MANUAL Published: 01 January 2007

Chapter 2-Alternatives to Testing: Modeling and Simulation


THE SCENARIO: A LUBRICANT IS NEEDED FOR A plain bearing of CDA 172 phosphor bronze sliding against nitrided steel to complete a project. Your company's “lubricant selection expert system” is called up on your CAD terminal; information is entered on shaft size, speed, torque, normal force, and desired service life; and the computer displays a trade name and type of a specific lubricant to use, how it is to be applied, and lubrication intervals.

This is what many designers would like to happen with most tribological design situations. Such an expert system does exist in which one can select a lubricant, but most engineers at the time did not have these tribological design aids on their terminals; also, many sliding interfaces do not have generic application conditions. That is the problem addressed in this chapter. There are limited usable models, computer simulations, and expert systems available to help designers deal with wear and friction problems, but this chapter will discuss what is out there. Hopefully, it will let newcomers in tribology become familiar with modeling and simulation in the various wear and friction categories. Specifically, this chapter will discuss expert systems, computer simulation, finite element (FEM) wear models, erosion models, friction models, wear maps, and lubrication models.

The concept of expert systems is to write software for computers that allows the computer to analyze existing data and experience and deduce a solution to a problem. This was a popular research and development effort that started in the 1990s. It is still very much in use, but under different names. In fact, just about any computer website that queries users would use expert system concepts. For example, some airlines in 2006 introduced computer screens to replace the ticket counter attendants. They ask you your name, where you are going, flight number, number of bags, etc. The end product is seat assignments, boarding passes, and luggage tags. The computer was programmed to perform the tasks of the “expert,” the ticketing agent. Ticketing agents used to look at your tickets, ask you questions, and then more questions based upon responses. All of these questions and possible answers can be put into the computer's memory. The computer becomes the expert, the ticketing agent.

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Developed by Committee: G02
Pages: 16–23
DOI: 10.1520/MNL11342M
ISBN-EB: 978-0-8031-6249-5
ISBN-13: 978-0-8031-4269-5