Influence of temperature on the nonlinear dynamic characteristics of hydraulic straight pipe subjected to random vibration

This paper studies the impacts of temperature and random vibration on the nonlinear dynamic characteristics of a fluid-conveying hydraulic straight pipe. By considering many factors, such as the random excitation, temperature change, and axial force, the fluid–solid interaction nonlinear dynamic equations of the straight pipe system are established using the Monte Carlo method combined with a stochastic harmonic function for simulating the random excitation. The nonlinear dynamic equations of the pipe are solved using the Galerkin and fourth-order Runge–Kutta methods. The impacts of the excitation frequency, temperature, and axial force on the vibration pattern of the pipe are analyzed, and its natural frequency, bifurcation, phase power spectrum, and time-course diagrams are then derived. The obtained results reveal the bifurcation phenomena of the pipe, including periodic and chaotic motions. The temperature differences and pressure increase accelerate the bifurcation and post-bifurcation flexural displacements of the pipe, while the opposite holds for axial forces. Comparison with existing experimental data has confirmed the accuracy of the results. The proposed method provides a theoretical basis for the design and stability analysis of pipes in random vibration environments.