检索结果-南通市图书馆

Computer Modeling in Engineering & Sciences 2023年第3期134卷 1871-1897页

作者： Hong Zhang Lukai Song guangchen bai School of Energy and Power Engineering Beihang UniversityBeijing100191China Research Institute of Aero-Engine Beihang UniversityBeijing100191China

The reliability and sensitivity analyses of stator blade regulator usually involve complex characteristics like highnonlinearity,multi-failure regions,and small failure probability,which brings in unacceptable computing efficiency and accuracy of the current *** this case,by fitting the implicit limit state function(LSF)with active Kriging(AK)model and reducing candidate sample poolwith adaptive importance sampling(AIS),a novel AK-AIS method is ***,theAKmodel andMarkov chainMonte Carlo(MCMC)are first established to identify the most probable failure region(s)(MPFRs),and the adaptive kernel density estimation(AKDE)importance sampling function is constructed to select the candidate *** the best samples sequentially attained in the reduced candidate samples and employed to update the Kriging-fitted LSF,the failure probability and sensitivity indices are acquired at a lower *** proposed method is verified by twomulti-failure numerical examples,and then applied to the reliability and sensitivity analyses of a typical stator blade *** comparison,the proposed AK-AIS is proven to hold the computing advantages on accuracy and efficiency in complex reliability and sensitivity analysis problems.

关键词： Markov chain Monte Carlo active Kriging adaptive kernel density estimation importance sampling

Macro-phenomenological high-strain-rate elastic fracture model for ice-impact simulations

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第3期36卷 146-160页

作者： Jiang FAN Qinghao YUAN Fulei JING guangchen bai Xiuli SHEN School of Energy and Power Engineering Beihang UniversityBeijing 100191China Beijing Key Laboratory of Aero-Engine Structure and Strength Beijing 100191China Collaborative Innovation Center of Advanced Aero-Engine Beijing 100191China Aero-Engine Academy of China Aero Engine(Group)Corporation of ChinaBeijing 101304China

The ice impact can cause a severe damage to an aircraft’s exposed structure,thus,requiring its *** numerical simulation represents an effective method to overcome this *** establishment of the ice material model is ***,ice is not a common structural material and exhibits an extremely complex material *** material models of ice reported so far are not able to accurately simulate the ice behavior at high strain *** study proposes a novel high-precision macro-phenomenological elastic fracture model based on the brittle behavior of ice at high strain *** developed model has been compared with five reported models by using the smoothed particle hydrodynamics method so as to simulate the ice-impact process with respect to the impact speeds and ice *** important metrics and phenomena(impact force history,deformation and fragmentation of the ice projectile and deflection of the target)were compared with the experimental data reported in the *** findings obtained from the developed model are observed to be most consistent with the experimental data,which demonstrates that the model represents the basic physics and phenomena governing the ice impact at high strain *** developed model includes a relatively fewer number of material ***,the used parameters have a clear physical meaning and can be directly obtained through ***,no adjustment of any material parameter is needed,and the consumption duration is also *** advantages indicate that the developed model is suitable for simulating the iceimpact process and can be applied for the anti-ice impact design in aviation.

关键词： Crack propagation Elastic fracture High strain rate Ice impact Impact force Material model

Dynamic Meta-Modeling Method to Assess Stochastic Flutter Behavior in Turbomachinery

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2022年第10期133卷 171-193页

作者： Bowei Wang Wenzhong Tang Lukai Song guangchen bai School of Computer Science and Engineering Beihang UniversityBeijing100191China Research Institute of Aero-Engine Beihang UniversityBeijing100191China School of Energy and Power Engineering Beihang UniversityBeijing100191China

With increasing design demands of turbomachinery,stochastic flutter behavior has become more prominent and even appears a hazard to reliability and *** flutter assessment is an effective measure to quantify the failure risk and improve aeroelastic ***,for complex turbomachinery with multiple dynamic influencing factors(i.e.,aeroengine compressor with time-variant loads),the stochastic flutter assessment is hard to be achieved effectively,since large deviations and inefficient computing will be incurred no matter considering influencing factors at a certain instant or the whole time *** improve the assessing efficiency and accuracy of stochastic flutter behavior,a dynamic meta-modeling approach(termed BA-DWTR)is presented with the integration of bat algorithm(BA)and dynamic wavelet tube regression(DWTR).The stochastic flutter assessment of a typical compressor blade is considered as one case to evaluate the proposed approach with respect to condition variabilities and load *** evaluation results reveal that the compressor blade has 0.95% probability to induce flutter failure when operating 100% rotative rate at t=170 *** total temperature at rotor inlet and dynamic operating loads(vibrating frequency and rotative rate)are the primary sensitive parameters on flutter failure *** comparisons,the presented approach is validated to possess high-accuracy and highefficiency in assessing the stochastic flutter behavior for turbomachinery.

