Simulation of Aircraft Landing

2018 ◽  
pp. 1-10
Author(s):  
S. G. Dzhamgarov ◽  
V. I. Oleynikov ◽  
V. A. Trudonoshin ◽  
V. G. Fedoruk
Keyword(s):  
Mathematical Model ◽  
Field Experiments ◽  
Shock Absorber ◽  
Three Dimensional ◽  
Soft Landing ◽  
Shock Absorbers ◽  
Aircraft Landing ◽  
Recovery Stroke ◽  
Object Oriented Approach ◽  
The Mathematical Model

The article proposes a mathematical model of the aircraft landing upon touchdown operation. The mathematical model can be used at the early design stages to select the rational parameters of shock absorbers to ensure soft landing. Unlike most of the papers in the field concerned, it describes the simulation of the aircraft's run-out process rather than the first touchdown impact or Dynamic Drop Testing. This is due to the use of three-dimensional mathematical models of mechanical systems, including the aircraft body. In addition to the forces on the aircraft, the article gives a sufficiently detailed representation of the forces that arise in the shock absorber. The simulation results obtained using the PA8 complex developed at the CAD Department in Bauman Moscow State Technical University are presented. The diagrams presented show the effect of the clearance in the chambers of recovery stroke on the operation of shock absorbers and, as a consequence, on ensuring the soft landing conditions. An object-oriented approach, implemented in the complex, allows us to evaluate the influence of each element on the system dynamics. The article presents the time diagrams of the force of a gas spring taking into account the dry friction and the hydraulic force in the shock absorber. In conclusion, a rational, in authors’ opinion, approach to designing shock absorbers is shown. One of the points of this approach is the validation of shock absorber parameters based on the results of Dynamic Drop Testing and, after that, simulation of the aircraft landing with validated parameters. Such a technique will allow us to minimize the number of field experiments, and as a result, will shorten the design time and put the product into operation.

The Design of Shock Absorbers for Chemical Equipments

2012 ◽  
Vol 479-481 ◽  
pp. 1283-1287
Author(s):  
Xin Yang ◽  
Xiao Yu Guo ◽  
Ming Liang Ding
Keyword(s):  
Mathematical Model ◽  
Chemical Process ◽  
Shock Absorber ◽  
Low Cost ◽  
Field Validation ◽  
Shock Absorption ◽  
Vibration Problem ◽  
Shock Absorbers ◽  
The Mathematical Model ◽  
Validation Testing

A low cost shock absorber easy to install and tune was designed to solve the vibration problem produced by the compressor in chemical process. By establishing the mathematical model of the dynamic shock absorption, the shock absorber characteristics were analyzed theoretically. The preliminary experiment was conducted on the testing platform to simulate the factory conditions. The shock absorber was then installed on the compressor for the field validation. Testing results agree well with theory and the shock absorber showed good damping performance.

Research on cargo-loading optimization based on genetic and fuzzy integration

2021 ◽  
Vol 40 (4) ◽  
pp. 8493-8500
Author(s):  
Yanwei Du ◽  
Feng Chen ◽  
Xiaoyi Fan ◽  
Lei Zhang ◽  
Henggang Liang
Keyword(s):  
Genetic Algorithm ◽  
Mathematical Model ◽  
Three Dimensional ◽  
Distribution Center ◽  
Long Time ◽  
Low Efficiency ◽  
Decision Making Model ◽  
The Mathematical Model ◽  
Loading Scheme

With the increase of the number of loaded goods, the number of optional loading schemes will increase exponentially. It is a long time and low efficiency to determine the loading scheme with experience. Genetic algorithm is a search heuristic algorithm used to solve optimization in the field of computer science artificial intelligence. Genetic algorithm can effectively select the optimal loading scheme but unable to utilize weight and volume capacity of cargo and truck. In this paper, we propose hybrid Genetic and fuzzy logic based cargo-loading decision making model that focus on achieving maximum profit with maximum utilization of weight and volume capacity of cargo and truck. In this paper, first of all, the components of the problem of goods stowage in the distribution center are analyzed systematically, which lays the foundation for the reasonable classification of the problem of goods stowage and the establishment of the mathematical model of the problem of goods stowage. Secondly, the paper abstracts and defines the problem of goods loading in distribution center, establishes the mathematical model for the optimization of single car three-dimensional goods loading, and designs the genetic algorithm for solving the model. Finally, Matlab is used to solve the optimization model of cargo loading, and the good performance of the algorithm is verified by an example. From the performance evaluation analysis, proposed the hybrid system achieve better outcomes than the standard SA model, GA method, and TS strategy.

