Research on parameter matching characteristics of pneumatic launch systems based on co-simulation

2021 ◽  
pp. 1-25
Author(s):  
Z. Zhang ◽  
Y. Peng ◽  
X. Wei ◽  
H. Nie ◽  
H. Chen ◽  
...  
Keyword(s):  
Theoretical Research ◽  
Engineering Research ◽  
Object A ◽  
System Parameters ◽  
Laboratory Test Results ◽  
Batch Simulation ◽  
Parameter Matching ◽  
Dynamic Simulation Model ◽  
Launch Systems ◽  
Coupling Characteristics

Abstract Pneumatic launch systems for Unmanned Aerial Vehicles (UAVs), including mechanical and pneumatic systems, are complex and non-linear. They are subjected to system parameters during launch, which leads to difficulty in engineering research analysis. For example, the mismatch between the UAV parameters and the parameter design indices of the launch system as well as the unclear design indices of the launching speed and overload of UAVs have a great impact on launch safety. Considering this situation, some studies are presented in this paper. Taking the pneumatic launch system as a research object, a pneumatic launcher dynamic simulation model is built based on co-simulation considering the coupling characteristics of the mechanical structure and transmission system. Its accuracy was verified by laboratory test results. Based on this model, the paper shows the effects of the key parameters, including the mass of the UAV, cylinder volume, pressure and moment of inertia of the pulley block, on the performance of the dynamic characteristics of the launch process. Then, a method for matching the parameter characteristics between the UAV and launch system based on batch simulation is proposed. The set of matching parameter values of the UAV and launch system that satisfy the launch take-off safety criteria are calculated. Finally, the influence of the system parameters of the launch process on the launch performance was analysed in detail, and the design optimised. Meaningful conclusions were obtained. The analysis method and its results can provide a reference for engineering and theoretical research and development of pneumatic launch systems.

Study on the effective discharge energy mechanism of vertical ultrasonic vibration assisted EDM processing

2021 ◽  
pp. 095440542110285
Author(s):  
Yinghuai Dong ◽  
Guangyan Li ◽  
Yan Wang ◽  
Jianbao Song ◽  
Shuo Yang ◽  
...  
Keyword(s):  
Ultrasonic Vibration ◽  
Theoretical Research ◽  
Discharge Energy ◽  
Movement Path ◽  
Energy Mechanism ◽  
Effective Discharge ◽  
Parameter Matching ◽  
Discharge Gap ◽  
Conventional Machining

Compared to traditional EDM processing, UEDM (Ultrasonic Vibration Assisted EDM) have a great improvement in optimizing discharge environment. In this study, ultrasonic vibration is attached to the electrode. According to the relative positional relationship between the movement path of the electrode tip and the discharge gap, four working states of UEDM are defined. The four working states are the path within the discharge gap, the path in contact with the edge of the discharge gap, part of the electrode end path outside the discharge gap, and the path in contact with the workpiece, respectively. States are analyzed from the effective discharge energy and discharge frequency. A mathematical model for effective discharge energy and surface roughness is established for two conventional working states. The correctness of the theoretical research is verified by experiments. As the experiment results shown, the influence of ultrasonic amplitude on the energy of UEDM is primary, while frequency is secondary. A working state with better discharge stability and higher discharge energy when the electrode end path is in contact with the edge of the discharge gap. In the first three conventional machining states, the surface quality of the workpiece increases with the increase of ultrasonic amplitude and frequency. The study can provide scientific guidance for parameter matching of UEDM.

scholarly journals Biomedical Engineering International joins the Family of Platinum Open Access Journals

2019 ◽  
Vol 1 (1) ◽  
pp. 1-1
Author(s):  
Cristina Chircov ◽  
Monica Cartelle Gestal ◽  
Alexandru Mihai Grumezescu
Keyword(s):  
Open Access ◽  
Biomedical Engineering ◽  
Open Access Journal ◽  
Research Field ◽  
Theoretical Research ◽  
Academic Publishing ◽  
Original Research ◽  
Communication Tool ◽  
Engineering Research ◽  
Open Access Journals

