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Isogeometric cohesive zone model for thin shell delamination analysis based on Kirchhoff-Love shell model

Tran Quoc THAI, Timon RABCZUK, Xiaoying ZHUANG

《结构与土木工程前沿(英文)》 2020年 第14卷 第2期   页码 267-279 doi: 10.1007/s11709-019-0567-x

摘要: We present a cohesive zone model for delamination in thin shells and composite structures. The isogeometric (IGA) thin shell model is based on Kirchhoff-Love theory. Non-Uniform Rational B-Splines (NURBS) are used to discretize the exact mid-surface of the shell geometry exploiting their C -continuity property which avoids rotational degrees of freedom. The fracture process zone is modeled by interface elements with a cohesive law. Two numerical examples are presented to test and validate the proposed formulation in predicting the delamination behavior of composite structures.

关键词: cohesive zone model     IGA     Kirchhoff-Love model     thin shell analysis     delamination    

A frequency error estimation for isogeometric analysis of KirchhoffLove cylindrical shells

《结构与土木工程前沿(英文)》 doi: 10.1007/s11709-023-0006-x

摘要: A frequency error estimation is presented for the isogeometric free vibration analysis of Kirchhoff–Love cylindrical shells using both quadratic and cubic basis functions. By analyzing the discrete isogeometric equations with the aid of harmonic wave assumption, the frequency error measures are rationally derived for the quadratic and cubic formulations for Kirchhoff–Love cylindrical shells. In particular, the governing relationship of the continuum frequency for Kirchhoff–Love cylindrical shells is naturally embedded into the frequency error measures without the need of explicit frequency expressions, which usually are not trivial for the shell problems. In accordance with these theoretical findings, the 2nd and 4th orders of frequency accuracy are attained for the isogeometric schemes using quadratic and cubic basis functions, respectively. Numerical results not only thoroughly verify the theoretical convergence rates of frequency solutions, but also manifest an excellent magnitude match between numerical and theoretical frequency errors for the isogeometric free vibration analysis of Kirchhoff–Love cylindrical shells.

关键词: isogeometric analysis     Kirchhoff–Love cylindrical shell     free vibration     frequency error     convergence    

Model server enabled management of collaborative changes in building information models

LOVE

《工程管理前沿(英文)》 2018年 第5卷 第3期   页码 298-306 doi: 10.15302/J-FEM-2018009

摘要:

The issues and challenges involved in controlling the collaborative changes in a Building Information Modeling (BIM) data repository, in a multi-model collaboration environment, are discussed. It is suggested that managing iterative changes in BIMs is a database problem, exacerbated by the long transaction times needed to support collaborative design progression. This is yet to be resolved in the construction industry and better solutions are needed to support the underlying workflows and computing operations for seamless collaboration on BIMs. With this in mind, this paper proposes the use of the structural and semantic characteristics of BIM objects as a mechanism for tracking changes across co-developed solutions. The creation of object signatures, using hash codes derived from their characteristics, provides a potential mechanism for object comparison and effective change recognition and management.

关键词: building information models     collaboration     IFC     change management     model-servers    

建筑领域计算机视觉的效益实现管理 Views & Comments

Love,Jane Matthews,Weili Fang,Hanbin Luo

《工程(英文)》 2023年 第27卷 第8期   页码 11-13 doi: 10.1016/j.eng.2022.09.009

Systems thinking in construction: Improving the productivity and performance of infrastructure projects

LOVE, Hanbin LUO

《工程管理前沿(英文)》 2018年 第5卷 第3期   页码 285-288 doi: 10.15302/J-FEM-2018205

摘要:

关键词: valign=     top     class=     J_zhaiyao    

Future-proofing ‘Next Generation’ infrastructure assets

LOVE, Lavagnon A. IKA, Giorgio LOCATELLI, Dominic D. AHIAGA-DAGBUI

《工程管理前沿(英文)》 2018年 第5卷 第3期   页码 407-410 doi: 10.15302/J-FEM-2018204

摘要:

