Multi-body coupling dynamic research of carrier-based aircraft catapult launch based on natural coordinate method

2018 ◽  
Vol 233 (2) ◽  
pp. 195-207
Author(s):  
Dong Apeng ◽  
Li Shu ◽  
Zhu Wenguo
Keyword(s):  
Dynamic Properties ◽  
Topological Analysis ◽  
Steam Flow ◽  
Flow Area ◽  
Coordinate Method ◽  
Mechanical Behaviours ◽  
Increasing Demand ◽  
New Perspective ◽  
Natural Coordinate ◽  
Multi Body

There is an increasing demand for predicting the dynamic behaviours of carrier-based aircrafts(CBAs) during catapult launch. This paper presents a maximal parameterised dynamic model of the launch process from a new perspective, and conducts a detailed study of its mechanical behaviours. Based on the topological analysis of the multi-body catapult launch system, the natural coordinate method is adopted to establish a comprehensive model including steam catapult, landing gears, ship motion, aerodynamic and multi-body modules. The predictive capability of the model is demonstrated by presenting the CBA launch dynamic properties under different conditions. First, effects of steam flow area rate and the coupling carrier movement in different directions on catapult performance are discussed. Second, the take-off characteristics as well as the initial catapult attitude are analysed. Then, by investigating Lagrange multipliers, the loads of torque arms, holdback bar and launch bar are compared. Finally, the loads of buffer struts and tyres during launch are also discussed. The results show that it is reasonable to keep the steam flow area increasing in a linear way, but the opening velocity needs to be strictly controlled. When the CBA departs from the deck, the possible sink of the bow is the major threat to the take-off safety, the larger the sink is, the more dangerous the flight becomes. The upwash at the bow may be the primary reason of stall and cannot be ignored. The model established is reliable with capacities of capturing the coupled behaviours between different sub-modules as well as the load change of each component in detail. The natural coordinate method proves to be efficient and accurate, which should be given more attention.

On the Application of the Lu-Gre Model to Simulate Joint Friction in Multi-Body Systems

2011 ◽  
Author(s):  
Kedar Gajanan Kale ◽  
Rajiv Rampalli
Keyword(s):  
Friction Model ◽  
Lugre Model ◽  
Friction Forces ◽  
Joint Friction ◽  
Modeling Techniques ◽  
Static Regime ◽  
Increasing Demand ◽  
Automotive Suspension ◽  
Multi Body

Advances in the application of multi-body simulation technology to real world problems have led to an ever increasing demand for higher fidelity modeling techniques. Of these, accurate modeling of friction is of strategic interest in applications such as control system design, automotive suspension analysis, robotics etc. Joints (sometimes referred to as constraints) play an important role in defining the dynamics of a multi-body system. Hence, it is imperative to accurately account for friction forces arising at these joints due to the underlying interface dynamics. In this paper, we discuss the application of LuGre, a dynamic friction model to simulate joint friction. We choose the LuGre model due to its ability to capture important effects such as the Stribeck effect and the Dahl effect. The native 1-d LuGre model is extended to formulate friction computations for non-trivial joint geometries and dynamics in 2 and 3 dimensions. It is also extended to work in the quasi-static regime. Specific applications to revolute, cylindrical and spherical joints in multi-body systems are discussed. Finally, an engineering case study on the effects of joint friction in automotive suspension analysis is presented.

Investigation on Innovative Design Method of Vehicles

2011 ◽  
Vol 311-313 ◽  
pp. 2182-2186
Author(s):  
Liang Jun Li ◽  
Zhao Hui Huang
Keyword(s):  
Creative Thinking ◽  
Design Method ◽  
Industrial Scale ◽  
Industrial Products ◽  
Innovative Design ◽  
Independent Innovation ◽  
Innovative Method ◽  
Increasing Demand ◽  
New Perspective

After thousands of years of evolution and innovation, transportation has become one of the most indispensible industrial products. Along with the increasing demand for transportation, its industrial scale is increasing and it is also a trend for the flourish development of relative disciplines. Based in the innovative method, this article discusses on the means and belief for creative thinking of transportation from a brand new perspective, which in order to promote and contribute to independent innovation of China transportation design.

