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Provision technological reliability details of the farm machinery restored with a polimeric compositional materials


Author: Vadim Sîrghii
Degree:doctor of engineering
Speciality: 05.20.03 - Exploitation and Maintenance of Agricultural Machinery and Food Industry
Year:2007
Scientific adviser: Grigore Marian
doctor habilitat, professor, Agrarian State University of Moldova
Institution:
Scientific council:

Status

The thesis was presented on the 2 March, 2007
Approved by NCAA on the 19 April, 2007

Abstract

Adobe PDF document – 1.58 Mb / in romanian

Keywords

absorption of oil, adhesive resistance, orifice, quenching, electrostatic field, composite, durability, sabidity, reliability, operational reliabilit, technological reliability, polymer, restoration, restoration, adhesive durability, roughness, status of a surface, surfaces of the response, thermal processing, wear process,deterioration

Summary

The study consists of 6 chapters and it is dedicated to an actual problem in agricultural engineering –provision of the improvement of the technical services of agricultural machineries as a result of the development of new recovering technology of worn-out parts by polymeric compositional coverage .

As a study object is taken the reliability of agricultural machineries parts, restored with a polymeric compositional coverage and their interfacing.

The goal of the study is the provision of parts reliability restored with polymeric compositional coverage, based on scientific justification of each element of technological process, providing improvement of the qualitative indices of reconstruction.

In the chapter one the analysis of the exiting problems referring to machines parts recovering is discussed , including the aspect of polymeric compounds use, which serves as scientific innovation of present study, justified the need of detailed studies oriented toward technological reliability of machines parts restored with polymeric compounds coverage. In the chapter two the theoretical premises of reliability provision of restored parts with polymeric compounds coverage and their interfaces are considered. The conclusion is made that the wear-out of interfacing surfaces, to some extent depends on the angle of supporting surface at the contact point of interfacing surfaces, which for metalpolymer systems have their own peculiarities and it is defined by the value of initial and working clearance. In this chapter is justified also the importance of scientific studies of the reliability of restored friction vapors for specified conditions of use for the reason of correction of brought forth hypothesizes.

In the chapter three are brought study methods of physical-mechanic characteristics of synthesized polymeric compounds coverage, methods of the mathematical programming and processing of experimental data, as well as estimation to validity of the results. The laboratory installation is described for fixing and shaping of covers; a stand was designed with purpose to study the vapor friction restored longevity, agreeable to real tribotechniques conditions for use of parts and their interfaces.

In the chapter four the results of the experimental studies based on which is motivated the optimal composition of substrate - intermediate conversion layer - main worker layer system, as well as results of the study of dependency of compositional compounds influence on different physical-mechanic characteristics of restored parts along with their junction are discussed. The studies were conducted for covers received in pseudo gel type of electrostatic field and pressing. In the chapter five are discussed results of the experimental study of restored polymeric compounds parts reliability depending on technological mode of their shaping.

For acknowledgement of experimental data validity and checking the working capacity of investigated covers in vapor medium formed of different metallic alloys are brought the results of the speed up stand tests of restored with polyamidepoxy covers parts. Tests were conducted before the appearance of limiting conditions of investigating vapor. The study ends with the description of the design of typical technological process of the recovering the worn-out parts of the machines based on undertaken experiments, as well as precise recommendations for technological mode choice, dimensioned accuracy, roughness of joining surfaces.

The conclusions are based on obtained experimental results. In the study are brought also the list of scientific references, list of abbreviations used in the Dissertation, keywords in Romanian, English and Russian languages.