scholarly journals Design and Mechanical Analysis of Bionic Foldable Beetle Wings

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Caidong Wang ◽  
Chen Wang ◽  
Yu Ning ◽  
Lumin Chen ◽  
Xinjie Wang
Keyword(s):  
Dihedral Angle ◽  
Dynamic Models ◽  
Kinematic Model ◽  
Mechanical Analysis ◽  
Physical Parameters ◽  
Flight Performance ◽  
Motion Simulation ◽  
Flexible Wings ◽  
The Relationship ◽  
Novel Design

In order to improve the flight performance of collapsible aircrafts, a novel mechanism of bionic foldable wings of beetle is designed based on the four-plate mechanism theory. The folding and unfolding movements of the bionic foldable wings are driven by motor and torsion hinges. Based on the D-H method, a kinematic model of wings is established to analyze the dihedral angle of adjacent plates. The folding ratio of an area in different plate creasing angles has been derived and calculated. Utilizing the kinematic and static models produced, as well as considering the folding ratio and output motor torque, the optimal physical parameters of folding wings are obtained. Dynamic models of rigid and flexible wings were established using ADAMS, and a motion simulation was performed. The relationship between dihedral angle and torque during the folding process of both rigid and flexible wings was obtained. The results provide a better understanding of the folding mechanism through the formulation of rigid-flexible wing analysis, as well as demonstrating a novel design of insect-mimicking artificial wings for small aerial vehicles.

scholarly journals Identical Limb Dynamics for Unilateral Impairments through Biomechanical Equivalence

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 705
Author(s):  
Fatemeh Rasouli ◽  
Kyle B. Reed
Keyword(s):  
Mathematical Model ◽  
Numerical Solution ◽  
Dynamic Models ◽  
Assistive Devices ◽  
Assistive Device ◽  
Human Walking ◽  
Physical Parameters ◽  
Gait Rehabilitation ◽  
And Performance ◽  
Two Sides

Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a limb or an assistive device. This study develops a mathematical model of dissimilar double pendulums that mimics human walking with unilateral gait impairment and establishes identical dynamics between asymmetric limbs. It introduces new coefficients that create biomechanical equivalence between two sides of an asymmetric gait. The numerical solution demonstrates that dissimilar double pendulums can have symmetric kinematic and kinetic outcomes. Parallel solutions with different physical parameters but similar biomechanical coefficients enable interchangeable designs that could be incorporated into gait rehabilitation treatments or alternative prosthetic and ambulatory assistive devices.

scholarly journals Online Reviews and Product Sales: The Role of Review Visibility

2021 ◽  
Vol 16 (4) ◽  
pp. 638-669
Author(s):  
Miriam Alzate ◽  
Marta Arce-Urriza ◽  
Javier Cebollada
Keyword(s):  
Decision Making ◽  
Dynamic Models ◽  
Generalized Method Of Moments ◽  
Online Reviews ◽  
Consumer Decision Making ◽  
Product Sales ◽  
The Impact ◽  
The Relationship ◽  
The Empirical Analysis

When studying the impact of online reviews on product sales, previous scholars have usually assumed that every review for a product has the same probability of being viewed by consumers. However, decision-making and information processing theories underline that the accessibility of information plays a role in consumer decision-making. We incorporate the notion of review visibility to study the relationship between online reviews and product sales, which is proxied by sales rank information, studying three different cases: (1) when every online review is assumed to have the same probability of being viewed; (2) when we assume that consumers sort online reviews by the most helpful mechanism; and (3) when we assume that consumers sort online reviews by the most recent mechanism. Review non-textual and textual variables are analyzed. The empirical analysis is conducted using a panel of 119 cosmetic products over a period of nine weeks. Using the system generalized method of moments (system GMM) method for dynamic models of panel data, our findings reveal that review variables influence product sales, but the magnitude, and even the direction of the effect, vary amongst visibility cases. Overall, the characteristics of the most helpful reviews have a higher impact on sales.