The Study of Elastic Dynamic of the Deployment Mechanism in Large Deployable Reflector

2013 ◽  
Vol 390 ◽  
pp. 246-250
Author(s):  
San Min Wang ◽  
Su Chen ◽  
Ru Yuan
Keyword(s):  
Elastic Deformation ◽  
Dynamic Properties ◽  
Rigid Body Dynamics ◽  
Dynamics Model ◽  
Satellite Antenna ◽  
Body Dynamics ◽  
Multi Body ◽  
Development Structure ◽  
Deployable Reflector ◽  
Method Analysis

The study regards the ETS-VIII satellite antenna unit deployment mechanism as object, uses multi-body dynamics theory as basement to build the rigid body dynamics model of the unit bodies, adopts the finite element method analysis of bending of elastic deformation of the linkage, to establish a unit elasticity of dynamics model and to research the components of flexible dynamic properties of the cell bodies of satellite antenna development. The result of the research shows that the flexibility of the component will lead to the elastic deformation of the cell bodies, in which beats significantly in the location of the maximum abduction, takes place in the deployment process. The research lies the foundation for the dynamic optimization of design of development structure.

scholarly journals OPTIMIZATION OF THE SUNFLOWER FERTILIZATION SYSTEM BASED ON THE USE OF MODERN MICROBIOLOGICAL FERTILIZERS

2020 ◽  
pp. 65-75
Author(s):  
Viacheslav Tsyhanskyi
Keyword(s):  
Food System ◽  
Crop Yields ◽  
Mineral Elements ◽  
Biological Origin ◽  
Action Mechanisms ◽  
Leaf Surface Area ◽  
Phosphorus And Potassium ◽  
Increasing Demand ◽  
New Perspective ◽  
Sowing Seed

In current conditions of agricultural production with intensive technologies of growing crops, fertilizer is one of the most expensive elements of agricultural machinery, as experienced agricultural experts say that the food system should be optimized. In recent years, biological preparations of various action mechanisms are in increasing demand among farmers. Particular attention is paid to mycorrhizal biopreparations, one of which is "Mykofriend" and preparations based on phosphorus and potassium mobilizing bacteria "Groundfix". Preparations stimulate the development of beneficial soil microorganisms, help preserve and increase soil fertility, activate its suppression against phytopathogens, improve productivity in crop yields, including sunflower. This article presents important aspects of the technology of growing sunflower with a variety of applications of biological origin, which optimize the process of plant nutrition through better use of mineral elements and improve growth processes. New perspective biological preparations, manufactured by BTU Center, for pre-sowing seed treatment and soil application were studied. It was found out that the treatment of seeds with mycorrhizal drug Mycofriend with the rate of 4 l / t and when applying pre-sowing cultivation of biological fertilizer Graunfix at a rate of 8 l / ha contributed to the formation of the best conditions for plant growth and development, and as a consequence of the best productivity parameters. In this variant, the maximum plant height of 189.3 cm, leaf surface area of 30.9 thousand m2 / ha (flowering phase), dry matter yield in the ripening phase of 5.28 t / ha, basket diameter of 23.1 cm, weight of 1000 seeds is 49.6 g and seed yield is 2.84 t / ha.

scholarly journals Simulation of running a vehicle with a Y25 bogie on a theoretical track

2021 ◽  
Vol 1199 (1) ◽  
pp. 012079
Author(s):  
S Solčanský ◽  
S Knap
Keyword(s):  
3D Model ◽  
Dynamic Properties ◽  
Academic Research ◽  
Simulation Software ◽  
Railway Vehicle ◽  
Vertical Load ◽  
Lateral Forces ◽  
Technical Specifications ◽  
Definition Of ◽  
Multi Body

Abstract This paper is focused on the simulation of a railway vehicle with a Y25 bogie running on a theoretical track and it will simulate its dynamic properties. The model was created in multi-body simulation software SIMULIA - SIMPACK. The first part mentions the basics theoretical information about the forces which acts in the bogie for example vertical load, slip or lateral forces of the wheelset. The definition of the theoretical track is listed as well. The second part deals with the basics information about technical specifications of the Y25 bogie and its usage. In the next part, the 3D model of the Y25 bogie is described. This section also describes the simulation, which is performed at different speeds. In the last part, results are evaluated and compared for each speed. Results will be suitable for further academic research and development.

