Joel Liebesfeld, MA, MAS, Post Grad Certs: Computer Sci., Elec. & Mech. Engineering
James F. Valentine & Associates, Inc.
Presented at the International Symposium on Fire Investigation Science and Technology, 2018
Tribology is a study within the field of mechanical engineering that focuses on the use and study of lubricants and age, wear and tear, as a function of the frictional interaction of sliding surfaces. The degradation of components, machinery, devices, appliances, et al, from the processes associated with age, wear and tear can adversely affect the surfaces formed between layers of sliding materials.
Tribology focuses mainly on the studies of plastics and metals, although many of the principles may also be applicable to other structural materials as well.
This paper will attempt to convey this intensely mathematical area of study into a more universally understandable written form of technical or lay language, but in some instances, there may be the use of formulae to exemplify models of the way in which, for example, friction can be the cause of vehicular fires. These formulae may be presented in words rather than symbolically.
It was while in a post-graduate certificate program in Tribology at the Massachusetts Institute of Technology (MIT) that I became aware of the application that Tribology had in regard to the investigation and analysis of electrical and electromechanical fires.
This paper will examine faults often found in polymers used for electrical insulation. Polymers that result in a fault are often used for strapping, harnessing/mounting of assorted wiring, especially vehicular wiring. Rotational machinery utilized in or in conjunction with passenger vehicles/work vehicles and most everywhere else, degrade as a result of a lack of improper lubrication, as well as age wear and tear. The polymers used in rotational machinery are particularly useful as resins/materials for windings, gaskets, et al. Small, but considerably irksome faults may ubiquitously appear in many types of commercial and passenger vehicles, residences and commercial structures. Example, a faulted starter motor will totally disable most vehicles manufactured with an internal combustion engine.
The paper will use examples taken from losses that were actually investigated by this author. These losses were the result of catastrophic faults that had developed in electrically energized machinery. These specific losses were discovered where the age, wear and tear of assorted materials lead to substantial fire losses.
Tribology studies involve a variety of specific data that is inclusive of time, material qualities, studies of heat production, a surface analysis of materials, assorted forces, etc.
Tribology, like many other studies, has a somewhat unique vocabulary that will be noted and explained as these words or phrases appear, such as the word ‘asperities’ which refers to certain specific surface qualities of assorted materials.
Unlike many studies or research reports, in this particular paper, an attempt will be made to have the reader learn the answers to questions regarding many common material faults and failures. And just to whet the reader’s appetite, wouldn’t it be scientifically useful to know that the contents of this paper may help Expert Fire Investigators explain what led up to the specific cause of a particular type of fire?
There are TWO easily obtainable data sources readily available to most investigators such as the Materials Safety Data Sheets (MADS) and an OSHA safety poster that together helps ensure that people will know how to use MADS, as required. These and other research resources can be helpful in the development of a report’s hypothesis, especially where such information can be integrated into a logical sequence that may be applied to the final determination of the cause for a fire.
For the reader to learn about the study of tribology it should be understood that the subject matter, in many instances, is fairly intuitive and therefore permits a broad, diversely educated audience to be able to understand and utilize most of the information as written and cited herein.
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