The relationship between physical parameters and wear of dental composites

Wear ◽  
2007 ◽  
Vol 263 (7-12) ◽  
pp. 1138-1146 ◽  
Author(s):  
S.D. Heintze ◽  
G. Zellweger ◽  
G. Zappini
Keyword(s):  
Dental Composites ◽  
Physical Parameters ◽  
The Relationship

scholarly journals Relation between photochromic properties and molecular structures in salicylideneaniline crystals

2012 ◽  
Vol 68 (3) ◽  
pp. 297-304 ◽  
Author(s):  
Kohei Johmoto ◽  
Takashi Ishida ◽  
Akiko Sekine ◽  
Hidehiro Uekusa ◽  
Yuji Ohashi
Keyword(s):  
Dihedral Angle ◽  
Steric Hindrance ◽  
Molecular Structures ◽  
Dihedral Angles ◽  
Clear Correlation ◽  
X Ray Diffraction ◽  
Photochromic Properties ◽  
X Ray ◽  
Benzene Rings ◽  
The Relationship

The crystal structures of the salicylideneaniline derivatives N-salicylidene-4-tert-butyl-aniline (1), N-3,5-di-tert-butyl-salicylidene-3-methoxyaniline (2), N-3,5-di-tert-butyl-salicylidene-3-bromoaniline (3), N-3,5-di-tert-butyl-salicylidene-3-chloroaniline (4), N-3,5-di-tert-butyl-salicylidene-4-bromoaniline (5), N-3,5-di-tert-butyl-salicylidene-aniline (6), N-3,5-di-tert-butyl-salicylidene-4-carboxyaniline (7) and N-salicylidene-2-chloroaniline (8) were analyzed by X-ray diffraction analysis at ambient temperature to investigate the relationship between their photochromic properties and molecular structures. A clear correlation between photochromism and the dihedral angle of the two benzene rings in the salicylideneaniline derivatives was observed. Crystals with dihedral angles less than 20° were non-photochromic, whereas those with dihedral angles greater than 30° were photochromic. Crystals with dihedral angles between 20 and 30° could be either photochromic or non-photochromic. Inhibition of the pedal motion by intra- or intermolecular steric hindrance, however, can result in non-photochromic behaviour even if the dihedral angle is larger than 30°.

scholarly journals On Designing an Expert Diagnostic System of the Aircraft Turbine Engine Functional Units

2020 ◽  
Vol 50 (1) ◽  
pp. 171-192
Author(s):  
Henryk Borowczyk ◽  
Jarosław Spychała
Keyword(s):  
Dynamic Models ◽  
Diagnostic System ◽  
Compact Representation ◽  
Diagnostic Model ◽  
Diagnostic Systems ◽  
Turbine Engine ◽  
Flight Data ◽  
Diagnostic Parameters ◽  
Functional Units ◽  
The Relationship

AbstractThe paper presents issues related to the design of an expert diagnostic system of turbine engine functional units. Dedicated diagnostic stations and on-board flight data recorders are the sources of diagnostic signals. The signals were parameterized or identified dynamic models to get a compact representation in the form of a set of parameters. The set of diagnostic parameters was subjected to integer encoding. On this basis, a multi-valued diagnostic model describing the relationship between the set of faults and the set of symptoms (code values of diagnostic parameters) was determined. The proposed approach can be used in the design of expert diagnostic systems for propulsion units of any aircraft.

scholarly journals Recycling Heat Losses of an Oil-Immersed Transformer: Feasibility Study

2021 ◽  
Vol 21 (1) ◽  
pp. 48-54
Keyword(s):  
High Efficiency ◽  
Power Transformer ◽  
Heat Losses ◽  
Power Transformers ◽  
Passive Mode ◽  
Active Mode ◽  
Short Circuits ◽  
Definition Of ◽  
The Relationship ◽  
Novel Design