关键词： Stochastic flutter assessment turbomachinery meta-model tube regression

Distributed Collaborative Response Surface Method for Mechanical Dynamic Assembly Reliability Design

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2013年第6期26卷 1160-1168页

作者： bai guangchen FEI Chengwei School of Energy and Power Engineering Beihang University

Because of the randomness of many impact factors influencing the dynamic assembly relationship of complex machinery, the reliability analysis of dynamic assembly relationship needs to be accomplished considering the randomness from a probabilistic perspective. To improve the accuracy and efficiency of dynamic assembly relationship reliability analysis, the mechanical dynamic assembly reliability（MDAR） theory and a distributed collaborative response surface method（DCRSM） are proposed. The mathematic model of DCRSM is established based on the quadratic response surface function, and verified by the assembly relationship reliability analysis of aeroengine high pressure turbine（HPT） blade-tip radial running clearance（BTRRC）. Through the comparison of the DCRSM, traditional response surface method（RSM） and Monte Carlo Method（MCM）, the results show that the DCRSM is not able to accomplish the computational task which is impossible for the other methods when the number of simulation is more than 100 000 times, but also the computational precision for the DCRSM is basically consistent with the MCM and improved by 0.40-4.63% to the RSM, furthermore, the computational efficiency of DCRSM is up to about 188 times of the MCM and 55 times of the RSM under 10000 times simulations. The DCRSM is demonstrated to be a feasible and effective approach for markedly improving the computational efficiency and accuracy of MDAR analysis. Thus, the proposed research provides the promising theory and method for the MDAR design and optimization, and opens a novel research direction of probabilistic analysis for developing the high-performance and high-reliability of aeroengine.

关键词： machinery dynamic assembly reliability analysis distributed collaborative response surface method,blade-tip radial running clearance

Application of Improved Hybrid Interface Substructural Component Modal Synthesis Method in Vibration Characteristics of Mistuned Blisk

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2014年第6期27卷 1219-1231页

作者： bai Bin bai guangchen LI Chao School of Energy and Power Engineering Beihang University

The large and complex structures are divided into hundreds of thousands or millions degrees of freedom（DOF） when they are calculated which will spend a lot of time and the efficiency will be extremely low. The classical component modal synthesis method （CMSM） are used extensively, but for many structures in the engineering of high-rise buildings, aerospace systemic engineerings, marine oil platforms etc, a large amount of calculation is still needed. An improved hybrid interface substructural component modal synthesis method（HISCMSM） is proposed. The parametric model of the mistuned blisk is built by the improved HISCMSM. The double coordinating conditions of the displacement and the force are introduced to ensure the computational accuracy. Compared with the overall structure finite element model method（FEMM）, the computational time is shortened by23.86%–31.56%and the modal deviation is 0.002%–0.157% which meets the requirement of the computational accuracy. It is faster 4.46%–10.57% than the classical HISCMSM. So the improved HISCMSM is better than the classical HISCMSM and the overall structure FEMM. Meanwhile, the frequency and the modal shape are researched, considering the factors including rotational speed, gas temperature and geometry size. The strong localization phenomenon of the modal shape’s the maximum displacement and the maximum stress is observed in the second frequency band and it is the most sensitive in the frequency veering. But the localization phenomenon is relatively weak in 1st and the 3d frequency band. The localization of the modal shape is more serious under the condition of the geometric dimensioning mistuned. An improved HISCMSM is proposed, the computational efficiency of the mistuned blisk can be increased observably by this method.

关键词： modal shape mistuned blisk vibration characteristics computational efficiency computational accuracy

New Neural Network Response Surface Methods for Reliability Analysis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2011年第1期24卷 25-31页

作者： REN Yuan bai guangchen School of Jet Propulsion Beijing University of Aeronautics and Astronautics Beijing 100191 China

This article presents two new kinds of artificial neural network （ANN） response surface methods （RSMs）： the ANN RSM based on early stopping technique （ANNRSM-1）, and the ANN RSM based on regularization theory （ANNRSM-2）. The following improvements are made to the conventional ANN RSM （ANNRSM-0）： 1） by monitoring the validation error during the training process, ANNRSM-1 determines the early stopping point and the training stopping point, and the weight vector at the early stopping point, which corresponds to the ANN model with the optimal generalization, is finally returned as the training result; 2） according to the regularization theory, ANNRSM-2 modifies the conventional training performance function by adding to it the sum of squares of the network weights, so the network weights are forced to have smaller values while the training error decreases. Tests show that the performance of ANN RSM becomes much better due to the above-mentioned improvements： first, ANNRSM-1 and ANNRSM-2 approximate to the limit state function （LSF） more accurately than ANNRSM-0; second, the estimated failure probabilities given by ANNRSM-1 and ANNRSM-2 have smaller errors than that obtained by ANNRSM-0; third, compared with ANNRSM-0, ANNRSM-1 and ANNRSM-2 require much fewer data samples to achieve stable failure probability results.