关键词: valign=     top     class=     J_zhaiyao    

技术发展现状——为什么施工中会出现返工?返工会造成什么后果?怎样才能减少返工? Review

Love, Jane Matthews, Michael C.P. Sing, Stuart R. Porter, Weili Fang

《工程(英文)》 2022年 第18卷 第11期   页码 246-258 doi: 10.1016/j.eng.2022.05.010

摘要:

已有大量研究对施工中的返工问题进行了研究,但解决返工问题的成效有限,仍然困扰着施工进程,这对项目的绩效产生不利影响。几乎所有返工研究都侧重于确定其近端或根本原因,因此忽略了导致返工的条件。本文借鉴了之前的实证研究,对这一空白进行了研究,以提供一个急需的理论框架,从而更好地理解返工原因、返工后果以及如何在施工期间减少返工。从审查中得出的理论框架使施工组织认识到,减少返工应首先建立一套差错管理文化,包括真正的领导力、心理安全、差错管理导向和复原力。本研究认为,一旦在施工组织及其项目中建立了差错管理文化,施工组织就能更好地认识用于解决返工问题的方法、工具和技术的益处,如精益生产®和建筑信息模型。本文还为未来研究提供了方向,并确定了对实践的意义,以便能够在施工中减少返工。

关键词: 施工     差错     差错管理文化     病原体     返工     违规    

环缝天线罩的近似分析方法 Article

罗康, 孟进, 韩江枫, 朱丹妮

《工程(英文)》 2023年 第30卷 第11期   页码 75-82 doi: 10.1016/j.eng.2023.07.015

摘要:

本文提出了一种基于近似分析方法的环缝天线罩带内和带外微波无线功率传输特性分析方法。本文的主要贡献是对环形天线罩的近似分析,推导了E平面和H平面扫描时天线罩表面入射场的统一表达式,并将环形天线罩近似分为30段直条。求解相应的60 × 60线性方程得到了沿环形带的电流分布。沿着互补槽环的磁电流是通过对偶获得的。得益于电流分布的全解析格式,使用Munk方案有效地计算了微波无线功率传输特性。以环缝双层对称混合天线罩为例,验证了该方法的准确性和有效性。HFSS和所提出的方法的CPU计算时间分别约为690 s和2.82 s。

关键词: 近似解析     环形     天线罩     基尔霍夫型电路    

Standard model of knowledge representation

Wensheng YIN

《机械工程前沿(英文)》 2016年 第11卷 第3期   页码 275-288 doi: 10.1007/s11465-016-0372-3

摘要:

Knowledge representation is the core of artificial intelligence research. Knowledge representation methods include predicate logic, semantic network, computer programming language, database, mathematical model, graphics language, natural language, etc. To establish the intrinsic link between various knowledge representation methods, a unified knowledge representation model is necessary. According to ontology, system theory, and control theory, a standard model of knowledge representation that reflects the change of the objective world is proposed. The model is composed of input, processing, and output. This knowledge representation method is not a contradiction to the traditional knowledge representation method. It can express knowledge in terms of multivariate and multidimensional. It can also express process knowledge, and at the same time, it has a strong ability to solve problems. In addition, the standard model of knowledge representation provides a way to solve problems of non-precision and inconsistent knowledge.

关键词: knowledge representation     standard model     ontology     system theory     control theory     multidimensional representation    

受限空间火灾模型研究进展

郑昕,袁宏永

《中国工程科学》 2004年 第6卷 第3期   页码 68-74

摘要:

火灾模型是从工程科学的角度出发,分析研究火灾的发生、发展,烟气蔓延以及火灾对周围环境诸如建筑设备、森林植被及大气环境等影响的数学模型。介绍了广泛应用于建筑物内部受限空间的场、区域、网模型以及经验模型的理论思想与数学方程,分析了4种模型在相应环境下应用的合理性,并对火灾模型的发展做出了展望。