scholarly journals Structure and Evolution of the International Pesticide Trade Networks

2021 ◽  
Vol 9 ◽  
Author(s):  
Jian-An Li ◽  
Wen-Jie Xie ◽  
Wei-Xing Zhou
Keyword(s):  
International Trade ◽  
Dynamic Properties ◽  
Network Size ◽  
Clustering Coefficient ◽  
Trade Networks ◽  
The World ◽  
Local Clustering ◽  
Increasing Demand ◽  
Positive Correlations ◽  
Local Clustering Coefficient

To meet the increasing demand for food around the world, pesticides are widely used and will continue to be widely used in agricultural production to reduce yield losses and maintain product quality. International pesticide trade serves to reallocate the distribution of pesticides around the world. We investigate the statistical properties of the international trade networks of five categories of pesticides from the view angle of temporal directed and weighted networks. We observed an overall increasing trend in network size, network density, average in- and out-degrees, average in- and out-strengths, temporal similarity, and link reciprocity, indicating that the rising globalization of pesticides trade is driving the networks denser. However, the distributions of link weights remain unchanged along time for the five categories of pesticides. In addition, all the networks are disassortatively mixed because large importers or exporters are more likely to trade with small exporters or importers. We also observed positive correlations between in-degree and out-degree, in-strength and out-strength, link reciprocity and in-degree, out-degree, in-strength, and out-strength, while node’s local clustering coefficient is negatively related to in-degree, out-degree, in-strength, and out-strength. We show that some structural and dynamic properties of the international pesticide trade networks are different from those of the international trade networks, highlighting the presence of idiosyncratic features of different goods and products in the international trade.

Schwingungseigenschaften effizient vorausbestimmen*/Efficient prediction of dynamic properties - Frequency-based substructuring for prediction of assembly properties during product development

2016 ◽  
Vol 106 (05) ◽  
pp. 294-301
Author(s):  
C. Prof. Brecher ◽  
M. Fey ◽  
M. Daniels
Keyword(s):  
Finite Element ◽  
Product Development ◽  
Dynamic Properties ◽  
Simulation Models ◽  
Experimental Models ◽  
Simple Design ◽  
Modeling Effort ◽  
Finite Elemente ◽  
Efficient Prediction ◽  
Multi Body

Zur qualitativen Vorhersage der Schwingungseigenschaften neuer Konstruktionen werden oftmals aufwendige Finite-Elemente- oder Mehrkörper-Simulationen vollständiger Werkzeugmaschinen durchgeführt. Mithilfe der hier vorgestellten Kopplungsrechnungen können experimentell und analytisch basierte Modelle miteinander verbunden werden. Insbesondere für Anpass- und Änderungskonstruktionen ergeben sich damit Vorteile bezüglich der Prognosegenauigkeit und des Modellierungsaufwands.   For the qualitative prediction of dynamic properties of new constructions, elaborate finite element or multi body simulation models are frequently applied. This paper deals with coupling calculations that combine analytical and experimental models. With these coupling calculations better predictions of dynamic properties are possible and less modeling effort is needed. This is particularly true if simple design adaptions or modifications shall be realized.

Steam Flow in Nozzle and the Nozzle Calculation

2013 ◽  
Vol 433-435 ◽  
pp. 1975-1978
Author(s):  
Ya Rong Wang ◽  
Pei Rong Wang
Keyword(s):  
Flow Velocity ◽  
Air Conditioning ◽  
Steam Flow ◽  
Power Equipment ◽  
Steam Turbines ◽  
Flow Process ◽  
Flow Area ◽  
Adiabatic Flow ◽  
Impeller Type ◽  
The Relationship

The adiabatic flow process of gas or steam in a nozzle is not only widely used in steam turbines or other power equipment, but also applied to ejectors, impeller-type compressors, burners and other thermal devices in air conditioning, ventilation and gas engineering. In this paper we will describe steam flow in nozzle and the nozzle calculation, especially the relationship between the flow velocity and the flow area. We will describe the calculation on the velocity through a nozzle and the calculation on the area of the nozzle by an example.

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