VIBRATION ATTENUATION VIA CONSTRAINED LAYER DAMPING AND DASHPOT ON A SPRING–MASS–PLATE SYSTEM

2003 ◽  
Vol 259 (5) ◽  
pp. 1181-1198 ◽  
Author(s):  
S.-C YU ◽  
S.-C HUANG
Keyword(s):  
Constrained Layer Damping ◽  
Vibration Attenuation ◽  
Plate System

Effectiveness of Active Constrained Layer Damping Treatments in Attenuating Resonant Oscillations

2002 ◽  
Vol 8 (6) ◽  
pp. 747-775 ◽  
Author(s):  
Farhan Gandhi ◽  
Brian Munsky
Keyword(s):  
Excitation Level ◽  
Viscoelastic Layer ◽  
Constrained Layer Damping ◽  
Velocity Feedback ◽  
Vibration Attenuation ◽  
Position Feedback ◽  
Active Constrained Layer Damping ◽  
Excitation Force ◽  
Viscoelastic Layers ◽  
Active Constrained Layer

This paper highlights the importance of considering the piezoelectric constraining layer voltage (or electric field) limits when evaluating the effectiveness of an active constrained layer damping treatment in attenuating resonant vibration. It is seen that, when position feedback is used, intermediate viscoelastic layer stiffness values are always optimal, and maximum allowable control gains and possible vibration attenuation progressively decrease with increasing excitation force levels. On the other hand, with velocity feedback, the optimal viscoelastic layer stiffness is dependent on the excitation level. For low excitation force amplitudes, stiff viscoelastic layers are most effective, with large velocity feedback gains producing substantial vibration attenuation without exceeding piezoelectric layer voltage limits. However, for higher excitation force levels, stiff viscoelastic layers result in excess voltages even at very small velocity feedback gains, and are unable to provide any vibration attenuation. In such a case, intermediate viscoelastic layer stiffness values are preferable, and maximum velocity feedback gains and possible vibration attenuation progressively decrease with increasing excitation level, as in the case of position feedback. For both position and velocity feedback, when excitation forces are beyond a certain level the allowable control gains are so limited that no additional damping is obtained beyond that already available through the passive treatment.

Analyses of multi-bandgap property of a locally resonant plate composed of periodic resonant subsystems

2018 ◽  
Vol 32 (24) ◽  
pp. 1850269 ◽  
Author(s):  
Qi Qin ◽  
Mei-Ping Sheng
Keyword(s):  
Unit Element ◽  
Vibration Modes ◽  
Plane Wave Expansion ◽  
Flexural Waves ◽  
Bandgap Width ◽  
Finite Plate ◽  
Vibration Attenuation ◽  
Different Types ◽  
Periodic Element ◽  
Plate System

A locally resonant (LR) plate made up of a thin plate attached with different types of resonators is analyzed in this paper. Each periodic element may consist of one or more spring-mass resonators attached onto one and the same surface of the plate lattice. The correctness of theoretical plane wave expansion (PWE) method adopted in this paper is validated through the comparisons with the classical theory and finite element method (FEM). When composing the LR plate system with two types of periodic resonant subsystems, there will appear two complete bandgaps, while other additional resonators may cause mainly directional gaps, calculated theoretically and numerically. From the comparisons of band-structure curves between a two-resonator-per-unit-element (TR-UE) system and both corresponding one-resonator-per-unit-element (OR-UE) systems, the bandgap width of the TR-UE system are not stacking effects of two OR-UE systems due to resonance interaction of different types of resonators. Moreover, via the deformation contours by FEM, the correspondence between the vibration modes of subsystems and the bandgap frequencies is demonstrated. The finite plate with limited resonators of two periodic types of parameters is modeled to show visually how flexural waves propagate within/without the bandgaps. Further, by adjusting the damping characteristic of both types of resonators, vibration attenuation band can be broadened widely.

Uncertainty Quantification of Vibration Attenuation with Shunted Piezo Patches

2019 ◽  
Author(s):  
Walid Larbi ◽  
Jean-François Deü ◽  
Roberta Lima ◽  
Rubens Sampaio
Keyword(s):  
Uncertainty Quantification ◽  
Vibration Attenuation

scholarly journals Complications of Poly-l-Lactic Acid and Polyglycolic Acid (PLLA/PGA) Osteosynthesis Systems for Maxillofacial Surgery: A Retrospective Clinical Investigation

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 889
Author(s):  
Yuhei Matsuda ◽  
Masaaki Karino ◽  
Tatsuo Okui ◽  
Takahiro Kanno
Keyword(s):  
Postoperative Complications ◽  
Clinical Investigation ◽  
Maxillofacial Surgery ◽  
Multivariate Logistic Regression Analysis ◽  
Polyglycolic Acid ◽  
Oral And Maxillofacial Surgery ◽  
Low Incidence ◽  
Adjusted Model ◽  
Pyriform Aperture ◽  
Plate System

Two second-generation PLLA/PGA bioresorbable osteosynthetic plate systems for oral and maxillofacial surgery are available in Japan. The two systems have different PLLA-PGA component ratios (RapidSorb®, 85:15; Lactosorb®, 82:18) and plate and screw shapes. We conducted a retrospective study to compare our clinical evaluation and examine the incidence of postoperative complications between the two plate systems. A retrospective survey was conducted in 148 patients (midfacial fracture/trauma (68.2%) and dentofacial deformity patients (31.8%); males (54.7%); median age, 37.5 years) treated using maxillofacial osteosynthetic plate systems. The complications included plate exposure (7.4%), infection, (2.7%), and plate breakage (0.7%). Multivariate logistic regression analysis showed a significant correlation between sex (female), plate system (Lactosorb®), number of plates, and pyriform aperture and periorbital sites of plate placement (p < 0.05). Additionally, the propensity score-adjusted model showed a significant correlation between Lactosorb® and postoperative complications (odds ratio 1.007 (95% confidence interval, 1.001–1.055), p < 0.01). However, the two plate systems showed a low incidence rate of complications, and the plate integration and survivability were similar using 2.0-mm or 1.5-mm resorbable plate regardless of the plate system. Our findings suggest that female sex and a greater number of plates are risk factors for postoperative complications, whereas pyriform aperture and periorbital plate placements reduce the risk.

scholarly journals Review of the Upright Balance Assessment Based on the Force Plate

2021 ◽  
Vol 18 (5) ◽  
pp. 2696
Author(s):  
Baoliang Chen ◽  
Peng Liu ◽  
Feiyun Xiao ◽  
Zhengshi Liu ◽  
Yong Wang
Keyword(s):  
Postural Balance ◽  
Force Plate ◽  
Assessment Method ◽  
Balance Assessment ◽  
Experimental Conditions ◽  
Methodological Research ◽  
Assessment Tests ◽  
Wide Range ◽  
Foot Posture ◽  
Plate System

Quantitative assessment is crucial for the evaluation of human postural balance. The force plate system is the key quantitative balance assessment method. The purpose of this study is to review the important concepts in balance assessment and analyze the experimental conditions, parameter variables, and application scope based on force plate technology. As there is a wide range of balance assessment tests and a variety of commercial force plate systems to choose from, there is room for further improvement of the test details and evaluation variables of the balance assessment. The recommendations presented in this article are the foundation and key part of the postural balance assessment; these recommendations focus on the type of force plate, the subject’s foot posture, and the choice of assessment variables, which further enriches the content of posturography. In order to promote a more reasonable balance assessment method based on force plates, further methodological research and a stronger consensus are still needed.

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