We are delightfully announcing the launch of Biomedical Engineering International, a new interdisciplinary international scholarly open-access journal dedicated to publishing original and innovative research in the field of biomedical engineering. Any type of scientific paper, including reviews, original research papers, communications, or short notes, are welcome to be submitted. Any paper will further undergo the process of peer-reviewing according to the scientific standards of the journal. The scope of Biomedical Engineering International comprises all the directions of interest for the development of (pre-)clinical applications that could improve the quality of life, from tissue engineering, regenerative medicine, and drug delivery systems, to microfluidics, neural engineering, and micro- and nanotechnology. Thus, Biomedical Engineering International aims to create an interdisciplinary communication tool for scientists in various fields, from chemists, engineers, biologists, to physicists, informaticians, and theoreticians. For this, the publication is done under the policy of Platinum Open Access, meaning that articles are free for readers and no article processing charges are demanded from authors, nor from their institutions. The publication charges for articles in Biomedical Engineering International are covered by AMG Transcend Association, Romania. Through this, Biomedical Engineering International addresses equality in academic publishing, by making the process available to both researchers and readers. Additionally, authors benefit from increased visibility of their research and thus, an increase of citations and higher influence in the academic world. There are no restrictions on the total length of the papers as the journal encourages the publication of detailed experimental and theoretical research. In this regard, Biomedical Engineering International paves the way to completely free academic publishing services in the biomedical engineering research field. In this manner, we gladly invite you to submit your papers in the field of biomedical engineering to be considered for publication in Biomedical Engineering International and we are looking forward to collaborating with you!

Research on the Propagation of the Crack Parallel to and Lying on the Interface in the Cermet Cladding Part

2012 ◽  
Vol 426 ◽  
pp. 287-292
Author(s):  
J.R. Yang ◽  
X.F. Wang ◽  
Y.K. Zhang ◽  
Z.Q. Li ◽  
C.Z. Huang
Keyword(s):  
Crack Propagation ◽  
Interface Crack ◽  
Propagation Direction ◽  
Theoretical Research ◽  
Propagation Property ◽  
Research Results ◽  
Object A ◽  
Crack Propagation Direction ◽  
Propagation Law ◽  
Crack Propagation Criterion

Taking the interface crack in the cermet cladding part as the study object, a new comparative propagation property parameter (CPPP) CP suitable to judge the interface crack propagation direction in the cladding part is proposed. The interface crack propagation criterion is established. Based on it, the theoretical research on the parameters (CP1, CP2 and CPi) for the crack parallel to and lying on the interface propagating to the clad, to the substrate, and along the interface is carried out. The interface crack propagation law is investigated with an example. The research results show that the crack will more easily deflect to the clad.

scholarly journals APL JANUS System Progress on Commercial Suborbital Launch Vehicles: Moving the Laboratory Environment to Near Space

2021 ◽  
Vol 9 (1) ◽  
pp. 30-49
Author(s):  
H. Todd Smith ◽  
Ryan T. Hacala ◽  
Erik M. Hohlfeld ◽  
Weston K. Edens ◽  
Charles A. Hibbitts ◽  
...  
Keyword(s):  
Launch Vehicles ◽  
Applied Physics ◽  
Core System ◽  
Laboratory Environment ◽  
Engineering Research ◽  
Reusable Launch Vehicles ◽  
Space Tourism ◽  
Near Space ◽  
Suborbital Flight ◽  
Launch Systems

