scholarly journals Design of athermalized mounting structure for the sub-aperture primary mirror of a synthetic aperture telescope

2022 ◽  
Vol 14 (1) ◽  
pp. 168781402110670
Author(s):  
Yunfeng Li ◽  
Zongxuan Li ◽  
Qiang Yong ◽  
Tiancong Wang ◽  
Defu Zhang
Keyword(s):  
Temperature Rise ◽  
Simulation Analysis ◽  
Structural Parameters ◽  
Thermal Sensitivity ◽  
Synthetic Aperture ◽  
Axial Position ◽  
Range Analysis ◽  
Primary Mirror ◽  
Good Imaging ◽  
Optical Test

The imaging quality of the synthetic aperture system is sensitive to the positioning accuracy of the sub-aperture primary mirror. A novel flexible mounting structure of bimetallic material is proposed for the athermalization of the sub-aperture primary mirror of the Fizeau Synthetic Aperture Telescope – which is composed of seven sub-aperture. The axial position accuracy of the sub-aperture primary mirror must be less than 5 µm under 10°C temperature rise to meet the requirements of the optical system. Firstly, a single mounting unit is analyzed theoretically, and the initial parameters are determined. The conceptual design of the mounting structure is carried out by using initial parameters. The orthogonal optimization algorithm and range analysis are used to optimize the structural parameters. The finite element model of the flexible mounting structure is established and the coupled thermal-mechanical simulation analysis is performed. Then the thermal sensitivity test of the sub-aperture primary mirror mounting structure was carried out. Under the effect of a temperature rise of 10°C, the axial displacement of the sub-aperture primary mirror mounting surface is less than 3 µm. Finally, the synthetic aperture system is assembled, and the optical test verifies that the synthetic aperture system has good imaging capabilities.

Optimal design of a high homogeneous and small-size shim coil for atomic spin gyroscope based on 0-1 linear programming

2020 ◽  
Vol 64 (1-4) ◽  
pp. 165-172
Author(s):  
Dongge Deng ◽  
Mingzhi Zhu ◽  
Qiang Shu ◽  
Baoxu Wang ◽  
Fei Yang
Keyword(s):  
Linear Programming ◽  
Power Consumption ◽  
Low Power ◽  
Optimization Design ◽  
Structural Parameters ◽  
Axial Position ◽  
Low Power Consumption ◽  
Optimal Method ◽  
Atomic Spin ◽  
Shim Coil

It is necessary to develop a high homogeneous, low power consumption, high frequency and small-size shim coil for high precision and low-cost atomic spin gyroscope (ASG). To provide the shim coil, a multi-objective optimization design method is proposed. All structural parameters including the wire diameter are optimized. In addition to the homogeneity, the size of optimized coil, especially the axial position and winding number, is restricted to develop the small-size shim coil with low power consumption. The 0-1 linear programming is adopted in the optimal model to conveniently describe winding distributions. The branch and bound algorithm is used to solve this model. Theoretical optimization results show that the homogeneity of the optimized shim coil is several orders of magnitudes better than the same-size solenoid. A simulation experiment is also conducted. Experimental results show that optimization results are verified, and power consumption of the optimized coil is about half of the solenoid when providing the same uniform magnetic field. This indicates that the proposed optimal method is feasible to develop shim coil for ASG.

An efficient procedure to predict the dynamic loads for piston liner systems in marine engines

2021 ◽  
pp. 146808742199698
Author(s):  
Lyu Xiuyi ◽  
Abdullah Azam ◽  
Wang Yuechang ◽  
Lu Xiqun ◽  
Li Tongyang ◽  
...  
Keyword(s):  
Simulation Analysis ◽  
Structural Parameters ◽  
Computation Time ◽  
Primary Source ◽  
Cylinder Liner ◽  
Accurate Method ◽  
Friction Behavior ◽  
Accuracy Requirement ◽  
Precise Prediction ◽  
Friction Prediction

