A test system is developed for the BESIII ETOF/MRPC beam tests of data acquisition, environment monitoring and automatic control. The software framework is based on the CAMAC bus, VME bus and Serial Port,which are res...A test system is developed for the BESIII ETOF/MRPC beam tests of data acquisition, environment monitoring and automatic control. The software framework is based on the CAMAC bus, VME bus and Serial Port,which are responsible for communications with the detectors. The monitor system works well in the beam test.展开更多
A prototype multi-gap resistive plate chamber （MRPC） with a 2 × 6 gap structure is developed for the upgrading of the endcap time-of-flight （ETOF） detector in the Beijing Spectrometer （BESⅢ ）. The prototyp...A prototype multi-gap resistive plate chamber （MRPC） with a 2 × 6 gap structure is developed for the upgrading of the endcap time-of-flight （ETOF） detector in the Beijing Spectrometer （BESⅢ ）. The prototype MRPC is tested in the E3 beam line of the Beijing Electron Positron Collider （BEPC） with secondary charged particles （π and p, etc） of 600 MeV/c. The test results show that the time resolution of the MRPC can reach 50 ps and that the detection efficiency is greater than 98%.展开更多
By the end of 2021, China's high-speed railway had operated more than 40,000 kilometers, and the transportation network of four vertical and four horizontal high-speed railway lines had basically taken shape. In o...By the end of 2021, China's high-speed railway had operated more than 40,000 kilometers, and the transportation network of four vertical and four horizontal high-speed railway lines had basically taken shape. In order to meet the needs of China's high-speed railway construction, China Railway Corporation launched a major scientific research project "Research on Key Technologies for the Construction of Long-span Simply Supported Beams for High-speed Railways" in 2016. Beijing Railway Fangshan Bridge Co., Ltd. is mainly responsible for the manufacture of 40-meter full-scale test beams, and template assembly is an important factor affecting the quality of the test beams. The summary of formwork assembling construction technology for 40-meter full-scale test beam can provide technical guarantee for formwork assembling construction for the production of high-speed railway long-span simply supported beam in the future.展开更多
A composite shear wall concept based on concrete filled steel tube （CFST） columns and steel plate （SP） deep beams is proposed and examined in this study. The new wall is composed of three different energy dissipat...A composite shear wall concept based on concrete filled steel tube （CFST） columns and steel plate （SP） deep beams is proposed and examined in this study. The new wall is composed of three different energy dissipation elements： CFST columns; SP deep beams; and reinforced concrete （RC） strips. The RC strips are intended to allow the core structural elements - the CFST columns and SP deep beams - to work as a single structure to consume energy. Six specimens of different configurations were tested under cyclic loading. The resulting data are analyzed herein. In addition, numerical simulations of the stress and damage processes for each specimen were carried out, and simulations were completed for a range of location and span-height ratio variations for the SP beams. The simulations show good agreement with the test results. The core structure exhibits a ductile yielding mechanism characteristic of strong column-weak beam structures, hysteretic curves are plump and the composite shear wall exhibits several seismic defense lines. The deformation of the shear wall specimens with encased CFST column and SP deep beam design appears to be closer to that of entire shear walls. Establishing optimal design parameters for the configuration of SP deep beams is pivotal to the best seismic behavior of the wall. The new composite shear wall is therefore suitable for use in the seismic design of building structures.展开更多
Wood beam-column frame is a popular structural system in United States and in ancient China. Chinese wood beam-column frame structures showed better seismic resistance properties than the US ones.The tenon joint is on...Wood beam-column frame is a popular structural system in United States and in ancient China. Chinese wood beam-column frame structures showed better seismic resistance properties than the US ones.The tenon joint is one of the reasons.This study performed monotonic and cyclic pushover tests to understand the behavior of Chinese tenon joints versus the behavior of the commonly used US wood beam-column connections. The test results indicate that the typical US wood beam-column connection is very strong under monotonic loads.The ancient Chinese tenon joint has the best behavior under cyclic loads.展开更多
In the past few decades,the navigation performance of ships and structures in ice-covered waters has not been fully studied,especially the influence of ice mechanical properties on icebreaking ability.Ice bending stre...In the past few decades,the navigation performance of ships and structures in ice-covered waters has not been fully studied,especially the influence of ice mechanical properties on icebreaking ability.Ice bending strength is a key ice parameter for predicting ship ice loads,and accurate ice bending strength is also the key to scaling model tests results to real ship.However,numerical simulation studies on model ice bending strength of ice tanks are often neglected.In this paper,an explicit finite element method model is used to simulate the ice cantilever beam test,and the failure load and bending strength of the ice are obtained.In this model,the Tsai-Wu failure criterion is used as the material constitutive model,and the required simulation parameters are obtained from the model ice test in ice tank.Parameter sensitivity analysis shows that the cantilever beam size of the model ice has a significant effect on the flexural strength.The results show that proper rounding at the root of the cantilever beam is beneficial to reduce stress concentration and obtain more accurate bending strength;the thickness,width and length of the cantilever beam should conform to a certain ratio,and consistent with the ITTC recommended reference.Therefore,the results of this study can promote model ice experiments and numerical studies and provide ice strength data support for ship design and polar ship maneuvering.展开更多
基金Supported by the State Key program of National Natural Science of China(No.10979003)National Natural Science Foundation of China(No.10775181)China Postdoctoral Science Foundation(No.20090460521)
文摘A test system is developed for the BESIII ETOF/MRPC beam tests of data acquisition, environment monitoring and automatic control. The software framework is based on the CAMAC bus, VME bus and Serial Port,which are responsible for communications with the detectors. The monitor system works well in the beam test.
