The fatigue life of aeroengine turbine disc presents great dispersion due to the randomness of the basic variables,such as applied load,working temperature,geometrical dimensions and material properties.In order to am...The fatigue life of aeroengine turbine disc presents great dispersion due to the randomness of the basic variables,such as applied load,working temperature,geometrical dimensions and material properties.In order to ameliorate reliability analysis efficiency without loss of reliability,the distributed collaborative response surface method(DCRSM) was proposed,and its basic theories were established in this work.Considering the failure dependency among the failure modes,the distributed response surface was constructed to establish the relationship between the failure mode and the relevant random variables.Then,the failure modes were considered as the random variables of system response to obtain the distributed collaborative response surface model based on structure failure criterion.Finally,the given turbine disc structure was employed to illustrate the feasibility and validity of the presented method.Through the comparison of DCRSM,Monte Carlo method(MCM) and the traditional response surface method(RSM),the results show that the computational precision for DCRSM is more consistent with MCM than RSM,while DCRSM needs far less computing time than MCM and RSM under the same simulation conditions.Thus,DCRSM is demonstrated to be a feasible and valid approach for improving the computational efficiency of reliability analysis for aeroengine turbine disc fatigue life with multiple random variables,and has great potential value for the complicated mechanical structure with multi-component and multi-failure mode.展开更多
This paper focuses on preparation of colloidal solution of graphene-like structures from different ranks of coals: brown coal,bituminous coal,low-volatile bituminous coal,anthracite. It was found that brown coal therm...This paper focuses on preparation of colloidal solution of graphene-like structures from different ranks of coals: brown coal,bituminous coal,low-volatile bituminous coal,anthracite. It was found that brown coal thermo-oxidative destruction leads to formation of small d = 32 nm( V = 17%) and large d = 122 nm( V = 11%) fractions of nanoparticles. The thermo-oxidative destruction of bituminous coal leads to formation of nanoparticles d = 50 nm( V = 5.2%) and d = 164 nm( V = 16%). Thermooxidative destruction of low-volatile bituminous coal and anthracite leads to formation of nanoparticles,predominantly,d = 122-190 nm. Carbon nanostructures obtained from coal are negatively charged at pH= 2-12. Colloidal solution of carbon nanostructures at dispersed phase concentration 0. 01 mg/mL is stable for 1 month. Electron diffraction patterns and X-ray analysis of carbon nanostructures showed that nanostructure from brown coal is amorphous and nanostructure from anthracite is crystalline. Results of coal macromolecules modeling and graphene-like structures obtained from them are presented.展开更多
With the evolution of application system, there are t wo different system architectures. One is the traditional application system suc h as MIS and Business Software. Along with its extension, the traditional applic a...With the evolution of application system, there are t wo different system architectures. One is the traditional application system suc h as MIS and Business Software. Along with its extension, the traditional applic ation system transforms from file-based structure to C/S and then CSS model. At the same time, following the prevalence of Internet/Intranet, Web application s ystem based on browser comes into being. In early time, Web application only pro vided functions of looking over or querying static data on browser. But with the development of Internet/Intranet widely, it’s expected that more and more trad itional applications can be performed on browser, or even E-Business trades and other complicated application systems such as MIS, ERP and CRM and so on. In or der to satisfy both traditional application and Web application, reduce the cost of developing system repeatedly, increase the repeated use of application syste m and take advantage of the functions of OOA/OOD sufficiently, a new distributed architecture structure (system solution based on repeated components) comes for th. In this article, this distributed architecture structure will be discuss ed in detail. Firstly, the evolution of traditional application system and Web application sys tem will be talked over, especially the advantages and disadvantages of these tw o architectures. Secondly, the distributed architecture (system solution based o n repeated components) will be described particular. Several prevalent technolog y of component, such as COM+, CORBA and EJB, will also be illustrate d in this part. Thirdly, the practice of the technology of repeated component wi ll be discussed by analysing and designing the management system of Science & Te chnology Articles. Lastly, the latest distributed techonlogy of E-business(Web service based on xml/soap) will be discussed. In the end, Based on summing-up o f the distributed technology of E-Business, the future distributed tenchnology of E-Business will be expected.展开更多
To monitor the stress state of prestressed reinforcement in large reinforcement prestressed structure, two sensing structures, namely the direct spiral-winding structure and sawtooth modulated structure, were designed...To monitor the stress state of prestressed reinforcement in large reinforcement prestressed structure, two sensing structures, namely the direct spiral-winding structure and sawtooth modulated structure, were designed based on the ordinary communication optical fiber. The sensing theories were analyzed, and the experimental studies were also carried out. The quasi-distributed sensing system based on optical time domain reflective technology was established. The detection wavelength and spatial resolution were analyzed, and the estimation formula of maximal number of sensing point was also given. The results show that the system can realize the quasi-distributed test of measurand with single fiber, which helps to simplify the in-out wires. Moreover it can take on the important task of long-term and continuous monitoring of prestress, which helps to realize the life cycle detection of prestress, and play an important role in the estimating of bridge health state.展开更多