Abstract Multiple private companies are building suborbital reusable launch vehicles possessing vastly different designs. Many of these companies originally focused on space tourism; however, revolutionary applications for scientific and engineering research as well as technology demonstrations and instrument development are emerging. The dramatic reduction in cost over traditional launch systems as well as a guaranteed (and rapid) safe payload return enable many new launch vehicle applications. These new capabilities will essentially move the laboratory environment up to the edge of space. To make use of these novel launch vehicles, the John Hopkins University Applied Physics Laboratory has established a Commercial Suborbital Program with a core system (JANUS) to support and enable many future suborbital missions. This program has already conducted six suborbital flight missions to establish vehicle interfaces and analyze the suitability and limits of each flight environment. Additionally, this program has also been selected by the NASA Flight Opportunities Program for five additional operational suborbital missions. Here we present the results of our completed missions as well as descriptions of future selected missions scheduled for 2021–2023.

scholarly journals A case study of floor failure characteristics under fully mechanised caving mining conditions in extra-thick coal seams

2020 ◽  
Vol 17 (5) ◽  
pp. 813-826
Author(s):  
Pingsong Zhang ◽  
Yuanchao Ou ◽  
Binyang Sun ◽  
Chang Liu
Keyword(s):  
Stress Distribution ◽  
Western China ◽  
Monitoring Method ◽  
Thick Coal Seam ◽  
Failure Characteristics ◽  
Engineering Research ◽  
Object A ◽  
Working Face ◽  
Floor Failure ◽  
Inclined Boreholes

Abstract To determine the failure characteristics and evolution regularity of the floor strata during fully mechanised top-coal cave mining in typical deep and extra-thick seams in western China, the 61303 working face of an Ordos mine was selected as the engineering research object. A comprehensive monitoring method combining a BOTDR (Brillouin Optical Time-Domain Reflection) distributed fiber strain test and a borehole resistivity CT (Computerised Tomography) test was adopted. The results show that floor stress distribution of the deep-buried and extra-thick coal seam is significantly affected by the different depths of rock lithology. At the interface of the rock strata with a large difference in the elastic modulus, phenomena such as the asynchronism of strata movement and obvious differences in failure easily occur. The failure depth of the floor strata in the 61303 working face is approximately 15.90 m, and the influence depth of the floor disturbance is approximately 32.70 m. Under the influence of the mining pressure, floor stress distribution and crack evolution have obvious spatial and temporal effects. In different inclined boreholes, the data captured by the cable have different values and the fracture locations of the cable also differ. Compared with a single borehole, multiple boreholes with different inclinations, directions and locations can provide more comprehensive and reliable data trends. The knowledge obtained by this monitoring can provide reference information for the study of floor damage under similar conditions and the formulation of technical measures such as those that prevent mine water disasters.

scholarly journals Power system parameters matching of in-wheel motor drive electric vehicle

2021 ◽  
Vol 257 ◽  
pp. 01044
Author(s):  
Wei Chen Ren ◽  
Yi Fang ◽  
Xiao Peng Li ◽  
Zheng Xu ◽  
Xu Long Wang
Keyword(s):  
Power System ◽  
Electric Vehicle ◽  
Electric Vehicles ◽  
Motor Drive ◽  
System Parameters ◽  
Type Selection ◽  
Power Battery ◽  
Outer Rotor ◽  
Parameter Matching ◽  
Avl Cruise

Based on the line-controlled chassis platform, the low-speed outer rotor motor is used to drive the wheel directly in the designed in-wheel motor line-controlled electric vehicle. The power system parameters of the designed four-wheel independent drive electric vehicle are matched and simulated by offline simulation. Firstly, based on the theoretical basis of the research on the parameter matching of the power system of pure electric vehicles, the type selection and parameter matching of the hub motor and power battery are carried out according to the established dynamic and economic indicators. Then, the designed component parameters are repeatedly corrected until the design goal is achieved; Finally, the vehicle model is built in AVL cruise, and the design results are simulated by software.

