Underwater Acoustic Manipulation Using Solid Metamaterials With Broadband Anisotropic Density

2018 ◽  
Vol 85 (12) ◽  
Author(s):  
Jianzhu Dong ◽  
Yuchen Zhao ◽  
Yong Cheng ◽  
Xiaoming Zhou
Keyword(s):  
Design Method ◽  
Hexagonal Lattice ◽  
Acoustic Method ◽  
Anisotropy Ratio ◽  
Underwater Acoustic ◽  
Full Wave ◽  
New Type ◽  
Control Capability ◽  
Modal Field ◽  
Inclusion Structure

A new type of all-solid metamaterial model with anisotropic density and fluid-like elasticity is proposed for controlling acoustic propagation in an underwater environment. The model consists of a regular hexagonal lattice as the host that defines the overall isotropic stiffness, in which all lattice beams have been sharpened at both ends to significantly diminish the shear resistance. The inclusion structure, which involves epoxy, rubber, and lead material constituents, is designed to attain a large density–anisotropy ratio in the broad frequency range. The wave-control capability of metamaterials is evaluated in terms of underwater acoustic stretching, shifting, and ground cloaking, which are generated by the transformation acoustic method. The decoupling design method was developed for the metamaterial microstructure using band-structure, effective-medium, and modal-field analyses. The acoustic performance of these metamaterial devices was finally verified with full-wave numerical simulations. Our study provides new insight into broadband underwater acoustic manipulation by all-solid anisotropic-density metamaterials.

Suspend-Dome Static Behavior Analysis

2013 ◽  
Vol 351-352 ◽  
pp. 1057-1060 ◽  
Author(s):  
Xi Yun Dai ◽  
Xiang Yun Kong ◽  
Lin Tian
Keyword(s):  
Design Method ◽  
Joint Stiffness ◽  
Hybrid Structure ◽  
Structure Form ◽  
Static Behavior ◽  
Structure System ◽  
Optimizing Design ◽  
New Type ◽  
Dome Structure ◽  
Cable Dome

Suspend-dome structure form which colligates advantages of cable dome and reticulated shell is a new type spatial hybrid structure system. This article introduced the configuration and principle of suspend-dome structure system, and researched the structural behavior influence by altering the joint stiffness, vector height of the suspend-dome and the loop cable pretension. The results show that suspend-dome structure should make comprehensive consideration on interaction between vector height, prestress application and other factors, and relevant optimizing design method can be adopted in the design.

scholarly journals Manipulate Vibration Propagation by Anisotropic Honeycomb Structure

2018 ◽  
Vol 175 ◽  
pp. 03040
Author(s):  
Xiang Chen ◽  
Xiao-ming Wang ◽  
Yu-lin Mei
Keyword(s):  
Design Method ◽  
Honeycomb Structure ◽  
Homogenization Method ◽  
Unit Cell ◽  
Field Analysis ◽  
Acoustic Wave Propagation ◽  
Asymptotic Homogenization ◽  
Fluid Properties ◽  
Asymptotic Homogenization Method ◽  
New Type

As a new type of acoustic metamaterial, the pentamode material has extensive application prospect in controlling acoustic wave propagation because of its fluid properties. Firstly, a kind of pentamode material unit cell is designed, which is a two-dimensional honeycomb truss structure. Then, the asymptotic homogenization method is used to calculate static parameters of the unit cell, and also the influence of the geometric parameters and material composition of the unit cell on its mechanical properties is studied. Besides, based on transformation acoustics and the design method of the cylindrical cloak proposed by Norris, an acoustic cloak with isotropic density and gradient elastic modulus is constructed by periodically assembling the unit cell to guide the wave to bypass obstacles. Finally, the full displacement field analysis is carried out to prove the stealth effect of the acoustic cloak.