The piston ring-cylinder liner (PRCL) is one of the most important parts of marine diesel engines and contributes 25% to 50% of total friction loss. The lubrication simulation analysis of the PRCL system is a challenging task. Complete understanding and precise prediction of lubrication loads is a key to understanding the friction behavior of PRCL systems as the accuracy of the friction prediction depends upon precise prediction of lubrication loads. Therefore, this paper focuses on the gas pressure calculation which is the primary source of lubrication loads. The procedure presented combines the advantages of two mainstream methods to predict loads in the PRCL system. The result is a significant reduction in the computation time without compromising on accuracy. Firstly, a comparison of both approaches is presented which suggests that each technique has its limitations (one is time-bound, and one is accuracy-bound). Then, the results from both calculation methods are verified against literature and a parametric study is performed to identify the key structural parameters of PRCL system that affect the calculation efficiency. Finally, a correlation coefficient is introduced into the analysis to combine the two approaches which then identifies the conditions under which the use of the faster method becomes invalid and replaces it with the more accurate approach. This ensures optimum performance of the calculation procedure by switching between the fast and the accurate method depending upon the accuracy requirement under given conditions, thereby, simplifying the dynamic and lubrication model of PRCL systems. The study has direct implications for the tribological design of the PRCL interface.

scholarly journals Optimal Design and Simulation Analysis of Spike Tooth Threshing Component Based on DEM

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1163
Author(s):  
Yajun Yu ◽  
Liangshan Li ◽  
Jiale Zhao ◽  
Xiangeng Wang ◽  
Jun Fu
Keyword(s):  
Optimal Design ◽  
Simulation Analysis ◽  
Process Analysis ◽  
Structural Parameters ◽  
Compressive Force ◽  
Microscopic Analysis ◽  
Analysis Software ◽  
Damage Rate ◽  
Tooth Type ◽  
Simulation Time

This paper takes a local drum-type corn thresher as an example. In order to make the threshing principle transform to the plate-tooth type, the width of the spike-tooth threshing component is increased gradually, and three threshing components of different shape and size are selected as the research objects. Based on the preliminary experimental research, the corn threshing process is simulation analyzed using the self-developed corn threshing process analysis software. The effects of the width of the threshing component on the corn ears threshing rate and kernel damage rate under different rates of drum rotation were studied from a macroscopic perspective. The results show that with the increase of drum rotation rate, both the corn ear threshing rate and kernel damage rate increase; with the increase of threshing component width, the threshing rate increases and the damage rate decreases; and when the component width is too large, the stacking between adjacent components has an impact on the threshing performance. The effects of threshing component width on the amount of kernel threshing and the total compressive force during the simulation time were investigated from microscopic perspective at different rates of drum rotation, and the results show that the microscopic analysis is consistent with the macroscopic analysis. Therefore, the optimization of the structural parameters and operating parameters of the threshing component was achieved. When the width of the threshing component was 25 mm and the roller speed was 187.50 rpm, the threshing performance was optimal, with a 98.04% corn ears threshing rate and a 2.56% kernel damage rate. This paper verifies the practical applicability of the corn threshing process analysis software and provides a reference for the optimal design of threshing devices.

A New Design of a Piezoelectric Triaxial Micro-Accelerometer

2015 ◽  
Vol 645-646 ◽  
pp. 841-846 ◽  
Author(s):  
Jian Yan Wang ◽  
Ting Ting Wang ◽  
Hang Guo
Keyword(s):  
Simulation Analysis ◽  
Structural Parameters ◽  
Sol Gel ◽  
Triaxial Accelerometer ◽  
Response Frequency ◽  
Pzt Films ◽  
New Type ◽  
The Cross ◽  
Cross Axis ◽  
Micro Accelerometer

