scholarly journals METHOD OF DETERMINING THE EFFECTIVENESS OF A MISSILE’S BLAST-FRAGMENTATION WARHEAD BY USE OF COMPUTATIONAL METHOD AND EXPERIMENT

2020 ◽  
pp. 83-91
Author(s):  
S. Moskalets ◽  
V. Zhyrnyi ◽  
A. Rudyk ◽  
A. Artikula
Keyword(s):  
High Speed ◽  
Specific Impulse ◽  
Development Trend ◽  
Computational Method ◽  
Total Probability ◽  
Explosive Power ◽  
Operational Characteristics ◽  
Blast Fragmentation ◽  
Debris Impact ◽  
Injurious Effects

Armaments are characterized by groups of technical and operational characteristics, each of which is divided into separate indicators. These include effectiveness, ranges of use; combat capability, reliability, operational safety. Under the effectiveness of the missile’s warhead it shall be understood the amount of damage that can cause an explosion in combat environment. The aim of the work is to evaluate the effectiveness of the blast-fragmentation warhead by modeling and analyzing the damaging of injurious effects. Primary blast-fragmentation warhead effects are a shock wave, which is characterized by a specific air pressure on its front and a specific impulse, as well as fragments that move at high speed. Determining the effectiveness of target neutralization by the fragmentation effect of the warhead is described by a set of positions of the j units, each of which is characterized by the fractional volume, the angle of inclination, the type of losses. Due to the independent impact on the target of several effects, their whole impact can be estimated by the total probability of individual injurious effects. The effectiveness of warhead is assessed by the probability of hitting the target. It is most rational to achieve the goal by reducing the distance to the explosion while increasing accuracy. This is a global development trend. Other ways are either to increase its explosive power or structurally - the number of fragments. It is necessary to indicate experimental data on the number of holes per unit area for a given distance and characteristics of the warhead of the missile. Assessing the probability of the debris impact requires clarification of the characteristics of the warhead, the characteristics of the vulnerable spots of the target and the angle of the missile approach. It is advisable to make the trajectory of the missile approach guided, taking into account the modularity of the configuration. This reduces ammunition consumption and increases the efficiency of the warhead.

Recent Patents on the Angular Contact Ball Bearing of High-Speed Motorized Spindle

2020 ◽  
Vol 13 ◽  
Author(s):  
Yudong Bao ◽  
Linkai Wu ◽  
Yanling Zhao ◽  
Chengyi Pan
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Rapid Development ◽  
Ceramic Materials ◽  
Development Trend ◽  
Numerical Control ◽  
Angular Contact Ball Bearing ◽  
Practical Applications ◽  
High Speed Cutting ◽  
Advantages And Disadvantages

Background:: Angular contact ball bearings are the most popular bearing type used in the high speed spindle for machining centers, The performance of the bearing directly affects the machining efficiency of the machine tool, Obtaining a higher value is the direction of its research and development. Objective:: By analyzing the research achievements and patents of electric spindle angular contact bearings, summarizing the development trend provides a reference for the development of electric spindle bearings. Methods:: Through the analysis of the relevant technology of the electric spindle angular contact ball bearing, the advantages and disadvantages of the angular contact ball bearing are introduced, and the research results are combined with the patent analysis. Results:: With the rapid development of high-speed cutting and numerical control technology and the needs of practical applications, the spindle requires higher and higher speeds for bearings. In order to meet the requirements of use, it is necessary to improve the bearing performance by optimizing the structure size and improving the lubrication conditions. Meanwhile, reasonable processing and assembly methods will also have a beneficial effect on bearing performance. Conclusion:: With the continuous deepening of bearing technology research and the use of new structures and ceramic materials has made the bearing's limit speed repeatedly reach new highs. The future development trend of high-speed bearings for electric spindles is environmental protection, intelligence, high speed, high precision and long life.