Lattice Light Steel Frame System and Application

2011 ◽  
Vol 105-107 ◽  
pp. 1110-1113
Author(s):  
Bo Ding ◽  
Huan Qing Jiang ◽  
Hong Xia Wan ◽  
Feng Zhang
Keyword(s):  
High Speed ◽  
Design Method ◽  
Calculation Model ◽  
Steel Frame ◽  
Calculation Results ◽  
Frame System ◽  
Practical Engineering ◽  
Steel Consumption ◽  
New Type ◽  
New System

Lattice light steel frame is a new type of structural system, combining general steel framework which is composed of lattice column and lattice beam with lattice light steel keel of the partitions and floors, the system takes full advantages of both structural systems, with high speed construction, less steel consumption, good earthquake-resistance etc., and possesses good prospects. The paper describes the system construction approach and the characteristics of lattice light steel frame system, and provides a project example of a villa. The design method and calculation model of the project are presented. Calculation results meet the specifications’ requirements, proving the new system can be applied to practical engineering. The paper gives guidance for application and research of this new system.

Form-finding analysis for a new type of cable–strut tensile structures generated by semi-regular tensegrity

2016 ◽  
Vol 20 (5) ◽  
pp. 772-783 ◽  
Author(s):  
JinYu Lu ◽  
Xiao Dong ◽  
XiLei Zhao ◽  
XiaoLong Wu ◽  
GanPing Shu
Keyword(s):  
Design Method ◽  
Geometric Transformation ◽  
Structural System ◽  
Form Finding ◽  
Practical Applications ◽  
New Type ◽  
Equilibrium Matrix ◽  
Cable Dome ◽  
Value Decomposition ◽  
Form Finding Analysis

A tensegrity structure is a type of self-balancing tensile structure, which consists of tension cables surrounding compression struts. Based on the geometry and topology of the classic half-octahedron tensegrity, this article presents a form-finding analysis of semi-regular tensegrity units using singular value decomposition of the equilibrium matrix. We propose the design formulas for the unit geometric transformation, obtain its internal self-stress modes and inextensional mechanism modes, and verify its geometric stability. Then, we devise a design method and compute the overall feasible self-stress of a tensegrity torus. A novel cable–strut tensile structural system is generated through combining a tensegrity torus and a Levy-type cable dome. Finally, a physical model is constructed to verify the feasibility of this structural system. This work enriches existing forms of tensegrity structures and contributes to further practical applications of tensegrity systems.

scholarly journals A Design Method to Assess the Primary Strength of the Delta-Type VLFS

2021 ◽  
Vol 9 (9) ◽  
pp. 1026
Author(s):  
Roy Gafter ◽  
Nitai Drimer
Keyword(s):  
Critical Load ◽  
Assessment Tool ◽  
Design Method ◽  
Axial Stress ◽  
Bending Moment ◽  
Initial Assessment ◽  
Floating Structure ◽  
Open Sea ◽  
Load Effects ◽  
New Type

Very large floating structure (VLFS) is a sustainable concept centered around creating solid platforms at sea. The Delta is a new type of VLFS, designed to withstand open-sea conditions and to form, in addition to a broad deck areas, a sheltered basin of year-round operability. The design of this unique hull relies on direct calculations in order to identify critical load cases and assess their load effects. This study formulates a theoretical procedure for the initial assessment of the primary strength. The procedure analytically integrates the floatation loads while the hull rests at hydrostatic equilibrium on a wave surface and obtains the vertical and horizontal bending moment. This preliminary assessment tool enables a fast review of many load cases and provides the basic insights necessary for a reasonable initial design. Using the procedure, we conducted a primary load assessment for the design of Delta. By calculating the load response to 588 load cases, we identified the critical load scenario and the maximal axial stress. As the stress was too high, we improved the geometry in order to reduce loads and assessed proper scantlings for the critical section. We present the formulation of the procedure, the validation of the results, and the implementation for the structural design of the Delta VLFS.

