To meet the needs of complex system equipment testing and realize the visual management of different test projects,this article establishes a test project management system based on the actual situation of aviation eq...To meet the needs of complex system equipment testing and realize the visual management of different test projects,this article establishes a test project management system based on the actual situation of aviation equipment testing system and the concept of big data,using visual data management and analysis techniques.This system solves the comprehensive management of multi-type test projects.Combined with the actual engineering verification process,it can be found that the system can realize the visual management of test projects and effectively ensure the smooth completion of the identification test project of a certain type of aircraft′s complex system.展开更多
Seismic isolation effectively reduces seismic demands on building structures by isolating the superstructure from ground vibrations during earthquakes.However,isolation strategies give less attention to acceleration-s...Seismic isolation effectively reduces seismic demands on building structures by isolating the superstructure from ground vibrations during earthquakes.However,isolation strategies give less attention to acceleration-sensitive systems or equipment.Meanwhile,as the isolation layer’s displacement grows,the stiffness and frequency of traditional rolling and sliding isolation bearings increases,potentially causing self-centering and resonance concerns.As a result,a new conical pendulum bearing has been selected for acceleration-sensitive equipment to increase self-centering capacity,and additional viscous dampers are incorporated to enhance system damping.Moreover,the theoretical formula for conical pendulum bearings is supplied to analyze the device’s dynamic parameters,and shake table experiments are used to determine the proposed device’s isolation efficiency under various conditions.According to the test results,the newly proposed devices have remarkable isolation performance in terms of minimizing both acceleration and displacement responses.Finally,a numerical model of the isolation system is provided for further research,and the accuracy is demonstrated by the aforementioned experiments.展开更多
Testing is the premise and foundation of realizing equipment health management (EHM). To address the problem that the static periodic test strategy may cause deficient test or excessive test, a dynamic sequential te...Testing is the premise and foundation of realizing equipment health management (EHM). To address the problem that the static periodic test strategy may cause deficient test or excessive test, a dynamic sequential test strategy (DSTS) for EHM is presented. Considering the situation that equipment health state is not completely observable in reality, a DSTS optimization method based on partially observable semi-Markov decision pro- cess (POSMDP) is proposed. Firstly, an equipment health state degradation model is constructed by Markov process, and the control limit maintenance policy is also introduced. Secondly, POSMDP is formulated in great detail. And then, POSMDP is converted to completely observable belief semi-Markov decision process (BSMDP) through belief state. The optimal equation and the corresponding optimal DSTS, which minimize the long-run ex- pected average cost per unit time, are obtained with BSMDP. The results of application in complex equipment show that the proposed DSTS is feasible and effective.展开更多
In order to research the effects of built-in test(BIT) on the system and select BITand test strategy,the complex repairable systems with BITequipment are modeled and simulated by using Simulink.Based on the model,the ...In order to research the effects of built-in test(BIT) on the system and select BITand test strategy,the complex repairable systems with BITequipment are modeled and simulated by using Simulink.Based on the model,the influences of different built-in test equipments,maintenance time and error probabilities on the system usability are evaluated.The simulation results showthat they effect on the system differently.The simulation method of complex system based on Simulink provides a technique approach to research the effects of BITon the system and select BITand test strategy.展开更多
To solve the problems of low precision of weak feature extraction,heavy reliance on labor and low efficiency of weak feature extraction in X-ray weld detection image of ultra-high voltage(UHV)equipment key parts,an au...To solve the problems of low precision of weak feature extraction,heavy reliance on labor and low efficiency of weak feature extraction in X-ray weld detection image of ultra-high voltage(UHV)equipment key parts,an automatic feature extraction algorithm is proposed.Firstly,the original weld image is denoised while retaining the characteristic information of weak defects by the proposed monostable stochastic resonance method.Then,binarization is achieved by combining Laplacian edge detection and Otsu threshold segmentation.Finally,the automatic identification of weld defect area is realized based on the sequential traversal of binary tree.Several characteristic analysis dimensions are established for weld defects of UHV key parts,including defect area,perimeter,slenderness ratio,duty cycle,etc.The experiment using theweld detection image of the actual production site shows that the proposedmethod can effectively extract theweak feature information ofweld defects and further provide reference for decision-making.展开更多