Accelerometer in MEMS always is made by capacitive or piezoresistive, whose dynamic response is not good, the operating frequency is narrow, and the cross-axis sensitivity is low. A new type of piezoelectric micro-accelerometer is designed, and its structure is “x” type. The sensing unit is piezoelectric PZT films, which is achieved by sol-gel method. The accelerometer is a triaxial accelerometer. The theoretical and simulation analysis is used to achieve the charge sensitivity and response frequency, and also get the optimal structural parameters. A new circuit connection is proposed to improve the sensitivity and avoid the cross-axis sensitivity. The design achieves the z-axis sensitivity with more than 40 pC/g, x, y-axis sensitivity with more than 8pC/g, and the response frequency is about 3000Hz.

scholarly journals Study on the sensitivity of the hydraulic response characteristics of the electronic fuel injector regarding the key structural parameters

2019 ◽  
Vol 11 (1) ◽  
pp. 168781401882259 ◽  
Author(s):  
Yaonan Feng ◽  
Jie Wang ◽  
Fukang Ma ◽  
Tiexiong Su ◽  
Chunlong Xu ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Influencing Factor ◽  
Response Characteristic ◽  
Fuel Injector ◽  
Closing Time ◽  
Range Analysis ◽  
Small Opening ◽  
Response Characteristics ◽  
And Control ◽  
Hydraulic Response

The sensitivity of key structural parameters to the hydraulic response characteristics in an electronic fuel injector is investigated. First, the hydraulic response characteristic is defined in detail (the opening/closing delay and the opening/closing time). Second, the key structural parameters influencing the hydraulic response characteristics are derived. Finally, the importance and effects of key structural parameters on hydraulic response characteristics are examined, by using the design of experiments method and the range analysis. Results show that the fuel inlet passage diameter is the primary influencing factor to the opening delay and closing delay, while the control piston diameter has the dominant effect on opening time and closing time. A small opening delay and a small opening time prefer a little fuel inlet passage diameter and control piston diameter; however, they contribute to a large closing time and closing delay. The fuel outlet passage diameter is the secondary influencing factor in opening delay, but the second factor that affects the opening time is the diameter of needle.

Numerical Calculation of Triangle Circulation Drip Irrigation Emitters

2010 ◽  
Author(s):  
Xinkun Wang ◽  
Junhong Li
Keyword(s):  
Flow Rate ◽  
Drip Irrigation ◽  
Simulation Analysis ◽  
Structural Parameters ◽  
Structure Design ◽  
Flow Channel ◽  
Channel Structure ◽  
Sudden Expansion ◽  
Flow Index ◽  
Circulation Flow

Based on the hydraulic characteristics of triangle circulation, sudden-expansion pipe and sudden contraction pipe, Construct a drip irrigation emitter with strong turbulent flow, large over-current cross-section and strong anti-clogging ability. Triangular circulation flow path emitters for the key structural parameters for the factors, application of computer numerical fluid dynamics CFD software FLUENT6.3, simulate triangular circulation flow channel structure, analyze the influence of various structural parameters on hydraulic performance of emitters, flow index, flow rate and the anti-clogging ability. The results show that increase unit cusp, unit chamfer, the flow index increased, but the effect to varying degrees; inlet dimension increase, flow index reduced; flow channel depth and flow channel width increases, the discharge increases. Increase unit cusp, unit chamfered, can improve the anti-clogging performance of emitters. Based on the above results, to design an emitter structure with good performance, and its numerical simulation analysis, the flow index, flow rate and anti-clogging ability have met the requirements of drip irrigation. Provide a theoretical basis for the triangle circulation emitter structure design and quantitative analysis. The research has a positive meaning for energy conservation.

scholarly journals Springback Study on Profile Flexible 3D Stretch-Bending Process Using the Neural Network

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Yi Li ◽  
Ce Liang ◽  
Xiangfeng Lin ◽  
Jicai Liang ◽  
Zhongyi Cai ◽  
...  
Keyword(s):  
Neural Network ◽  
Bp Neural Network ◽  
Material Properties ◽  
Simulation Analysis ◽  
Orthogonal Experiment ◽  
Range Analysis ◽  
Finite Element Software ◽  
Stretch Bending ◽  
Aluminum Profile ◽  
Bending Process