Design and Research of a New Ultrasonic Atomizing Vibrator

2013 ◽  
Vol 328 ◽  
pp. 468-472
Author(s):  
Hua Li ◽  
Jiang Jiang Zhao ◽  
Zhen Yin ◽  
Kun Ren
Keyword(s):  
Finite Element Analysis ◽  
Steel Sheet ◽  
Vibration Mode ◽  
Simulation Analysis ◽  
Design Method ◽  
Analysis Software ◽  
Element Analysis ◽  
Vibration Displacement ◽  
The Finite Element Analysis ◽  
New Type

Based on the theory of ultrasonic vibration, a new type of ultrasonic atomizing vibrator (UAV) with a vibrating steel sheet was proposed. By using the finite element analysis software to simulation analysis and research for the new type of vibrator, the frequency and vibration mode of atomizing steel sheet was obtained and the prototype of vibrator was fabricated. The impedance and vibration displacement of the vibrator was tested and the experiment of the new type of vibrator was carried out, which verified the feasibility of the new type of vibrator design method.

scholarly journals The Development of a Stair-climbing Robot with Wavy Movement by Rotating Crosses

2002 ◽  
Vol 14 (3) ◽  
pp. 298-303
Author(s):  
Ato Kitagawa ◽  
◽  
Liang Zhang ◽  
Takashi Eguchi ◽  
Hideyuki Tsukagushi ◽  
...  
Keyword(s):  
Simple Structure ◽  
Control Method ◽  
Design Method ◽  
Fire Fighting ◽  
Stair Climbing ◽  
Experimental Result ◽  
Climbing Robot ◽  
New Type ◽  
Fire Fighting Robot

A new type of movement called wavy movement, which is realized by rotating crosses, is proposed to build a stair-climbing fire-fighting robot. The prototype robot consists of 12 crosses, which are driven by 2 motors via sprockets and chains. In this paper, the principle of wavy movement, the mechanism, the design method, and the experimental result of the developed robot are discussed. It is confirmed through experiment that a robot with wavy movement is able to climb stairs with simple structure and easy control method.

A Passive Third-Order Cascade PLL Filter

2011 ◽  
Vol 255-260 ◽  
pp. 2262-2266
Author(s):  
Lin Feng ◽  
Chu Wu ◽  
Bo Jin ◽  
Zhen Yu Wu
Keyword(s):  
Design Method ◽  
Step Response ◽  
Design Parameters ◽  
Frequency Noise ◽  
Third Order ◽  
Loop Filter ◽  
Order Filter ◽  
New Type ◽  
The Stability ◽  
Phase Design

In this paper, the traditional passive loop filter is improved, and a new type of Cascade Third-order filter structure and Graphical Phase Design method is proposed, which greatly simplifies high-order PLL filter’s design, analysis and calculation. According to graphical phase design principle, parameters for cascade third-order filter could be figured out from the given formula, the derived result is simulated in the form of Bode plots and Unit-step response with Pspice software and the loop target under different parameters is compared. Experiments show that this third-order filter could significantly improve the stability of PLL, deeply attenuate the phase detector’s high-frequency noise and is well adapted to the loop gain change. Users can also change the design parameters flexibly according to the system requirements with this filter.

Configuration Design and Finite Element Analysis for Key Components of the New-Type Sprayer

2014 ◽  
Vol 701-702 ◽  
pp. 853-857
Author(s):  
Yuan Zhang ◽  
Kun Li ◽  
Qiang Wei ◽  
Bo Yang Meng
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Structural Optimization ◽  
Power Transmission ◽  
Design Method ◽  
Rear Wheel ◽  
Element Analysis ◽  
Steering Mechanism ◽  
New Type ◽  
High Clearance

According to the three-wheeled high clearance sprayer on the current market, the traditional empirical design method can hardly be used for effective stress distribution calculation and structural optimization, so it leads to the unreasonable structural design. Based on the overall structure of the sprayer design, a new-type high clearance sprayer designed, It is mainly composed of the engine-powered diaphragm pump power transmission parts, the power steering of scalable universal joint, the rear wheel steering mechanism and other components. Meanwhile, the finite element analysis and structural optimization on the sprayer frame have been finished. Therefore, the results showed that the frame realized the lightweight on the premise of the demand of performance and stiffness, each mechanism’s matching performance of sprayer meets the design requirements, and this approach provides a beneficial investigation into the future sprayer design.

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