Double-layer deployable mechanical network constructed of Threefold-symmetric Bricard linkages and Sarrus linkages

2021 ◽  
pp. 1-18
Author(s):  
Xiaoke Song ◽  
Hongwei Guo ◽  
Jingjing Chen ◽  
Wenhui Yuan ◽  
Younan Xu
Keyword(s):  
Double Layer ◽  
Engineering Application ◽  
Performance Properties ◽  
Mechanical Networks ◽  
Relationship Of ◽  
Scissor Mechanism

Abstract Threefold-symmetric (TFS) Bricard linkages are known for their excellent deployment performance properties. This paper proposes a novel networking method of TFS Bricard linkages and a double-layer mechanical network. First, the angle relationship for parts of the TFS Bricard linkage is analyzed. Then, the angle relationship of two TFS Bricard linkages connected by a scissor mechanism is studied. The result suggests that when the twist angles of the two TFS Bricard linkages are equal, their corresponding planes are parallel, and the link lengths have no effect on the parallel relationship. A novel networking method of the TFS Bricard linkage is recommended according to these results. This mechanical network is constructed of two different sized units and can be plane deployed and be folded with a smaller height. We also propose a hybrid linkage constructed of the TFS Bricard linkage and Sarrus linkage. Two kinds of double-layer mechanical networks are suggested by applying the hybrid linkage to a smaller unit in the mechanical network and using the hybrid linkage as the interlayer pillar. The new networking method and the double-layer mechanical network provide convenience for the TFS Bricard linkage's engineering application.

scholarly journals Research on dynamic characteristics test of wooden floor structure for gymnasium

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Adam Guo
Keyword(s):  
Double Layer ◽  
Load Distribution ◽  
Optimization Design ◽  
Absorption Rate ◽  
Damping Ratio ◽  
Engineering Application ◽  
Single Layer ◽  
Structural Vibration ◽  
Wooden Floor ◽  
Floor Structure

In order to better evaluate the structural performance of the wooden floor used in the gymnasium and realize the structural optimization design, this research considered two gymnasium’s floors in Nanjing as the research object and used the transient excitation method to test the natural frequency and damping ratio parameters of the three types of floor structures. The results showed that three kinds of floor structures all meet the requirements of building comfort; under the premise that the types and specifications of the constituent materials were the same, the order of the damping ratios of the three kinds of floor structures from large to small was: the fixed floor structure with double-layer load distribution strip, the suspended floor structure with single-layer load distribution strip, and the suspended floor structure with double-layer load distribution strip; compared with the fixed floor structure, the suspended floor structure had low damping ratio characteristics, the energy dissipation was slow during structural vibration, which means its impact absorption rate was small, and its impact buffering ability was good. The integral structure had good resilience performance; compared with the floor structure using single-layer load distribution strip. The floor structure using a double-layer load distribution strip had a low damping ratio characteristic. The absorption rate of the structure was small and the resilience performance was good. The research conclusion had certain engineering application value.

scholarly journals Kinematics, Dynamics, and Optimal Control of Pneumatic Hexapod Robot

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Long Bai ◽  
Lu-han Ma ◽  
Zhifeng Dong ◽  
Xinsheng Ge
Keyword(s):  
Engineering Application ◽  
Pseudospectral Method ◽  
Hexapod Robot ◽  
Dynamics Modeling ◽  
Rescue Operation ◽  
The Matrix ◽  
Calculation Results ◽  
Practical Engineering ◽  
Body Joints ◽  
Relationship Of

Pneumatic hexapod robot is driven by inert gas carried by itself, which has board application prospect in rescue operation of disaster conditions containing flammable gas. Cruising ability is main constraint for practical engineering application which is influenced by kinematics and dynamics character. The matrix operators and pseudospectral method are used to solve dynamics modeling and numerical calculation problem of robot under straight line walking. Kinematics model is numerically solved and relationship of body, joints, and drive cylinders is obtained. With dynamics model and kinematics boundary conditions, the optimal input gas pressure of leg swing and body moving in one step is obtained by pseudospectral method. According to action character of magnetic valve, calculation results of control inputs satisfy engineering design requirements, and cruising ability under finite gas is obtained.

