Energy Extraction-Based Robust Linear Quadratic Gaussian Control of Acoustic-Structure Interaction in Three-Dimensional Enclosure

2014 ◽  
Vol 136 (4) ◽  
Author(s):  
F. Liu ◽  
B. Fang ◽  
A. G. Kelkar
Keyword(s):  
Three Dimensional ◽  
Boundary Surface ◽  
Acoustic Energy ◽  
Linear Quadratic ◽  
Linear Quadratic Gaussian ◽  
Acoustic Structure ◽  
Structure Interaction ◽  
Weighting Matrix ◽  
Simulation And Experiment ◽  
Identification Techniques

This paper presents an linear quadratic Gaussian (LQG)-based robust control strategy for active noise reduction in a 3D enclosure wherein acoustic-structure interaction dynamics is present. The acoustic disturbance is created by the piezo-actuated vibrating boundary surface of the enclosure. The control signal is generated by the speaker which is noncollocated with the sensing microphone mounted inside the enclosure. The dynamic model of the system is obtained using frequency-domain system identification techniques. The state weighting matrix in the LQG cost function is determined analytically in the closed-form which allows the control designer to directly penalize the total acoustic energy of the system. The robustness of the controller is also ensured to guarantee the closed-loop stability against the unmodeled dynamics and parametric uncertainties. Simulation and experiment results are given which demonstrate the effectiveness of the proposed control methodology.

Acoustic-Structure Interaction in an Adaptive Helmholtz Resonator by Compliance and Constraint

2019 ◽  
Vol 142 (2) ◽  
Author(s):  
Shichao Cui ◽  
Ryan L. Harne
Keyword(s):  
Flexible Structures ◽  
Helmholtz Resonator ◽  
Acoustic Resonator ◽  
Acoustic Energy ◽  
Coupled Resonators ◽  
Acoustic Structure ◽  
Structure Interaction ◽  
Helmholtz Resonators ◽  
Rigid Walls ◽  
Flexible Member

Abstract The acoustic energy attenuation capabilities of traditional Helmholtz resonators are enhanced by various methods, including by coupled resonators, absorbing materials, or replacement of rigid walls with flexible structures. Drawing from these concepts to envision a new platform of adaptive Helmholtz resonator, this research studies an adaptive acoustic resonator with an internal compliant structural member. The interaction between the structure and acoustic domain is controlled by compression constraint. By applying uniaxial compression to the resonator, the flexible member may be buckled, which drastically tailors the acoustic-structure interaction mechanisms in the overall system. A phenomenological analytical model is formulated and experimentally validated to scrutinize these characteristics. It is found that the compression constraint may enhance damping capabilities of the resonator by adapting the acoustic-structure interaction between the resonator and the enclosure. The area ratio of the flexible member to the resonator opening and the ratio of the fundamental natural frequency of the flexible member to that of the enclosure are discovered to have a significant influence on the system behavior. These results reveal new avenues for acoustic resonator concepts exploiting compliant internal structures to tailor acoustic energy attenuation properties.

scholarly journals Fluid–structure interaction in a fully coupled three-dimensional mitral–atrium–pulmonary model

2021 ◽  
Author(s):  
Liuyang Feng ◽  
Hao Gao ◽  
Nan Qi ◽  
Mark Danton ◽  
Nicholas A. Hill ◽  
...  
Keyword(s):  
Mitral Valve ◽  
Left Atrium ◽  
Left Atrial ◽  
Left Atrial Appendage ◽  
Pulmonary Veins ◽  
Three Dimensional ◽  
Left Heart ◽  
Structure Interaction ◽  
Acute Mitral Regurgitation ◽  
Reversal Flow

AbstractThis paper aims to investigate detailed mechanical interactions between the pulmonary haemodynamics and left heart function in pathophysiological situations (e.g. atrial fibrillation and acute mitral regurgitation). This is achieved by developing a complex computational framework for a coupled pulmonary circulation, left atrium and mitral valve model. The left atrium and mitral valve are modelled with physiologically realistic three-dimensional geometries, fibre-reinforced hyperelastic materials and fluid–structure interaction, and the pulmonary vessels are modelled as one-dimensional network ended with structured trees, with specified vessel geometries and wall material properties. This new coupled model reveals some interesting results which could be of diagnostic values. For example, the wave propagation through the pulmonary vasculature can lead to different arrival times for the second systolic flow wave (S2 wave) among the pulmonary veins, forming vortex rings inside the left atrium. In the case of acute mitral regurgitation, the left atrium experiences an increased energy dissipation and pressure elevation. The pulmonary veins can experience increased wave intensities, reversal flow during systole and increased early-diastolic flow wave (D wave), which in turn causes an additional flow wave across the mitral valve (L wave), as well as a reversal flow at the left atrial appendage orifice. In the case of atrial fibrillation, we show that the loss of active contraction is associated with a slower flow inside the left atrial appendage and disappearances of the late-diastole atrial reversal wave (AR wave) and the first systolic wave (S1 wave) in pulmonary veins. The haemodynamic changes along the pulmonary vessel trees on different scales from microscopic vessels to the main pulmonary artery can all be captured in this model. The work promises a potential in quantifying disease progression and medical treatments of various pulmonary diseases such as the pulmonary hypertension due to a left heart dysfunction.

Modeling of aortic valve stenosis using fluid-structure interaction method

Perfusion ◽  
2021 ◽  
pp. 026765912199854
Author(s):  
Mohammad Javad Ghasemi Pour ◽  
Kamran Hassani ◽  
Morteza Khayat ◽  
Shahram Etemadi Haghighi
Keyword(s):  
Blood Flow ◽  
Aortic Valve ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Relaxation Phase ◽  
Exercise Condition ◽  
Time Dependent Domain ◽  
Comparison Of The Results

Background and objectives: Fluid structure interaction (FSI) is defined as interaction of the structures with contacting fluids. The aortic valve experiences the interaction with blood flow in systolic phase. In this study, we have tried to predict the hemodynamics of blood flow through a normal and stenotic aortic valve in two relaxation and exercise conditions using a three-dimensional FSI method. Methods: The aorta valve was modeled as a three-dimensional geometry including a normal model and two others with 25% and 50% stenosis. The geometry of the aortic valve was extracted from CT images and the models were generated by MMIMCS software and then they were implemented in ANSYS software. The pulsatile flow rate was used for all cases and the numerical simulations were conducted based on a time-dependent domain. Results: The obtained results including the velocity, pressure, and shear stress contours in different systolic time sequences were explained and discussed. The maximum blood flow velocity in relaxation phase was obtained 1.62 m/s (normal valve), 3.78 m/s (25% stenosed valve), and 4.73 m/s (50% stenosed valve). In exercise condition, the maximum velocities are 2.86, 4.32, and 5.42 m/s respectively. The maximum blood pressure in relaxation phase was calculated 111.45 mmHg (normal), 148.66 mmHg (25% stenosed), and 164.21 mmHg (50% stenosed). However, the calculated values in exercise situation were 129.57, 163.58, and 191.26 mmHg. The validation of the predicted results was also conducted using existing literature. Conclusions: We believe that such model are useful tools for biomechanical experts. The further studies should be done using experimental data and the data are implemented on the boundary conditions for better comparison of the results.

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