multi objective optimization of the vibration analysis of composite natural gas pipelines in nonlinear thermal and humidity environment under non-uniform magnetic field

Adhesive in the field of fluid structure interactions fluid conveying pipe is a basic dynamical problem. in recent years considerable attention has been given to the lateral vibrations of pipes containing by a moving fluid. in this article, the vibration analysis of composite natural gas pipeline in the thermal and humidity environment is studied. the effect of the non-uniform magnetic field is investigated. the equation of motion is derived by applying the hamilton's principle for the pipe with the effects of both linear and nonlinear stress temperature cases. the differential quadrature method (dqm) has been utilized in computing the results for the fluid conveying pipe. the bees algorithm and genetic algorithm nsga ii for multi-objective optimization of a pipe model are used. sample results are presented for several cases with varying values of the system parameter. results are demonstrated for the dependence of natural frequencies on the flow velocity as well as temperature change and humidity percent. the effect of temperature change on critical flow velocity which causes to occur buckling instability is investigated. it is summarized that the influence of temperature change on the instability of fluid conveying pipe is significant.