scholarly journals Accuracy analysis and optimization of infrared guidance test device

2020 ◽  
Vol 12 (6) ◽  
pp. 168781402092265
Author(s):  
Zhou Wang ◽  
Yin Chen ◽  
Tao Wang ◽  
Bo Zhang
Keyword(s):  
Physical Simulation ◽  
Orthogonal Experiment ◽  
Target Position ◽  
Design Parameters ◽  
Test Device ◽  
Factors Affecting ◽  
Pointing Error ◽  
Maximum Deformation ◽  
Minimum Deformation ◽  
Shell Optimization

As an important modern weapon, the development of infrared-guided missile reflects comprehensive national strength of a country. Therefore, it is especially important to establish a semi-physical simulation device to test the performance of missile, and the test device requires high accuracy. Based on the above background, an infrared guidance test device is designed in this article. The accuracy of its shell and rotating mechanism are studied in detail, and the error factors are quantified to provide theoretical basis for structural optimization. The orthogonal experiment design reduces the number of sensitivity analysis experiments on key design parameters. Factors affecting the maximum deformation and overall quality of the shell were determined. The range method was used to analyze sensitivity factors, and the final optimization result that met the minimum deformation and minimum quality was determined. Experimental results show that the rotation error of the main shaft of the rotating mechanism includes axial, radial, and angular motion errors, and experimental value is basically consistent with theoretical value. After the shell optimization, the infrared target pointing error [Formula: see text] and the infrared target position offset error ξ′ = 0.1525 mm meet the accuracy requirements. This method can provide new ideas for precision research and optimization of structural design of rotating mechanism.

PARAMETER OPTIMIZATION AND EXPERIMENTAL RESEARCH ON THE HAMMER MILL 锤片式粉碎机参数优化与试验研究

2020 ◽  
pp. 341-350
Author(s):  
Di Wang ◽  
Changbin He ◽  
Haiqing Tian ◽  
Liu Fei ◽  
Zhang Tao ◽  
...  
Keyword(s):  
Moisture Content ◽  
Orthogonal Experiment ◽  
Electricity Consumption ◽  
Spindle Speed ◽  
Hammer Mill ◽  
Factors Affecting ◽  
Evaluation Indexes ◽  
Grain Moisture ◽  
Validation Experiment ◽  
Corn Grain

Low productivity and high electricity consumption are considered problems of the hammer mill, which is widely used in current feed production. In this paper, the mechanical properties of corn grain ground by a hammer mill were analysed, and the key factors affecting the performance of the hammer mill were determined. The single-factor experiment and three-factor, three-level quadratic regression orthogonal experiment were carried out with the spindle speed, corn grain moisture content and number of hammers as experimental factors and the productivity and electricity consumption per ton as evaluation indexes. The results showed that the order of influence on the productivity was spindle speed > corn grain moisture content > number of hammers and that the order of influence on the electricity consumption per ton was corn grain moisture content > spindle speed > number of hammers. The parameters were optimized based on the response surface method with the following results: the spindle speed was 4306 r/min, the corn grain moisture content was 10%, and the number of hammers was 24. The validation experiment was carried out with the optimal parameters’ combination. The productivity and electricity consumption per ton were 988.12 kg/h and 5.37 kW·h/t, respectively, which were consistent with the predicted results of the model.

Green roof hydrologic performance and modeling: a review

2013 ◽  
Vol 69 (4) ◽  
pp. 727-738 ◽  
Author(s):  
Yanling Li ◽  
Roger W. Babcock
Keyword(s):  
Peak Flow ◽  
Green Roof ◽  
Field Measurements ◽  
Green Roofs ◽  
Economic Benefits ◽  
Design Parameters ◽  
Technical Literature ◽  
Factors Affecting ◽  
Model Soil ◽  
Runoff Volume

Green roofs reduce runoff from impervious surfaces in urban development. This paper reviews the technical literature on green roof hydrology. Laboratory experiments and field measurements have shown that green roofs can reduce stormwater runoff volume by 30 to 86%, reduce peak flow rate by 22 to 93% and delay the peak flow by 0 to 30 min and thereby decrease pollution, flooding and erosion during precipitation events. However, the effectiveness can vary substantially due to design characteristics making performance predictions difficult. Evaluation of the most recently published study findings indicates that the major factors affecting green roof hydrology are precipitation volume, precipitation dynamics, antecedent conditions, growth medium, plant species, and roof slope. This paper also evaluates the computer models commonly used to simulate hydrologic processes for green roofs, including stormwater management model, soil water atmosphere and plant, SWMS-2D, HYDRUS, and other models that are shown to be effective for predicting precipitation response and economic benefits. The review findings indicate that green roofs are effective for reduction of runoff volume and peak flow, and delay of peak flow, however, no tool or model is available to predict expected performance for any given anticipated system based on design parameters that directly affect green roof hydrology.

