Evaluation of structural and performance aspects of chock shield support designs using a finite element technique

Abstract A continuous process of design improvement, based upon operational experience, usually follows the introduction of a new engineering concept, and in this respect lemniscate linkage hydraulic powered supports are no exception. The features of this particular support design have enabled success to be achieved in thin and thick seams which were previously difficult to mine. Since their introduction, design development has concentrated upon structural configuration and automation of hydraulic control systems. A structural analysis procedure is described which incorporates the finite element stress analysis technique and results of in situ performance monitoring, which yields information relating to induced working loads, support component attitude, component stress intensity and overall structural stability. Such an evaluation assists assessment of areas of over- or underdesign, structural configuration, and operational performance. Concurrent with support performance evaluation, monitoring using a comprehensive instrumentation approach of support design parameters on longwall coalfaces is described. Structural evaluation under operating conditions has enabled development of a method to predict lemniscate linkage stress intensity which uses monitored hydraulic leg pressure.