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Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

《机械工程前沿(英文)》 2022年 第17卷 第2期 doi: 10.1007/s11465-022-0676-4

摘要: The control system presently used in shield posture rectification is based on driver experience, which is marginally reliable. The study of the related theory is flawed. Therefore, a decision-making approach for the deviation correction trajectory and posture rectification load for an earth pressure balance (EPB) shield is proposed. A calculation model of posture rectification load of an EPB shield is developed by considering the interactions among the cutter head, shield shell, and ground. The additional position change during the shield attitude correction is highlighted. The posture rectification loads and shield behaviors results can be solved by the proposed method. The influences of the stratum distribution (i.e., bedrock height in the upper-soft and lower-hard strata) on shield behaviors and posture rectification loads are analyzed. Results indicated that the increase of pitch angle in the upper-soft and lower-hard strata causes a sharp rise in vertical displacement. The bedrock height increases the magnitudes of the required posture rectification moments when hr/D > 0.5. For a tunnel with hr/D ≤ 0.5, the variation of hr/D has little effect on the posture rectification moments. Finally, the posture rectifying curves based on the theoretical model are compared with the target ones based on the double circular arc interpolation method. The required results can be obtained regardless of the soil–rock compound stratum distribution. The maximum rectification moment in the rock layer is almost 12.6 times that in the soil layer. Overall, this study provides a valuable reference for moment determination and the trajectory prediction of posture rectification in compound strata.

关键词: additional position change     deviation correction trajectory     earth pressure balance shield     mechanical model     posture rectification    

A reliable and practical reference objective for the deviation diagnosis of energy system parameters

Liping LI, Zheng LI,

《能源前沿(英文)》 2009年 第3卷 第4期   页码 440-445 doi: 10.1007/s11708-009-0051-8

摘要: The core objective to optimize a complex energy system is to set the reference target to guide the parameter adjustment of system operation. In this paper, a new case-based approach is proposed based on an online performance assessment program and its long-term operation data for a large power unit. The online model of a coal-fired power unit’s performance assessment is demonstrated, and the distribution pattern of the performance index is revealed by statistical analysis of the abundant data. The fundamental issues (representation of the similarity of two thermal processes, similarity measure, etc.) are tackled. The key sections and key parameters for the completion of similarity determination are proposed, which are essential to realize a case-based strategy. A full-scope simulator of power unit is used to test the availability of the method. The advantage of the case-based approach is the integrality of information over other methods.

关键词: energy system     case-based     optimization     power unit operation     performance    

Scrutiny of non-linear differential equations Euler-Bernoulli beam with large rotational deviation by

M. R. AKBARI,M. NIMAFAR,D. D. GANJI,M. M. AKBARZADE

《机械工程前沿(英文)》 2014年 第9卷 第4期   页码 402-408 doi: 10.1007/s11465-014-0316-8

摘要:

The kinematic assumptions upon which the Euler-Bernoulli beam theory is founded allow it to be extended to more advanced analysis. Simple superposition allows for three-dimensional transverse loading. Using alternative constitutive equations can allow for viscoelastic or plastic beam deformation. Euler-Bernoulli beam theory can also be extended to the analysis of curved beams, beam buckling, composite beams and geometrically nonlinear beam deflection. In this study, solving the nonlinear differential equation governing the calculation of the large rotation deviation of the beam (or column) has been discussed. Previously to calculate the rotational deviation of the beam, the assumption is made that the angular deviation of the beam is small. By considering the small slope in the linearization of the governing differential equation, the solving is easy. The result of this simplification in some cases will lead to an excessive error. In this paper nonlinear differential equations governing on this system are solved analytically by Akbari-Ganji’s method (AGM). Moreover, in AGM by solving a set of algebraic equations, complicated nonlinear equations can easily be solved and without any mathematical operations such as integration solving. The solution of the problem can be obtained very simply and easily. Furthermore, to enhance the accuracy of the results, the Taylor expansion is not needed in most cases via AGM manner. Also, comparisons are made between AGM and numerical method (Runge-Kutta 4th). The results reveal that this method is very effective and simple, and can be applied for other nonlinear problems.

