H. Ahmad, M. Yasin, K. Thambiratnam and S.W. Harun
The purpose of this paper is to propose and demonstrate a simple yet accurate optical fibre based sensor capable of performing micron and sub‐micron thickness measurement.
Abstract
Purpose
The purpose of this paper is to propose and demonstrate a simple yet accurate optical fibre based sensor capable of performing micron and sub‐micron thickness measurement.
Design/methodology/approach
The proposed sensor consists of a multimode plastic probe, three He‐Ne lasers and translation stages along with a silicon photodiode and a lock‐in amplifier to measure the output voltage as the displacement of the sensor is increased.
Findings
The system operating with a source wavelength of 633 nm can provide measurements of up to 3 μm with a sensitivity of 0.0054 mV/μm.
Originality/value
The thickness of the sample can be obtained from a linear equation correlating the thickness of the sample to the displacement of the sensor at which the peak output voltage is obtained, or by correlating the thickness of the sample directly to the peak output voltage measured.
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Abstract
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S.W. Harun, H.Z. Yang and H. Ahmad
The purpose of this paper is to investigate, theoretically and experimentally the performance of liquid refractive index sensor (LRIS).
Abstract
Purpose
The purpose of this paper is to investigate, theoretically and experimentally the performance of liquid refractive index sensor (LRIS).
Design/methodology/approach
The proposed LRIS is based on the intensity modulation and a bundle fiber. The mathematical model is used to study the effect of inclination angle on performance of the sensor.
Findings
The theoretical result shows that the highest sensitivity can be achieved by using a probe inclined with angle 20° which is almost 13 times higher than that of 0° inclination. In the experiment, three different liquids: isopropyl alcohol, water and methanol are used to investigate the sensor response. Both theoretical and experimental results show that the peak power and the location of the displacement curve changes with refractive index. The sensitivities are obtained at 0.11/mm and 0.04/mm for the sensors with 10° and 0° inclination angles, respectively.
Originality/value
In this paper, a simple LRIS is proposed using a bundle fiber as a probe at various inclination angles.
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Weena Lokuge, Nirdosha Gamage and Sujeeva Setunge
Deterioration of timber bridges can often be related to a number of deficiencies in the bridge elements, connectors and/or as a result of been in aggressive environments which…
Abstract
Purpose
Deterioration of timber bridges can often be related to a number of deficiencies in the bridge elements, connectors and/or as a result of been in aggressive environments which they are exposed to. The maintenance cost of timber bridges is affected significantly by a number of deterioration mechanisms which require a systematic approach for diagnosis and treatment. Evaluating the risk of failure of these bridges is of importance in bridge performance assessment and decision making to optimize rehabilitation options. The paper aims to discuss these issues.
Design/methodology/approach
This paper identifies common causes for timber bridge deterioration and demonstrates an integrated approach based on fault tree analysis to obtain qualitative or quantitative estimation of the risk of failure of timber bridge sub-systems. Level 2 inspection report for a timber bridge in Queensland, Australia has been utilized as a case study in this research to identify the failure modes of the bridge.
Findings
A diagnostic tool for timber bridge deterioration will benefit asset inspectors, managers, and engineers to identify the type, size and the distress mechanisms in order to recognize the proper corrective measures either to prevent or to reduce further deterioration. Timber bridge maintenance is a major issue in Queensland, Australia. If a decision support tool can be developed, it will benefit road authorities and local councils.
Originality/value
Timber bridge maintenance is a major issue in Queensland, Australia. If a decision support tool can be developed as initiated in this research paper it will benefit road authorities and local councils.
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Mahmoud Mawed and Assem Al-Hajj
This paper aims to explore how big data analytics (BDA) collected and stored through specific data software [Construction Operations Building Information Exchange [COBie]…
Abstract
Purpose
This paper aims to explore how big data analytics (BDA) collected and stored through specific data software [Construction Operations Building Information Exchange [COBie], integrated workplace management systems [IWMS], computer aided facilities management (CAFM), etc.] can play an essential role in improving the performance management system in the facility management (FM) industry. It defines the big data components and explores the benefit of BDA in any business through an extensive literature review and a pilot case study in the UAE.
Design/methodology/approach
The research was carried out based on a qualitative approach. It attempts to identify through a case study how the data collected and the technologies that go along with will increase the functionality and the efficiency of the FM services. The research studies the implementation of a big FM organization, hereafter referred as “M” of software that exports the data collected from COBie and the computer aided facilities management (CAFM) system and shapes them into input to improve the performance of the FM service providers. The study includes two components in anticipation of providing a complete picture: first, five semi-structured interviews with industry experts and company employees representing the hierarchy of the staff, i.e. top, middle and operational levels; one director, two managers and two operational-level employees were interviewed to determine the current situation of the company in terms of BDA; and second, detailed documents and archives records review for the data collected on a randomly chosen sample of facilities for the period 2013-2015. The interviews were designed to achieve two specific objectives. Primarily, they were aimed at collecting empirical evidence on the existing status of big data within the UAE FM context and at investigating the importance of the data collected for performance measurement in the industry as supported in the literature. Second, these interviews sought to identify any critical issues that need to be addressed within the data collection process when devising the big data platform for FM.
Findings
The paper seeks to provide a guideline to the service providers in the FM market to understand the importance of big data to be shared from the design and construction to the operational phase as it improves their operational performance.