关键词: 受限空间     场模型     区域模型     网模型     场区网模型     经验模型    

Elevated temperature creep model of parallel wire strands

《结构与土木工程前沿(英文)》   页码 1060-1071 doi: 10.1007/s11709-023-0981-y

摘要: Parallel wire strands (PWSs), which are widely used in prestressed steel structures, are typically in high-stress states. Under fire conditions, significant creep effects occur, reducing the prestress and influencing the mechanical behavior of PWSs. As there is no existing approach to analyze their creep behavior, this study experimentally investigated the elevated temperature creep model of PWSs. A charge-coupled camera system was incorporated to accurately obtain the deformation of the specimen during the elevated temperature creep test. It was concluded that the temperature level had a more significant effect on the creep strain than the stress level, and 450 °C was the key segment point where the creep rate varied significantly. By comparing the elevated temperature creep test results for PWSs and steel strands, it was found that the creep strain of PWSs was lower than that of steel strands at the same temperature and stress levels. The parameters in the general empirical formula, the Bailey–Norton model, and the composite time-hardening model were fitted based on the experimental results. By evaluating the accuracy and form of the models, the composite time-hardening model, which can simultaneously consider temperature, stress, and time, is recommended for use in the fire-resistance design of pre-tensioned structures with PWSs.

关键词: parallel wire strands     experimental study     elevated temperature creep model    

Impact of crude distillation unit model accuracy on refinery production planning

Gang FU, Pedro A. Castillo CASTILLO, Vladimir MAHALEC

《工程管理前沿(英文)》 2018年 第5卷 第2期   页码 195-201 doi: 10.15302/J-FEM-2017052

摘要: In this work, we examine the impact of crude distillation unit (CDU) model errors on the results of refinery-wide optimization for production planning or feedstock selection. We compare the swing cut+ bias CDU model with a recently developed hybrid CDU model (Fu et al., 2016). The hybrid CDU model computes material and energy balances, as well as product true boiling point (TBP) curves and bulk properties (e.g., sulfur % and cetane index, and other properties). Product TBP curves are predicted with an average error of 0.5% against rigorous simulation curves. Case studies of optimal operation computed using a planning model that is based on the swing cut+ bias CDU model and using a planning model that incorporates the hybrid CDU model are presented. Our results show that significant economic benefits can be obtained using accurate CDU models in refinery production planning.

关键词: impact of model accuracy on production planning     swing cut+ bias CDU model     hybrid CDU model     refinery feedstock selection optimization     optimization of refinery operation    

Test-driven verification/validation of model transformations

László LENGYEL,Hassan CHARAF

《信息与电子工程前沿(英文)》 2015年 第16卷 第2期   页码 85-97 doi: 10.1631/FITEE.1400111

摘要: Why is it important to verify/validate model transformations? The motivation is to improve the quality of the transformations, and therefore the quality of the generated software artifacts. Verified/validated model transformations make it possible to ensure certain properties of the generated software artifacts. In this way, verification/validation methods can guarantee different requirements stated by the actual domain against the generated/modified/optimized software products. For example, a verified/validated model transformation can ensure the preservation of certain properties during the model-to-model transformation. This paper emphasizes the necessity of methods that make model transformation verified/validated, discusses the different scenarios of model transformation verification and validation, and introduces the principles of a novel test-driven method for verifying/validating model transformations. We provide a solution that makes it possible to automatically generate test input models for model transformations. Furthermore, we collect and discuss the actual open issues in the field of verification/validation of model transformations.

关键词: Graph rewriting based model transformations     Verification/validation     Test-driven verification    

Digital twin-assisted gearbox dynamic model updating toward fault diagnosis

《机械工程前沿(英文)》 2023年 第18卷 第2期 doi: 10.1007/s11465-023-0748-0

摘要: One of the core challenges of intelligent fault diagnosis is that the diagnosis model requires numerous labeled training datasets to achieve satisfactory performance. Generating training data using a virtual model is a potential solution for addressing such a problem, and the construction of a high-fidelity virtual model is fundamental and critical for data generation. In this study, a digital twin-assisted dynamic model updating method for fault diagnosis is thus proposed to improve the fidelity and reliability of a virtual model, which can enhance the generated data quality. First, a virtual model is established to mirror the vibration response of a physical entity using a dynamic modeling method. Second, the modeling method is validated through a frequency analysis of the generated signal. Then, based on the signal similarity indicator, a physical–virtual signal interaction method is proposed to dynamically update the virtual model in which parameter sensitivity analysis, surrogate technique, and optimization algorithm are applied to increase the efficiency during the model updating. Finally, the proposed method is successfully applied to the dynamic model updating of a single-stage helical gearbox; the virtual data generated by this model can be used for gear fault diagnosis.

