Nauka ta progres transportu (Oct 2014)
OPERATING ELEMENTS DAMAGE OF TOOLS CONNECTED WITH THE PLASTIC DEFORMATION OF HARDENED ORGANIC COMPOUNDS
Abstract
Purpose. Most of the freight traffic in Ukraine is made by railway transport. Government statistics of annual railway freight traffic (January-November) records the following data: 2011 - 468 million tons (108.2% to 2010); 2012 – 421.5 million tons (98.5% to 2011); 2013 – 441.8 million tons (96.6% by 2012). Despite the annual decrease of freight traffic volumes, a significant contribution during the freight traffic belongs to transportation in tanks. That is why the term of their service life extension is very topical today at the operation of tanks. Modern ideas about the accumulation of fatigue damages in the details of railway vehicles are based on models that assess the service life of metallic systems, depending on the load conditions. These models with sufficient accuracy let carry out an assessment of softening of metallic systems in high-cycle fatigue conditions and at the presence of elastic deformation. At the same time, peculiarities of counterbodies′ behavior these models do not take into account. The purpose of this paper is to construct a mathematical model to evaluate the durability of the operating tools, which are used in the purification of solidified organic cargo of tank cars. Methodology. With the use of modern approaches of deformed solid body mechanics the parameters impact of organic substances structure on the service life of heavy structural elements was analyzed. We present the interaction of damages ratio in this article. It relates mainly to those elements of the tool structure, which due to the influence of broadband Gaussian random loadings oscillate with their resonant or near-resonant frequencies. Findings. The influence of the fatigue loads features on the structure durability was studied. Thus, the obtained results suggest the increase of damages that are entered with low-amplitude cycles of strain, because of the nonlinear effect of the interaction between instrument operational elements with organic material. For the given example durability with fatigue which, according to an updated assessment, had been reduced by 10...15% was calculated. A decrease of 10% corresponds to the maximum amplitude of the voltage 5σ , and a decrease of 15% - the maximum amplitude 7σ . Originality. It is analytically shown that parameters of the metallic systems softening are connected with the kinetics of fatigue damages that accumulate in the metal structures under external loads. Practical value. Authors have proposed correlation that allows estimating the residual life of the part in conditions of a given sequence of multilevel cyclic loading.
Keywords
