The Analysis Of Fatigue Life Of Hydraulic Support Test-bed In Various Working Conditions

Hydraulic support is the core safety supporting equipment of in a modern fully mechanized working mining face,its reliability has a great influence on the safety of fully mechanized production.Hydraulic support test bed as the testing equipment for the hydraulic support’testing and maintenance,which is directly related to whether it can meet the safe reliability when people under the mine producing, Hydraulic support test rig under complex working conditions,such as bears large loads, various working conditions and high number of cyclic loadings, and our nation put forward higher standards of the mine’s safety production. So the inspection is very important to the hydraulic support’s final factory test and overhaul,it also demands the hydraulic support test bed has a higher strength,especially, it’s very necessary to estimate the fatigue damage of the platform.This thesis did research to the fatigue damage which was mainly caused by the durability test under multiple cyclic loading condition of20000KN hydraulic support test rig of a certain coal electricity group. After the understanding of the dynamic characteristics about the domestic and foreign research in the field of the hydraulic support test rig, and referred to the articles written by the scientific research personnel,proposed a method about how to estimate the fatigue life of hydraulic support test-bed under various working condition in durability tests.First,simply analysed the hydraulic support test bed,the pin and pin boss were in the state of two-direction stress.In all conditions,the stress value of torsion and eccentric load were the maximal.Finished the three-dimensional modeling of hydraulic support test rig, leaved out hydraulic system,electrical control system and some non-critical chamfering or bolts,etc.Because some positions were the key bearing component,so we taken different ways to mesh the different parts of hydraulic support test-bed,especially,taken the contact sizing control method to mesh the key bearing interface,prepared for the finite element analysis of hydraulic support test rig.Builded a automatic control system for hydraulic support test rig which were composed of an industrial control PC as upper computer and a S7-1200PLC as lower computer,realized the control of various kinds of actions in the hydraulic support test process, and also achieved the automatical loading of different working conditions. And the problem that the loading time was too long which due to the unload process was too fast was analyzed, proposed a unload method: time-sharing unloading and unload in stages,it did not affected other control processes,and also avoided the vibration caused by the fast unloading of the bench. Sended the received data collected by sensor to the control interface which could displayed the feedback data,got the durability test loading curve.Imported the loading curve into the finite element analysis software ANSYS Workbench, took a transient dynamic analysis of this platform,obtained the stress-time curves of vulnerable spot,after the correction by Goodman empirical formula,combined with the P-S-N curve of16Mn and40Cr,we got the weakest point at the corner of the pin set after the all tests of one platform,the value of fatigue damage was1-2052×10-3.At the last,according to the fatigue damage characteristics, as the16Mn material of the pin set could not meet the requirement of the strength, we put forward the improvements of replace the higher strength material of fragile parts.This had a certain reference value to improve the fatigue strength and the service life of hydraulic support test rig.