DETERMINATION OF MECHANICAL CONSTANTS OF THE STERN TUBE BEARING

https://doi.org/10.33815/2313-4763.2019.2.21.163-171

Abstract

To solve the problem of improving the service characteristics of the components of a stern tube device, materials are used, in particular, polymers, the physical and mechanical properties of which require further study. This paper is devoted to the determination of mechanical constants as a Young’s modulus and Poisson’s ratio of a stern tube bearing made of a Thordon compac polymer material. The modulus of the longitudinal elasticity of the material was obtained by an analytical and experimental method, as well as by testing for axial compression. Analytical and experimental method for determining the Young’s modulus is based on calculation of local deformations that occur in the stern tube bearing material under the action of an indenter on a small area by the finite element method and by mechanical tests. Poisson’s ratio is determined experimentally. Statistical estimates of indirect measurements of mechanical constants of the stern tube bearing material are found. Trust intervals for estimating random variables of Young modulus and Poisson’s ratios were obtained In this work, in two ways: analytical-experimental and axial compression test of the finished product, - obtained values of mechanical constants in the form of Young’s modulus and Poisson’s coefficient of the material of the insert of DP Thordon compac. The modulus of longitudinal elasticity of the liner material is determined with a relative error of 3.8% when using the analytical-experimental method and 4.4 % when tested for UM-5. Poisson’s ratio is calculated with a relative error of 2 %. The obtained mechanical characteristics are significantly different from those provided by the manufacturer Thordon Bearings Inc. According to the documentation, the Young’s module MPa, Poisson’s ratio. Such deviations can be the result of a single test to determine the mechanical constants of a material of a randomly selected sample from a batch of finished products in the form of inserts of SE Thordon compac.  The obtained results can be used for calculations of the deudwood devices of transport vessels, shafts of oil and gas platforms, hydropower turbines, and pumps.  Investigation of mechanical properties of the Thordon compac SE liner was carried out at the request of a private enterprise Intelligent Marine Technologies (Mykolayiv) at the CDMA Laboratory "Polymeric Composite Materials in Shipbuilding". The obtained results are used in the calculations of the motor-propulsion complexes of sea transport vessels.