PREFACE, Lev M. Klyatis............................................................................................................................................................xiii INTRODUCTION, Lev M. Klyatis.......................................................................................................................................................xix CHAPTER 1. ACCURATE PHYSICAL SIMULATION OF FIELD INPUT INFLUENCES ON THE ACTUAL PRODUCT, Lev M. Klyatis...........................................................................1 CHAPTER 2. USEFUL ACCELERATED RELIABILITY TESTING PERFORMANCE, Lev M. Klyatis, Eugene L. Klyatis..................................................................................93 CHAPTER 3. ACCURATE PREDICTION OF RELIABILITY, DURABILITY, AND MAINTAINABILITY ON THE BASIS OF USEFUL ACCELERATED RELIABILITY TESTING RESULTS, Lev M. Klyatis.....................285 CHAPTER 4. PRACTICAL ACCELERATED QUALITY DEVELOPMENT AND IMPROVEMENT IN MANUFACTURING AND DESIGN, Eugene L. Klyatis...............................................................363 CHAPTER 5. BASIC CONCEPTS OF SAFETY RISK ASSESSMENT Lev M. Klyatis................................................................................................................413 Index of Authors....................................................................................................................................................................471 List of figures.....................................................................................................................................................................475 List of tables......................................................................................................................................................................481
1 INTRODUCTION: THE GROWING IMPORTANCE OF SIMULATION FOR ACCELERATED DEVELOPMENT AND IMPROVEMENT OF PRODUCT QUALITY
1.1 GENERAL
Experiment is considered to be an essential, integral part of scientific development.
Experiment is also one of the basic components of knowledge. Therefore, the theory and practice of simulation in its new and wider sense, make possible the concentration of information and are the basis of experimentation. This gives directions for conducting experiments, and shows the regularity of their results, which has a specific, as well as a very important value. Quality is one of the goals of these experiments which make it possible for development and improvement problem solving.
The common goal of the theory of simulation is the establishment of the methodology whose purpose is to direct and to regulate the processing of information about subjects (systems) which exist outside of our consciousness, and their mutual interconnection within and outside of the exterior environment.
Simulation simplifies obtaining general information and also correctly provides the necessary experiments and processing of their results. This can be provided with the help of both the theory and the practice of simulation (modeling).
The model is a natural or artificial object which corresponds to the studied object or to any of its facets. In general, simulation (modeling) is a reflection of a real situation in order to study its objective regularity.
1.2 ELEMENTS OF HISTORY OF PHYSICAL SIMULATION DEVELOPMENT
The study of simulation was created more than four hundred years ago. Leonardo da Vinci began to work on the development of simulation from the middle of the 15th Century. He wrote: "Somebody mentioned that small models do not represent to a similar effect as a large model. I want to show that this is wrong...". He created the common analytical regularities and described many examples. For example, he established the ratio between square, power, and the quantity of wood which is removed by different sizes of augers, used for wood drilling.
Similar problems arose often in the 16th and 17th Centuries. Galileo Galilei wrote in his work "Speaking about two new sciences" that much attention was given to the science of simulation in the 17th Century when the Venetians began to build larger galleys. Galileo Galilei established that "... Fatigue of similar bodies does not preserve the same ratio as between body sizes".
In 1679 Marriott was engaged with the problems of the theory of mechanical simulation in his treatise about the collision of bodies, and developed the ideas of Leonardo and Galileo.
At the end of 17th Century Newton completed these theories in his work "Mathematical introduction of natural philosophy". It was the first major scientific formulation of the conditions of simulation in relation to mechanical motion. He described the movements of the material bodies and established the law of the similarity of these movements. The direct theorem of similarity and the basic principles of similarity which were formulated by Newton, are the basis of the modern science of similarity which shows the conditions of similar mechanical systems and the criteria which are characteristic of the movement of the systems (1st theorem of similarity).
Newton opened the way for the implementation of similarity and a model for a description of theoretical regulations. To this analogous similarity, as it is now called, is related, for example, the creation of a natural mechanical model for the description of luminous phenomena, the mathematical model for description of gravitation, etc. Newton's works on the theory of similarity and modeling did not last long and what followed was development and practical implementation. Although there were many experiments on models of arcs and testing of different hypotheses of their work at the beginning of the 18th Century in France and other countries.
The famous Russian inventor I.P. Kulibin was one of the first to use static similarity in his development of the project of an arch bridge over the river Neva with a span of 300 m. He provided the research using wooden models at 10% of the natural scale, with a weight of more than a ton, which were built and tested in Petersburg in 1775 - 1776. It was the first project to take into account that a change of the linear size by k times changes the original weight by k3 times, and the square of the cross-section of the elements–by k2 times. He established that the physical models in l/k natural value had tensions based on its original weight of k times less than the original tensions. It is possible that the similarity of influence of its own weight in the model can carry an additional load. The working load which acts on the bridge must be less in k2 times more. These levels of advances were checked and approved by L. Eelier.
