Nonlinear Vibration Characteristics and Optimization Analysis of Diaphragm Pump Mass Valves

2021 ◽  
pp. 834-844
Author(s):  
Jiameng Zhang ◽  
Tao Chen ◽  
Fangzhong Li ◽  
Wensheng Ma ◽  
Chunchuan Liu
Keyword(s):  
Nonlinear Vibration ◽  
Vibration Characteristics ◽  
Optimization Analysis ◽  
Diaphragm Pump

Nonlinear Vibration Characteristics of Helical Spring

2010 ◽  
Vol 29-32 ◽  
pp. 1317-1322
Author(s):  
Nan Nan Wang ◽  
You Fu Hou ◽  
Zu Zhi Tian
Keyword(s):  
Nonlinear Vibration ◽  
Constitutive Relations ◽  
Low Frequency ◽  
Vibration Characteristics ◽  
Rigid Body Dynamics ◽  
Helical Spring ◽  
Low Frequency Vibration ◽  
Near Resonance ◽  
Finite Element Technology ◽  
Dynamics Response

A helical spring has large deformation under the condition of near resonance, in order to obtain the nonlinear vibration characteristics, the single-integral constitutive relations of helical spring based on nonlinear theory are discussed firstly, then nonlinear dynamic characteristics of helical spring are analyzed based on finite element technology. Finally, the dynamic simulation associated with flexible characteristics for helical spring is studied in ADAMS. The results show that the maximum stress of helical spring appears at transition region between different radius which is consistent with fracture position actually. Flexible dynamic response of helical spring mainly behaves low frequency vibration which is different from rigid body dynamics response.

Nonlinear vibration characteristics of the rotor bearing system with bolted flange joints

2019 ◽  
Vol 233 (4) ◽  
pp. 910-930
Author(s):  
Yifu Zhou ◽  
Zhong Luo ◽  
Zifang Bian ◽  
Fei Wang
Keyword(s):  
Nonlinear Vibration ◽  
Time Domain ◽  
Harmonic Balance ◽  
Harmonic Balance Method ◽  
Rolling Bearing ◽  
Vibration Characteristics ◽  
Rotor System ◽  
Rotor Bearing ◽  
Bolted Flange ◽  
Bearing System

As sophisticated mechanical equipment, the rotor system of aero-engine is assembled by various parts; bolted flange joints are one of the essential ways of joints. Aiming at the analysis of the nonlinear vibration characteristics of the rotor-bearing system with bolted flange joints, in this paper, a finite element modeling method for a rotor-bearing system with bolted flange joints is proposed, and an incremental harmonic balance method combined with arc length continuation is proposed to solve the dynamic solution of the rotor system. In order to solve the rotor system with rolling bearing nonlinearity, the alternating frequency/time-domain process of the rolling bearing element is deduced. Compared with the conventional harmonic balance method and the time-domain method, this method has the characteristics of fast convergence and high computational efficiency; solving the rotor system with nonlinear bearing force; overcome the shortcoming that the frequency–response curve of the system is too sharp to continue solving. By using this method, the influence of bearing clearance and stiffness on vibration characteristics of the rotor system with bolted flange joints is studied. The evolution law of the state of the rotor system with bolt flange is investigated through numerical simulation and experimental data. The results indicated that the modeling and solving method proposed in this paper could accurately solve the rotor-bearing system with bolted flange joints and analyze its vibration characteristics.

scholarly journals Nonlinear dynamical behaviors of a moving membrane under external excitation

2018 ◽  
Vol 37 (4) ◽  
pp. 774-788
Author(s):  
Mingyue Shao ◽  
Jimei Wu ◽  
Yan Wang ◽  
Shudi Ying
Keyword(s):  
Nonlinear Vibration ◽  
Plate Theory ◽  
State Equation ◽  
Vibration Characteristics ◽  
The State ◽  
External Excitation ◽  
Nonlinear Dynamical ◽  
Runge Kutta Method ◽  
Time Histories ◽  
The Stability

In this paper, the nonlinear vibration characteristics of a moving printing membrane under external excitation are studied. Based on the Von Karman nonlinear plate theory, the nonlinear vibration equation of the axial motion membrane under the external excitation is deduced. The Galerkin’s method is used to discretize the vibration differential equations of the membrane, and then the state equation of the system is obtained. The state equation of the system is numerically solved by the fourth-order Runge–Kutta method. The relationship between the nonlinear vibration characteristics and the amplitude of external excitation, damping coefficient, and aspect ratio of the printing membrane is analyzed by using the time histories, phase-plane portraits, Poincare maps, and bifurcation diagrams. Chaotic intervals and the stable working range of the moving membrane are obtained. This study provides a theoretical basis for predicting and controlling the stability of the membrane.

Non-Linear Coupled Dynamics of a Flexible Propeller-Shaft System Supported by Water Film Bearings

2020 ◽  
Vol 142 (3) ◽  
Author(s):  
Chang-Gang Lin ◽  
Ming-Song Zou ◽  
Can Sima ◽  
Li-Bo Qi ◽  
Yue Yu
Keyword(s):  
Nonlinear Vibration ◽  
Damping Ratio ◽  
Water Film ◽  
Vibration Characteristics ◽  
Superposition Method ◽  
Propeller Shaft ◽  
Chaotic Motions ◽  
Mode Superposition Method ◽  
Shaft System ◽  
Slice Method

Abstract A slice method to determine the boundary conditions between the stern bearing and shaft by dividing the journal in the stern bearing into several slice elements along the axial direction is proposed for the first time. A comprehensive finite element model considering the nonlinear force of the water film and the flexibility of the propeller blade is established for a propeller-shaft system. The long bearing approximation is adopted to calculate the pressure distribution around each journal element in the stern bearing. The mode superposition method is employed. The nonlinear equation of motion is solved iteratively using the Newmark method. A parametric study is implemented to analyze the nonlinear vibration characteristics of the system. It is shown that the real motion state of the journal in the stern bearing can be simulated more precisely by the slice method proposed. The responses of the system alternate among period-one, quasi-periodic, multi-periodic, and chaotic motions as the rotating speed increases. The damping ratio has a significant effect on the dynamic characteristics of the propeller-shaft system. The motion of the system is unstable when the damping ratio is very small. At this time, the modes of the flexible propeller blades can be excited readily. The slice method, which can also be extensively used in similar rotor-bearing systems in the engineering field, is very simple and efficient to analyze the nonlinear vibration characteristics of a flexible propeller-shaft system supported by water film bearings.

Detection of a Rotor Crack Based on the Nonlinear Vibration Diagnosis Using Periodic Excitation

2005 ◽  
Author(s):  
Yukio Ishida ◽  
Tsuyoshi Inoue
Keyword(s):  
Nonlinear Vibration ◽  
Equations Of Motion ◽  
Frequency Component ◽  
Dominant Frequency ◽  
Vibration Characteristics ◽  
Periodic Excitation ◽  
Cracked Rotor ◽  
On Line ◽  
Linear And Nonlinear ◽  
Excitation Force

Detection of a rotor crack based on the nonlinear vibration diagnosis using periodic excitation force is investigated. Due to the open-close mechanism of the crack, the equations of motion of a cracked rotor have linear and nonlinear parametric terms. When a periodic excitation force is applied to the cracked rotor, various kinds of resonances due to the unique vibration characteristics of a crack. Furthermore, types of resonances, resonance points and dominant frequency component of these resonances are clarified theoretically and experimentally. These results enable us to detect a crack on-line without stopping the system.

Sign in / Sign up

Export Citation Format

Share Document