scholarly journals Exploring mechanical assonance for impact energy harvesting using acoustic metamaterials

2021 ◽  
pp. 1045389X2110482
Author(s):  
Milkyas B Afework ◽  
James M Manimala
Keyword(s):  
Numerical Study ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Building Blocks ◽  
Local Features ◽  
Host Material ◽  
Wave Transformation ◽  
Acoustic Metamaterials ◽  
Electric Voltage ◽  
Specific Loading

Acoustic metamaterials are engineered to possess unique dynamic properties that are not commonly found in nature. It has been demonstrated that customizing the characteristics of their local features can help optimize their dynamic performance under specific loading conditions. Drawing inspiration from the literary device called “assonance,” the term “mechanical assonance” may be ascribed to the dynamic phenomenon realized by sequencing oscillators with tuned responses within a waveguide to engineer a prescribed wave transformation across it. In this context, assonance provides a framework to utilize resonant local features within a host structure or material and interactive mechanisms thereof as building blocks to create enriched functionalities for acoustic metamaterials. Using a discrete element representation for an acoustic metamaterial barrier (AMB), a numerical study is conducted to ascertain parametric dependence for assonant mechanisms related to resonator frequencies, their sequencing, and host material stiffness. Normalized metrics are extracted to estimate transmitted pulse mitigation under impact-type loading. It is found that resonator sets with octave spacing having the number of resonators of a specific frequency proportional to that frequency’s amplitude in the input spectrum is desirable for lower transmissibility. Further, sequencing the lowest frequency resonator set closest to the incident-side gives better performance. Engineering a high degree of impedance mismatch between host material sections is also preferable. The energy sequestered by the local resonators can be harvested utilizing the resonator’s mass as the multifunctional kernel for a linear electromagnetic generator. A multiphysical model is developed to predict the harvested electric voltage and power from the AMB and validated using proof-of-concept experiments. Finally, various coil placement and voltage rectification schemes are also studied using simulations to ascertain preferable design configurations.

Study on the Dynamic Performance of Asphalt Concrete under Passive Confined Pressure

2012 ◽  
Vol 226-228 ◽  
pp. 1755-1759
Author(s):  
Hua Zhang ◽  
Fei Li ◽  
Yu Wei Gao
Keyword(s):  
Elastic Modulus ◽  
Asphalt Concrete ◽  
Poisson Ratio ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Dynamic Strength ◽  
Confining Pressure ◽  
Mechanical Behaviors ◽  
One Dimensional ◽  
Stress States

An improved passive confining pressure SHPB method was used to study the dynamic mechanical behaviors of asphalt concrete under quasi-one dimensional strain state. The effect of confining jacket material and its geometrical sizes on the confining pressure were discussed. The dynamic strength, dynamic modulus of elasticity and dynamic Poisson ratio of asphalt concrete were obtained. The influential rules of confining pressure on the dynamic properties were studied by comparing the stress-strain curves of asphalt concrete under different stress states. The study found that passive confining greater impact on the strength of asphalt concrete than elastic modulus and Poisson ratio, but the elastic modulus improved with the increase of confining pressure.

Numerical study and improvement of the dynamic performance of dilation x-ray imager

2021 ◽  
Vol 92 (12) ◽  
pp. 123305
Author(s):  
Qiangqiang Wang ◽  
Zhurong Cao ◽  
Tao Chen ◽  
Bo Deng ◽  
Keli Deng ◽  
...  
Keyword(s):  
Numerical Study ◽  
Dynamic Performance ◽  
X Ray

Experimental and Numerical Analyses of a Head Arm Assembly of a Micro-Drive

2006 ◽  
Vol 326-328 ◽  
pp. 1585-1588
Author(s):  
B.J. Shi ◽  
Dong Wei Shu ◽  
J. Luo ◽  
Q.Y. Ng ◽  
J.H.T. Lau
Keyword(s):  
Finite Element ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Hard Disk Drives ◽  
Element Model ◽  
Information Storage ◽  
Experimental Results ◽  
Disk Drives ◽  
Element Simulation ◽  
Important Means

Hard disk drives (HDD) are now the most important means of information storage, and they continue to be made smaller in size, higher in capacity, and lower in cost. The dynamic performance of an HDD has been an increasingly important consideration for its design, as we move forward toward its consumer applications. The dynamic properties of the head arm assembly (HAA) of a micro-drive were investigated using both experimental and numerical techniques. A finite element model for studying the dynamic property of the HAA was created and modified according to the experimental results. Good correlation between the experimental results and those by finite element simulation was achieved.

