• International Journal of High-Rise Buildings
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• v.6 no.1
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• pp.49-72
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• 2017

The Guangzhou International Finance Centre (IFC) is a landmark building that symbolizes the emerging international strength of Guangzhou, China's third largest city. It is also one of the dual iconic towers along the main axis of Guangzhou Zhujiang New Town. Arup adopted a total engineering approach in embracing sustainability and aiming at high efficiency solutions based on performance-based design principles covering structures, building services, fire engineering, vertical transportation, and façade performance to constitute an efficient and cost-effective overall building design. Through dynamic integration of architectural and engineering principles, Guangzhou IFC represents a pioneering supertall building in China. It adopts a diagrid exoskeleton structural form that is clearly expressed through the building's façade and gives the building its distinctive character. The aerodynamic shape of the building not only presents the aesthetic quality of elegant simplicity, but also reduces the effects of wind, thereby reducing the size and weight of the structure. State-of-the-art advanced engineering methods, such as optimization techniques and nonlinear finite element modelling, were applied in parallel with large-scale experimental programs to achieve an efficient and high-performance design taking into account the constructability and cost-effectiveness for a project of this scale.

• Composites Research
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• v.16 no.1
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• pp.42-49
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• 2003

Brittle matrix composites often have interfacial debonding between the fiber and matrix which may lead to strength and stiffness degradation. The effect of interfacial debonding and fiber volume fraction on the mechanical properties of composite material were studied by using finite element method. Firstly, the modelling of fiber and matrix constituting the composite material was simplified under some assumptions. Traction and displacement continuity conditions were imposed along the boundary of adjacent representative volume elements. In order to obtain the effective material properties of composite material, stiffness constants were inverted. Numerical values of longitudinal moduli in case of perfect bonding were compared with theoretical values obtained by rule of mixtures and yielded consistency. Material properties of composite with large debonding an81e were found to decrease even though the fiber volume fraction increased.

• Computers and Concrete
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• v.3 no.2_3
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• pp.79-90
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• 2006

This paper describes the results of an investigation into high mass-low velocity impact behaviour of reinforced concrete beams. Tests have been conducted on fifteen 2.7 m or 1.5 m span beams under drop-weight loads. A high-speed video camera has been used at rates of up to 4,500 frames per second in order to record the crack formation, propagation, particle spallation and scabbing. In some tests the strain in the reinforcement has been recorded using "Durham" strain gauged bars, a technique developed by Scott and Marchand (2000) in which the strain gauges are embedded in the bars, so that the strains in the reinforcement can be recorded without affecting the bond between the concrete and the reinforcement. The impact force acting on the beams has been measured using a load cell placed within the impactor. A high-speed data logging system has been used to record the impact load, strains, accelerations, etc., so that time histories can be obtained. This research has led to the development of computational techniques based on combined continuum/discontinuum methods (finite/discrete element methods) to permit the simulation of impact loaded reinforced concrete beams. The implementation has been within the software package ELFEN (2004). Beams, similar to those tested, have been analysed using ELFEN a good agreement has been obtained for both the load-time histories and the crack patterns.

• Structural Engineering and Mechanics
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• v.15 no.1
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• pp.53-70
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• 2003

The motivation of this paper is to introduce the modern technology of large-scale cooling tower design. Thereby the innovative design concept for the world's largest cooling tower with a height of 200 m is briefly presented (Harte & Kr$\ddot{a}$tzig 2002, Bush et al. 2002). The new concept was considered not only for safety, but also for preservation of the durability of the structure, because cracking damage in large cooling towers in general cause extremely high cost of maintenance and repair. The paper demonstrates numerically the damage process in large cooling towers (Kr$\ddot{a}$tzig et al. 2001), and describes some basics of the numerical finite element approach for damage propagation modelling of shell structure. A prototype is analysed to trace the progressive damage process, whereby the changes in the dynamical behaviour of the structure, as mirrored in its natural frequencies and the corresponding mode shapes, are presented and discussed. Finally, the example shows that such damage processes develop progressively over the life-time of the shell structure.

• Steel and Composite Structures
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• v.20 no.1
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• pp.147-166
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• 2016

The paper presents comprehensive quasi-static stability analysis results for a real funnel-flow cylindrical steel silo composed of horizontally corrugated sheets strengthened by vertical thin-walled column profiles. Linear buckling and non-linear analyses with geometric and material non-linearity were carried out with a perfect and an imperfect silo by taking into account axisymmetric and non-axisymmetric loads imposed by a bulk solid following Eurocode 1. Finite element simulations were carried out with 3 different numerical models (single column on the elastic foundation, 3D silo model with the equivalent orthotropic shell and full 3D silo model with shell elements). Initial imperfections in the form of a first eigen-mode for different wall loads and from 'in-situ' measurements with horizontal different amplitudes were taken into account. The results were compared with Eurocode 3. Some recommendations for the silo dimensioning were elaborated.