基金Project(51335003)supported by the National Natural Science Foundation of ChinaProject(20111102110011)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘The fatigue life of aeroengine turbine disc presents great dispersion due to the randomness of the basic variables,such as applied load,working temperature,geometrical dimensions and material properties.In order to ameliorate reliability analysis efficiency without loss of reliability,the distributed collaborative response surface method(DCRSM) was proposed,and its basic theories were established in this work.Considering the failure dependency among the failure modes,the distributed response surface was constructed to establish the relationship between the failure mode and the relevant random variables.Then,the failure modes were considered as the random variables of system response to obtain the distributed collaborative response surface model based on structure failure criterion.Finally,the given turbine disc structure was employed to illustrate the feasibility and validity of the presented method.Through the comparison of DCRSM,Monte Carlo method(MCM) and the traditional response surface method(RSM),the results show that the computational precision for DCRSM is more consistent with MCM than RSM,while DCRSM needs far less computing time than MCM and RSM under the same simulation conditions.Thus,DCRSM is demonstrated to be a feasible and valid approach for improving the computational efficiency of reliability analysis for aeroengine turbine disc fatigue life with multiple random variables,and has great potential value for the complicated mechanical structure with multi-component and multi-failure mode.
基金supported by the Ministry of Education and Science of the Russian Federation(the Agreement number 02.a03.21.0008)
文摘This paper focuses on preparation of colloidal solution of graphene-like structures from different ranks of coals: brown coal,bituminous coal,low-volatile bituminous coal,anthracite. It was found that brown coal thermo-oxidative destruction leads to formation of small d = 32 nm( V = 17%) and large d = 122 nm( V = 11%) fractions of nanoparticles. The thermo-oxidative destruction of bituminous coal leads to formation of nanoparticles d = 50 nm( V = 5.2%) and d = 164 nm( V = 16%). Thermooxidative destruction of low-volatile bituminous coal and anthracite leads to formation of nanoparticles,predominantly,d = 122-190 nm. Carbon nanostructures obtained from coal are negatively charged at pH= 2-12. Colloidal solution of carbon nanostructures at dispersed phase concentration 0. 01 mg/mL is stable for 1 month. Electron diffraction patterns and X-ray analysis of carbon nanostructures showed that nanostructure from brown coal is amorphous and nanostructure from anthracite is crystalline. Results of coal macromolecules modeling and graphene-like structures obtained from them are presented.
文摘With the evolution of application system, there are t wo different system architectures. One is the traditional application system suc h as MIS and Business Software. Along with its extension, the traditional applic ation system transforms from file-based structure to C/S and then CSS model. At the same time, following the prevalence of Internet/Intranet, Web application s ystem based on browser comes into being. In early time, Web application only pro vided functions of looking over or querying static data on browser. But with the development of Internet/Intranet widely, it’s expected that more and more trad itional applications can be performed on browser, or even E-Business trades and other complicated application systems such as MIS, ERP and CRM and so on. In or der to satisfy both traditional application and Web application, reduce the cost of developing system repeatedly, increase the repeated use of application syste m and take advantage of the functions of OOA/OOD sufficiently, a new distributed architecture structure (system solution based on repeated components) comes for th. In this article, this distributed architecture structure will be discuss ed in detail. Firstly, the evolution of traditional application system and Web application sys tem will be talked over, especially the advantages and disadvantages of these tw o architectures. Secondly, the distributed architecture (system solution based o n repeated components) will be described particular. Several prevalent technolog y of component, such as COM+, CORBA and EJB, will also be illustrate d in this part. Thirdly, the practice of the technology of repeated component wi ll be discussed by analysing and designing the management system of Science & Te chnology Articles. Lastly, the latest distributed techonlogy of E-business(Web service based on xml/soap) will be discussed. In the end, Based on summing-up o f the distributed technology of E-Business, the future distributed tenchnology of E-Business will be expected.
文摘To monitor the stress state of prestressed reinforcement in large reinforcement prestressed structure, two sensing structures, namely the direct spiral-winding structure and sawtooth modulated structure, were designed based on the ordinary communication optical fiber. The sensing theories were analyzed, and the experimental studies were also carried out. The quasi-distributed sensing system based on optical time domain reflective technology was established. The detection wavelength and spatial resolution were analyzed, and the estimation formula of maximal number of sensing point was also given. The results show that the system can realize the quasi-distributed test of measurand with single fiber, which helps to simplify the in-out wires. Moreover it can take on the important task of long-term and continuous monitoring of prestress, which helps to realize the life cycle detection of prestress, and play an important role in the estimating of bridge health state.
