Intentional Mistuning Design Space Reduction Based on Vibration Energy Flow in Bladed Disks

2004 ◽  
Author(s):  
Sang-Ho Lim ◽  
Matthew P. Castanier ◽  
Christophe Pierre
Keyword(s):  
Energy Flow ◽  
Design Space ◽  
Flow Analysis ◽  
Design Guidelines ◽  
Vibration Energy ◽  
Bladed Disk ◽  
Space Reduction ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Random Mistuning

Intentional mistuning is the deliberate incorporation of blade-to-blade parameter variations in the nominal design of a bladed disk. Previous studies have shown that this is a promising strategy for mitigating the damaging effects of unintended, random mistuning. In this paper, the mechanisms of intentional mistuning are studied by investigating the relation between blade response and vibration energy flow in lumped parameter models. Based on key observations from the energy flow analysis, a few design guidelines are proposed that drastically reduce the design space for intentional mistuning patterns. Thus, an optimization may be performed on the reduced design space or skipped altogether, yielding dramatic reductions in computational costs. The guidelines are validated by extensive Monte Carlo simulations for the lumped parameter models as well as for a finite-element-based reduced-order model of an industrial rotor. It is shown that the reduced design space includes optimal or near-optimal intentional mistuning patterns.

Vibration Localization Analysis of Bladed Disk with Grouped Blades

2010 ◽  
Vol 139-141 ◽  
pp. 2307-2311
Author(s):  
Ai Lun Wang ◽  
Bo Hai Sun ◽  
Jin Bo Chen
Keyword(s):  
Natural Frequency ◽  
Vibration Localization ◽  
Bladed Disk ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Periodic Groups ◽  
Localization Analysis ◽  
Random Mistuning ◽  
Nature Frequency ◽  
Grouped Blades

Vibration localization of bladed disk turns to be much complex when a number of blades are assembled into periodic groups. This work focused on natural frequency distribution and modal localization of bladed disks with grouped blades based on the lumped parameter models, and effects of the blade number in each group on natural frequency were studied. Then Monte Carlo method was applied to analyze the sensitivity of modal localization to the random mistuning of blade stiffness. The results show that the number of blades in each group influences the nature frequency of bladed disk with grouped blades, and modal localization of tuned bladed disk with grouped blades is found in the closely spaced modal region. Moreover, compared to the bladed disk with free blades, the modal localization of bladed disk with grouped blades is much less sensitive to random mistuning of blade stiffness.

Theoretical Study of the Vibration Suppression on a Mistuned Bladed Disk Using a Bi-periodic Piezoelectric Network

2018 ◽  
Vol 35 (1) ◽  
pp. 17-28 ◽  
Author(s):  
Lin Li ◽  
Pengcheng Deng ◽  
Jiuzhou Liu ◽  
Chao Li
Keyword(s):  
Vibration Suppression ◽  
Robustness Analysis ◽  
Forced Response ◽  
Lumped Parameter Model ◽  
Modal Assurance Criterion ◽  
Vibration Localization ◽  
Bladed Disk ◽  
Lumped Parameter ◽  
Random Mistuning ◽  
Response Amplification

AbstractThe paper deals with the vibration suppression of a bladed disk with a piezoelectric network. The piezoelectric network has a different period (so called bi-period) from that of the bladed disk and there is no inductor in it. The system is simulated by an electromechanical lumped parameter model with two DOFs per sector. The research focuses on suppressing the amplitude magnification or reducing the vibration localization of the mistuned bladed disk. The dynamic equations of the system are derived. Both mechanical mistuning and electrical mistuning have been taken into account. The Modified Modal Assurance Criterion (MMAC) is used to evaluate the vibration suppression ability of the bi-periodic piezoelectric network. The Monte Carlo simulation is used to calculate the MMAC of the system with the random mistuning. As a reference, the forced responses of the bladed disk with and without the piezoelectric network are given. The results show that the piezoelectric network would effectively suppress amplitude magnification induced by mistuning. The vibration amplitude is even smaller than that of the tuned system. The robustness analysis shows that the bi-periodic piezoelectric network can provide a reliable assurance for avoiding the forced response amplification of the mistuned bladed disk. The amplified response induced by the mechanical mistuning with standard deviation 0.2 can be effectively suppressed through the bi-periodic piezoelectric network.