The springback is one of the main defects in the flexible 3D stretch-bending process. In this paper, according to the orthogonal design of experiments, the numerical simulation analysis of the springback for the 3D stretch-bending aluminum profile is carried out by the ABAQUS finite element software. And to investigate the effect of material properties on the springback, the range analysis of the orthogonal experiment is performed. The results show that these material properties of the aluminum profile (elastic modulus E, yield strength σy, and tangent modulus E1) might have the biggest influence on the springback of the aluminum profile, and the optimized forming parameters are founded as follows: the horizontal bending degree is 14°, the vertical bending degree is 14°, the number of multipoint stretch-bending dies is 10, the friction coefficient is 0.15, and aluminum alloy grade is 6063. Moreover, the model of the BP neural network for the prediction of the springback is established and trained based on the orthogonal experiment, and the results with the BP neural network model are in good agreement with experimental results. So it is obvious that the BP neural network could predict effectively the springback of 3D multipoint stretch-bending parts.

scholarly journals Proposal of an Equal-Stiffness and Equal-Stroke 2D Micro-Positioning Platform Driven by Piezoelectric Actuators

Actuators ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 47
Author(s):  
Feng Sun ◽  
Yansong Hao ◽  
Fangchao Xu ◽  
Junjie Jin ◽  
Qiang Li ◽  
...  
Keyword(s):  
Simulation Analysis ◽  
Structural Parameters ◽  
Piezoelectric Actuators ◽  
Static Stiffness ◽  
Coupling Ratio ◽  
Stiffness Analysis ◽  
Magnification Ratio ◽  
Measurement Experiment ◽  
Nested Structure ◽  
Long Stroke

Micro-positioning platform plays an important role in the field of precision positioning such as microelectronics, robotics and biomedicine. This paper proposes an equal-stiffness and equal-stroke 2D micro-positioning platform, which is driven by piezoelectric actuators. The overall structure of the 2D micro-positioning platform adopts a nested structure and the displacement magnification mechanism adopts two hourglass displacement magnification mechanisms. The displacement magnification ratio of the hourglass displacement magnification mechanism was studied, and its structural parameters were optimized. Static stiffness analysis and simulation analysis of the micro-positioning platform were carried out. The simulation stiffness of the micro-positioning platform in the XY direction is 46873 N/m and 46832 N/m respectively. The experimental prototype of the micro-positioning platform was built. Through the measurement experiment with the prototype, the maximum stroke of the micro-positioning platform in the XY direction is 489 μm and 493 μm respectively; the maximum coupling ratio in the XY direction is 2.38% and 2.70% respectively. The research indicates that the micro-positioning platform had the characteristics of small size, equal long stroke, equal stiffness and low coupling ratio in the XY direction.

Optical test for the primary mirror of a space telescope using a CGH null lens

2006 ◽  
Author(s):  
Jae Bong Song ◽  
Yun Woo Lee ◽  
Hoi Youn Lee ◽  
Ho Soon Yang ◽  
In Won Lee
Keyword(s):  
Space Telescope ◽  
Primary Mirror ◽  
Optical Test

Optimal Design of a New Type of Savonius Rotor Using Simulation Analysis

2012 ◽  
Vol 499 ◽  
pp. 120-125 ◽  
Author(s):  
Zhi Peng Tang ◽  
Ying Xue Yao ◽  
Liang Zhou ◽  
Q. Yao
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Optimal Design ◽  
Simulation Analysis ◽  
Structural Parameters ◽  
Sliding Mesh ◽  
Savonius Rotor ◽  
Mesh Method ◽  
New Type

In order to enhance the efficiency of the Savonius rotor, this paper designs a new type of Savonius rotor with a rectifier. By using Computational Fluid Dynamics software to simulate and optimize the various parameters which affect the efficiency of the rotor. The sliding mesh method is applied here. The Cp-λ curves of wind turbine with different structural parameters are obtained after numerical simulation of flow field. On this basis, this paper gets the optimal structural parameters. And the results indicated that this new type of Savonius rotor has great improvement of efficiency compared with the traditional Savonius-type rotor.

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