METHOD FOR PASSENGER RESERVED SEAT CAR LIFE INCREASE

In the paper there is considered a car basic bearing element – center sill which because of long operation is subjected to corrosion destruction (on surface and in depth). The elimination of such corrosion spots mechanically is not effective and results in local decrease of a unit thickness and also in some cases in through corrosion. The authors of the paper have carried out investigations in places where intensive corrosion took place. For this there were cut out four fragments of the center sill and carried out etching-out and measuring residual stresses and a deformation value from etching depth of each fragment through Davidenkov’s method and CNIITMach’s procedure. As a result of the investigation carried out there is offered a fulfillment of center sill strengthening in the area of intermediate and end girder welding by means of shot cleaning in these areas, and also by additional corrosion resistant coating application on these surfaces. The investigations are carried out through Davidenkov’s method and on the basis of CNIITMach’s procedure. The work novelty: there are defined conditions for corrosion spot formation and technology is developed to ensure units life increase. According to the results of the investigations carried out there is made a conclusion: for the purpose of decrease and exclusion of corrosion processes and service life increase of both the center sill and a car in the whole it is necessary to carry out strengthening center sill elements in the areas of intermediate and end girders welding by means of the shot cleaning fulfillment in these places, and also an additional corrosion resistant coating application on these areas.

Research on the electrical contact degradation model of plug-in connectors under corrosion and wear

Failures due to corrosion are common for connectors operating under atmospheric environment. Results of previous studies lacked universal applicability and neglected the degradation process of contact resistance. Also, wear is rarely considered in studies on corrosion degradation, which is an inevitable mechanical process for plug connectors. Considering these problems, the atmospheric corrosion process and copper dynamics were analyzed. The consistency of the atmospheric corrosion mechanism was used to study the local corrosion degradation law and its influencing factors. The wear mechanism on corrosion degradation was determined through the analysis of the influencing factors. The corrosion model of the gold-plated parts under atmospheric wear was established. To study the degradation process of electrical contacts, a degradation model of contact resistance based on the multi-spot contact mechanism was established combined with the previous corrosion degradation model. Experimentally, the corrosion spot density increases as a function of time and varies with plated thickness, whereas the corrosion spot size distribution is still relatively independent of time. The skew phenomenon appears in the cumulative distribution probability of contact resistance as exposure time increases. Whereas the degradation of electrical contact resistance increases as a function of time, the median remains relatively unchanged. A brief analysis of the contact reliability under wear and corrosive environments was also carried out.

METHOD FOR DETECTING DEFECTS IN MARINE PIPELINES BY WAVELET ANALYSIS OF REMOTE MAGNETOMETRY SIGNAL

The paper considers a method for detecting offshore pipelines defects using a wavelet transform of a remote magnetometry signal. This method makes it easier and faster to process large amounts of information obtained as the measuremens result. According to statistics, 40% to 50% of accidents with offshore pipelines occur due to the pipe walls corrosion. Thus, the research aimed to development the methods for offshore pipelines inspection and diagnostics is very important. For the testing of the suggested method for detecting pipeline defects, on the engineering analysis software ELCUT base a numerical model describing the magnetic field distribution in the area of corrosion spot located on the pipe wall was developed. It is shown that the suggested method can be used for detecting the defects and evaluating the offshore pipelines technical condition.