Originality/value
This paper studies the impact of big data on the FM performance management, a very recent topic where only few researches were conducted earlier.
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Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the…
Abstract
Gives a bibliographical review of the finite element methods (FEMs) applied for the linear and nonlinear, static and dynamic analyses of basic structural elements from the theoretical as well as practical points of view. The range of applications of FEMs in this area is wide and cannot be presented in a single paper; therefore aims to give the reader an encyclopaedic view on the subject. The bibliography at the end of the paper contains 2,025 references to papers, conference proceedings and theses/dissertations dealing with the analysis of beams, columns, rods, bars, cables, discs, blades, shafts, membranes, plates and shells that were published in 1992‐1995.
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E. HINTON, N.V.R. RAO and J. SIENZ
This paper deals with structural shape and thickness optimization of axisymmetric shell structures loaded symmetrically. In the finite element stress analysis use is made of newly…
Abstract
This paper deals with structural shape and thickness optimization of axisymmetric shell structures loaded symmetrically. In the finite element stress analysis use is made of newly developed linear, quadratic, and cubic, variable thickness, C(0) elements based on axisymmetric Mindlin‐Reissner shell theory. An integrated approach is used to carry out the whole shape optimization process in a fully automatic manner. A robust, versatile and flexible mesh generator is incorporated with facilities for generating either uniform or graded meshes, with constant, linear, or cubic variation of thickness, pressure etc. The midsurface geometry and thickness variations of the axisymmetric shell structure are defined using cubic splines passing through certain key points. The design variables are chosen as the coordinates and/or the thickness at the key points. Variable linking procedures are also included. Sensitivity analysis is carried out using either a semi‐analytical method or a global finite difference method. The objective of the optimization is the weight minimization of the structure. Several examples are presented illustrating optimal shapes and thickness distributions for various shells. The changes in the bending, membrane and shear strain energies during the optimization process are also monitored.
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Arturo Cruz, Vaughan Coffey, Tommy H.T. Chan and Miljenka Perovic
This paper aims to set out the role of engineers in heritage conservation and investigates and evaluates the proposed available tools, technology and innovations that are…
Abstract
Purpose
This paper aims to set out the role of engineers in heritage conservation and investigates and evaluates the proposed available tools, technology and innovations that are currently available in the civil engineering sector that can be applied in heritage conservation.
Design/methodology/approach
As society has become more aware of the grandeur of heritage spaces and structures, there is increasing pressure to preserve historic buildings. But, it is the economic cost of maintaining this important heritage legacy that has become the prime consideration of every state in Australia. Dedicated intelligent monitoring systems supplementing the traditional building inspections will enable the involved and interested stakeholders to carry out not only timely reactive response, but also to plan the maintenance of such buildings in a more vigilant and systematic manner. This will, in future, help to prevent further degradation of heritage buildings, which is very costly, often difficult and sometimes impossible to address if neglected. Savings in time and resources can be achieved, but only if a building's pathological monitoring and inspection results are on hand for use to guide major decisions to be made on how to best prevent further decay, or to save an important historical structure or building fabric.
Findings
The emergence of technological tools will enable the realization of a maintenance-focused conservation model. However, aside from the cost, these tools are still experimental in nature. These technologies are yet to be applied within the conservation industry with hopes of creating an easier and economically effective systematic method of heritage conservation.
Originality/value
The paper discusses the emerging tools and technologies in easing the monitoring aspect of a maintenance-focused conservation model.
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Presents a review on implementing finite element methods on supercomputers, workstations and PCs and gives main trends in hardware and software developments. An appendix included…
Abstract
Presents a review on implementing finite element methods on supercomputers, workstations and PCs and gives main trends in hardware and software developments. An appendix included at the end of the paper presents a bibliography on the subjects retrospectively to 1985 and approximately 1,100 references are listed.
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Muzaffer Metin, Arif Ulu, Ozgur Demir and Aytac Arikoglu
In this study, a railway superstructure is modeled with a new approach called locally continuous supporting, and its behavior under the effect of moving load is analyzed by using…
Abstract
Purpose
In this study, a railway superstructure is modeled with a new approach called locally continuous supporting, and its behavior under the effect of moving load is analyzed by using analytical and numerical techniques. The purpose of the study is to demonstrate the success of the new modeling technique.
Design/methodology/approach
In the railway superstructure, the support zones are not modeled with discrete spring-damping elements. Instead of this, it is considered to be a continuous viscoelastic structure in the local areas. To model this approach, the governing partial differential equations are derived by Hamilton’s principle and spatially discretized by the Galerkin’s method, and the time integration of the resulting ordinary differential equation system is carried out by the Newmark–Beta method.
Findings
Both the proposed model and the solution technique are verified against conventional one-dimensional and three-dimensional finite element models for a specific case, and a very good agreement between the results is observed. The effects of geometric, structural, and loading parameters such as rail-pad length, rail-pad stiffness, rail-pad damping ratio, the gap between rail pads and vehicle speed on the dynamic response of railway superstructure are investigated in detail.
Originality/value
There are mainly two approaches to the modeling of rail pads. The first approach considers them as a single spring-damper connected in parallel located at the centroid of the rail pad. The second one divides the rail pad into several parts, with each of part represented by an equivalent spring-damper system. To obtain realistic results with minimum CPU time for the dynamic response of railway superstructure, the rail pads are modeled as continuous linearly viscoelastic local supports. The mechanical model of viscoelastic material is considered as a spring and damper connected in parallel.