Double packer equipment for hydraulic test can be used to measure pressure of test zone directly, and it is frequently used to perform many kinds of hydraulic tests and take groundwater sample from borehole. The test ...Double packer equipment for hydraulic test can be used to measure pressure of test zone directly, and it is frequently used to perform many kinds of hydraulic tests and take groundwater sample from borehole. The test method of this equipment mainly includes the test design, implementation, interpretation and synthetic analysis. By adopting the double packer equipment for hydraulic test, the parameter distribution of rock permeability along borehole can be acquired, as well as the connectivity, water conductivity and water bearing capacity of the disclosed structure and the chemical characteristics of the deep groundwater. It is a necessary method for the research and evaluation of the complex hypotonicity terrace site selection under geological conditions. This method is not only suitable for the geological disposal of high level radioactive waste, but also can be used in the site selection of underground facilities such as storage of petroleum and carbon dioxide. Meanwhile, it has a good application prospect in other hydrogeological investigation fields.展开更多
This paper discusses causes of the rate ripple in inertia guidance test equipment IGET, systematically analyses their effects an the rate ripple in IGTE. The analysis result shows: The rate ripple caused by the perio...This paper discusses causes of the rate ripple in inertia guidance test equipment IGET, systematically analyses their effects an the rate ripple in IGTE. The analysis result shows: The rate ripple caused by the periodic errors of inductosyn and angular encoder is higher at high speed than that caused by magnetic ripple torque and friction torque, and it cannot be eliminated by adjusting control parameters of the system. And based on the nonlinear adaptive control system theory, the paper puts forward a new control system scheme to eliminate the rate ripple caused by the periodic errors of inductosyn and angular encoder, develops the adaptive control rules and makes simulation and test. Experimental result shows a significant improvement on those tables for the period disturbs under the system scheme designed. By this plan, with the input of rate 200°/s, the rate ripple falls from 5°/s to 0. 4°/s within about 6s adaptive adjustment time, being a twelfth of before adaptation, which can not be reached by common classical controls. The experimental results conform with the simulation, which proves the validity and practicability of the plan.展开更多
National Quality Supervision & Inspection Center for Refractories Business scope: Selective examination for national quality supervision; Identification of production license; Arbitration inspection and technical ac...National Quality Supervision & Inspection Center for Refractories Business scope: Selective examination for national quality supervision; Identification of production license; Arbitration inspection and technical achievements evaluation; Commodities inspection and otherquality inspections .展开更多
The objective of this work was to study the use of standard equipment in amplitude and frequency tests of dental scaler tip according to ISO 18397.Four types of standard equipment:a laser displacement sensor,a microsc...The objective of this work was to study the use of standard equipment in amplitude and frequency tests of dental scaler tip according to ISO 18397.Four types of standard equipment:a laser displacement sensor,a microscope,a tachometer,and an ultrasonic frequency meter,were experimentally investigated to test a tip.The standard laser displacement sensor and the standard microscope were used to test the unloaded amplitude of the scaler tip.It was found that two types of standard equipment were able to measure the unloaded amplitude of the tip.The standard microscope was also employed for the loaded amplitude test.This test was performed by pressing the scaler tip with a load of 1 N,which was measured by a load cell set.The peak-to-peak amplitude found from the test was 116.7 m.The frequency test of the scaler tip was conducted using the standard laser displacement sensor,the tachometer and the ultrasonic frequency meter.All three types of standard equipment were found to be able to test the frequency of the tip without cooling liquid.Nevertheless,only the standard tachometer was capable of measuring the frequency of the tip with cooling liquid applied.展开更多
A mobile in-situ testing equipment used to detect geotechnical thermophysical properties was developed. The equipment is composed of a heat pump, frequency pumps, an electric tee joint regulator valve, some sensors, a...A mobile in-situ testing equipment used to detect geotechnical thermophysical properties was developed. The equipment is composed of a heat pump, frequency pumps, an electric tee joint regulator valve, some sensors, an electric control system, data acquisition and control system, which can do tests under the condition of extracting and storing subsurface heat. Applying the line source and the cylinder source heat transfer model, and combining the parameters estimation, the average thermophysieal property parameters of rock and soil will be calculated, which provides the basis for designing the ground source heat pump systems.展开更多
