scholarly journals Dynamic Response of Pipe Conveying Fluid with Lateral Moving Supports

2018 ◽  
Vol 2018 ◽  
pp. 1-17 ◽  
Author(s):  
Baohui Li ◽  
Zhengzhong Wang ◽  
Lina Jing
Keyword(s):  
Dynamic Response ◽  
Galerkin Method ◽  
Dynamic Equation ◽  
Fluid Velocity ◽  
Extreme Condition ◽  
Superposition Method ◽  
Pipe Conveying Fluid ◽  
Mode Superposition Method ◽  
The Galerkin Method ◽  
Conveying Fluid

The Galerkin method is proposed to reveal the dynamic response of pipe conveying fluid (PCF), with lateral moving supports on both ends of the pipe. Firstly, the dynamic equation is derived by the Newtonian method after calculating the acceleration of the fluid element via the dynamics approach. Secondly, the discrete form of the dynamic equation is formulated by the Galerkin method. Thirdly, the numerical analysis of the system is carried out through the fourth-order Runge–Kutta method, and the effectiveness of the proposed method is validated by comparison with the analytical results obtained by the mode superposition method. In the example analysis, the responses of the lateral deflection and bending moment are investigated for the pinned-pinned, clamped-pinned, and clamped-clamped PCF. The effects of fluid velocity and the moving frequencies of supports are discussed. Especially, the deflection responses are analyzed under extreme condition; i.e., the moving frequency of a support is identical to the natural frequency of PCF.

Flutter instabilities of cantilevered piezoelectric pipe conveying fluid

2019 ◽  
Vol 30 (4) ◽  
pp. 606-617 ◽  
Author(s):  
Gang Wang ◽  
Jinwei Shen
Keyword(s):  
Electromechanical Coupling ◽  
Piezoelectric Materials ◽  
Fluid Velocity ◽  
Pipe Conveying Fluid ◽  
Performance Predictions ◽  
Parametric Studies ◽  
Cycle Oscillation ◽  
And Performance ◽  
The Galerkin Method ◽  
Conveying Fluid

In this article, a nonlinear model was developed for a cantilevered piezoelectric pipe conveying fluid that included geometric nonlinearity and electromechanical coupling. The Galerkin method discretized the system in order to characterize its behavior. Critical flutter velocity and its associated unstable mode can be determined based on linear analysis. Due to the presence of piezoelectric materials, the critical flutter velocity depends on the resistive piezoelectric damping and electromechanical coupling. This added resistive piezoelectric damping tends to decrease the flutter velocity. Comprehensive simulations were also conducted to characterize the post-flutter behaviors. System parameters including amplitude, deformed pipe shape, and collected voltage in piezoelectric materials were calculated. The system will undergo limited cycle oscillation when the fluid velocity passes the flutter velocity. Parametric studies were conducted as well to investigate the system responses under different flow velocities. Physical insights can be collected from these simulation results to conduct piezoelectric pipe design and performance predictions for future pipe vibration control and energy harvesting applications.

Dynamics of a Rod-Fastened Rotor Considering the Bolt Loosening Effect

2019 ◽  
Author(s):  
Pu Li ◽  
Qi Yuan ◽  
Bingxi Zhao ◽  
Jin Gao
Keyword(s):  
Dynamic Response ◽  
Gas Turbines ◽  
Equations Of Motion ◽  
Bending Moment ◽  
Extreme Condition ◽  
Superposition Method ◽  
Mode Superposition Method ◽  
Joint Element ◽  
Bolt Loosening ◽  
Fundamental Insight

Abstract Rod-fastened rotors are widely applied in heavy duty gas turbines and aircraft engines due to a good stiffness-to-weight behavior compared to conventional forged rotors. In order to achieve a continuous and stable power output, it is critical to guarantee the mechanical integrity. Therefore, the clamping force is of great importance which influences the distribution of the contact pressure. In an extreme condition, the bolt loosening resulting in an additional bending moment entails a different dynamic response. In this paper, the dynamics of a rod-fastened rotor subjected to the unbalance force, combined loads from the residual bow as well as the bolt loosening will be analyzed. First of all, an accurate rod-fastened rotor model is generated incorporating 1D beam element and zero-length joint element. Next, the mode superposition method is applied to derive the equations of motion and the analytical solution of the rod-fastened rotor will be achieved. Furthermore, experimental results are used to verify the simulations. It has demonstrated that the rod loosening yields a remarkably different behavior compared to the normal rotor after balancing. The dynamic response is also closely dependent on the unbalance as well as the relative phase angle between the location of unbalance and rod loosening. This paper provides a fundamental insight into the steady response of the rod-fastened rotor and may be used for fault identification as well as balancing of combined rotors.

Dynamic Response of the Pipe Conveying Fluid with the Pressure Pulsation

2015 ◽  
Vol 1094 ◽  
pp. 491-494 ◽  
Author(s):  
Hong Bo Zhai ◽  
Jian Jun Su ◽  
Xiao Min Yan ◽  
Wei Liu
Keyword(s):  
Dynamic Response ◽  
Pressure Pulsation ◽  
Fluid Pressure ◽  
Response Characteristic ◽  
Pipe Conveying Fluid ◽  
Hydraulic Power ◽  
Working Pressure ◽  
Pipe System ◽  
Output Pressure ◽  
Conveying Fluid

The dynamic response characteristic of the pipe conveying fluid was researched with the fluid pressure pulsation in this article. For some hydraulic power pipe system, formed the mathematic models and the transfer matrices of the main hydraulic elements based on the fluid network algorithm, deduced the calculation formulae of input-output pressure pulsation, gained the transitive relationship of the fluid flow pulsation and pressure pulsation, and then studied the pressure pulsation amplitude of the hydraulic power pipes with different working pressures. This study, which analyzed the dynamic response of the pipe conveying fluid and discussed the feasibility of increasing the working pressure, is valuable for the design and the application of the pipes conveying fluid.

Dynamic Response of Functionally Graded Circular Cylindrical Shells

2008 ◽  
Vol 47-50 ◽  
pp. 608-611 ◽  
Author(s):  
Seyyed Mohammad Reza Khalili ◽  
K. Malekzadeh ◽  
A. Davar
Keyword(s):  
Dynamic Response ◽  
Power Law ◽  
Volume Fraction ◽  
Shear Deformation Theory ◽  
Functionally Graded ◽  
Geometrical Parameters ◽  
Superposition Method ◽  
Equilibrium Equations ◽  
Mode Superposition Method ◽  
Impulse Load

In this paper the response of circular cylindrical shell made of Functionally Graded Material (FGM) subjected to lateral impulse load was investigated. The effective material properties are assumed to vary continuously along the thickness direction according to a volume fraction power law distribution. First order shear deformation theory (FSDT) and Love's first approximation theory were utilized in the equilibrium equations. The boundary condition was considered to be simply supported. Displacement components are product of functions of position and time. Equilibrium equations for free and forced vibrations were solved using the Galerkin method. The impulse load in the form of time varying uniform pressure was applied onto a small rectangular area of the shell surface. The function of time for displacement components is obtained using the results of free vibration and convolution integral. Finally time response of displacement components is derived using mode superposition method. The influence of material composition (power law exponent), geometrical parameters (length to radius and radius to thickness ratios) and load parameters (position and size of the area of the applied load and peak pressure value for different pulse type) on the dynamic response was investigated.

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