关键词: digital twin     gearbox     model construction     model updating     physical–virtual interaction    

Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid

Nitin Kumar SAXENA,Ashwani Kumar SHARMA

《能源前沿(英文)》 2015年 第9卷 第4期   页码 472-485 doi: 10.1007/s11708-015-0373-7

摘要: It is well recognized that the voltage stability of a power system is affected by the load model and hence, to effectively analyze the reactive power compensation of an isolated hybrid wind-diesel based power system, the loads need to be considered along with the generators in a transient analysis. This paper gives a detailed mathematical modeling to compute the reactive power response with small voltage perturbation for composite load. The composite load is a combination of the static and dynamic load model. To develop this composite load model, the exponential load is used as a static load model and induction motors (IMs) are used as a dynamic load model. To analyze the dynamics of IM load, the fifth, third and first order model of IM are formulated and compared using differential equations solver in Matlab coding. Since the decentralized areas have many small consumers which may consist large numbers of IMs of small rating, it is not realistic to model either a single large rating unit or all small rating IMs together that are placed in the system. In place of using a single large rating IM, a group of motors are considered and then the aggregate model of IM is developed using the law of energy conservation. This aggregate model is used as a dynamic load model. For different simulation studies, especially in the area of voltage stability with reactive power compensation of an isolated hybrid power system, the transfer function of the composite load is required. The transfer function of the composite load is derived in this paper by successive derivation for the exponential model of static load and for the fifth and third order IM dynamic load model using state space model.

关键词: isolated hybrid power system (IHPS)     composite load model     static load     dynamic load     induction motor load model     aggregate load    

标题 作者 时间 类型 操作

Isogeometric cohesive zone model for thin shell delamination analysis based on Kirchhoff-Love shell model

Tran Quoc THAI, Timon RABCZUK, Xiaoying ZHUANG

期刊论文

A frequency error estimation for isogeometric analysis of KirchhoffLove cylindrical shells

期刊论文

Model server enabled management of collaborative changes in building information models

LOVE

期刊论文

建筑领域计算机视觉的效益实现管理

Love,Jane Matthews,Weili Fang,Hanbin Luo

期刊论文

Systems thinking in construction: Improving the productivity and performance of infrastructure projects

LOVE, Hanbin LUO

期刊论文

Future-proofing ‘Next Generation’ infrastructure assets

LOVE, Lavagnon A. IKA, Giorgio LOCATELLI, Dominic D. AHIAGA-DAGBUI

期刊论文

技术发展现状——为什么施工中会出现返工?返工会造成什么后果?怎样才能减少返工?

Love, Jane Matthews, Michael C.P. Sing, Stuart R. Porter, Weili Fang

期刊论文

环缝天线罩的近似分析方法

罗康, 孟进, 韩江枫, 朱丹妮

期刊论文

Standard model of knowledge representation

Wensheng YIN

期刊论文

受限空间火灾模型研究进展

郑昕,袁宏永

期刊论文

Elevated temperature creep model of parallel wire strands

期刊论文

Impact of crude distillation unit model accuracy on refinery production planning

Gang FU, Pedro A. Castillo CASTILLO, Vladimir MAHALEC

期刊论文

Test-driven verification/validation of model transformations

László LENGYEL,Hassan CHARAF

期刊论文

Digital twin-assisted gearbox dynamic model updating toward fault diagnosis

期刊论文

Estimation of composite load model with aggregate induction motor dynamic load for an isolated hybrid

Nitin Kumar SAXENA,Ashwani Kumar SHARMA

期刊论文