The situation is constructed when the tests are considered as events and the spare test equipments are considered as strategies. The model of grey situation decision for the test equipment selection and deployment (T...The situation is constructed when the tests are considered as events and the spare test equipments are considered as strategies. The model of grey situation decision for the test equipment selection and deployment (TESD) is founded. Through analyzing each decision objectives, their relative weights are calculated via analytic hierarchy process (AHP). The grey situation effect matrix under each objective is computed so that the comprehensive effect measure matrix can be obtained when all of the objectives are traded off by their weights. Finally, the decision-maker can select the optimal situations by the value of the measures and such situations form the overall concept for TESD. The paper combines the AHP with grey situation decision to select and deploy the test equipments optimally. Our experimental results show that the proposed method is effective and efficient.展开更多
Using Planet ATE's SOC 'all-in-one' pin electronics solutions it is easy to make your owntester, ATE or to modify load boards for more advanced test capabilities.
In order to reduce the labor intensity and improve the efficiency of pruning,this study designed a multi-section luffing apple pruning equipment suitable for apple orchards in hilly and mountainous areas of China.In t...In order to reduce the labor intensity and improve the efficiency of pruning,this study designed a multi-section luffing apple pruning equipment suitable for apple orchards in hilly and mountainous areas of China.In the essay,the structure and working principle of the equipment are expounded,the cutter was analyzed,and the parameters were determined.Using the self-made test bench to simulate the field experiment,this study selected the ratio of cutting speed to feeding speed and feeding speed as the influencing factors and took the cut-off rate,cutting efficiency and cutting power as the objectives to carry out single factor experiment and quadratic regression orthogonal experiment.The test results show that the cutting power increases with the increase of ratio of cutting speed to feeding speed,and the cut-off rate and cutting efficiency first increase and then decrease.As the feeding speed increases,the cutting efficiency and power increase,and the cut-off rate decreases.When the cutoff rate was greater than 80%,the optimal combination of operating parameters was the feeding speed of 0.55 m/s and ratio of cutting speed to feeding speed of 1.29.Under this combination,the cut-off rate was 84.9%,the cutting efficiency was 13.1,and the cutting power was 175.7 W.The error between the predicted target value of the model and the average measured target value was less than 7%,so the test results are reliable.According to the obtained optimal operating parameters,the actual cutting experiment of the pruning equipment in the field was carried out,and the cutting rate was 96.3%,which meet the design requirements.This study can also meet the needs of mechanized pruning of fruit trees with different crown shapes,improve the applicability of pruning equipment,and provide support for the development of mechanized pruning equipment in China.展开更多
Porcelain electrical equipment (PEE), such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic ...Porcelain electrical equipment (PEE), such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic performance of two typical types of PEE and proposes a damping method for PEE based on multiple tuned mass dampers (MTMD). An MTMD damping device involving three mass units, named a triple tuned mass damper (TTMD), is designed and manufactured. Through shake table tests and finite element analysis, the dynamic characteristics of the PEE are studied and the effectiveness of the MTMD damping method is verified. The adverse influence of MTMD redundant mass to damping efficiency is studied and relevant equations are derived. MTMD robustness is verified through adjusting TTMD control frequencies. The damping effectiveness of TTMD, when the peak ground acceleration far exceeds the design value, is studied. Both shake table tests and finite element analysis indicate that MTMD is effective and robust in attenuating PEE seismic responses. TTMD remains effective when the PGA far exceeds the design value and when control deviations are considered.展开更多
In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency,the finite element analysis software-ANSYS is used to simulate the test...In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency,the finite element analysis software-ANSYS is used to simulate the tests of random vibrations of the cabinet system and obtain the isopleths graph of deformation and stress of the cabinet.It can confirm maximum of deformation and stress of the cabinet and position happened.Through more analysis of the frequency response curve,which can confirm harm- ful consequences random vibrations caused and weak link of the cabinet structure.The numerical simulation results are in good a- greement with the experimental results.It shows that this research provides an efficient method for the anti-seismic design and the dynamic optimization design.展开更多