The paper investigates the feasibility of adding a liquid heater to an oil-immersed transformer. It proves that design the high efficiency of power transformers, losses due to idling and short circuits are substantial and are scattered in the environment as heat. The paper proposes a novel design that implements a liquid (coolant) heater to enable the unit not only to convert electricity, but also to generate heat. In order to analyze the feasibility of such heat recycling, the authors have developed an equivalent thermal circuit and a mathematical model thereof. Said heater can operate in two modes. In the passive mode, the coolant it contains only absorbs the heat emitted (lost) by the power transformer. In the active mode, it also receives the heat emitted due to the passage of electric current through the pipes of the heater. The paper further introduces the definition of heater efficiency. Studies have shown that up to 50 % of transformer heat losses can be recycled by heating the coolant in the heater. The paper presents the relationship between utilized heat and transformer losses, as well as heater efficiency as a function of coolant flow rate. The heater efficiency exceeds 90 % in the active mode.

scholarly journals Constraining families of dynamic models using geological, geodetic and strong ground motion data: the Mw 6.5, October 30th, 2016, Norcia earthquake, Italy

2021 ◽  
Author(s):  
Elisa Tinti ◽  
Emanuele Casarotti ◽  
Thomas Ulrich ◽  
Duo Li ◽  
Taufiqurrahman Taufiqurrahman ◽  
...  
Keyword(s):  
Dynamic Models ◽  
Central Italy ◽  
Kinematic Model ◽  
Seismic Wave Propagation ◽  
Dynamic Rupture ◽  
Friction Coefficients ◽  
Multiple Faults ◽  
Central Italy Earthquake ◽  
Trade Offs ◽  
Kinematic Models

The 2016 Central Italy earthquake sequence is characterized by remarkable rupture complexity, including highly heterogeneous slip across multiple faults in an extensional tectonic regime. The dense coverage and high quality of geodetic and seismic data allow to image intriguing details of the rupture kinematics of the largest earthquake of the sequence, the Mw 6.5 October 30th, 2016 Norcia earthquake, such as an energetically weak nucleation phase. Several kinematic models suggest multiple fault planes rupturing simultaneously, however, the mechanical viability of such models is not guaranteed.Using 3D dynamic rupture and seismic wave propagation simulations accounting for two fault planes, we constrain 'families' of spontaneous dynamic models informed by a high-resolution kinematic rupture model of the earthquake. These families differ in their parameterization of initial heterogeneous shear stress and strength in the framework of linear slip weakening friction.First, we dynamically validate the kinematically inferred two-fault geometry and rake inferences with models based on only depth-dependent stress and constant friction coefficients. Then, more complex models with spatially heterogeneous dynamic parameters allow us to retrieve slip distributions similar to the target kinematic model and yield good agreement with seismic and geodetic observations. We discuss the consistency of the assumed constant or heterogeneous static and dynamic friction coefficients with mechanical properties of rocks at 3-10 km depth characterizing the Italian Central Apennines and their local geological and lithological implications. We suggest that suites of well-fitting dynamic rupture models belonging to the same family generally exist and can be derived by exploiting the trade-offs between dynamic parameters.Our approach will be applicable to validate the viability of kinematic models and classify spontaneous dynamic rupture scenarios that match seismic and geodetic observations at the same time as geological constraints.

scholarly journals The Mobile Robot HILARE: Dynamic Modeling and Motion Simulation

2015 ◽  
Vol 4 (2) ◽  
pp. 150
Author(s):  
M. Ghazal ◽  
A. Talezadeh ◽  
M. Taheri ◽  
M. Nazemi-Zade
Keyword(s):  
Mobile Robot ◽  
Dynamic Analysis ◽  
Dynamic Modeling ◽  
Kinematic Model ◽  
Dynamic Equations ◽  
Motion Simulation ◽  
Governing Equations ◽  
Kinematic Constraints ◽  
Extended Application ◽  
The Matrix

