Open AccessAnalysis of the reliability of the plates of complex shapes for the cams of automatic half-hose machines by the criterion of fatigue strength
Author(s) -
Leonid Berezin,
Mykola Rubanka,
Kyrylo Savchenko,
Oleh Polishchuk
Publication year - 2021
Publication title -
iop conference series. materials science and engineering
Language(s) - English
Resource type - Journals
eISSN - 1757-899X
pISSN - 1757-8981
DOI - 10.1088/1757-899x/1164/1/012012
Subject(s) - finite element method , reliability (semiconductor) , structural engineering , node (physics) , fatigue limit , limit (mathematics) , stress (linguistics) , computer science , minification , software , algorithm , reliability engineering , engineering , mathematics , mathematical analysis , power (physics) , linguistics , physics , philosophy , quantum mechanics , programming language
The purpose of the work is to develop the algorithm for calculation of the probability of failure-free operation of flexible plates of complex shapes for the cams, using the criterion of fatigue strength, to make decisions on minimization of their sizes with the subsequent evaluation of the implemented measures. The studies are performed on the example of a plate for the cam, the configuration of which provides both beam and double console deformations at the same time. The comprehensive approach is presented, which includes dynamic analysis of the needle impact on the cam surface, computer simulation of geometric parameters of the plate by the finite element method (FEM) according to the condition of strength, and classical principles of mathematical statistics and Theory of Probability. The finite-element model with a volumetric 8-node element is used, which allows, with ease of calculations, to obtain the results with a high accuracy when determining the stress-deformed state of the study object. The computer simulation is performed using Code_Aster software with free access. Also, in the calculation of reliability, the random nature of the multifactorial influence on the value of the plate fatigue limit and the loading variations of the cam are considered. When determining the equivalent forces, taking into account the cyclical operation of the machine, the forces that affect the cams during the production of one product are taken as a loading. The numbers of cycles corresponding to these loadings are calculated by the formulas, which are made as a result of the analysis of trajectories of needles motion concerning the cams when knitting different sections of the product. When calculating equivalent stresses, only stresses that influence the accumulation of fatigue failures are used, that is, the values greater than the half of the detail fatigue limit. The proposed computational approach can be used to generate the cams with flexible work plates of different configurations, including under the equal stress condition.