Innovation Technology TRIZ
  40 Inventive Principles to overcome technical contradictions

40 Inventive Principles
The analysis of several thousand patents led to the conclusion that inventive tasks and technical contradictions from all kinds of industrial branches could be solved by a limited number of basic principles (techniques). Modern TRIZ contains 40 basic Inventive Principles. Here are some examples:

11. Principle of the “safety cushion in advance” (preventative measure).
18. Principle of the utilization of mechanical vibration.
22. Principle of the conversion of harmful influences into beneficial ones.
27. Principle of disposability (using of cheap short-livings objects).
28. Replacement of the mechanical system.
35. Transformation of the physical and chemical properties.



Contradiction Table

The application of these principles takes place in a matrix called a Contradiction Table with 39 lines and 39 columns (see Fig. 3). The 39 engineering input parameters are the most important characteristics of technical systems:

• Mass, length, volume.
• Reliability.
• Speed.
• Temperature.
• Waste (loss) of material.
• Accuracy of measurement.
• Accuracy of manufacturing.
• Convenience of use; etc.

These parameters appear in the table as the properties of a technical contradiction and help to formulate a technical contradiction in a system in standardized terms, for example:

• Speed vs. Reliability
• Mass vs. Strength
• Temperature vs. Accuracy of measurement etc.

As a result of the analysis of the many hundred thousand patents the table shows the inventive principles which are most likely to resolve the formulated technical contradiction. Even though not all of the cells of the Contradiction Table are filled in, it still gives solution principles for more than 1200 types of technical contradictions, substantially reducing the scope of the search to only the most appropriate solution concepts.


Example "Speed-Reliability"

At speeds of over 60mph, the risk of serious car accidents due to a tyre damage is greatly increased. This already formulates a technical contradiction and can directly be put into the table: increasing the speed of the vehicle (row 9) has a negative influence on the reliability of its running gear (column 27). Looking up the intersection of row 9 and column 27 (table cell 9/27), we find the following solutions in the following order of priority: 11, 35, 27, 28 (see illustration). According to principle 11, the insufficient reliability is to be compensated for by the pre-installation of damage prevention equipment. A possible solution would be to fix a steel disk behind each rim, which in the case of a tyre damage, keeps the car in a level position, thus reducing the risk of a serious accident (US Pat. 2879821).

Another example of the principle no. 11 “safety cushion in advance” is to be found in the pharmaceutical industry. Sleeping pills are covered with a thin film of an emetic substance. If more than the prescribed number of pills is swallowed at one time, the concentration of the emetic substance reaches a threshold value in the stomach, which then provokes vomiting.


Magic of Contradiction Matrix

Holding no less power of attraction is the Contradiction Matrix, as a method of using the 40 principles. As known, the Matrix - as a result of about 7 years of investigation work – delivers an approach on how to select the best principles to resolve one specific technical contradiction, in order to reduce the trial-and-error work involved in applying all 40 principles.

In spite of the fact that in TRIZ cradle - Russia even in the 1980’s the Matrix was no longer the most recommended of strong TRIZ tools, a lot of attempts to improve this empirical and early TRIZ method are still known nowadays:

• Adding/reducing the number of lines or columns,
• Changing the titles of 39 technical parameters,
• Up-dating the matrix cells or filling the «empty» matrix cells,
• «Customising» matrix: The user can re-invent the matrix according their experience,
• Other mathematical experiments, up to random choice of matrix cells etc.

Although such attempts are being undertaken with the best intentions, they do not contribute to TRIZ significantly, neither practically nor theoretically. Also, the best and fullest matrix would not guarantee the solution of difficult problem. Not the Matrix but the Principles are crucial for problem solving. They are good to enhance technical creativity but only scratch the surface of the problem in complicated situations.

In practice one should warn all newcomers to TRIZ about «blind trust» to the Matrix. One can remember the earlier experience of using the matrix in Russia, still in printed form: the pointer often unintentionally hit the false matrix cell, but nevertheless it did work.

For the matrix-fans we recommend hence formulating several contradictions for one problem situation, forming a set of recommended principles and as the next step using those principles which were recommended more than once. The correct application of the matrix in this case gives a small number of principles, which were recommended 3…8 times (e.g. principles N.35 - 8 times; N.5 - 5 times, N.19 - 3 times etc.), and a longer «tail» of principles which were recommended only once. In any case this approach helps to understand and to document the bundle of underlying technical contradictions in the system that may be of high importance for problem analysis.

It is also possible to apply the principles according to their general, statistical frequency of use. In our experience, the first 10 principles from this list produce workable solutions to approx. 50% of all problems.



List of the 40 Inventive Principles ordered in their statistical frequency of use:

35. Transformation of the physical and chemical properties
10. Prior action
1. Segmentation
28. Replacement of the mechanical system
2. Extraction
15. Dynamism
19. Periodic action
18 Mechanical vibration
32. Changing colour
13. Inversion

The contradiction matrix  today belongs to the history of TRIZ. We recommend that all users keep their own usage statistics and add their own examples and sub-principles to the list of the 40 inventive principles.

Author: Dr. Pavel Livotov