To perform mission in variant environment, several types of mobile robot has been developed an implemented. The mobile robot HILARE is a known wheeled mobile robot which has two fixed wheels and an off-entered orientable wheel. Due to extended application of this robot, its dynamic analysis has attracted a great deal of interests. This article investigates dynamic modeling and motion analysis of the mobile robot HILARE. As the wheels of the robot have kinematic constraints, the constraints of wheels are taken into consideration and the matrix form of the kinematic model of the robot is derived. Furthermore, dynamic model of the robot is developed by consideration of kinematic constraints. To derive dynamic equations of the robot, the Lagrange multiplier method is employed and the governing equations of the robot in state-pace form are presented. Then, some simulations are presented to show applicability of the proposed formulation for dynamic analysis of the mobile robot HILARE.

Study on the Relationship between Canal System Conveyance Efficiency and Basic Physical Parameters of Gravity Irrigation Districts

2014 ◽  
Vol 955-959 ◽  
pp. 3422-3426
Author(s):  
Hong Wei Jia ◽  
Ke Ke Hu ◽  
Fei Su
Keyword(s):  
Physical Parameters ◽  
Irrigation Canal ◽  
Canal System ◽  
Positive Role ◽  
Engineering Construction ◽  
Irrigation Districts ◽  
Basic Parameters ◽  
Irrigation Engineering ◽  
Operation Status ◽  
The Relationship

Canal system conveyance efficiency (CSCE ) is a basic parameter of engineering construction and water management of the irrigation districts, either the response of operation status of an irrigation canal system. It plays great significance in searching quantity relationship between ICSCE and other basic parameters reflecting the condition of irrigation engineering. This paper, gravity irrigation districts in Zhejiang province as an example, sets up the relationship between basic parameters such as irrigation canal lining rate, canal flow and the CSCE, based on determining the CSCE in 61 typical gravity irrigation districts. And it also reflects the influence of basic parameters on CSCE, having a certain accuracy. This result plays a positive role on the further research and actual work on CSCE.

Obstacle negotiation analysis of track-legged robot based on terramechanics

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Zhu Hongbiao ◽  
Yueming Liu ◽  
Weidong Wang ◽  
Zhijiang Du
Keyword(s):  
Kinematic Model ◽  
Interaction Model ◽  
Experimental Results ◽  
Physical Parameters ◽  
Negotiation Analysis ◽  
Content Type ◽  
Practical Applications ◽  
Loose Soil ◽  
Key Steps ◽  
Drawbar Pull

Purpose This paper aims to present a new method to analyze the robot’s obstacle negotiation based on the terramechanics, where the terrain physical parameters, the sinkage and the slippage of the robot are taken into account, to enhance the robot’s trafficability. Design/methodology/approach In this paper, terramechanics is used in motion planning for all-terrain obstacle negotiation. First, wheel/track-terrain interaction models are established and used to analyze traction performances in different locomotion modes of the reconfigurable robot. Next, several key steps of obstacle-climbing are reanalyzed and the sinkage, the slippage and the drawbar pull are obtained by the models in these steps. In addition, an obstacle negotiation analysis method on loose soil is proposed. Finally, experiments in different locomotion modes are conducted and the results demonstrate that the model is more suitable for practical applications than the center of gravity (CoG) kinematic model. Findings Using the traction performance experimental platform, the relationships between the drawbar pull and the slippage in different locomotion modes are obtained, and then the traction performances are obtained. The experimental results show that the relationships obtained by the models are in good agreement with the measured. The obstacle-climbing experiments are carried out to confirm the availability of the method, and the experimental results demonstrate that the model is more suitable for practical applications than the CoG kinematic model. Originality/value Comparing with the results without considering Terramechanics, obstacle-negotiation analysis based on the proposed track-terrain interaction model considering Terramechanics is much more accurate than without considering Terramechanics.

Sign in / Sign up

Export Citation Format

Share Document