In response to the growing complexity and performance of integrated circuit(IC),there is an urgent need to enhance the testing and stability of IC test equipment.A method was proposed to predict equipment stability us...In response to the growing complexity and performance of integrated circuit(IC),there is an urgent need to enhance the testing and stability of IC test equipment.A method was proposed to predict equipment stability using the upper side boundary value of normal distribution.Initially,the K-means clustering algorithm classifies and analyzes sample data.The accuracy of this boundary value is compared under two common confidence levels to select the optimal threshold.A range is then defined to categorize unqualified test data.Through experimental verification,the method achieves the purpose of measuring the stability of qualitative IC equipment through a deterministic threshold value and judging the stability of the equipment by comparing the number of unqualified data with the threshold value,which realizes the goal of long-term operation monitoring and stability analysis of IC test equipment.展开更多
In order to explore the seed drop characteristics by aerial seeding equipment,taking aerial seeding for Pinus tabulaeformis as an example,the Gaussian curve fitting and chi-square goodness-of-fit test were carried out...In order to explore the seed drop characteristics by aerial seeding equipment,taking aerial seeding for Pinus tabulaeformis as an example,the Gaussian curve fitting and chi-square goodness-of-fit test were carried out on the data of fallen seed distribution,and the seed distribution models of domestic FB-85 and imported PZLM-18 equipment were established.The seeding performance indexes of the two kinds of equipment were calculated and compared by using the model,the existing problems of domestic equipment and their causes are analyzed,and finally,some suggestions for equipment optimization were put forward.The results indicated that the seed drop of the two kinds of equipment showed the characteristics of dense distribution in the middle and sparse distribution on both sides,and followed the Gaussian distribution as a whole;compared with PZLM-18,FB-85 had better seeding performance,but it also had the problem of uneven seed distribution;in addition to the influence of aircraft flow field,the fishtail structure design of diffuser is another important reason for the uneven seed distribution of domestic equipment;without changing the fishtail structure design,it is suggested that the principle of cross-superposition of two seeding belts should be used to replace a single large-size diffuser with two small-size diffusers,which can reduce the number of seeds in the middle and increase the number of seeds on both sides,so as to improve the uniformity of seed distribution.展开更多
文摘To meet the needs of complex system equipment testing and realize the visual management of different test projects,this article establishes a test project management system based on the actual situation of aviation equipment testing system and the concept of big data,using visual data management and analysis techniques.This system solves the comprehensive management of multi-type test projects.Combined with the actual engineering verification process,it can be found that the system can realize the visual management of test projects and effectively ensure the smooth completion of the identification test project of a certain type of aircraft′s complex system.
基金Scientific Research Fund of Institute of Engineering Mechanics,CEA under Grant No.2019A03Scientific Research Fund of Institute of Engineering Mechanics,CEA under Grant No.2021D12National Key R&D Program of China under No.2018YFC1504404。
文摘Seismic isolation effectively reduces seismic demands on building structures by isolating the superstructure from ground vibrations during earthquakes.However,isolation strategies give less attention to acceleration-sensitive systems or equipment.Meanwhile,as the isolation layer’s displacement grows,the stiffness and frequency of traditional rolling and sliding isolation bearings increases,potentially causing self-centering and resonance concerns.As a result,a new conical pendulum bearing has been selected for acceleration-sensitive equipment to increase self-centering capacity,and additional viscous dampers are incorporated to enhance system damping.Moreover,the theoretical formula for conical pendulum bearings is supplied to analyze the device’s dynamic parameters,and shake table experiments are used to determine the proposed device’s isolation efficiency under various conditions.According to the test results,the newly proposed devices have remarkable isolation performance in terms of minimizing both acceleration and displacement responses.Finally,a numerical model of the isolation system is provided for further research,and the accuracy is demonstrated by the aforementioned experiments.
