FATIGUE LIFE TESTING OF THE ROUND LINK MINING CHAINS

The material fatigue phenomenon consists of progressive material damage through the appearance and development of fractures under the influence of variable, periodically recurring stresses. Engineers designing machinery and structures to be fatigue resistant can gain useful insights about design and material properties by reviewing the literature. In this way, we can avoid costly research, but in the case of complex loading phenomena and the interaction of components, we must carry out such research. Fatigue strength calculations are less accurate than simple static calculations. The wear of link chains is concentrated in three areas, depending on the installation location and function of the individual links, namely: in the joints (the points of contact between two links), on the outer surfaces of the arches and on the outer surfaces of the straight sections of the links. During operation, chains are particularly vulnerable to wear through abrasion, corrosion and fatigue. These ageing factors, which act with varying intensity depending on the properties of the deposit, determine the service life of the chain, unless other unforeseen damage occurs, e.g. "hard " blockage of the chain. In many cases, users are guided by their own subjective criteria for assessing the technical condition of chains, which does not always lead to fully rational decisions regarding the continued use of used chains. To date, there have been no attempts to transfer the results of chain fatigue tests to behaviour of real objects. This paper presents issues related to mining chain fatigue testing. The test results presented are for both new and used chains. The experimental tests conducted at GIG made it possible to solve the problem of applying fatigue test results in industrial practice.