• 한국구조물진단유지관리공학회 논문집
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• 제9권4호
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• pp.149-158
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• 2005

본 논문에서는 전통 목조 건축물의 보다 실제에 가까운 구조특성을 파악하고 건물에 대한 안전성을 평가하기 위하여 현존하는 대표적인 전통 목조 건축물인 부석사 무량수전을 대상으로 하여 최대한 실제와 유사한 거동상태가 되도록 건축물을 3차원 및 2차원으로 모델링하여 범용 구조해석 프로그램을 통한 구조해석을 실시한 후에 해석결과를 비교, 분석하고 검토하였다.

• Structural Engineering and Mechanics
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• 제84권2호
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• pp.285-293
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• 2022

Lumped damage mechanics (LDM) is a recent nonlinear theory with several applications to civil engineering structures, such as reinforced concrete and steel buildings. LDM apply key concepts of classic fracture and damage mechanics on plastic hinges. Therefore, the lumped damage models are quite successful in reproduce actual structural behaviour using concepts well-known by engineers in practice, such as ultimate moment and first cracking moment of reinforced concrete elements. So far, lumped damage models are based in the strain energy equivalence hypothesis, which is one of the fictitious states where the intact material behaviour depends on a damage variable. However, there are other possibilities, such as the energy equivalence hypothesis. Such possibilities should be explored, in order to pursue unique advantages as well as extend the LDM framework. Therewith, a lumped damage model based on the energy equivalence hypothesis is proposed in this paper. The proposed model was idealised for reinforced concrete structures, where a damage variable accounts for concrete cracking and the plastic rotation represents reinforcement yielding. The obtained results show that the proposed model is quite accurate compared to experimental responses.

• Computers and Concrete
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• 제8권5호
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• pp.541-561
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• 2011

The Finite Element Method (FEM) was employed to demonstrate that accurate simulations of seismically repaired and retrofitted reinforced concrete shear walls can be achieved provided a good analysis program with comprehensive models for material and structural behaviour is used. Furthermore, the analysis tool should have the capability to retain residual damage experienced by the original structure and carry it forward in the repaired and retrofitted structure. The focus herein is to provide quick, simple, but reliable modelling procedures for repair and retrofitting strategies such as concrete replacement, addition of diagonal reinforcing bars, bolting of external steel plates, and bonding of external steel plates and fibre reinforced polymer sheets, thus illustrating versatility in the modelling. Slender, squat, and slender-squat shear walls were investigated. The modelling utilized simple rectangular membrane elements for the concrete, truss bar elements for the steel and FRP retrofitting materials, and bond-link elements for the bonding interface between steel or FRP to concrete. The analyses satisfactorily simulated seismic behaviour, including lateral load capacity, displacement capacity, energy dissipation, hysteretic response, and failure mode.

• Structural Engineering and Mechanics
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• 제63권6호
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• pp.703-712
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• 2017

The composite blades of offshore wind turbines accumulate structural damage such as fatigue cracking due to harsh operation environments during their service time, leading to premature structural failures. This paper investigates various fatigue crack models for reproducing crack development in composite blades and proposes a stochastic approach to predict fatigue crack evolution and to analyse failure probability for the composite blades. Three typical fatigue models for the propagation of fatigue cracks, i.e., Miner model, Paris model and Reifsnider model, are discussed to reproduce the fatigue crack evolution in composite blades subjected to cyclical loadings. The lifetime probability of fatigue failure of the composite blades is estimated by stochastic deterioration modelling such as gamma process. Based on time-dependent reliability analysis and lifecycle cost analysis, an optimised maintenance policy is determined to make the optimal decision for the composite blades during the service time. A numerical example is employed to investigate the effectiveness of predicting fatigue crack growth, estimating the probability of fatigue failure and evaluating an optimal maintenance policy. The results from the numerical study show that the stochastic gamma process together with the proper fatigue models can provide a useful tool for remaining useful life predictions and optimum maintenance strategies of the composite blades of offshore wind turbines.

• 유통과학연구
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• 제14권2호
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• pp.5-12
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• 2016

Purpose - The present study examines the interrelationship between various components constituting shopping experience in the context of the Indian shopping malls. Research design, data, and methodology - Extracting components of shopping experience from the literature review, the study used Interpretive Structural Modelling (ISM) to propose a conceptual model. The study adopted a mixed methods research involving theoretical constructs from past research, qualitative assessment of relationship between the constructs and imposing definite order and direction to qualitative relations based on mathematical computations. Results - Proposed model indicates that the five components of shopping experience (ambience, physical infrastructure, convenience, marketing focus and safety and security) do not converge directly into shopping experience. Rather, they operate following a hierarchy of influences in which marketing focus plays the role of the initiator. Conclusions - This model points at the order of preference of different components of shopping experience and can be a useful guide for retail industry, especially mall developers and supermarket/hypermarket, may use the findings in key decisions about development of physical infrastructure, which are based on marketing focus.