基金Supported by National Natural Science Foundation of China (10979003, 10875120)Major State Basic Research Development Program (2008CB817702)
文摘A prototype multi-gap resistive plate chamber （MRPC） with a 2 × 6 gap structure is developed for the upgrading of the endcap time-of-flight （ETOF） detector in the Beijing Spectrometer （BESⅢ ）. The prototype MRPC is tested in the E3 beam line of the Beijing Electron Positron Collider （BEPC） with secondary charged particles （π and p, etc） of 600 MeV/c. The test results show that the time resolution of the MRPC can reach 50 ps and that the detection efficiency is greater than 98%.
文摘By the end of 2021, China's high-speed railway had operated more than 40,000 kilometers, and the transportation network of four vertical and four horizontal high-speed railway lines had basically taken shape. In order to meet the needs of China's high-speed railway construction, China Railway Corporation launched a major scientific research project "Research on Key Technologies for the Construction of Long-span Simply Supported Beams for High-speed Railways" in 2016. Beijing Railway Fangshan Bridge Co., Ltd. is mainly responsible for the manufacture of 40-meter full-scale test beams, and template assembly is an important factor affecting the quality of the test beams. The summary of formwork assembling construction technology for 40-meter full-scale test beam can provide technical guarantee for formwork assembling construction for the production of high-speed railway long-span simply supported beam in the future.
基金National Natural Science Foundation of China under Grant No.51148009National Natural Science Foundation of China under Grant No.50978005Project High-level Personnel in Beijing under Grant No.PHR20100502
文摘A composite shear wall concept based on concrete filled steel tube （CFST） columns and steel plate （SP） deep beams is proposed and examined in this study. The new wall is composed of three different energy dissipation elements： CFST columns; SP deep beams; and reinforced concrete （RC） strips. The RC strips are intended to allow the core structural elements - the CFST columns and SP deep beams - to work as a single structure to consume energy. Six specimens of different configurations were tested under cyclic loading. The resulting data are analyzed herein. In addition, numerical simulations of the stress and damage processes for each specimen were carried out, and simulations were completed for a range of location and span-height ratio variations for the SP beams. The simulations show good agreement with the test results. The core structure exhibits a ductile yielding mechanism characteristic of strong column-weak beam structures, hysteretic curves are plump and the composite shear wall exhibits several seismic defense lines. The deformation of the shear wall specimens with encased CFST column and SP deep beam design appears to be closer to that of entire shear walls. Establishing optimal design parameters for the configuration of SP deep beams is pivotal to the best seismic behavior of the wall. The new composite shear wall is therefore suitable for use in the seismic design of building structures.
文摘Wood beam-column frame is a popular structural system in United States and in ancient China. Chinese wood beam-column frame structures showed better seismic resistance properties than the US ones.The tenon joint is one of the reasons.This study performed monotonic and cyclic pushover tests to understand the behavior of Chinese tenon joints versus the behavior of the commonly used US wood beam-column connections. The test results indicate that the typical US wood beam-column connection is very strong under monotonic loads.The ancient Chinese tenon joint has the best behavior under cyclic loads.
文摘In the past few decades,the navigation performance of ships and structures in ice-covered waters has not been fully studied,especially the influence of ice mechanical properties on icebreaking ability.Ice bending strength is a key ice parameter for predicting ship ice loads,and accurate ice bending strength is also the key to scaling model tests results to real ship.However,numerical simulation studies on model ice bending strength of ice tanks are often neglected.In this paper,an explicit finite element method model is used to simulate the ice cantilever beam test,and the failure load and bending strength of the ice are obtained.In this model,the Tsai-Wu failure criterion is used as the material constitutive model,and the required simulation parameters are obtained from the model ice test in ice tank.Parameter sensitivity analysis shows that the cantilever beam size of the model ice has a significant effect on the flexural strength.The results show that proper rounding at the root of the cantilever beam is beneficial to reduce stress concentration and obtain more accurate bending strength;the thickness,width and length of the cantilever beam should conform to a certain ratio,and consistent with the ITTC recommended reference.Therefore,the results of this study can promote model ice experiments and numerical studies and provide ice strength data support for ship design and polar ship maneuvering.