Damage Diagnosis of Radial Gate Based on Modal Strain Energy

2011 ◽  
Vol 71-78 ◽  
pp. 4240-4243
Author(s):  
Jian Wei Zhang ◽  
Yi Na Zhang ◽  
Sheng Zhao Cheng
Keyword(s):  
Structural Damage ◽  
Strain Energy ◽  
Theoretical Research ◽  
Destructive Testing ◽  
Modal Strain Energy ◽  
Damage Diagnosis ◽  
Engineering Research ◽  
Research Problems ◽  
Good Identification ◽  
Radial Gate

Non-destructive testing and safety monitoring of structure has been a hot and difficult engineering research problems, and an effective extraction of damage characteristic factor is a critical and theoretical research on structural damage detection and monitoring technology. The basic theory of modal strain energy and the steps to damage diagnosis are discussed in the paper.A a radial gate with different damaged locations and damaged degree is studied,and the results show that modal strain energy can be used as structural damage location sensitive factor,and that the indicator can be a very good identification of the location and extent of structural damage,and that the results of damage diagnosis are clear and reliable.

scholarly journals An Enhanced Dynamic Simulation Model of a Hybrid Magnetic Bearing Taking Account of the Sensor Noise

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1116 ◽  
Author(s):  
Dawid Wajnert ◽  
Jan K. Sykulski ◽  
Bronislaw Tomczuk
Keyword(s):  
Mathematical Model ◽  
Control System ◽  
Dynamic Simulation ◽  
Electric Circuit ◽  
Magnetic Bearing ◽  
Calculation Model ◽  
Object A ◽  
Control Signals ◽  
Dynamic Simulation Model ◽  
Simulation Results

The paper presents simulation and experimental verification of the hybrid magnetic bearing (HMB) performance characteristics. It has been demonstrated that the additional errors from the eddy current sensors have a significant impact on the control signals. An improved mathematical model combines a nonlinear magnetic equivalent circuit of the HMB with the ordinary differential equations of its transients. These equations describe the rotor motion and the electric circuit of the system, as well as the control system required for stable levitation of the rotor. Certain harmonics have been observed in the displacement signals of frequencies equal to the multiples of the cylinder rotations. The calculation model has, therefore, been improved, taking into account the interference of the harmonics. Simulation results were validated by comparing the time responses of the transients obtained from the numerical calculations with those measured on a real object; a satisfactory agreement between the results has been achieved.

Models of Cataclysmic Variables from Photometric and Spectroscopic Data

1979 ◽  
Vol 46 ◽  
pp. 65-74 ◽  
Author(s):  
A.C. Fabian ◽  
J.E. Pringle ◽  
J.A.J. Whelan ◽  
J.A. Bailey
Keyword(s):  
Spectroscopic Data ◽  
Cataclysmic Variables ◽  
System Parameters ◽  
Dwarf Nova ◽  
Spectroscopic Observations ◽  
Photometric And Spectroscopic Observations

Abstract.Recent photometric and spectroscopic observations of the dwarf nova system Z Cha are discussed. Methods for constraining the system parameters are applied and the disc emissivity is deduced as a function of radius. Indications are found that the disc shrinks in size with increasing time after outburst.

Reconstruction of Objects from their Projections Using Orthogonal Functions

1973 ◽  
Vol 31 ◽  
pp. 268-269
Author(s):  
Elrnar Zeitler
Keyword(s):  
Unit Area ◽  
Three Dimensional ◽  
One Dimension ◽  
Spatial Density ◽  
Dimensional Representation ◽  
Orthogonal Functions ◽  
Object A ◽  
Plane Normal ◽  
Dimensional Object ◽  
Spatial Density Distribution

Considering any finite three-dimensional object, a “projection” is here defined as a two-dimensional representation of the object's mass per unit area on a plane normal to a given projection axis, here taken as they-axis. Since the object can be seen as being built from parallel, thin slices, the relation between object structure and its projection can be reduced by one dimension. It is assumed that an electron microscope equipped with a tilting stage records the projectionWhere the object has a spatial density distribution p(r,ϕ) within a limiting radius taken to be unity, and the stage is tilted by an angle 9 with respect to the x-axis of the recording plane.

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