A Parametric Examination of the Factors Affecting the Performance of a Diffusion Absorption Refrigeration System

2021 ◽  
pp. 1-38
Author(s):  
Noman Yousuf ◽  
Timothy Anderson ◽  
Roy Nates
Keyword(s):  
Waste Heat ◽  
Operating Conditions ◽  
Design Parameters ◽  
Working Fluid ◽  
Low Grade ◽  
Absorption Refrigeration ◽  
Factors Affecting ◽  
Thermally Driven ◽  
Mass Flowrate ◽  
Diffusion Absorption

Abstract Despite being identified nearly a century ago, the diffusion absorption refrigeration (DAR) cycle has received relatively little attention. One of the strongest attractions of the DAR cycle lies in the fact that it is thermally driven and does not require high value work. This makes it a prime candidate for harnessing low grade heat from solar collectors, or the waste heat from stationary generators, to produce cooling. However, to realize the benefits of the DAR cycle, there is a need to develop an improved understanding of how design parameters influence its performance. In this vein, this work developed a new parametric model that can be used to examine the performance of the DAR cycle for a range of operating conditions. The results showed that the cycle's performance was particularly sensitive to several factors: the rate of heat added and the temperature of the generator, the effectiveness of the gas and solution heat exchangers, the mass flowrate of the refrigerant and the type of the working fluid. It was shown that can deliver good performance at low generator temperatures if the refrigerant mass fraction in the strong solution is made as high as possible. Moreover, it was shown that a H2O-LiBr working pair could be useful for achieving cooling at low generator temperatures.

Effect of End Rubber Gasket on the Performance of Parabolic Leaf Spring

2020 ◽  
Author(s):  
Junhong Zhang ◽  
Feiqi Long ◽  
Hongjie Jia ◽  
Jiewei Lin
Keyword(s):  
Ride Comfort ◽  
Orthogonal Experiment ◽  
Element Model ◽  
Considerable Effect ◽  
Leaf Spring ◽  
Static Stiffness ◽  
Rubber Gasket ◽  
Maximum Deformation ◽  
Leaf Springs ◽  
Parabolic Leaf Spring

Abstract Leaf springs play an important role in the handling stability and ride comfort of vehicle. End rubber gaskets are widely used to reduce the friction between leaves, but they also have considerable effect on the stiffness of the suspension assembly. The ride comfort may deteriorate with the stiffness of leaf spring changes. In this paper the influence of the end rubber gasket on the static stiffness performance of a parabolic leaf spring is studied. A finite element model of the leaf spring is developed and verified against the static stiffness test. Effects of the end rubber gasket parameters on the static stiffness of the leaf spring are analyzed based on an orthogonal experiment. The sensitivities of the five parameters are identified including the width, the length, the end thickness, the tail thickness and the distance to the end of the middle leaf. It is found that the contributions can be ranked in descending order as the tail thickness, the end thickness, the distance from end rubber gasket to the end of Leaf 2, and the width and length. The first two factors are considered of significant effects on the leaf spring stiffness. According to single-factor analysis, it is found that under the same load, as the tail thickness and the end thickness increase, the maximum deformation of the rubber gasket decreases, the stiffness of the rubber gasket increases, and the stiffness of the leaf spring increases, which provides a reference for the forward design of the end rubber gasket and the stiffness matching of leaf springs.

Factors affecting the accuracy of control of internal combustion engine with a common rail fuel system

2020 ◽  
Keyword(s):  
Internal Combustion Engine ◽  
Combustion Engine ◽  
Internal Combustion ◽  
Design Parameters ◽  
Repeated Injection ◽  
Fuel System ◽  
Factors Affecting ◽  
Fuel Supply ◽  
Wave Phenomena ◽  
Control Accuracy

The article presents an overview of the operation of the battery fuel system with multiple injection, as well as the factors affecting the control accuracy of an internal combustion engine with a battery fuel system. The amount of preliminary fuel supply and the delay between preliminary and subsequent fuel supply by the electrohydraulic nozzle, as well as the tolerances for the design parameters of the electrohydraulic nozzle, are considered as influencing factors. Keywords wave phenomena; repeated injection; battery fuel system; electro hydraulic injector

scholarly journals Study on level-of-service for urban rail transit passages from the passenger perspective