• Journal of the Korean Data and Information Science Society
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• 제22권2호
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• pp.313-322
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• 2011

대학생들의 취업률 향상을 위하여 각 대학에서는 취업상담, 채용정보 제공, 취업강좌 개설, 모의면접, 각종 어학 모의고사 실시 등 다양하게 시행을 하고, 학생 스스로도 학점관리, 자격증 취득, 외국어시험 등 다양한 취업준비활동을 하고 있다. 본 연구는 계명대학교 학생들을 대상으로 학생들의 취업을 위한 학교 지원에 대한 인식정도, 학생들의 취업준비 정도와 취업스트레스가 취업에 대한 자신감과 어떠한 관계를 가지고 있는지에 대하여 분석하였다. 연구 결과 취업에 대한 학교의 지원이 많을수록 학생들의 취업준비 정도가 높았으며, 취업스트레스가 높을수록 취업에 대한 자신감은 떨어졌다.

• Advances in concrete construction
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• 제3권2호
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• pp.127-143
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• 2015

Steel fibre reinforced concrete (SFRC) is an anisotropic material due to the random orientation of the fibres within the cement matrix. Fibres under different inclination angles provide different strength contribution of a given crack width. For that the pull-out response of inclined fibres is of great importance to understand SFRC behaviour, particularly in the case of fibres with hooked ends, which are the most widely used. The paper focuses on the numerical modelling of the pull-out response of this kind of fibres from high-strength cementitious matrix in order to study the effects of different inclination angles of the fibres to the load-displacement pull-out curves. The pull-out of the fibres is studied by means of accurate three-dimensional finite element models, which take into account the nonlinearities that are present in the physical model, such as the nonlinear bonding between the fibre and the matrix in the early stages of the loading, the unilateral contact between the fibre and the matrix, the friction at the contact areas, the plastification of the steel fibre and the plastification and cracking of the cementitious matrix. The bonding properties of the fibre-matrix interface considered in the numerical model are based on experimental results of pull-out tests on straight fibres.

• Computers and Concrete
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• 제16권2호
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• pp.287-309
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• 2015

FormWorks-Plus is a generalized public domain user-friendly preprocessor developed to facilitate the process of creating finite element models for structural analysis programs. The lack of a graphical user interface in most academic analysis programs forces users to input the structural model information into the standard text files, which is a time-consuming and error-prone process. FormWorks-Plus enables engineers to conveniently set up the finite element model in a graphical environment, eliminating the problems associated with conventional input text files and improving the user's perception of the application. In this paper, a brief overview of the FormWorks-Plus structure is presented, followed by a detailed explanation of the main features of the program. In addition, demonstration is made of the application of FormWorks-Plus in combination with VecTor programs, advanced nonlinear analysis tools for reinforced concrete structures. Finally, aspects relating to the modelling and analysis of three case studies are discussed: a reinforced concrete beam-column joint, a steel-concrete composite shear wall, and a SFRC shear panel. The unique mixed-type frame-membrane modelling procedure implemented in FormWorks-Plus can address the limitations associated with most frame type analyses.

• Steel and Composite Structures
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• 제2권2호
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• pp.147-160
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• 2002

This paper summarises results of the research performed at the Department of Steel Structures and Structural Mechanics from the "Politehnica" University of Timisoara, Romania, in order to evaluate the performance of beam-to-column extended end plate connections for steel and composite joints. It comprises laboratory tests on steel and composite joints, and numerical modelling of joints, based on tests. Tested joints are double-sided, with structural elements realised of welded steel sections. The columns are of cruciform cross-section, while the beams are of I section. Both monotonic and cyclic loading, symmetrically and antisymmetrically, has been applied. On the basis of tested joints, a refined computer model has been calibrated using a special connection element of the computer code DRAIN 2DX. In this way, a static/dynamic structural analysis of framed structures with real characteristics of the beam to column joints is possible.

• Steel and Composite Structures
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• 제23권5호
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• pp.501-516
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• 2017

Numerical simulations are prevalently used to evaluate the seismic behaviour of structures. The accuracy of the simulation results depends directly on the accuracy of the modelling techniques employed to simulate the behaviour of individual structural members. An empirical modelling technique is employed in this paper to simulate the behaviour of column members under cyclic and seismic loading. Despite the common modelling techniques, this technique is capable of simulating two important aspects of the cyclic and seismic behaviour of columns simultaneously. The proposed fiber-based modelling technique captures explicitly the interaction between the bending moment and the axial force in columns, and the cyclic deterioration of the hysteretic behaviour of these members is implicitly taken into account. The fiber-based model is calibrated based on the cyclic behaviour of square hollow steel sections. The behaviour of several column archetypes is investigated under a dual cyclic loading protocol to develop a benchmark database before the calibration procedure. The dual loading protocol used in this study consists of both axial and lateral loading cycles with varying amplitudes. After the calibration procedure, a regression analysis is conducted to derive an equation for predicting a varying calibrated modelling parameter. Finally, several nonlinear time-history analyses are conducted on a 6-story steel special moment frame in order to investigate how the results of numerical simulations can be affected by employing the intended modelling technique for columns instead of other common modelling techniques.