Critical load, dynamic characteristics and parametric instability of electrorheological material-based adaptive beams

2005 ◽  
Vol 83 (25-26) ◽  
pp. 2162-2174 ◽  
Author(s):  
Zi-Fong Yeh ◽  
Yan-Shin Shih
Keyword(s):  
Critical Load ◽  
Dynamic Characteristics ◽  
Parametric Instability ◽  
Electrorheological Material

Dynamics Design of the Aero-Engine Rotor Joint Structures Based on Experimental and Numerical Study

2010 ◽  
Author(s):  
Shuguo Liu ◽  
Jun Wang ◽  
Jie Hong ◽  
Dayi Zhang
Keyword(s):  
Critical Load ◽  
Dynamic Characteristics ◽  
External Load ◽  
Structural Parameter ◽  
Contact State ◽  
Rotor Imbalance ◽  
Fatigue Damage Accumulation ◽  
Study Results ◽  
Aero Engine ◽  
Rotor Dynamic

This study investigated the rigidity and contact state of joint structures that influenced the rotor dynamic characteristics and imbalance response, and the curve for variable structure parameters and the external load. The consideration of rotor joint structures dynamics design was also discussed. The finite-element models were established by using 3D solid elements and surface-to-surface nonlinear contact elements between the interfaces for numerical analysis. The rotor dynamic characteristics were affected by the rigidity of joint structures, and the rotor imbalance response was affected by the contact state of the interfaces. The experimentation for measuring the static rigidity and dynamic contact state of bolted joints with different experimental cycles were performed. Both numerical simulation and experimental results showed that: Firstly, the stiffness of joint structures was not constant. There was a critical load Fcr, when the external load was less than Fcr, the stiffness of joint structures was K1; when the external load was more than Fcr, the bend stiffness of joint structures would drop to K2. The critical load Fcr was influenced by the length of interfaces and preload. Secondly, the contact state of joint structure interfaces varied after a long time of operating with alternating loads. The rotor imbalance was increased by fatigue damage accumulation and irreversible deformation. The study results show that the rigidity and contact state of joint structures vary with external loads and geometry structures, and would affect the rotor system operating. It is advisable to consider the influence of the position, structural parameter and external load of the rotor joint structures on aero-engine structure dynamics design.

scholarly journals Nonlinear Dynamics of an Electrorheological Sandwich Beam with Rotary Oscillation

2012 ◽  
Vol 2012 ◽  
pp. 1-17 ◽  
Author(s):  
Kexiang Wei ◽  
Wenming Zhang ◽  
Ping Xia ◽  
Yingchun Liu
Keyword(s):  
Dynamic Characteristics ◽  
Loss Factor ◽  
Natural Frequencies ◽  
Multiple Scales ◽  
Parametric Instability ◽  
Sandwich Beam ◽  
The Finite Element Method ◽  
Rotating Beam ◽  
Flexible Beams ◽  
Instability Regions

The dynamic characteristics and parametric instability of a rotating electrorheological (ER) sandwich beam with rotary oscillation are numerically analyzed. Assuming that the angular velocity of an ER sandwich beam varies harmonically, the dynamic equation of the rotating beam is first derived based on Hamilton's principle. Then the coupling and nonlinear equation is discretized and solved by the finite element method. The multiple scales method is employed to determine the parametric instability of the structures. The effects of electric field on the natural frequencies, loss factor, and regions of parametric instability are presented. The results obtained indicate that the ER material layer has a significant effect on the vibration characteristics and parametric instability regions, and the ER material can be used to adjust the dynamic characteristics and stability of the rotating flexible beams.

Experimental Investigation on Dynamic Characteristics of a FEAD System: Affected by Serpentine Belt Length

2010 ◽  
Vol 34-35 ◽  
pp. 533-537 ◽  
Author(s):  
Xiang Kun Zeng ◽  
Wen Bin Shangguan
Keyword(s):  
Dynamic Characteristics ◽  
Transverse Vibration ◽  
Parametric Instability ◽  
Slip Rate ◽  
Transverse Displacement ◽  
Rotational Angle ◽  
Automotive Engine ◽  
Serpentine Belt ◽  
Multifrequency Excitations ◽  
Belt System

Serpentine belt is widely used in the front end accessory drive (FEAD) system of automotive engine. Experimental setup and dynamic behaviors of a FEAD system are demonstrated in this paper. Some dynamic characteristics are investigated, subjected to multifrequency excitations and different crankshaft (CRK) loads. Experimental results show that the parametric instability of belt transverse vibration occurs mainly in the frequency regions of secondary resonance, and the instability regions are shifted to lower frequencies according to the increasing of CRK speed. With the same CRK load and speed, the rotational angle of tensioner arm, the hubload of tensioner pulley and the slip rate of ALT pulley in the short-belt system are smaller than that in the long-belt system. But with the increase of CRK loads, the parametric instability of belt transverse vibration in the short-belt system is stronger than that in the long-belt system, the higher CRK speed, the greater belt transverse displacement.

Invited PaperTemperature dependence of SiGe HBT static and dynamic characteristics

1998 ◽  
Vol 08 (PR3) ◽  
pp. Pr3-81-Pr3-86
Author(s):  
F. Aniel ◽  
N. Zerounian ◽  
A. Gruhle ◽  
C. Mähner ◽  
G. Vernet ◽  
...  
Keyword(s):  
Dynamic Characteristics ◽  
Static And Dynamic Characteristics ◽  
Sige Hbt

Some Dynamic Characteristics of Binary Near-Earth Asteroids

2017 ◽  
Vol 13 (1) ◽  
pp. 30-33
Author(s):  
N.V. Ivanenko ◽  
◽  
О.A. Bazyey ◽  
Keyword(s):  
Dynamic Characteristics ◽  
Near Earth Asteroids
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