2021 ◽  
Vol 283 ◽  
pp. 02041
Author(s):  
Yibing Chen ◽  
Xiao Liang ◽  
Yizhuo Fu
Keyword(s):  
Public Transportation ◽  
Orthogonal Experiment ◽  
Reliability And Validity ◽  
Service Level ◽  
Urban Rail Transit ◽  
Classification Method ◽  
Rail Transit ◽  
Factors Affecting ◽  
Passenger Satisfaction ◽  
Urban Rail

With the acceleration of urbanization and the shortage of transportation resources in large cities, urban rail transit has gradually become the backbone of urban public transportation system. In order to improve the service level of urban rail transit, this paper studies the factors influencing the service level of subway station passages and the classification method based on the passenger-perception method. Through investigation and research, the passage service level evaluation indicators (width, walking time, per capita area, illumination intensity and guide signage) have been determined. Based on orthogonal experiment, 3ds max was used to set up 25 passage scenes with different parameters from passengers' perspective. A passenger satisfaction questionnaire was designed and distributed, the reliability and validity of the questionnaire were tested to ensure the validity of the data. And based on the factor analysis method, the factors affecting passenger perception are analyzed. A well-fitting model of the relationship between passenger scores and passage parameters is established, and the passenger scores are converted into service levels. Finally, a service level classification method is given, which can provide reference for the service level evaluation of existing stations and the design of physical attributes and environmental factors of new station passages.

scholarly journals Study on Generating Machining Performance of Two-Dimensional Ultrasonic Vibration-Composited Electrolysis/Electro-Discharge Technology for MMCs

Materials ◽  
2022 ◽  
Vol 15 (2) ◽  
pp. 617
Author(s):  
Jing Li ◽  
Wanwan Chen ◽  
Yongwei Zhu
Keyword(s):  
Ultrasonic Vibration ◽  
Orthogonal Experiment ◽  
Spindle Speed ◽  
Machining Efficiency ◽  
Matrix Composites ◽  
Two Dimensional ◽  
Machining Performance ◽  
Factors Affecting ◽  
Electro Discharge Machining ◽  
Workpiece Vibration

Ultrasonic vibration-composited electrolysis/electro-discharge machining technology (UE/DM) is effective for machining particulate-reinforced metal matrix composites (MMCs). However, the vibration of the tool or workpiece suitable for holes limits the application of UE/DM. To improve the generating machining efficiency and quality of flat and curved surfaces, in this study, we implemented two-dimensional ultrasonic vibration into UE/DM and constructed a novel method named two-dimensional ultrasonic vibration-composited electrolysis/electro-discharge machining (2UE/DM). The influence of vibration on the performance of 2UE/DM compared to other process technologies was studied, and an orthogonal experiment was designed to optimize the parameters. The results indicated that the materiel remove rate (MRR) mainly increased via voltage and tool vibration. The change current was responsible for the MRR in the process. Spindle speed and workpiece vibration were not dominant factors affecting the MRR; the spindle speed and tool and workpiece vibration, which reduced the height difference between a ridge and crater caused by abrasive grinding, were responsible for surface roughness (Ra) and form precision (δ). Additionally, the optimized parameters of 1000 rpm, 3 V, and 5 um were conducted on MMCs of 40 SiCp/Al and achieved the maximum MRR and minimum Ra and δ of 0.76 mm3/min, 3.35 um, and 5.84%, respectively. This study’s findings provide valuable process parameters for improving machining efficiency and quality for MMCs of 2UE/DM.

Behavioral Reference Frames for Planning Human Reaching Movements

2006 ◽  
Vol 96 (1) ◽  
pp. 352-362 ◽  
Author(s):  
Sabine M. Beurze ◽  
Stan Van Pelt ◽  
W. Pieter Medendorp
Keyword(s):  
Reference Frame ◽  
Visual Information ◽  
Reference Frames ◽  
Target Position ◽  
Movement Planning ◽  
Reaching Movements ◽  
Hand Position ◽  
Pointing Error ◽  
Movement Vector ◽  
Common Reference