Simulation Investigation on Environment-Induced Pitting Corrosion on the Metal Surface

2021 ◽  
Vol 13 (5) ◽  
pp. 820-828
Author(s):  
Wei Zhang ◽  
Shengli Lv ◽  
Leijiang Yao ◽  
Xiaoyan Tong
Keyword(s):  
Mathematical Model ◽  
Pitting Corrosion ◽  
Three Dimensional ◽  
Corrosion Damage ◽  
Sudden Onset ◽  
Ion Concentration ◽  
Two Dimensional Image ◽  
Aging Aircraft ◽  
Efficient Calculation ◽  
The Mathematical Model

The prediction of corrosion damage is one of effective research methods in the safety inspection of aging aircraft structures. A mathematical model for quantifying corrosion damage is used in this paper to predict the onset of corrosion on structural surfaces exposed to aggressive environments. Based on the finite difference technique, the evolution process of local pitting corrosion on the surface of aluminum alloy in the medium is simulated, which can consider the sudden onset and the randomness of pitting corrosion. The effect of local ion concentration and oxide film damage on subsequent pitting nucleation was analyzed. Based on the efficient calculation program, the effectiveness of the mathematical model is verified by the comparison between the corrosion damage morphology and the experimental data in the literature. The results show a more widespread distribution of subsequent pits because of stronger aggressive ions are released during the life cycle of active pits and the higher diffusion coefficient of the aggressive ions. The three dimensional morphology is generated by image processing method based on the gray value of the two dimensional image of pits.

Investigation into the dynamic characteristics of downhole perforation tools with multiple shock absorbers

2019 ◽  
Vol 20 (6) ◽  
pp. 622
Author(s):  
Xiaoqiang Guo ◽  
Jun Liu ◽  
Guorong Wang ◽  
Qingyou Liu ◽  
Xianming Song
Keyword(s):  
Dynamic Characteristics ◽  
Field Experiments ◽  
Shock Absorber ◽  
Response Amplitude ◽  
Ansys Software ◽  
Maximum Acceleration ◽  
Shock Absorbers ◽  
Tubing String ◽  
Testing Instruments ◽  
Multiple Shock

The use of large-charged perforating bullets after well perforation produces large impact loads, which can easily lead to early unsealing of packers, damage to testing instruments, stress failure of tubing strings, buckling deformation, and other adverse incidents. This study focuses on the safety of large-charged perforating bullets used in downhole tools. In addition, a dynamic model of downhole perforation tools with multi-shock absorber was designed, and ANSYS software was used to validate its accuracy. Perforation impact loading field experiments were developed, and the loading pressure was measured over time to obtain an even more accurate equation to calculate loading. Analysis of the effects of different numbers of shock absorbers on the dynamic characteristics of downhole tools was conducted, finding that increasing the number of shock absorbers from one to two significantly decreased the dynamic response amplitude of the downhole tools (displacement, axial force, and packer force). However, when the number was increased to three, the change in response amplitude was not significant. Based on the maximum acceleration of each section of the tubing string, the testing instrument is best installed at its upper end. As the number of shock absorbers is increased, the number of regions of the tubing string that undergo buckling deformation decreases. Increasing the number of shock absorbers helps prevent buckling deformation in the tubing string, and increases its service life.

Mathematical modeling of a generic multi-profile form milling cutter

2012 ◽  
Vol 227 (5) ◽  
pp. 1036-1046 ◽  
Author(s):  
Mohammed Rajik Khan ◽  
Puneet Tandon
Keyword(s):  
Mathematical Model ◽  
Three Dimensional ◽  
Sculptured Surfaces ◽  
Three Dimensional Model ◽  
Machining Time ◽  
Milling Cutter ◽  
Machined Parts ◽  
Rotary Cutting ◽  
Three Dimensional Models ◽  
The Mathematical Model

In order to machine multiple sculptured surfaces with reduced machining time and high accuracy of the machined parts, shape design of a customised multi-point rotary cutting tool needs to be evolved. In the present work, a novel design of a generic multi-profile form milling cutter is developed for machining various multiple sculptured surfaces. This article describes in detail the mathematical model to design an accurate three-dimensional geometry of a generic multi-profile form milling cutter. Use of non-uniform rational B-spline curve(s) and sweep surfaces enables to control the shape of cutting flutes of the generic multi-profile form milling cutter. The article also discusses the methodology to develop a variety of cutters lying in the same conceptual family of multi-profile form milling cutter. To physically visualise the cutter and to show one of the downstream applications once a three-dimensional model of the cutter is available, one of the multi-profile form milling cutters is fabricated. The proposed methodology offers an intuitive high-quality mathematical model for a generic family of multi-profile form milling cutters, which is different from the traditional three-dimensional models.

Computations of Three-Dimensional Gas-Turbine Combustion Chamber Flows

1979 ◽  
Vol 101 (3) ◽  
pp. 326-336 ◽  
Author(s):  
M. A. Serag-Eldin ◽  
D. B. Spalding
Keyword(s):  
Mathematical Model ◽  
Turbulent Flows ◽  
Combustion Process ◽  
Three Dimensional ◽  
Solution Algorithm ◽  
Physical Models ◽  
Turbulence Energy ◽  
Experimental Conditions ◽  
Diffusion Controlled ◽  
The Mathematical Model

The paper presents a mathematical model for three-dimensional, swirling, recirculating, turbulent flows inside can combustors. The present model is restricted to single-phase, diffusion-controlled combustion, with negligible radiation heat-transfer; however, the introduction of other available physical models can remove these restrictions. The mathematical model comprises differential equations for: continuity, momentum, stagnation enthalpy, concentration, turbulence energy, its dissipation rate, and the mean square of concentration fluctuations. The simultaneous solution of these equations by means of a finite-difference solution algorithm yields the values of the variables at all internal grid nodes. The prediction procedure, composed of the mathematical model and its solution algorithm, is applied to predict the fields of variables within a representative can combustor; the results are compared with corresponding measurements. The predicted results give the same trends as the measured ones, but the quantitative agreement is not always acceptable; this is attributed to the combustion process not being truly diffusion-controlled for the experimental conditions investigated.