J. Fourier's work, "The analytical theory of heat conductivity" was published in 1882 and in this it was shown that the components of an equation, which is described as a physical phenomenon, always have the same dimensional representation. This property was called "Fourier's right".
Bertrand has established the common properties of a similar mechanical movement, and shown the methods of similarity for complicated mechanical movements, as well as having formulated the requirement for the presence of the criterion of similarity. He showed in 1878 how one could find the mathematical dependence for physical quantities when the equation for the connection for these quantities is unknown. The mathematical dependence between these quantities must be a dependence between dimensionless complexes which are composed from these quantities.
Shortly thereafter, there were some works published such as the connection of the theory of similarity to different mechanical phenomena. For example, Koshee published the laws of sound phenomena in all geometrically similar bodies from the equation for the movements of elastic bodies.
Gelmgolz obtained the conditions of similarity for hydraulically phenomena. Philips established the laws of bridge vibrations, not only for static, but also for dynamic loading.
Even after the methods of similarity were obtained practical implementation was not easy.
Here is one example of physical simulation. In 1870 a big ship was built called "Captain", was launched by the Admiralty of England. Earlier research showed that this ship could be overturned by even minimal waves, but the lords of the Admiralty of England did not believe in the research of scientists with their toy model. The "Captain" overturned as it left for the open sea and 523 sailors perished. There is a memorial desk in London which serves to forever memorialize the ignorance of the lords of the Admiralty of England.
Ignorance on the part of executive personnel of the process of simulation continues to the present day.
There are many examples in which ignoring accurate simulation continues even now in aerospace and other areas. The result is the existence of very expensive crash disaster research stations and not enough reliability, maintainability, and availability (RAM) of many other types of technical products. These problems can be solved if the modern research results of similarity are employed along with accelerated reliability testing as well as accurate RAM prediction.
Often the low level of a professional's knowledge which only considers traditional approaches is the major obstacle to the use of other, especially new, approaches.
During the last Century the following science of similarity was developed in two basic directions:
1. Analysis of equations which describe mathematically the studied phenomena;
2. Analysis of the dimensionless physical quantities that characterize these phenomena.
The first direction was called analysis of equations. The second direction was called analysis of dimensionless.
In the 20th Century Reynolds, Nusselt, and other researchers proposed methods for the establishment of similarity and criteria processing of research results related to the problems of hydromechanics.
Now research into complicated, nonlinear, and non - homogeneous systems provides the next basic problems in the development of the theory of similarity. The above is about the development of a common theory of similarity.
Now the meaning of similarity (modeling) includes a wider content than previously. In modern scientific meaning the words "simulation" and "modeling" also include informational modeling, and many other types.
Above is a description of the history of the physical simulation of the test (research) subject, but there is a large area of physical simulation which is less developed and which was not fully described earlier. This is the physical simulation of the field input influences in the laboratory.
This type of simulation relates to laboratory experimental work with the actual test subject, as well as accelerated laboratory testing of the actual product that is used by most of the industrial companies as well as the university research centers during the development, improvement, and control of the quality of products. This is the physical simulation of field input influences on the actual product. For these goals one uses different types of test chambers (temperature/humidity/ /vibration/input voltage, temperature/humidity/vibration, temperature/humidity, etc), vibration equipment, dynamometers, and many others. The technique of this simulation is not sufficiently developed.
Below, this type of physical simulation will be described, as well as its development.
1.3 SIMULATION FOR ACCELERATED QUALITY DEVELOPMENT AND IMPROVEMENT THROUGH ACCELERATED RELIABILITY TESTING AND EXPERIMENTAL RESEARCH
As was mentioned earlier, accelerated testing as practiced today usually offers a minimum of all the possible benefits. One basic reason for this situation is that most companies and research centers cannot accurately simulate the basic combination of real life input influences on the actual product. As a result, they cannot provide successful accelerated reliability testing (ART) for obtaining accurate initial information for quality, reliability, maintainability, and availability evaluation and prediction in the field, and the solving of other problems such as accelerated experimental laboratory research, accelerated development and improvement of the product's quality, reliability, maintainability, availability, effectiveness, etc.
Experimental research (ER), especially in engineering, also offers only a minimum of possible benefits, because usually it isn't possible to accurately simulate in the laboratory the real life input influences on the research subject. Therefore, the experimental results are often different from field results.
The basic reason for the above situation is that there are insufficiently developed techniques and equipment for this simulation. Unfortunately, literature in experimental research as well as in the accelerated testing area is for the most part about theory of experiments, statistical models, models for reliability analysis of Accelerated Life Testing (ALT), selecting the best distribution, research and test plans, analysis of results, computer simulation for providing a computer test without an actual
(Continues...)
Excerpted from ACCELERATED QUALITY AND RELIABILITY SOLUTIONS by Lev M. Klyatis Eugene L. Klyatis Copyright © 2006 by Elsevier Ltd.. Excerpted by permission of ELSEVIER. All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.