• Computers and Concrete
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• v.5 no.2
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• pp.117-134
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• 2008

An experimental and numerical research was conducted to gain a deeper insight on the structural behaviour of deep-beams with indirect supports and to assess the size effects in the ultimate state behaviour. The experimental campaign focused on the influence of the reinforcement tie distribution height on the compression check of the support region and on the benefits of using unbonded prestressing steel. Three reduced scale specimens were tested and used to validate the results obtained with a nonlinear finite element model. As a good agreement could be found between the numerical and the experimental results, the numerical model was then further used to perform simulations in large scale deep-beams, with dimensions similar to the ones to be adopted in a practical case. Two sources of size effects were identified from the simulation results. Both sources are related to the concrete quasi-brittle behaviour and are responsible for increasing failure brittleness with increasing structural size. While in the laboratory models failure occurred both in the experimental tests as well as in the numerical simulations after reinforcement yielding, the numerically analysed large scale models exhibited shear failures with reinforcement still operating in the elastic range.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.8 no.3
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• pp.27-32
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• 2009

In this study, static and dynamic stability estimations on the diecutter with finite element modelling were carried out to be creased and cut away printed sheet exactly. To cut away the sheet exactly, the large force should be pressured on diecutter. And which affects not only the quality of produced sheets but also the stability of diecutter. The analyses with and without the tare of diecutter were carried out with NASTRAN software on applying 400 ton force to its top and moving table respectively. It was known that maximum von-Mises stress of 221 Mpa in diecutter was occurred at the toggle, and it was smaller than the yield stress of 280 Mpa. And maximum deformation of 0.75 mm was occurred at the top table. The natural frequencies of 41, 102, 108, 115, and 134 Hz for the 1st, 2nd, 3rd, 4th and 5th mode, which had been determined by numerical simulation, were not coincided with the max. speeds of motor and moving table of 29 and 2 Hz. And which was verified by vibration test. Therefore it may be estimated that the structure of the diecutter is statically and dynamically stable.

• Journal of international Conference on Electrical Machines and Systems
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• v.2 no.3
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• pp.349-355
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• 2013

This paper presents the multi-objective optimisation of an Inductive Coupled Power Transfer (ICPT) device. A setup as complicated as the one at hand in this paper is extremely hard to model analytically. To acquire some knowledge about the influence of the geometric factors, a sensitivity analysis is first performed using design of experiment (DoE) and finite-element modelling (FEM). It allows validating that the choice of the free factors is relevant. This being done, the optimisation itself is performed using a genetic algorithm (GA), with two objectives and a strict functioning constraint.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.929-931
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• 1993

The design sensitivity analysis based on the finite element method is presented for the eddy current problem with a voltage source. Since, in this problem, the complex variable is used as the state variable, new approach to the sensitivity calculation for the complex variable system is required. Its result is applied to the design of the rotor slot shape of squirrel cage induction motor. As a analysis model, only one slot pitch of rotor is analyzed by using a Periodic boundary condition. The use of this minimal modelling method leads to much saving of calculation time. The design objective is to obtain the desired slip-torque characteristic. Because the shape of rotor slot has much influence on the slip torque characteristic, the design variables are taken on the interface shape between rotor core and rotor bar. The initial shape of rotor slot is the trapezoidal type with rounding corners. The obtained final shape is quite similar to the double squirrel cage type.

• Computers and Concrete
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• v.25 no.2
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• pp.181-192
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• 2020

Nowadays, steel fiber reinforced concretes (SFRCs) are widely used in practical applications. Significant experimental research has thus been carried out to determine the constitutive equations that represent the behavior of SFRCs under multiaxial loadings. However, numerical modelling of SFRCs via FEM has been challenging due to the complexities of the implementation of these constitutive equations. In this study, following the literature, a plasticity model is constructed for the behavior of SFRCs that involves the Willam-Warnke failure surface with the relevant evolution laws and a non-associated flow rule for determining the plastic deformations. For the precise (yet rapid) integration of the constitutive equations, an explicit substepping scheme consisting of yield intersection and drift correction algorithms is employed and thus implemented in ABAQUS via UMAT. The FEM model includes various material parameters that are determined from the experimental data. Three sets of parameters are used in the numerical simulations. While the first set is from the experiments that are conducted in this study on SFRC specimens with various contents of steel fibers, the other two sets are from the experiments reported in the literature. The response of SFRCs under multiaxial compression obtained from various numerical simulations are compared with the experimental data. The good agreement between numerical results and the experimental data indicates that not only the adopted plasticity model represents the behavior of SFRCs very well but also the implemented integration scheme can be employed in practical applications of SFRCs.