Review of Research on Hydrostatic Bearings

2020 ◽  
Vol 13 ◽  
Author(s):  
Xiaodong Yu ◽  
Yu Wang ◽  
Junfeng Wang ◽  
Wenkai Zhou ◽  
Hongwei Bi ◽  
...  
Keyword(s):  
High Speed ◽  
Static Pressure ◽  
Development Trend ◽  
Cnc Machining ◽  
Pressure Effects ◽  
Cnc Machine Tools ◽  
Future Research ◽  
Theoretical Formula ◽  
Hydrostatic Bearing ◽  
Hydrostatic Bearings

Background: Hydrostatic bearings have the advantages of strong bearing capacity, good stability, small friction coefficient and long life. The performance of liquid hydrostatic bearings directly affect the accuracy and efficiency of CNC machining equipment. The performance is conducive to the development of CNC machine tools towards high speed and heavy load, so it is necessary to sort out and summarize the existing research results. Objective: This study summarizes the current development status of hydrostatic bearings and explains the development trend of hydrostatic bearings. Methods: According to the recently published journal articles and patents, the recent experimental research on hydrostatic thrust bearings is summarized. This paper summarizes many factors that affect the performance of hydrostatic bearings, and discusses the causes of various factors on hydrostatic bearings. Finally, future research on hydrostatic bearings is presented. Results: The study discusses experimental methods, simulation processes, and experimental results. Conclusion: This study can produce dynamic and static pressure effects by changing the structure of the oil cavity of the hydrostatic bearing. This effect can make up for the static pressure loss. By improving the theoretical formula and mathematical model and proposing a new simulation method, the accuracy of the hydrostatic bearing simulation is satisfied; the future development trend of the hydrostatic bearing is proposed.

scholarly journals Part-optimized forming by spatially distributed vaporizing foil actuators

2021 ◽  
Author(s):  
Marlon Hahn ◽  
A. Erman Tekkaya
Keyword(s):  
Process Design ◽  
High Speed ◽  
Specific Impulse ◽  
Design Procedure ◽  
Mathematical Optimization ◽  
Starting Point ◽  
Spatially Distributed ◽  
Lower Tool ◽  
A Minor ◽  
Charging Energy

AbstractElectrically vaporizing foil actuators are employed as an innovative high speed sheet metal forming technology, which has the potential to lower tool costs. To reduce experimental try-outs, a predictive physics-based process design procedure is developed for the first time. It consists of a mathematical optimization utilizing numerical forming simulations followed by analytical computations for the forming-impulse generation through the rapid Joule heating of the foils. The proposed method is demonstrated for an exemplary steel sheet part. The resulting process design provides a part-specific impulse distribution, corresponding parallel actuator geometries, and the pulse generator’s charging energy, so that all process parameters are available before the first experiment. The experimental validation is then performed for the example part. Formed parts indicate that the introduced method yields a good starting point for actual testing, as it only requires adjustments in the form of a minor charging energy augmentation. This was expectable due to the conservative nature of the underlying modeling. The part geometry obtained with the most suitable charging energy is finally compared to the target geometry.

scholarly journals Additively Manufactured Parts Made of a Polymer Material Used for the Experimental Verification of a Component of a High-Speed Machine with an Optimised Geometry—Preliminary Research

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 137
Author(s):  
Artur Andrearczyk ◽  
Bartlomiej Konieczny ◽  
Jerzy Sokołowski
Keyword(s):  
Polymer Material ◽  
High Speed ◽  
Numerical Models ◽  
Flow Analysis ◽  
Experimental Tests ◽  
Strength Analysis ◽  
Compressor Wheel ◽  
Operational Characteristics ◽  
3D Printed ◽  
Novel Method

This paper describes a novel method for the experimental validation of numerically optimised turbomachinery components. In the field of additive manufacturing, numerical models still need to be improved, especially with the experimental data. The paper presents the operational characteristics of a compressor wheel, measured during experimental research. The validation process included conducting a computational flow analysis and experimental tests of two compressor wheels: The aluminium wheel and the 3D printed wheel (made of a polymer material). The chosen manufacturing technology and the results obtained made it possible to determine the speed range in which the operation of the tested machine is stable. In addition, dynamic destructive tests were performed on the polymer disc and their results were compared with the results of the strength analysis. The tests were carried out at high rotational speeds (up to 120,000 rpm). The results of the research described above have proven the utility of this technology in the research and development of high-speed turbomachines operating at speeds up to 90,000 rpm. The research results obtained show that the technology used is suitable for multi-variant optimization of the tested machine part. This work has also contributed to the further development of numerical models.