基金supported by the National Natural Science Foundation of China (51175502)
文摘Testing is the premise and foundation of realizing equipment health management (EHM). To address the problem that the static periodic test strategy may cause deficient test or excessive test, a dynamic sequential test strategy (DSTS) for EHM is presented. Considering the situation that equipment health state is not completely observable in reality, a DSTS optimization method based on partially observable semi-Markov decision pro- cess (POSMDP) is proposed. Firstly, an equipment health state degradation model is constructed by Markov process, and the control limit maintenance policy is also introduced. Secondly, POSMDP is formulated in great detail. And then, POSMDP is converted to completely observable belief semi-Markov decision process (BSMDP) through belief state. The optimal equation and the corresponding optimal DSTS, which minimize the long-run ex- pected average cost per unit time, are obtained with BSMDP. The results of application in complex equipment show that the proposed DSTS is feasible and effective.
文摘In order to research the effects of built-in test(BIT) on the system and select BITand test strategy,the complex repairable systems with BITequipment are modeled and simulated by using Simulink.Based on the model,the influences of different built-in test equipments,maintenance time and error probabilities on the system usability are evaluated.The simulation results showthat they effect on the system differently.The simulation method of complex system based on Simulink provides a technique approach to research the effects of BITon the system and select BITand test strategy.
文摘To solve the problems of low precision of weak feature extraction,heavy reliance on labor and low efficiency of weak feature extraction in X-ray weld detection image of ultra-high voltage(UHV)equipment key parts,an automatic feature extraction algorithm is proposed.Firstly,the original weld image is denoised while retaining the characteristic information of weak defects by the proposed monostable stochastic resonance method.Then,binarization is achieved by combining Laplacian edge detection and Otsu threshold segmentation.Finally,the automatic identification of weld defect area is realized based on the sequential traversal of binary tree.Several characteristic analysis dimensions are established for weld defects of UHV key parts,including defect area,perimeter,slenderness ratio,duty cycle,etc.The experiment using theweld detection image of the actual production site shows that the proposedmethod can effectively extract theweak feature information ofweld defects and further provide reference for decision-making.
文摘Double packer equipment for hydraulic test can be used to measure pressure of test zone directly, and it is frequently used to perform many kinds of hydraulic tests and take groundwater sample from borehole. The test method of this equipment mainly includes the test design, implementation, interpretation and synthetic analysis. By adopting the double packer equipment for hydraulic test, the parameter distribution of rock permeability along borehole can be acquired, as well as the connectivity, water conductivity and water bearing capacity of the disclosed structure and the chemical characteristics of the deep groundwater. It is a necessary method for the research and evaluation of the complex hypotonicity terrace site selection under geological conditions. This method is not only suitable for the geological disposal of high level radioactive waste, but also can be used in the site selection of underground facilities such as storage of petroleum and carbon dioxide. Meanwhile, it has a good application prospect in other hydrogeological investigation fields.
文摘This paper discusses causes of the rate ripple in inertia guidance test equipment IGET, systematically analyses their effects an the rate ripple in IGTE. The analysis result shows: The rate ripple caused by the periodic errors of inductosyn and angular encoder is higher at high speed than that caused by magnetic ripple torque and friction torque, and it cannot be eliminated by adjusting control parameters of the system. And based on the nonlinear adaptive control system theory, the paper puts forward a new control system scheme to eliminate the rate ripple caused by the periodic errors of inductosyn and angular encoder, develops the adaptive control rules and makes simulation and test. Experimental result shows a significant improvement on those tables for the period disturbs under the system scheme designed. By this plan, with the input of rate 200°/s, the rate ripple falls from 5°/s to 0. 4°/s within about 6s adaptive adjustment time, being a twelfth of before adaptation, which can not be reached by common classical controls. The experimental results conform with the simulation, which proves the validity and practicability of the plan.