Computer Simulation of Static Buckling of Double-Layer Portal Frame

2011 ◽  
Vol 94-96 ◽  
pp. 2070-2073
Author(s):  
Zuo Yi Kang ◽  
Zhi Jun Han ◽  
Guo Yun Lu ◽  
Zhi Fang Liu
Keyword(s):  
Computer Simulation ◽  
Double Layer ◽  
Engineering Application ◽  
Buckling Load ◽  
Uniform Load ◽  
Buckling Mode ◽  
Critical Buckling Load ◽  
Portal Frame

The buckling of no-way double-layer portal frame that column is fixed is simulated by using ANSYS. Through analyzing the portal frame subjected to different loads on the roof of the structure that are uniform load, trapezoidal load and triangular load, the critical buckling load of the double-layer portal frame and buckling mode are obtained. The regular between the critical buckling load and the form of the load on the roof can be acquired by the analysis of the results, which can be used as a reference for engineering application.

scholarly journals Adaptive PID Control and Its Application Based on a Double-Layer BP Neural Network

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1475
Author(s):  
Ming-Li Zhang ◽  
Yi-Jie Zhang ◽  
Xiao-Long He ◽  
Zheng-Jie Gao
Keyword(s):  
Double Layer ◽  
Working Conditions ◽  
Pid Control ◽  
Control Method ◽  
Back Propagation ◽  
Engineering Application ◽  
Hydraulic Drive ◽  
Control Parameters ◽  
Hydraulic Drive Unit ◽  
The Relationship

In this paper, focusing on the inconvenience of variable value PID based on manual parameter adjustment for the hydraulic drive unit (HDU) of a legged robot, a method employing double-layer back propagation (BP) neural networks for learning the law of PID control parameters is proposed. The first layer is used to learn the relationship between different control parameters and the control performance of the system under various working conditions. The second layer is used to study the relationship between the parameters of the working conditions and the optimizing control parameters under various working conditions. The effectiveness of the proposed control method was verified by simulation and experiment. The results showed that the proposed method can provide a theoretical and experimental basis for the selection of control parameters, and can be extended to similar controllers, therefore possessing engineering application value.

Research on Compressive Stress - Strain Relationship of Fiber Reinforced Concrete

2010 ◽  
Vol 168-170 ◽  
pp. 384-392 ◽  
Author(s):  
Tie Cheng Wang ◽  
Hai Long Zhao ◽  
Jin Jin Hao ◽  
Jian Quan Zu
Keyword(s):  
Reinforced Concrete ◽  
Constitutive Model ◽  
Engineering Application ◽  
Fiber Reinforced Concrete ◽  
Constitutive Relationship ◽  
Peak Strain ◽  
Test Results ◽  
Fiber Reinforced ◽  
Damage Constitutive Model ◽  
Relationship Of

The marked brittleness of concrete could be overcome by the addition of fibers. This paper experimentally investigated the mechanical properties and constitutive relationship of different fiber reinforced concrete. It is shown from the results that the compressive strength and peak strain of concrete with fiber have little improvement, but the ultimate strain, deformation capacity, toughness and energy dissipation capacity are improved greatly. The damage constitutive model recommended by the emendatory code for design of concrete structure (appendix C) (GB50010-2002) is applied for calculations and analyses according to the test results. The damage constitutive model and non-elastic constitutive model of different fiber reinforced concrete are established based on the test results. It is indicated from the analyses that the constitutive models established in this paper are in accordance with the characteristic of the fiber reinforced concrete in loading process. The damage constitutive model in appendix C in code could be applied directly in some low precision calculation and engineering application.

Frequency-Demodulated Analysis Based on Cyclostationarity for Local Fault Detection in Gears

2005 ◽  
Vol 293-294 ◽  
pp. 87-94 ◽  
Author(s):  
Jun He ◽  
Jin Chen ◽  
Guo Bi ◽  
Fuchang Zhou
Keyword(s):  
Experimental Data ◽  
Carrier Frequency ◽  
Engineering Application ◽  
Phase Relationship ◽  
Application Range ◽  
Cyclic Frequency ◽  
Frequency Demodulation ◽  
Cyclic Statistics ◽  
Relationship Of ◽  
Frequency Feature

