ZHANG P, HU X P, ZHANG K. Static and dynamic mechanical characteristics analysis of hydraulic support relay bar［J］Journal of Henan Polytechnic University(Natural Science)，doi:10.16186/j.cnki.1673-9787.2024120052.

doi: 10.16186/j.cnki.1673-9787.2024120052.

Received：2024-12-2

Revised：2025-2-27

Online：2025-6-16

Static and dynamic mechanical characteristics analysis of hydraulic support relay bar

Zhang Peng¹, Hu Xiangpeng², Zhang Kun³

（1. Ningxia Tiandi Benniu Industrial Group Co., Ltd., Shizuishan 753001, Ningxia, China; 2. Tiandi Ningxia support equipment Co., Ltd., Yinchuan 750001, Ningxia, China; 3. School of Electrical and Automation Engineering, Shandong University of Science and Technology, Qingdao 266590, Shandong, China ）

Abstract: Objectives To investigate the failure mechanisms of the relay bar under various working conditions. Methods Based on the pushing and moving actions of hydraulic supports and the loading methods specified by the national standard, four working condition models were established using the fourth strength theory: pushing, advancing, lateral loading, and vertical loading. The stress characteristics of typical cross-sections of the push rod under these conditions were derived, and the mechanical equations were solved using MATLAB. Results All four working conditions resulted in composite stress states within the relay bar, with the advancing action condition presenting the most complex force distribution. The mechanical equations were nonlinear. In the pushing and vertical loading conditions, the stress state was characterized by "upper compression and lower tension," while in the lateral loading condition, it exhibited "leftward compression and rightward tension" with equal tensile and compressive stresses. As the pushing action progressed, the stress in the cross-section gradually increased, with tensile stress increasing more significantly than compressive stress. Compared to the initial position, the tensile stress at the three sections at the end position increased by approximately 22.2%, 11.3%, and 11.4%, respectively, while the compressive stress increased by approximately 2.8%, 5.4%, and 6.2%. The force from the lifting ram and the position of reaction force from floor significantly influenced the force on the relay bar during the advancing action. The former had the greatest impact on the vertical component force of the connecting head hinge hole, reaching approximately 75%, while the latter reached approximately 97%. As the advancing action proceeded, the stress in the cross-section gradually decreased. Compared to the end position, the tensile stress at section 1-1 at the starting position increased by approximately 74%, and the compressive stress increased by approximately 79%. Sections 2-2 and 3-3 showed increases of approximately 15% and 17%, respectively. Conclusions For design purposes, the strength of the relay bar should be based on the starting position of the advancing action condition, and the phenomenon of the relay bar front end being lifted should be strictly avoided. These findings provide a quantitative theoretical basis for material selection, structural optimization, and manufacturing process parameter matching.

Key words: hydraulic support; relay bar; static; dynamic; mechanical property