scholarly journals Development of a wind turbine gearbox virtual load sensor using multibody simulation and artificial neural networks

2021 ◽  
Author(s):  
Baher Azzam ◽  
Ralf Schelenz ◽  
Björn Roscher ◽  
Abdul Baseer ◽  
Georg Jacobs
Keyword(s):  
Time Series ◽  
Wind Turbine ◽  
High Speed ◽  
Time Series Data ◽  
Development Trend ◽  
Series Data ◽  
Ann Model ◽  
Wind Turbine Gearbox ◽  
Virtual Sensor ◽  
Artificial Neural

AbstractA current development trend in wind energy is characterized by the installation of wind turbines (WT) with increasing rated power output. Higher towers and larger rotor diameters increase rated power leading to an intensification of the load situation on the drive train and the main gearbox. However, current main gearbox condition monitoring systems (CMS) do not record the 6‑degree of freedom (6-DOF) input loads to the transmission as it is too expensive. Therefore, this investigation aims to present an approach to develop and validate a low-cost virtual sensor for measuring the input loads of a WT main gearbox. A prototype of the virtual sensor system was developed in a virtual environment using a multi-body simulation (MBS) model of a WT drivetrain and artificial neural network (ANN) models. Simulated wind fields according to IEC 61400‑1 covering a variety of wind speeds were generated and applied to a MBS model of a Vestas V52 wind turbine. The turbine contains a high-speed drivetrain with 4‑points bearing suspension, a common drivetrain configuration. The simulation was used to generate time-series data of the target and input parameters for the virtual sensor algorithm, an ANN model. After the ANN was trained using the time-series data collected from the MBS, the developed virtual sensor algorithm was tested by comparing the estimated 6‑DOF transmission input loads from the ANN to the simulated 6‑DOF transmission input loads from the MBS. The results show high potential for virtual sensing 6‑DOF wind turbine transmission input loads using the presented method.

The Measurement of Water Bursting Volume of Jianfeng Mountain Tunnel and Treatment Techniques of Water Bursting

2012 ◽  
Vol 204-208 ◽  
pp. 1335-1342
Author(s):  
Jun Huang ◽  
Guo Ming Li ◽  
Bing Wang ◽  
Hong Zhou Liu ◽  
Rui Gang Song
Keyword(s):  
High Speed ◽  
Development Trend ◽  
Water Inflow ◽  
Treatment Techniques ◽  
Design Changes ◽  
Chongqing City ◽  
Survey Results ◽  
Large Water ◽  
Water Bursting ◽  
The Development Trend

The measurement of tunnel water inflow is not only an important basis for engineering design changes, but also an effective verification of design. This paper combines with the analysis of the measured data of groundwater of large water inflow section, which appeared in the construction of high-speed Jianfeng mountain super long tunnel in Fuling Fengdu, Chongqing city, and detailed information of hydrological survey results. This paper has re-evaluated the engineering geology and hydro-geological of large gushing sections to clear the reason of water inflow, the development trend characteristics of groundwater and stability of surrounding rock. It is shown in this paper that the measures such as strengthening the support parameters, optimizing the waterproof and drainaging design schemes, and other measures can be adopted to ensure the safety of tunnel construction and effectively realize the concept of dynamic construction.

Study on Kinematics Sensitivities of Folder Mechanism with Clearance

2011 ◽  
Vol 121-126 ◽  
pp. 4764-4769
Author(s):  
Ying Cai Yuan ◽  
Yan Li ◽  
Yi Ming Wang ◽  
Qiang Guo
Keyword(s):  
Sensitivity Analysis ◽  
High Velocity ◽  
High Speed ◽  
Development Trend ◽  
Matrix Analysis ◽  
Analysis Model ◽  
Design Variables ◽  
The Matrix ◽  
The Stability ◽  
Definition Of