关键词： neural networks response surface reliability analysis early stopping regularization

Extremum selection method of random variable for nonlinear dynamic reliability analysis of turbine blade deformation

在线全文

学校读者我要写书评

暂无评论

Propulsion and Power Research 2012年第1期1卷 58-63页

作者： Chengwei Fein guangchen bai School of Energy and Power Engineering Beihang UniversityBeijing 100191China

To effectively select random variable in nonlinear dynamic reliability analysis,the extremum selection method(ESM)is ***,the basic idea was introduced and the mathematical model was established for the *** nonlinear dynamic reliability analysis of turbine blade radial deformation was taken as an example to verify the *** results show that the analysis precision of the ESM is 99.972%,which is almost kept consistent with that of the Monte Carlo method;moreover,the computing time of the ESM is shorter than that of the traditional ***,it is demonstrated that the ESM is able to save calculation time and improve the computational efficiency while keeping the calculation precision for nonlinear dynamic reliability *** present study provides a method to enhance the nonlinear dynamic reliability analysis in selecting the random variables and offers a way to design structure and machine in future work.

关键词： Extremum selection method(ESM) Turbine blade Radial deformation Reliability analysis Random variable Nonlinear Dynamic

A RBNN BASED RESPONSE SURFACE CONSTRUCTION METHOD FOR MECHANICAL SYSTEMS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

A RBNN BASED RESPONSE SURFACE CONSTRUCTION METHOD FOR MECHAN...

基于GA-BP贝叶斯算法的可靠性分析近似模型

2007中国宁波国际计算机科学与技术学术大会

作者： Ren Yuan bai guangchen School of Jet Propulsion Beijing University of Aeronautics ＆ Astronautics

ISBN: (纸本)9780972147903

Response surface functions are often used as simple replacements for computationally expensive computer models of mechanical systems over some parameter space.A response surface construction method based on radial basis neural networks（RBNN） was *** kinds of RBNN were *** are the exact design network（EDN） and the generalized regression network（GRN）.The developed method was compared with the polynomial regression model（PRM） in two example *** Centroidal Voronoi Tessellation（CVT）experimental design was *** was found that both of the two RBNN methods produced smaller errors for a given set of sample points than the PRM *** EDN method was the most accurate method for the example problems *** GRN method,while better than the PRM,still did not perform as well as the EDN *** with the commonly used PRM method,the suggested approach is a better choice to construct a response surface for a mechanical system.

关键词： Response surface Radial basis neural networks Mechanical systems Polynomial regression Centroidal voronoi tessellation

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

北京航空航天大学学报 2009年第5期35卷 532-535页

作者：任远白广忱北京航空航天大学能源与动力工程学院北京100191

研究了GA-BP(Genetic Algorithm-Backpropagation)贝叶斯算法在可靠性仿真中的应用.GA-BP贝叶斯算法是一种新型前馈神经网络训练算法,它建立在遗传算法(GA)、L-M(Levenberg-Marquardt)BP算法以及贝叶斯方法这三者的基础上.由于该算法的... 详细信息

研究了GA-BP(Genetic Algorithm-Backpropagation)贝叶斯算法在可靠性仿真中的应用.GA-BP贝叶斯算法是一种新型前馈神经网络训练算法,它建立在遗传算法(GA)、L-M(Levenberg-Marquardt)BP算法以及贝叶斯方法这三者的基础上.由于该算法的训练目标是获取对应于后验分布最大值的权值向量,并且在搜索过程中融入了遗传算法,因此能够使前馈神经网络具有更佳、更稳定的泛化性能.在可靠性仿真中,采用GA-BP贝叶斯算法来构造前馈神经网络近似模型,再用它来替代复杂费时的数值仿真程序进行Monte Carlo模拟,就能够在计算成本得到有效控制的同时获取随机输出变量的概率分布情况.

关键词：可靠性 MonteCarlo法神经网络 BP算法遗传算法

在线全文

学校读者我要写书评

暂无评论

两点指数计算方法在可靠性指标计算中的应用

机械强度 2009年第6期31卷 919-925页

作者：郭秩维白广忱北京航空航天大学能源与动力工程学院北京100083

Hasofer-Lind(HL)所提出的方法不能很好解决高度非线性的功能函数可靠度指标的求解问题。Wang和Gran-dhi提出的高效的可靠度指标计算方法弥补了HL方法存在的不足,但此方法对功能函数中的所有变量都采用相同的非线性指标,并且在迭代过程... 详细信息

Hasofer-Lind(HL)所提出的方法不能很好解决高度非线性的功能函数可靠度指标的求解问题。Wang和Gran-dhi提出的高效的可靠度指标计算方法弥补了HL方法存在的不足,但此方法对功能函数中的所有变量都采用相同的非线性指标,并且在迭代过程中要通过求解一个关于非线性指标的隐式非线性方程来确定非线性指标,因此计算难度和计算量大。文中借助Fadel解决结构优化问题提出的两点指数优化方法,改进Wang等提出的方法,不但弥补了HL方法的不足,而且通过对功能函数的不同变量取不同的非线性指标,并利用迭代过程中前后两步的信息,给出非线性指标的显示表达式,降低计算难度的同时减少了计算量。

关键词：一次二阶矩法可靠度指标两点指数近似可靠性