective in helping organizations in understanding
where creative ideas are needed, also if it has no
tools to create new concepts to meet the customers’
often-contradictory requirements. Making use of
TRIZ it was possible to elaborate plenty of valuable
ideas and solutions, solving the contradictions
emerged in the preliminary conceptual design steps.
QFD provided, moreover, an adequate support to the
design team to sort between all the possible design
alternatives and to recognize the best one to be
engineered and produced on an industrial scale.
The application of this integrated methodology on a
real study case, related to the design of a new anti-
slippery device for the car industry, brought, at the
end, to the definition of a very promising and
innovative concept which it will be object of further
development in the next months.
9. DISCUSSION
One of the main differences with commonly in use
methodologies integrating TRIZ and QFD is the use
of a structured framework to classify already in used
tools and patents and to identify possible area of
interventions. The paper propose, in fact, a three-
layers matrix to guide designers and engineers in the
detection the most promising starting points for the
application of TRIZ in a specific problem domain.
The framework suggests investigating a problem
from a System, Sub-System and Super-System point
of view, in order to elaborate a larger set of possible
solution alternatives and to ensure a more structured
evaluation process in the last step of concept
development.
On the other side, developing a correct and reliable
metrics is very important for the selection of the best
design alternative. The methodology is worth,
therefore, in order to support the design team in
designing quantitative and qualitative indicators
really able to reflect initial expectations and to satisfy
previously stated Business and Functional
Requirements.
Improving initial HLOs traceability along the design
process will be the main scope of further researches
in this field. One of the problems emerging from the
application of this integrated approach is linked to
the fact that original targets can evolve during
product development. Although the proposed
methodology is conceived to promote iterative
mechanisms, a more structured and rigorous
approach is needed in order to continuously update
system requirements and to better address evolving
user’s needs.
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