At some stage in the process of a sensorimotor transformation for a reaching movement, information about the current position of the hand and information about the location of the target must be encoded in the same frame of reference to compute the hand-to-target difference vector. Two main hypotheses have been proposed regarding this reference frame: an eye-centered and a body-centered frame. Here we evaluated these hypotheses using the pointing errors that subjects made when planning and executing arm movements to memorized targets starting from various initial hand positions while keeping gaze fixed in various directions. One group of subjects ( n = 10) was tested without visual information about hand position during movement planning (unseen-hand condition); another group ( n = 8) was tested with hand and target position simultaneously visible before movement onset (seen-hand condition). We found that both initial hand position and gaze fixation direction had a significant effect on the magnitude and direction of the pointing error. Errors were significantly smaller in the seen-hand condition. For both conditions, though, a reference frame analysis showed that the errors arose at an eye- or hand-centered stage or both, but not at a body-centered stage. As a common reference frame is required to specify a movement vector, these results suggest that an eye-centered mechanism is involved in integrating target and hand position in programming reaching movements. We discuss how simple gain elements modulating the eye-centered target and hand-position signals can account for these results.

Effect of Electrical Pulsing on Various Heat Treatments of 5XXX Series Aluminum Alloys

2008 ◽  
Author(s):  
Wesley A. Salandro ◽  
Joshua J. Jones ◽  
Timothy A. McNeal ◽  
John T. Roth ◽  
Sung-Tae Hong ◽  
...  
Keyword(s):  
Aluminum Alloys ◽  
Superplastic Deformation ◽  
Deformation Process ◽  
Electrical Current ◽  
Heat Treatments ◽  
Maximum Deformation ◽  
Aluminum Specimen ◽  
Electrical Pulses ◽  
Minimum Deformation ◽  
Diffuse Neck

Previous studies have shown that the presence of a pulsed electrical current, applied during the deformation process of an aluminum specimen, can significantly improve the formability of the aluminum without heating the metal above its maximum operating temperature range. The research herein extends these findings by examining the effect of electrical pulsing on 5052 and 5083 Aluminum Alloys. Two different parameter sets were used while pulsing three different heat treatments (As Is, 398°C, and 510°C) for each of the two aluminum alloys. For this research, the electrical pulsing is applied to the aluminum while the specimens are deformed, without halting the deformation process. The analysis focuses on establishing the effect the electrical pulsing has on the aluminum alloy’s various heat treatments by examining the displacement of the material throughout the testing region of dogbone shaped specimens. The results from this research show that pulsing significantly increases the maximum achievable elongation of the aluminum (when compared to baseline tests conducted without electrical pulsing). Significantly reducing the engineering flow stress within the material is another beneficial effect produced by electric pulsing. The electrical pulses also cause the aluminum to deform non-uniformly, such that the material exhibits a diffuse neck where the minimum deformation occurs near the ends of the specimen (near the clamps) and the maximum deformation occurs near the center of the specimen (where fracture ultimately occurs). This diffuse necking effect is similar to what can be experienced during superplastic deformation. However, when comparing the presence of a diffuse neck in this research, electrical pulsing does not create as significant of a diffuse neck as superplastic deformation. Electrical pulsing has the potential to be more efficient than traditional methods of incremental forming since the deformation process is never interrupted. Overall, with the greater elongation and lower stress, the aluminum can be deformed quicker, easier, and to a greater extent than is currently possible.

Advanced Hydrodynamic Design of Vertical Diffuser Pumps Using Computational Fluid Dynamics

2002 ◽  
Author(s):  
Kristis V. Michaelides ◽  
Antonios Tourlidakis
Keyword(s):  
Development Process ◽  
Three Dimensional ◽  
Detailed Examination ◽  
Product Development Process ◽  
Design Parameters ◽  
Factors Affecting ◽  
Performance Predictions ◽  
Overall Performance ◽  
Industrial Use ◽  
Optimisation Procedure

The current paper describes an investigation into the industrial use of CFD and other computational technologies for the three-dimensional hydrodynamic design of vertical diffuser pumps and outlines the complete product development process. Detailed description of the complete design process is described and numerous CFD predictions of the flow are presented with detailed examination of the several factors affecting the hydrodynamics of impeller and diffuser and staging of the pump. Furthermore, variations of important geometrical design parameters based on the design optimisation procedure are discussed in accordance to the CFD results. The capabilities of the 3-D hydrodynamic design through CFD and the importance of the three dimensional blade geometry are demonstrated by the fact that two different pump impellers were designed based on strict design constraints affecting their basic dimensions. Finally, an overview of the functional prototypes development is described and comparisons are carried out between overall performance predictions and experimental results.

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