Radial strains in two-stage hydraulic extension legs

Authors: Бяков М. А., Буялич Г. Д., Буялич К. Г., Увакин С. В. 

The article presents the stress–strain analysis results for a two-stage extensible hydraulic leg of powered roof support Joy case at the maximum seam height and hydraulic fluid pressure of 32 MPa with regard to friction coefficient in the supports of the canopy and base, fabrication tolerances of cylinders, pistons, main bushes and rods, as well as to misalignments of rods and cylinders of the first and second extension stages due to noncentral application of external load in the supports. The displacements of the joint surfaces, which govern the change in the sealed clearances that regulate operation of cups and proofness of the leg, are evaluated. The calculations involved the optimal number of finite element across the thickness of the wall of the cylinder; furthermore, generation of a regular mesh composed of 3D hexagons with 6 points was ensured. As a result, for the hydraulic leg of powered roof support Joy, given the leg is in vertical position relative to the canopy and base support, it is calculated that the displacements of the lines on the same but diametrally opposite surfaces have different values, up to 0.2 mm, which is comparable with the fabrication tolerance and points at the related displacement of the longitudinal axis of the leg due to misalignments of rods and cylinders.

Keywords: Hydraulic leg, powered roof support, finite element method, strength, underground coal mining, production face, proofness, sealed clearance, radial strain of cylinders, two-stage hydraulic extension, misalignments of rods and cylinders.
For citation:

Byakov M. A., Buyalich G. D., Buyalich K. G., Uvakin S. V. Radial strains in two-stage hydraulic extension legs. MIAB. Mining Inf. Anal. Bull. 2020;(1):133-140. [In Russ]. DOI: 10.25018/02361493-2020-1-0-133-140.

 

Acknowledgements:
Issue number: 1
Year: 2020
Page number: 133-140
ISBN: 0236-1493
UDK: 622.285
DOI: 10.25018/0236-1493-2020-1-0-133-140
Article receipt date: 06.09.2019
Date of review receipt: 14.10.2019
Date of the editorial board′s decision on the article′s publishing: 20.12.2019
About authors:

M. A. Byakov1, Chief Geologist, AO «SUEK-Kuzbass»,
Leninsk-Kuznetsky, 652507, Russia,
G. D. Buyalich1, Dr. Sci. (Eng.), Assistant Professor,
Head of Chair,
K. G. Buyalich1, Cand. Sci. (Eng.), Assistant Professor,
S. V. Uvakin1, Graduate Student,
1 T. Gorbachev Kuzbass State Technical University,
650000, Kemerovo, Russia.

For contacts:

G. D. Buyalich, e-mail: gdb@kuzstu.ru

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