关键词: AGM     critical load of columns     large deformations of beam     nonlinear differential equation    

Optimal localization of complex surfaces in CAD-based inspection

XU Jinting, LIU Weijun, SUN Yuwen

《机械工程前沿(英文)》 2008年 第3卷 第4期   页码 426-433 doi: 10.1007/s11465-008-0068-4

摘要: Complex surface inspection requires the optimal localization of the measured surface related to the design surface so that the two surfaces can be compared in a common coordinate frame. This paper presents a new technique for solving the localization problem. The basic approach consists of two steps: 1) rough localization of the measured points to the design surface based on curvature features, which can produce a good initial estimate for the optimal localization; 2) fine localization based on the least-square principle so that the deviation between the measured surface and the design surface is minimized. To efficiently compute the closest points on the design surface of the measured points, a novel method is proposed. Since this approach does not involve an iterative process of solving non-linear equations for the closest points, it is more convenient and robust. The typical complex surface is used to test the developed algorithm. Analysis and comparison of experimental results demonstrate the validity and applicability of the algorithm.

关键词: deviation     comparison     non-linear     localization     inspection    

Application and evaluation of optical distance measurements in geometrical quality testing of microgears

Albert ALBERS, Duotai PAN, Leif MARXEN, Claudia BECKE,

《机械工程前沿(英文)》 2010年 第5卷 第3期   页码 261-269 doi: 10.1007/s11465-010-0100-3

摘要: Microgears are increasingly important in industry. Compared to normal gears, the quality assurance of microgears needs more accurately measured data and simple but feasible measurement methods because of their dimension particula

关键词: microgear     optical distance measurement     profile deviation     CWL sensor     micromechanical technology (MMT)    

齿轮测量技术100年——回顾与展望

石照耀,费业泰,谢华锟

《中国工程科学》 2003年 第5卷 第9期   页码 13-17

摘要:

全面概述了过去100年齿轮测量技术的发展历程,给出了6件标志性事情;着重论述了测量原理的演变、实现测量原理技术方式的发展以及测量结果的表述与利用;介绍了当今CNC齿轮测量中心的原理、组成和特点;结合90年代以来齿轮测量技术领域中几股新潮流,展望了未来齿轮测量技术的一些研究方向。

关键词: 齿轮     齿轮测量     齿轮误差     齿轮测量仪器    

Quantitative standard of eco-compensation for the water source area in the middle route of the South-to-North Water Transfer Project in China

Zhanfeng DONG, Jinnan WANG

《环境科学与工程前沿(英文)》 2011年 第5卷 第3期   页码 459-473 doi: 10.1007/s11783-010-0288-9

摘要: The Middle Route Project(MRP) of the South-to-North Water Transfer Scheme (SNWT) in China will require a very large financial expenditure to ensure the water supply and the associated water quality to northern China. An eco-compensation mechanism between the water service source areas and its beneficiaries is essential. This paper establishes an analytic framework of eco-compensation standard for the protection of the water source area, including both the calculation of eco-compensation based on opportunity cost method (OCM) and calculation of the burden sharing of eco-compensation between the water source area and the external water reception area based on the deviation square method (DSM). Taking Shiyan City, Hubei Province in China as a case study, our results show that the eco-compensation in the first-phase of MRP for the water source area in Shiyan, Hubei Province should be 1.63×10 CNY, about four times of planned eco-construction investment budget(4.33×10 CNY). In addition, the burden sharing of eco-compensation varied greatly in terms of different methods. It would be better to integrate the results of different single-factor burden sharing methods by determining the corresponding weighting coefficient with DSM and form one unanimous consent result by the interested parties.