Dynamic Characteristics of Balanced Robotic Manipulators with Joint Flexibility

Robotica ◽  
1992 ◽  
Vol 10 (6) ◽  
pp. 485-495 ◽  
Author(s):  
S.B. Lee ◽  
H.S. Cho
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Robotic Manipulators ◽  
Open Loop ◽  
Joint Flexibility ◽  
Damping Characteristics ◽  
Large Joint ◽  
Joint Deformation

SUMMARYThe mass balancing of robotic manipulators has been shown to have favorable effects on the dynamic characteristics. In actual practice, however, since conventional manipulators have flexibility at their joints, the improved dynamic properties obtainable for rigid manipulators may be influenced by those joint flexibilities. This paper investigates the effects of the joint flexibility on the dynamic properties and the controlled performance of a balanced robotic manipulator. The natural frequency distribution and damping characteristics were investigated through frequency response analyses. To evaluate the dynamic performance a series of simulation studies of the open loop dynamics were made for various trajectories, operating velocities, and joint stiffnesses. These simulations were also carried out for the balanced manipulator with a PD controller built-in inside motor control loop. The results show that, at low speed, the joint flexibility nearly does not influence the performance of the balanced manipulator, but at high speed it tends to render the balanced manipulator susceptible to vibratory motion and yields large joint deformation error.

Design of Parallel Mechanisms for Flexible Manufacturing With Reconfigurable Dynamics

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
Gianmarc Coppola ◽  
Dan Zhang ◽  
Kefu Liu ◽  
Zhen Gao
Keyword(s):  
Flexible Manufacturing ◽  
Dynamic Properties ◽  
Dynamic Performance ◽  
Parallel Robot ◽  
Test Subject ◽  
Design Parameters ◽  
Parallel Mechanisms ◽  
Reconfigurable Mechanisms ◽  
Kinematic Properties ◽  
Full Simulation

Reconfigurable robotic systems can enhance productivity and save costs in the ever growing flexible manufacturing regime. In this work, the idea to synthesize robotic mechanisms with dynamic properties that are reconfigurable is studied, and a methodology to design reconfigurable mechanisms with this property is proposed, named reconfigurable dynamics (Re-Dyn). The resulting designs have not only the kinematic properties reconfigurable, such as link lengths, but also properties that directly affect the forces and accelerations, such as masses and inertias. A 2-degree of freedom (DOF) parallel robot is used as a test subject. It is analyzed and redesigned with Re-Dyn. This work also presents the robots forward dynamic model in detail, which includes the force balancing mediums. The connection method is directly utilized for this derivation, which is well suited for multibody dynamics and provides insight for design parameters (DPs). Dynamic performance indices are also briefly discussed as related to the Re-Dyn method. After redesigning the robot, a full simulation is conducted to compare performances related to a flexible manufacturing situation. This illustrates the advantages of the proposed method.

A Preliminary Analysis of Ski Release Binding Dynamic Properties

1976 ◽  
Vol 98 (3) ◽  
pp. 301-308 ◽  
Author(s):  
C. D. Mote ◽  
M. L. Hull
Keyword(s):  
Dynamic Properties ◽  
Piecewise Linear ◽  
Dynamic Performance ◽  
Performance Criteria ◽  
Loading Path ◽  
Practical Application ◽  
Binding Properties ◽  
Binding Function ◽  
Elementary Analysis ◽  
Two Degree Of Freedom

A piecewise, linear, two degree of freedom, ski release binding dynamic system model is presented for an elementary analysis of binding performance. Dynamic performance criteria and techniques for quantitative evaluation of ski release binding properties are discussed. Desirable binding properties along the loading path, where the ski and boot are separating, and desirable binding properties along the return path where the boot is returning to the ski centerline are discussed separately. General characteristics of the loading and return paths have practical application for binding function.

