Study on the influence of eccentric loading on the mechanical properties of energy-absorbing FRP anchor bolts

TANG Zhi; JIA Dunwei; WU Zhiwei; LÜ Jinguo; CHANG Dezhi

doi:10.16579/j.issn.1001.9669.2026.04.011

Abstract：[Objective]Aiming at the problem of performance degradation of bolts under eccentric loading in coal mine roadway support,the influence law of deflection angle on the mechanical properties of energy-absorbing FRP bolts was investigated,and the normal working angle range was determined to provide reference for similar roadway support design.[Methods]Firstly,the maximum deflection angle of energy-absorbing fiber reinforced plastic(FRP)bolts and the stress-strain compliance matrix relationship of FRP rod body were derived through mechanical analysis,and the stress characteristics and applicable judgment criteria of bolts under eccentric loading were clarified;Secondly,the key mechanical parameters of FRP rod body were measured by tensile test with universal testing machine to provide basic data for numerical simulation;Subsequently,the Vumat subroutine was compiled based on Hashin failure criterion,and the numerical models of conventional and energy-absorbing FRP bolts were established by Abaqus finite element software;Finally,the core mechanical indexes such as elongation,breaking force and energy absorption of bolts under static load and dynamic load with different impact parameters were compared and analyzed.[Results]Under static load,the breaking force,elongation and energy absorption of the two types of bolts decrease nonlinearly with the increase of deflection angle,and the applicable deflection angle of energy-absorbing FRP bolts is determined to be no more than 4°;Under the working condition of 4° deflection angle,the dynamic mechanical indexes of the bolt are significantly better than those of conventional FRP bolts,and its energy absorption is about 12 times that of conventional bolts,which has excellent impact resistance and energy absorption characteristics;Under different impact conditions,all indexes of the bolt with 4° deflection angle meet the preset applicable criteria.