文摘National Quality Supervision & Inspection Center for Refractories Business scope: Selective examination for national quality supervision; Identification of production license; Arbitration inspection and technical achievements evaluation; Commodities inspection and otherquality inspections .
文摘The objective of this work was to study the use of standard equipment in amplitude and frequency tests of dental scaler tip according to ISO 18397.Four types of standard equipment:a laser displacement sensor,a microscope,a tachometer,and an ultrasonic frequency meter,were experimentally investigated to test a tip.The standard laser displacement sensor and the standard microscope were used to test the unloaded amplitude of the scaler tip.It was found that two types of standard equipment were able to measure the unloaded amplitude of the tip.The standard microscope was also employed for the loaded amplitude test.This test was performed by pressing the scaler tip with a load of 1 N,which was measured by a load cell set.The peak-to-peak amplitude found from the test was 116.7 m.The frequency test of the scaler tip was conducted using the standard laser displacement sensor,the tachometer and the ultrasonic frequency meter.All three types of standard equipment were found to be able to test the frequency of the tip without cooling liquid.Nevertheless,only the standard tachometer was capable of measuring the frequency of the tip with cooling liquid applied.
基金Supported by Special Project of Public Sector Funding for Scientific Research,Ministry of Land and Resources,China(No.200811066)
文摘A mobile in-situ testing equipment used to detect geotechnical thermophysical properties was developed. The equipment is composed of a heat pump, frequency pumps, an electric tee joint regulator valve, some sensors, an electric control system, data acquisition and control system, which can do tests under the condition of extracting and storing subsurface heat. Applying the line source and the cylinder source heat transfer model, and combining the parameters estimation, the average thermophysieal property parameters of rock and soil will be calculated, which provides the basis for designing the ground source heat pump systems.
基金supported by the Advanced Research Project of a National Department of China under Grant No.51317040102
文摘The situation is constructed when the tests are considered as events and the spare test equipments are considered as strategies. The model of grey situation decision for the test equipment selection and deployment (TESD) is founded. Through analyzing each decision objectives, their relative weights are calculated via analytic hierarchy process (AHP). The grey situation effect matrix under each objective is computed so that the comprehensive effect measure matrix can be obtained when all of the objectives are traded off by their weights. Finally, the decision-maker can select the optimal situations by the value of the measures and such situations form the overall concept for TESD. The paper combines the AHP with grey situation decision to select and deploy the test equipments optimally. Our experimental results show that the proposed method is effective and efficient.
文摘Using Planet ATE's SOC 'all-in-one' pin electronics solutions it is easy to make your owntester, ATE or to modify load boards for more advanced test capabilities.
基金the Ningxia Key Research and Development Program(Grant No.2019BBF02009).
文摘In order to reduce the labor intensity and improve the efficiency of pruning,this study designed a multi-section luffing apple pruning equipment suitable for apple orchards in hilly and mountainous areas of China.In the essay,the structure and working principle of the equipment are expounded,the cutter was analyzed,and the parameters were determined.Using the self-made test bench to simulate the field experiment,this study selected the ratio of cutting speed to feeding speed and feeding speed as the influencing factors and took the cut-off rate,cutting efficiency and cutting power as the objectives to carry out single factor experiment and quadratic regression orthogonal experiment.The test results show that the cutting power increases with the increase of ratio of cutting speed to feeding speed,and the cut-off rate and cutting efficiency first increase and then decrease.As the feeding speed increases,the cutting efficiency and power increase,and the cut-off rate decreases.When the cutoff rate was greater than 80%,the optimal combination of operating parameters was the feeding speed of 0.55 m/s and ratio of cutting speed to feeding speed of 1.29.Under this combination,the cut-off rate was 84.9%,the cutting efficiency was 13.1,and the cutting power was 175.7 W.The error between the predicted target value of the model and the average measured target value was less than 7%,so the test results are reliable.According to the obtained optimal operating parameters,the actual cutting experiment of the pruning equipment in the field was carried out,and the cutting rate was 96.3%,which meet the design requirements.This study can also meet the needs of mechanized pruning of fruit trees with different crown shapes,improve the applicability of pruning equipment,and provide support for the development of mechanized pruning equipment in China.
