Tham khảo tài liệu 'tribology - lubricants and lubrication part 2', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 12 Tribology - Lubricants and Lubrication According to the second axiom in tribology the property of elements and systems is time depended. The structure is a description of intrinsic facts but it is not invariable for a tribosystem. There are recoverable changes and irrecoverable changes in the structure due to the interaction and relative motion of surfaces. As described in formula 3 E is obvious invariable the only variable things in S are P and H. Each element hw hei i in the sub-set H are too complex to be described with parameters usually they are a series of records in natural language. Using H rather than using a time parameter t here is because of that t notes only a time scale but what happened at t is more important for understanding the change of the structure. The elements of H do not act directly upon the structure but affect the values of parameters in pg and pp. For each effect some principles which govern the progress of effect can be found in related discipline. For example an elastic deformation of the surfaces is a recoverable change of pg which follows the change of interacting load on the surfaces governed by principles in the theory of elasticity while a plastic deformation or wear of the surfaces is an irrecoverable change of pg it is defined by what happened in the history and governed by principles in the theory of plasticity and tribology. The behavior simulation of a tribo-system Different from what used in references Dai Xue 2003 Ge Zhu 2005 a state space method is applied here to simulate the behaviors. The state space method is a combination of general systems theory with engineering systems analysis and has wide application in dynamic system analysis control engineering and many non-engineering analysis Ogata 1970 1987 . It takes a vector quantity called state as a scale to coordinate and evaluate the results of behaviors. When an input is applied upon a system the system behaves from one state to another state and gives an .
