A systematic, accurate and robust evaluating method for fine pitch printed circuit board （PCB） positioning assessment in testing fixture is developed. Targeting reliability of bed-of-nails tester is successfully eva...A systematic, accurate and robust evaluating method for fine pitch printed circuit board （PCB） positioning assessment in testing fixture is developed. Targeting reliability of bed-of-nails tester is successfully evaluated by the 2D pattern transform. Probe offset vector with its Weibull and Gaussian distribution estimates are obtained for further investigation about the causes of misalignment on the basis of a batch tests for same kind of PCBs.展开更多
The testing on the bearing strength of single-shear bolt jointed composite laminates structure is done.And the effect of the fixture on the testing results is analyzed. Then a macro-micro multi-scale analytical model ...The testing on the bearing strength of single-shear bolt jointed composite laminates structure is done.And the effect of the fixture on the testing results is analyzed. Then a macro-micro multi-scale analytical model combined with the improved"Generalized Method of Cells( GMC) "is developed,which is used to predict the macro bearing strength and to characterize the micro constitute material failure of the bolt jointed composite laminates structure. Both the contact conditions at the bolt/hole boundary and the contact conditions at the specimen/fixture boundary,progressive damage,and the material properties degradation are all taken account into the analytical model. Thus,the numerical simulation results agree well with the experimental results.Finally,the effect of the fixture on the testing results is characterized. The results show that the incomplete contaction between the fixture and the specimen or the lack of the lateral constraint on the specimen will affect the limited bearing strength and the offset bearing strength of the bolt jointed composite laminates structure. In addition,the lower support rigid of the fixture will affect the rigid of the bolt jointed composite laminates structure.展开更多
This work aims to improve the setup of an electrodynamic triaxial shaker prototype with respect to its usability for the automotive industry.Triaxial shakers being capable of meeting the corresponding requirements are...This work aims to improve the setup of an electrodynamic triaxial shaker prototype with respect to its usability for the automotive industry.Triaxial shakers being capable of meeting the corresponding requirements are not available as standard test equipment.Modifications on the fixture have to be conducted in order to ensure an effective control.The first part of the work is the qualitative description of the system behavior.Therefore,the shaker is treated as a black box.The second part is the modification of the test fixture in order to handle the resonances of the shaker,which is elementary for its usage.A setup is found,that improves testing within the desired frequency range.Thereby,acceleration levels are considered as well as excitation phases and coherences.The proposed setup is used for an exemplary specimen with two different control scenarios.Conclusions are then drawn about the usage of triaxial shakers.展开更多
Purpose The Taishan Neutrino Experiment(TAO),also known as JUNO-TAO,serves as a satellite experiment for the Jiangmen Underground Neutrino Experiment(JUNO).Its primary objective is to measure the neutrino energy spect...Purpose The Taishan Neutrino Experiment(TAO),also known as JUNO-TAO,serves as a satellite experiment for the Jiangmen Underground Neutrino Experiment(JUNO).Its primary objective is to measure the neutrino energy spectrum of the reactor,which serves as input data for JUNO.A key component of TAO is the ton-size liquid-flash detector,utilizing high-detection-efficiency Silicon photomultipliers(SiPMs)capable of observing around 4500 photons per MeV.Due to the pivotal role of SiPMs in the experiment,it is crucial to conduct a burn-in test to ensure their stability under light-avoidance conditions prior to the main experiment.The SiPM burn-in test is designed to verify the stable dark current of each SiPM.Methods To support the test,a specialized SiPM burn-in system is developed,intended to run stably for half a year.It incorporates a complete hardware setup to ensure reliable power supply and current output for each SiPM tile.On the software side,PyQt5 serves as the Graphical User Interface(GUI)development tool,while the logic control script is written in pure Python,facilitating integration with various hardware interface protocols.The data acquisition system encompasses modules for device control,data acquisition,storage,alarm,and logging,optimizing the system's stability and ease of operation.Results and conclusions Throughout the burn-in test,the system achieves real-time display of SiPM current and promptly issues abnormal alarms when necessary.This dynamic functionality demonstrates the system's stability and flexibility,effectively laying a solid foundation for the TAO experiment's success.展开更多
基金This project is supported by US Pennsylvania Dept. of Community & Economic Development(No.20-906-0015)National Natural Science Foundation of China(No.50390064, No.50575230)National Basic Research Program of China(973 Program, No.2003CB716202).