基金Scientific Research Fund of IEM,CEA under Grant Nos.2016B09,2014B12China Natural Science Foundation under Grant Nos.51478442,51408565
文摘Porcelain electrical equipment (PEE), such as current transformers, is critical to power supply systems, but its seismic performance during past earthquakes has not been satisfactory. This paper studies the seismic performance of two typical types of PEE and proposes a damping method for PEE based on multiple tuned mass dampers (MTMD). An MTMD damping device involving three mass units, named a triple tuned mass damper (TTMD), is designed and manufactured. Through shake table tests and finite element analysis, the dynamic characteristics of the PEE are studied and the effectiveness of the MTMD damping method is verified. The adverse influence of MTMD redundant mass to damping efficiency is studied and relevant equations are derived. MTMD robustness is verified through adjusting TTMD control frequencies. The damping effectiveness of TTMD, when the peak ground acceleration far exceeds the design value, is studied. Both shake table tests and finite element analysis indicate that MTMD is effective and robust in attenuating PEE seismic responses. TTMD remains effective when the PGA far exceeds the design value and when control deviations are considered.
文摘In order to understand the vibration characteristic of system structure of electronic equipment cabinet within the particular vibration frequency,the finite element analysis software-ANSYS is used to simulate the tests of random vibrations of the cabinet system and obtain the isopleths graph of deformation and stress of the cabinet.It can confirm maximum of deformation and stress of the cabinet and position happened.Through more analysis of the frequency response curve,which can confirm harm- ful consequences random vibrations caused and weak link of the cabinet structure.The numerical simulation results are in good a- greement with the experimental results.It shows that this research provides an efficient method for the anti-seismic design and the dynamic optimization design.
基金the National Natural Science Foundation of China(61306046,61640421)the Yicheng Elite Project(202371)+3 种基金the Open Project of National Local Joint Engineering Laboratory of RF Integration and Micro-assembly Technology(KFJJ20230101)the National Key Laboratory of Integrated Chips and Systems Project(SLICS-K202316)the Anhui University Research Project(2023AH050481)the Research on Testing Methods and Accuracy of High Frequency Signal Chips(2023AH050500)。
文摘In response to the growing complexity and performance of integrated circuit(IC),there is an urgent need to enhance the testing and stability of IC test equipment.A method was proposed to predict equipment stability using the upper side boundary value of normal distribution.Initially,the K-means clustering algorithm classifies and analyzes sample data.The accuracy of this boundary value is compared under two common confidence levels to select the optimal threshold.A range is then defined to categorize unqualified test data.Through experimental verification,the method achieves the purpose of measuring the stability of qualitative IC equipment through a deterministic threshold value and judging the stability of the equipment by comparing the number of unqualified data with the threshold value,which realizes the goal of long-term operation monitoring and stability analysis of IC test equipment.
文摘In order to explore the seed drop characteristics by aerial seeding equipment,taking aerial seeding for Pinus tabulaeformis as an example,the Gaussian curve fitting and chi-square goodness-of-fit test were carried out on the data of fallen seed distribution,and the seed distribution models of domestic FB-85 and imported PZLM-18 equipment were established.The seeding performance indexes of the two kinds of equipment were calculated and compared by using the model,the existing problems of domestic equipment and their causes are analyzed,and finally,some suggestions for equipment optimization were put forward.The results indicated that the seed drop of the two kinds of equipment showed the characteristics of dense distribution in the middle and sparse distribution on both sides,and followed the Gaussian distribution as a whole;compared with PZLM-18,FB-85 had better seeding performance,but it also had the problem of uneven seed distribution;in addition to the influence of aircraft flow field,the fishtail structure design of diffuser is another important reason for the uneven seed distribution of domestic equipment;without changing the fishtail structure design,it is suggested that the principle of cross-superposition of two seeding belts should be used to replace a single large-size diffuser with two small-size diffusers,which can reduce the number of seeds in the middle and increase the number of seeds on both sides,so as to improve the uniformity of seed distribution.