关键词: the South-to-North Water Transfer Scheme     eco-compensation standard     opportunity costs     deviation square method    

Fuzzy stochastic long-term model with consideration of uncertainties for deployment of distributed energy resources using interactive honey bee mating optimization

Iraj AHMADIAN,Oveis ABEDINIA,Noradin GHADIMI

《能源前沿(英文)》 2014年 第8卷 第4期   页码 412-425 doi: 10.1007/s11708-014-0315-9

摘要: This paper presents a novel modified interactive honey bee mating optimization (IHBMO) base fuzzy stochastic long-term approach for determining optimum location and size of distributed energy resources (DERs). The Monte Carlo simulation method is used to model the uncertainties associated with long-term load forecasting. A proper combination of several objectives is considered in the objective function. Reduction of loss and power purchased from the electricity market, loss reduction in peak load level and reduction in voltage deviation are considered simultaneously as the objective functions. First, these objectives are fuzzified and designed to be comparable with each other. Then, they are introduced into an IHBMO algorithm in order to obtain the solution which maximizes the value of integrated objective function. The output power of DERs is scheduled for each load level. An enhanced economic model is also proposed to justify investment on DER. An IEEE 30-bus radial distribution test system is used to illustrate the effectiveness of the proposed method.

关键词: component     distributed energy resources     fuzzy optimization     loss reduction     interactive honey bee mating optimization (IHBMO)     voltage deviation reduction     stochastic programming    

Multiple target implementation for a doubly fed induction generator based on direct power control under unbalanced and distorted grid voltage

Heng NIAN,Yi-peng SONG

《信息与电子工程前沿(英文)》 2015年 第16卷 第4期   页码 321-334 doi: 10.1631/FITEE.1400170

摘要: This paper presents a multiple target implementation technique for a doubly fed induction generator (DFIG) under unbalanced and distorted grid voltage based on direct power control (DPC). Based on the mathematical model of DFIG under unbalanced and distorted voltage, the proportional and integral (PI) regulator is adopted to regulate the DFIG average active and reactive powers, while the vector PI (VPI) resonant regulator is used to achieve three alternative control targets: (1) balanced and sinusoidal stator current; (2) smooth instantaneous stator active and reactive powers; (3) smooth electromagnetic torque and instantaneous stator reactive power. The major advantage of the proposed control strategy over the conventional method is that neither negative and harmonic sequence decomposition of grid voltage nor complicated control reference calculation is required. The insensitivity of the proposed control strategy to DFIG parameter deviation is analyzed. Finally, the DFIG experimental system is developed to validate the availability of the proposed DPC strategy under unbalanced and distorted grid voltage.

关键词: Direct power control     Doubly fed induction generator     Unbalanced and distorted grid voltage     Vector proportional and integral resonant regulator     Parameter deviation    

标题 作者 时间 类型 操作

Deviation correction strategy for the earth pressure balance shield based on shield–soil interactions

期刊论文

A reliable and practical reference objective for the deviation diagnosis of energy system parameters

Liping LI, Zheng LI,

期刊论文

Scrutiny of non-linear differential equations Euler-Bernoulli beam with large rotational deviation by

M. R. AKBARI,M. NIMAFAR,D. D. GANJI,M. M. AKBARZADE

期刊论文

Optimal localization of complex surfaces in CAD-based inspection

XU Jinting, LIU Weijun, SUN Yuwen

期刊论文

Application and evaluation of optical distance measurements in geometrical quality testing of microgears

Albert ALBERS, Duotai PAN, Leif MARXEN, Claudia BECKE,

期刊论文

齿轮测量技术100年——回顾与展望

石照耀,费业泰,谢华锟

期刊论文

Quantitative standard of eco-compensation for the water source area in the middle route of the South-to-North Water Transfer Project in China

Zhanfeng DONG, Jinnan WANG

期刊论文

Fuzzy stochastic long-term model with consideration of uncertainties for deployment of distributed energy resources using interactive honey bee mating optimization

Iraj AHMADIAN,Oveis ABEDINIA,Noradin GHADIMI

期刊论文

Multiple target implementation for a doubly fed induction generator based on direct power control under unbalanced and distorted grid voltage

Heng NIAN,Yi-peng SONG

期刊论文