The demodulation analysis has been extensively used for gear diagnosis. However these techniques mainly deal with the amplitude-modulated signal instead of the frequency-modulated signal. Due to the symmetrical phase relationship of the sidebands, the amplitude-demodulated methods are not suitable for the frequency-modulated signal. This paper introduces the theory of cyclostationary processes as a powerful frequency-demodulation tool for the diagnosis of gears. The Cyclic Autocorrelation Function (CAF) is an important second-order cyclic statistics and acts as an efficient parameter to the frequency-demodulated analysis. In this paper, the CAF of frequency-modulated signal is deduced carefully. Through the discussion of frequency feature of the CAF slice at different cyclic frequency, two useful conclusions have been arrived about the frequency-demodulation. Firstly, the CAF slice at even multiples of the modulator-frequency can demodulate the frequency-modulated signal directly. Secondly, the amplitude-demodulated methods are suitable for the CAF slice of frequency-modulated signal at some special cyclic frequencies, which are equal to odd multiples of the modulator-frequency or close to the double carrier-frequency. These features of the CAF slice mentioned above overcome the invalidation of amplitude-demodulated methods for the frequency-modulated signal and increase it’s application range in engineering. Application in simulated and experimental data from a gear rig verifies the effectiveness of the frequency-demodulated method based on cyclostationarity.

Experimental Study and Recommendation on Concrete Cover Thinkness of GFRP

2014 ◽  
Vol 578-579 ◽  
pp. 1410-1414
Author(s):  
Yan Yan Gao ◽  
Jian Xiong Liu ◽  
Chen Xi Yue ◽  
Xiu Hua Li
Keyword(s):  
Experimental Study ◽  
Bond Strength ◽  
Test Data ◽  
Theoretical Basis ◽  
Concrete Strength ◽  
Engineering Application ◽  
Concrete Cover ◽  
Relationship Of ◽  
The Relationship

Concrete cover thinkness of GFRP to ensure the safety, applicability and durability of the structure is of great significance. Based on studies to 30 the drawing specimens of concrete ,get bond strength of same GFRP diameter,same concrete strength, different concrete cover thinkness. Through the analysis of test data,it is concluded the relationship of the bond strength and the concrete cover thinkness.And basis on the relationship,it is determine the suggestive values on concrete cover thinkness of GFRP.Experimental data and suggestion can provide reference and theoretical basis for the GFRP engineering application and the establishment of the relevant specification.

Fractal Research in Metal Material Fracture Invalidation

2013 ◽  
Vol 703 ◽  
pp. 8-11
Author(s):  
Li Hui Guo ◽  
Wan Qiang Hu
Keyword(s):  
Fractal Theory ◽  
Engineering Application ◽  
Metal Material ◽  
Fractal Models ◽  
Metal Fracture ◽  
Fractal Characteristics ◽  
Material Fracture ◽  
Reasonable Description ◽  
Relationship Of ◽  
The Relationship

Though there are a lot of rules and models for metal material fracture, it makes lots of troubles for engineering application, because of the lacking of reasonable description of fracture principle and change law. This article discusses some basic problems of applying fractal geometry to fracture research, mainly including sectional fractal characteristics and measurement, the relationship of fractal dimension and fracture toughness, and some kinds of metal fractal models. At last, application of fractal theory in metal fracture is stated.

Synthetic Design of High Aspect Ratio Folding Wings Based on Aeroelastic Analysis

2014 ◽  
Vol 607 ◽  
pp. 409-412
Author(s):  
Sheng Li Lv ◽  
Cheng Wang ◽  
Yang Biao Ou ◽  
Guang Jun Yang ◽  
Xiao Yan Tong
Keyword(s):  
Engineering Application ◽  
Element Model ◽  
Expansion Process ◽  
Sweep Angle ◽  
Flutter Speed ◽  
Aeroelastic Analysis ◽  
Flutter Analysis ◽  
Practical Engineering ◽  
Analysis Models ◽  
Relationship Of

Finite element model of folding wings was designed in the light of structural scheme, and each part of the model used composites. Different aeroelastic analysis models were built from emission to cruise, and then the models were made the study focus on flutter analysis. The result showed the change relationship of the critical flutter speed of wings and flutter frequency with sweep angle in state of expansion process, and the change relationship of the critical flutter speed of wings and flutter frequency of folding wings with cruising altitude and cruise Mach number in state of cruise. The whole flight state was analyzed if the folding wings might flutter, and if it took place the structure optimization of wings was needed. Simulation results have a certain guiding significance for practical engineering application.

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