Research On Application Of Bellows In Complex Stress Conditions

Metal bellows due to its excellent properties, particularly by virtue of its ability toabsorb deformation, which more and more used in pipeline transportation systems.However, as it is widely used among various engineering, there have been variousproblems regarding the corresponding bellows, particularly in the complex stresssituations bellows subjected to bending state. In engineering practice, some specialpositions need to bend to install, so the research bellows in such complicated bendingstress and the corresponding improvement program increasingly has practicalsignificance.This paper is to select a natural gas pipeline project in a corrugated metal hosewrinkling problems studied. In order to study the reasons for this phenomenon, thispaper analyzes the theoretical and numerical simulation from two aspects. In thetheoretical analysis, a simplified model of the structure and simplified model for theassembly of stress, and the calculation formula of the simplified correlation coefficient.In the numerical simulation, calculation results with theoretical calculations bycomparing to identify key issues and the corresponding laws.By theoretical calculations and numerical simulations are given bellowsimprovement program this bending complex stress state. Namely:1, using better316Lmaterial;2, using single bellows of1.5mm;3, at both ends of each variable bellows plus25°to the elbow.By theoretical calculations and numerical simulations to determine the periodictemperature load displacement is the main reason for the problem arising from thestructure in the form of natural gas pipeline and the bellows curved. For these tworeasons then proposed to solve the problem of optimization scheme that better use316Lmaterial, bellows switch to1.5mm thickness, and change each plus25degrees at bothends of the bellows to the elbow. This optimization is to improve the aspect of thestrength of the bellows itself, the other is to change the form of the curved configurationof the bellows, the bellows can be in a linear state, so that the force of the bellows toachieve a better state.Through the improved scheme to simulate the study, the following conclusions:1、two simplified theoretical model calculations, the error is small, it is possible to calculate complex situations bellows provides a simplified way;2、 in the bent state bycomplex stress prone columnar instability.3、the object of this study is to fold the mainreason leading to discontinuity bent structure under temperature stress and assemblystress, resulting in failure of the bellows trough position.4、 from the study of thispaper, this bellows, and the proposed improvement program can solve part of theproblem, can be applied to engineering practice similar conditions.