Experimental and Numerical Study on Dynamic Properties of Viscoelastic Microvibration Damper Considering Temperature and Frequency Effects

2016 ◽  
Vol 11 (6) ◽  
Author(s):  
Chao Xu ◽  
Zhao-Dong Xu ◽  
Teng Ge ◽  
Ya-Xin Liao
Keyword(s):  
Loss Factor ◽  
Numerical Study ◽  
Dynamic Properties ◽  
Frequency Effect ◽  
Solid Model ◽  
Temperature Dependent ◽  
Frequency Effects ◽  
Proposed Model ◽  
Different Temperatures ◽  
Increasing Temperature

This work presents an experimental and numerical study on the dynamic properties of viscoelastic (VE) microvibration damper under microvibration conditions at different frequencies and temperatures. The experimental results show that the storage modulus and the loss factor of VE microvibration damper both increase with increasing frequency but decrease with increasing temperature. To explicitly and accurately represent the temperature and frequency effects on the dynamic properties of VE microvibration damper, a modified standard solid model based on a phenomenological model and chain network model is proposed. A Gaussian chain spring and a temperature-dependent dashpot are employed to reflect the temperature effect in the model, and the frequency effect is considered with the nature of the standard solid model. Then, the proposed model is verified by comparing the numerical results with the experimental data. The results show that the proposed model can accurately describe the dynamic properties of VE microvibration damper at different temperatures and frequencies.

Characterization of Hydrophobic Forces for in Liquid Self-Assembly of Micron-Sized Functional Building Blocks

2011 ◽  
Vol 1299 ◽  
Author(s):  
M. R. Gullo ◽  
L. Jacot-Descombes ◽  
L. Aeschimann ◽  
J. Brugger
Keyword(s):  
Atomic Force Microscopy ◽  
Self Assembly ◽  
Hydrophobic Interactions ◽  
Numerical Study ◽  
Building Blocks ◽  
Dynamic Simulations ◽  
Hydrophobic Force ◽  
Force Microscopy ◽  
Molecular Arrangement ◽  
Atomic Force

ABSTRACTThis paper presents the experimental and numerical study of hydrophobic interaction forces at nanometer scale in the scope of engineering micron-sized building blocks for self-assembly in liquid. The hydrophobic force distance relation of carbon, Teflon and dodeca-thiols immersed in degassed and deionized water has been measured by atomic force microscopy. Carbon and dodeca-thiols showed comparable attractive and binding forces in the rage of pN/nm2. Teflon showed the weakest binding and no attractive force. Molecular dynamic simulations were performed to correlate the molecular arrangement of water molecules and the hydrophobic interactions measured by atomic force microscopy. The simulations showed a depletion zone of 2Å followed by a layered region of 8Å in the axis perpendicular to the hydrophobic surface.

Effective Dynamic Properties and Multi-Resonant Design of Acoustic Metamaterials

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
R. Zhu ◽  
G. L. Huang ◽  
G. K. Hu
Keyword(s):  
Dynamic Properties ◽  
Wave Dispersion ◽  
Wave Band ◽  
Energy Transfer Mechanism ◽  
Acoustic Metamaterials ◽  
Multiple Wave ◽  
Reflection And Transmission ◽  
Acoustic Metamaterial ◽  
Effective Dynamic ◽  
The Difference

In the study, a retrieval approach is extended to determine the effective dynamic properties of a finite multilayered acoustic metamaterial based on the theoretical reflection and transmission analysis. The accuracy of the method is verified through a comparison of wave dispersion curve predictions from the homogeneous effective medium and the exact solution. A multiresonant design is then suggested for the desirable multiple wave band gaps by using a finite acoustic metamaterial slab. Finally, the band gap behavior and kinetic energy transfer mechanism in a multilayered composite with a periodic microstructure are studied to demonstrate the difference between the Bragg scattering mechanism and the locally resonant mechanism.

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