High velocity and stability are the development trend and inevitable requirement, but the clearance would make the stability of mechanical system deceased, especially in high speed. To the folder mechanism with clearances in high velocity, combined with the definition of sensitivity and the kinematics analysis, the kinematics sensitivity analysis model is derived by the matrix analysis method. Through the sensitivity analysis model, it can be easy to get the relationship of the design variables and the mechanism’s robustness, which provides the base to design the folder mechanism in high velocity.

scholarly journals Computational Test Design for High-Speed Liquid Impact and Dispersal

2011 ◽  
Author(s):  
Alexander L. Brown ◽  
Kurt E. Metzinger
Keyword(s):  
High Speed ◽  
Water Channel ◽  
Computational Method ◽  
Computational Fluid Mechanics ◽  
Reacting Flow ◽  
Validation Data ◽  
Sled Test ◽  
The Impact ◽  
Scale Data ◽  
Limited Scope

Transportation accidents frequently involve liquids dispersing in the atmosphere. An example is that of aircraft impacts, which often result in spreading fuel and a subsequent fire. Predicting the resulting environment is of interest for design, safety, and forensic applications. This environment is challenging for many reasons, one among them being the disparate time and length scales that must be resolved for an accurate physical representation of the problem. A recent computational method appropriate for this class of problems has been developed for modeling the impact and subsequent liquid spread. This involves coupling a structural dynamics code to a turbulent computational fluid mechanics reacting flow code. Because the environment intended to be simulated with this capability is difficult to instrument and costly to test, the existing validation data are of limited scope, relevance, and quality. A rocket sled test is being performed where a scoop moving through a water channel is being used to brake a pusher sled. We plan to instrument this test to provide appropriate scale data for validating the new modeling capability. The intent is to get high fidelity data on the break-up and evaporation of the water that is ejected from the channel as the sled is braking. These two elements are critical to fireball formation for this type of event involving fuel in the place of water. We demonstrate our capability in this paper by describing the pre-test predictions which are used to locate instrumentation for the actual test. We also present a sensitivity analysis to understand the implications of length scale assumptions on the prediction results.

Study on the Green Processing of Impeller

2010 ◽  
Vol 136 ◽  
pp. 148-152
Author(s):  
Ming Jun Feng ◽  
C.T. Sun ◽  
Xue Feng Wang ◽  
H.J. Sun
Keyword(s):  
High Speed ◽  
Production Cost ◽  
Development Trend ◽  
Virtual Manufacturing ◽  
Machining Process ◽  
High Speed Machining ◽  
Good Surface ◽  
Green Processing ◽  
Compressor Impeller ◽  
Good Surface Roughness

According to the characteristics and cutting requirements of the compressor impeller, such as low rigidity, easy to produce deformation and vibration in machining process, the high speed machining technology was adopted to reduce time, the virtual manufacturing technology was used to solve processing problems in computer before the trial machining and improved programming speed and other key supporting technologies were adopted. The study shows that this green processing of impeller had high machining efficiency, good surface roughness and product quality, low production cost and light environmental pollution. It accords with modern green machining development trend.

The Overview of Smart Grid

2014 ◽  
Vol 552 ◽  
pp. 103-106
Author(s):  
Xue Song Zhou ◽  
Xiao Li Kong ◽  
You Jie Ma
Keyword(s):  
Smart Grid ◽  
Electric Power ◽  
Communication Networks ◽  
High Speed ◽  
Measurement Techniques ◽  
Development Trend ◽  
Electric Power System ◽  
Power Development ◽  
Generation Network ◽  
Technology Control

Smart Grid is the newest direction of electric power development, and is regarded as the significant technology innovation and development trend of the electric power system in 21st century. It is also regarded as the inevitable result of the development of economic and technology. It has flexible, clean, safe, economical, and friendly functions. Smart grid is a new "second generation" network, which is built on an integrated basis of two-way high-speed communication networks, through the application of advanced sensing and measurement techniques, equipment technology, control technology and decision support system technology in order to achieve reliable, safe, high-quality, economical, efficient, environmentally friendly and safe using target. Smart Grid’s background, significance key technologies, technical difficulties and prospects are introduced in this paper.

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