Study On The Structure Integrity Of The Bolted Flange Joint Under External Bending Moment

Metal to metal contact(MMC)type and Floating(FLT)type bolted flange connections are widely used in nuclear and petroleum chemical industry.Bolted flange connection stress distribution is complex,especially when external axial load and external bending are applied.Until now,the bolted flange joints under external load are calculated normally with the method of equivalent stress method or the equivalent axial force method,while the two methods are conservative in most cases.Therefore,to study the strength and tightness of the bolted flange joint under external loads is particularly important.In order to identify the bolted flange joint’s stress distribution and tightness performance under external bending moment.The finite element approach and experiment approach are used here.Based on the gasket compression and leak rate test experiment at room temperature,the experiment devices are built to test the mechanical properties of flange connections under external bending moment.The experiment results verify the finite element analysis as well.The structure strength and sealing performance of the two type flange connections are also quantitative assessed.Finally,because of no available criterion on the specifications of MMC gaskets at present,the influence of the MMC graphite’s dimensions on their performance is also studied with finite element method.The mechanical property and sealing performance of the MMC flange connections are studied to clarify the effect of the MMC graphite dimensions on the integrity of the flange connections.This study has positive influence on the design of bolted flange connection with the external loads.Meanwhile,the study of different dimensions MMC gasket can provide some reference for the supplier of the gasket.