文摘A systematic, accurate and robust evaluating method for fine pitch printed circuit board （PCB） positioning assessment in testing fixture is developed. Targeting reliability of bed-of-nails tester is successfully evaluated by the 2D pattern transform. Probe offset vector with its Weibull and Gaussian distribution estimates are obtained for further investigation about the causes of misalignment on the basis of a batch tests for same kind of PCBs.
基金Sponsored by the National Natural Science Foundation of China(Grant No.11272105)the Heilongjiang Province Science Foundation for Youths(Grant No.QC2015003)the Harbin Science and Technology Bureau Young Talent Reserve Project(Grant No.RC2016QN001011,RC2016QN017023)
文摘The testing on the bearing strength of single-shear bolt jointed composite laminates structure is done.And the effect of the fixture on the testing results is analyzed. Then a macro-micro multi-scale analytical model combined with the improved"Generalized Method of Cells( GMC) "is developed,which is used to predict the macro bearing strength and to characterize the micro constitute material failure of the bolt jointed composite laminates structure. Both the contact conditions at the bolt/hole boundary and the contact conditions at the specimen/fixture boundary,progressive damage,and the material properties degradation are all taken account into the analytical model. Thus,the numerical simulation results agree well with the experimental results.Finally,the effect of the fixture on the testing results is characterized. The results show that the incomplete contaction between the fixture and the specimen or the lack of the lateral constraint on the specimen will affect the limited bearing strength and the offset bearing strength of the bolt jointed composite laminates structure. In addition,the lower support rigid of the fixture will affect the rigid of the bolt jointed composite laminates structure.
文摘This work aims to improve the setup of an electrodynamic triaxial shaker prototype with respect to its usability for the automotive industry.Triaxial shakers being capable of meeting the corresponding requirements are not available as standard test equipment.Modifications on the fixture have to be conducted in order to ensure an effective control.The first part of the work is the qualitative description of the system behavior.Therefore,the shaker is treated as a black box.The second part is the modification of the test fixture in order to handle the resonances of the shaker,which is elementary for its usage.A setup is found,that improves testing within the desired frequency range.Thereby,acceleration levels are considered as well as excitation phases and coherences.The proposed setup is used for an exemplary specimen with two different control scenarios.Conclusions are then drawn about the usage of triaxial shakers.
文摘Purpose The Taishan Neutrino Experiment(TAO),also known as JUNO-TAO,serves as a satellite experiment for the Jiangmen Underground Neutrino Experiment(JUNO).Its primary objective is to measure the neutrino energy spectrum of the reactor,which serves as input data for JUNO.A key component of TAO is the ton-size liquid-flash detector,utilizing high-detection-efficiency Silicon photomultipliers(SiPMs)capable of observing around 4500 photons per MeV.Due to the pivotal role of SiPMs in the experiment,it is crucial to conduct a burn-in test to ensure their stability under light-avoidance conditions prior to the main experiment.The SiPM burn-in test is designed to verify the stable dark current of each SiPM.Methods To support the test,a specialized SiPM burn-in system is developed,intended to run stably for half a year.It incorporates a complete hardware setup to ensure reliable power supply and current output for each SiPM tile.On the software side,PyQt5 serves as the Graphical User Interface(GUI)development tool,while the logic control script is written in pure Python,facilitating integration with various hardware interface protocols.The data acquisition system encompasses modules for device control,data acquisition,storage,alarm,and logging,optimizing the system's stability and ease of operation.Results and conclusions Throughout the burn-in test,the system achieves real-time display of SiPM current and promptly issues abnormal alarms when necessary.This dynamic functionality demonstrates the system's stability and flexibility,effectively laying a solid foundation for the TAO experiment's success.