Measurement of Vibration Power Flow through Elastomeric Powertrain Mounts in Passenger Car

2013 ◽  
Vol 471 ◽  
pp. 30-34
Author(s):  
Mohd Noor Arib Rejab ◽  
Roslan Abdul Rahman ◽  
Raja Ishak Raja Hamzah ◽  
Jawaid Iqbal Inayat Hussain ◽  
Nazirah Ahmad ◽  
...  
Keyword(s):  
Energy Flow ◽  
Power Flow ◽  
Engine Speed ◽  
Flow Analysis ◽  
Load Condition ◽  
Vertical Direction ◽  
Vibration Energy ◽  
Vibration Source ◽  
Vibration Power Flow ◽  
Flow Through

The effectiveness of vibration isolator or mount can be done by quantifying the vibration energy flow through the isolators. This can provide information on the quantification of the vibration energy flow from the powertrain to the structure or chassis. Vibration energy flow through mount is identified as vibration power flow that is one of vibration transmission paths. This paper presents vibration power flow through four elastomeric mount. The vibration (source and receiver of accelerations) was measured by running engine at constant speed and without load conditions in varying speeds starting from 1050 RPM to 4000 RPM. The vibration was measured only in z-direction (vertical direction). The noise inside compartment was measured at the condition of engine run-up without load condition and was measured starting from 1050 RPM to 4000 RPM engine speed. The results from vibration power flow analysis showed that the main vibration energy transmission was high from front mount and rear mount, around engine speed 3200 RPM, and booming noise occurred around 3200 RPM due to structure-borne noise.

A Mistuning Sensitivity Suppression Method of Bladed Disk

2012 ◽  
Vol 479-481 ◽  
pp. 1350-1354
Author(s):  
Yi Xuan Li ◽  
Chuang Shao ◽  
Zhi Jun Zhang
Keyword(s):  
Element Model ◽  
Vibration Response ◽  
Modal Shape ◽  
Free System ◽  
Response Characteristics ◽  
Bladed Disk ◽  
Lumped Parameter ◽  
Random Mistuning ◽  
Suppression Method ◽  
Shape Characteristics

Based on the lumped parameter modal, the modal shape characteristics of the tuned free bladed disk and the random mistuned bladed disk was studied. It can be concluded that the vibration energy is evenly distributed in the tuned free system, but in the mistuned system, the modal localization dose exist. And the localization degree gets stronger while the mistuning strength is bigger .Then based on the finite element model of a bladed disk. The intentional mistuning technology’s role in reducing the sensitivity of the bladed disk to random mistuning was studied in this paper. The blades vibration response characteristics and the intentional mistuning technology was also studied through magnification factor for amplitude and localization factor. The result shows that the mistuning sensitivity level can be reduced by adding the quantity of intentional mistuning, and intentional mistuning has an important meaning to reduce the adverse effect of the random mistuning to the blades vibration response.

Effects of Harmonic Intentional Mistuning on the Free Response of Bladed Disks

1999 ◽  
Author(s):  
Michael E. Brewer ◽  
Matthew P. Castanier ◽  
Christophe Pierre
Keyword(s):  
Forced Response ◽  
Lumped Parameter Model ◽  
Free Response ◽  
Bladed Disks ◽  
Nodal Diameter ◽  
Bladed Disk ◽  
Lumped Parameter ◽  
Engine Order ◽  
Bladed Disk Assembly ◽  
Random Mistuning

Abstract In this paper, the free response of bladed disks with intentional mistuning is considered in detail. A simple lumped-parameter model of a bladed disk is employed. Intentional mistuning is included by applying a sinusoidal variation to the nominal blade stiffnesses. It is shown that if the intentional mistuning harmonic number and the number of blades have a common integer factor greater than one, then the eigenvalue problem reduces to a set of smaller problems. It is found that the ratio of intentional mistuning strength to the interblade coupling strength is a key parameter for the free response. As this ratio increases, the modes become localized. More importantly, the modes of the intentionally mistuned system have several non-zero nodal diameter components, in contrast to the tuned system which has pure nodal diameter modes. Furthermore, if only random mistuning is present, each mode of the bladed disk assembly still retains a strong nodal diameter component. However, the modes of the system with intentional mistuning and random mistuning tend to have more evenly distributed nodal diameter components. This shows why intentional mistuning can be effective in reducing the maximum blade forced response for engine order excitation.

Energy flow analysis of straw-return agricultural modes in the Central Shaanxi Plain

2013 ◽  
Vol 20 (10) ◽  
pp. 1388-1393
Author(s):  
Bi JIANG ◽  
Fa-Qi WU ◽  
Xi-Hui WU ◽  
Ming LI ◽  
Xiao-Gang TONG
Keyword(s):  
Energy Flow ◽  
Flow Analysis ◽  
Energy Flow Analysis ◽  
Straw Return
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