PSI - Issue 20

G.Yu. Zudov et al. / Procedia Structural Integrity 20 (2019) 300–305

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G.Yu. Zudov et al. / Structural Integrity Procedia 00 (2019) 000–000

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1. Introduction Intensive development of the Arctic and northern regions of Russia is one of strategic objectives of the country's development, as pointed by Shtyrov (2019). Therefore, ensuring the working capacity and reliability of transportation in the harsh natural and climatic conditions of the North is of particular relevance, by Ishkov et al. (2018). The intensity and conditions of the operation affect the working capacity of the machinery in the cryolithozone. The irregularity of the intensity of the operation of technical objects during the year is associated with supply of goods as well as the seasonal changes in the road conditions, as shown by Kugaevsky (2015). The climatic conditions place special requirements for structural and operational materials of the trucks. Under the conditions of the sharply continental climate, starting properties of engines deteriorate, thermal conditions of sets are violated, the characteristics of the structural and operational materials, the wear intensity of the parts increases, etc. At the low temperatures, the parts fail, which experience the increased dynamic loads caused by the road and other operating conditions of the truck, as proposed by Levin and Vinokurov (2017, 2018). The analysis of statistical data on the equipment failures in the real operating conditions allows one to identify the elements and systems limiting the working capacity of the technical object as a whole. A study aimed at identifying the main faults of the KAMAZ trucks, caused by action of the climatic factors of the cryolithozone, helps to increase safety of the truck operation in such extreme conditions. In addition, this study will allow developing measures in the future to ensure the reliability of the most frequently failing elements of the machinery. 2. Object of research: For the analysis, we selected 50 new trucks that had worked for at least 5 years since a start of the operation. The distribution of the number of the failures by groups according to a catalog of the parts and assembly units of the KAMAZ trucks by Catalog of parts (1983) showed that about 73% of all failures occur in seven groups out of 27. For these systems, the systematic study of the main causes affecting the working capacity of the KAMAZ trucks operating under the extreme conditions of the crylithozone was carried out. In a system approach to the study of the technical objects, interaction of the object with an environment is recognized as determining by Ishkov et al. (2018) according GOST (1971). The characteristic of the external impacts is unpredictability of their intensity and time of appearance. To assess the influence of the climatic factors of the cryolithozone on the working capacity of the elements, the database on the failures of the KAMAZ trucks was supplemented with information on the climatic factors for a corresponding period. This made it possible to determine the climatic data on the day of the failure: the maximum, minimum, average air temperature and effective temperature taking into account humidity and wind speed; a difference between the maximum and minimum temperatures during the day; atmospheric pressure; the pressure change from the previous day; the wind speed; precipitation. Table 1 shows the number of the failures of the main systems of the KAMAZ truck at the positive and negative outdoor temperatures. For the selected systems, the elements limiting the reliability of these systems are identified, and the number of the failures at the positive and negative air temperatures is shown. On average, almost 75% of the system failures occur at the low temperatures. The engine and steering fail at the negative temperatures more often, then the cooling and fuel systems, the electrical equipment, the brake system and suspension follow.

Table 1 - Failures of elements of KAMAZ truck systems limiting its reliability

Number of failures at air temperatures

System

Name

Total

negative

positive

Brake system

Brake hoses and tubes

1202 (75.3 %) 440 (70.7 %) 429 (74.9 %) 171 (78.8 %) 2791 (73.6 %)

395 (24.7 %) 182 (29.3 %) 144 (25.1 %) 45 (21.2 %) 1001 (26.4 %)

1597

Brake chambers

622 573 216

Brake valve Compressor

Total brake system failures

3792