Calculations of three-dimensional viscous flow in a multiblade centrifugal fan by modelling blade forces

2003 ◽  
Vol 217 (3) ◽  
pp. 287-297 ◽  
Author(s):  
S-J Seo ◽  
K-Y Kim ◽  
S-H Kang
Keyword(s):  
Mathematical Model ◽  
Turbulent Flows ◽  
Numerical Study ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Centrifugal Fan ◽  
Complex Flows ◽  
Flow Through ◽  
Volume Method ◽  
The Mathematical Model

A numerical study is presented for Reynolds-averaged Navier-Stokes analysis of three-dimensional turbulent flows in a multiblade centrifugal fan. Present work aims at development of a relatively simple analysis method for these complex flows. A mathematical model of impeller forces is obtained from the integral analysis of the flow through the impeller. A finite volume method for discretization of governing equations and a standard k-ɛ model as turbulence closure are employed. For the validation of the mathematical model, the computational results for velocity components, static pressure, and flow angles at the exit of the impeller were compared with experimental data. The comparisons show generally good agreement, especially at higher flow coefficients.

Modeling and Simulation Analysis of the Twist Drill Conical Grinding Method Based on Pro/E Software

2010 ◽  
Vol 160-162 ◽  
pp. 1680-1684
Author(s):  
Xing Jun Gao ◽  
Qing Liu ◽  
Ping Zou ◽  
Jian Song ◽  
Ping Li
Keyword(s):  
Mathematical Model ◽  
Simulation Analysis ◽  
Three Dimensional ◽  
Fundamental Principle ◽  
Drilling Process ◽  
Twist Drill ◽  
Three Dimensional Modeling ◽  
Grinding Method ◽  
Dimensional Modeling ◽  
The Mathematical Model

The fundamental principle of the twist drill conical grinding method was introduced. The mathematical model of the twist drill was established. Mathematical model to establish drill bit is the geometric design, manufacture, cutting analysis and modeling on the basis of the drilling process. According to the twist drill grinding principle, using Pro/E the three-dimensional modeling of the twist drill was completed, and the feature of the conical grinding method was analyzed.

Updating the Mathematical Model of a Structure Using Vibration Data

2005 ◽  
Vol 11 (12) ◽  
pp. 1469-1486 ◽  
Author(s):  
Ashutosh Bagchi
Keyword(s):  
Mathematical Model ◽  
Model Updating ◽  
Three Dimensional ◽  
Field Tests ◽  
Mode Shapes ◽  
Actual Structure ◽  
Shell Elements ◽  
Vibration Data ◽  
The Difference ◽  
The Mathematical Model

Model updating is an important step for correlating the mathematical model of a structure to the real one. There are a variety of techniques available for model updating using dynamic and static measurements of the structure’s behavior. This paper concentrates on the model updating techniques using the natural frequencies or frequencies and mode shapes of a structure. An iterative technique is developed based on the matrix update method. The method hasbeenappliedtothefiniteelement models of a three span continuous steel free deck bridge located in western Canada. The finite element models of the bridge have been constructed using three-dimensional beam and facet shell elements and the models have been updated using the measured frequencies. From the study it is clear that the initial model needs to be built such that it represents the actual structure as closely as possible. The results demonstrate that the difference between the modal parameters from the model and field tests affect the quality of the model updating process.

Research on Damping Properties of Seperated and Manually Adjustable Shock Absorber Oriented to Damping Matching

2013 ◽  
Vol 694-697 ◽  
pp. 36-40 ◽  
Author(s):  
Da Feng Song ◽  
Gong Ke Yang ◽  
Chun Xiao Du
Keyword(s):  
Mathematical Model ◽  
Structural Changes ◽  
Shock Absorber ◽  
Structural Parameters ◽  
Characteristic Curve ◽  
Bench Test ◽  
Damping Properties ◽  
Damping Characteristics ◽  
Test Use ◽  
The Mathematical Model

On the basis of the structure characteristics of the seperated manually adjustable damper and its working principles, establish the shock absorber mathematical model, at the same time, get test data and curves of seperated manually adjustable shock absorber damping characteristics by bench test. Use MATLAB to simulate the characteristic curve of the speed of the shock absorber based on the mathematical model. The simulation curves and experimental curves were compared to verify the correctness and accuracy of the model. Further simulation and analysis affect of parts of structural changes on the damping characteristics. In order to provide a theoretical basis to structural parameters designing and vehicle damping matching.

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