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Article
Publication date: 19 March 2021

Supen Kumar Sah and Anup Ghosh

The purpose of this paper is to carry out free vibration and buckling analysis of functionally graded material (FGM) plate.

Abstract

Purpose

The purpose of this paper is to carry out free vibration and buckling analysis of functionally graded material (FGM) plate.

Design/methodology/approach

Equilibrium and stability equations of FGM rectangular plate under different boundary conditions are derived using finite element method-based inverse trigonometric shear deformation theory (ITSDT). Eight-noded rectangular plate element with seven degrees of freedom at each node is used for the present analysis. The power-law distribution method has been considered for the continuously graded variation in composition of the ceramic and metal phases across the thickness of a functionally graded plate.

Findings

The finite element formulation incorporated with ITSDT and provisions of the constitutive model of FGM plate has been implemented in a numerical code to obtain the natural frequency and critical buckling load under uniaxial and biaxial compressive load. The influence of material gradation, volume fraction index, span to thickness ratio and boundary constraints over free vibration and buckling response has been studied.

Originality/value

Development and validation of finite element methodology using ITSDT to predict the structural response of the FGM plates under different loading, geometric and boundary conditions.

Details

Aircraft Engineering and Aerospace Technology, vol. 93 no. 2
Type: Research Article
ISSN: 1748-8842

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Book part
Publication date: 25 May 2021

Anca Băndoi, Claudiu George Bocean, Aurelia Florea, Lucian Mandache, Cătălina Soriana Sitnikov and Anca Antoaneta Vărzaru

Global warming is a process that takes place 11,500 years after the end of the last Ice Age. The main identified reason is the increased emissions of greenhouse gases…

Abstract

Global warming is a process that takes place 11,500 years after the end of the last Ice Age. The main identified reason is the increased emissions of greenhouse gases (GHGs). Since the nineteenth century, GHG evolution has recorded a quantum leap from the previous linear development. Human is the main factor behind this evolution, through industrialization and the exponential increase of population. Based on these, the chapter’s primary goal was to highlight an original method of predicting the future evolution of GHG emissions in the domains of Energy (including Transportation), Industry Processes and Product Use, Agriculture, and Waste Management. The novelty of the research consisted of testing several variants of functions (power, exponential, inverse trigonometric) to identify, from a group of variants. This optimal function would generate those predictions, which are closest to the real values. The causes that create GHG emissions in each of the four domains were the foundation for the analysis. This chapter focuses on two main subjects: first, the identification of a smooth function to predict the evolution of GHG emissions, and second, the function’s use to estimate the projections of GHG emissions in the coming years for the four domains: Energy (including Transportation), Industry Processes and Product Use, Agriculture, and Waste Management. An observation was that the weights of these four domains remain relatively the same despite the reductions in the total GHG emissions.

Details

Contemporary Issues in Social Science
Type: Book
ISBN: 978-1-80043-931-3

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Book part
Publication date: 25 May 2021

Abstract

Details

Contemporary Issues in Social Science
Type: Book
ISBN: 978-1-80043-931-3

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Article
Publication date: 21 June 2011

Venketesh N. Dubey and Richard M. Crowder

The purpose of this paper is to present the design and analysis of a robotic finger mechanism for robust industrial applications.

Abstract

Purpose

The purpose of this paper is to present the design and analysis of a robotic finger mechanism for robust industrial applications.

Design/methodology/approach

The resultant design is a compact rigid link finger, which is adaptive to different shapes and sizes providing necessary grasping features. A number of such fingers can be assembled to function as a special purpose end effector.

Findings

The mechanism removes a number of significant problems usually experienced with tendon‐based designs. The finger actuation mechanism forms a compact and positive drive unit within the end effector's body using solid mechanical linkages and integrated actuators.

Practical implications

The paper discusses the design issues associated with a limited number of actuators to operate in a constrained environment and presents various considerations necessary to ensure safe and reliable operations.

Originality/value

The design is original in existence and developed for special purpose handling applications that offers a strong and reliable system where space and safety is of prime concern.

Details

Industrial Robot: An International Journal, vol. 38 no. 4
Type: Research Article
ISSN: 0143-991X

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Article
Publication date: 31 May 2019

André Greiner-Petter, Moritz Schubotz, Howard S. Cohl and Bela Gipp

Modern mathematicians and scientists of math-related disciplines often use Document Preparation Systems (DPS) to write and Computer Algebra Systems (CAS) to calculate…

Abstract

Purpose

Modern mathematicians and scientists of math-related disciplines often use Document Preparation Systems (DPS) to write and Computer Algebra Systems (CAS) to calculate mathematical expressions. Usually, they translate the expressions manually between DPS and CAS. This process is time-consuming and error-prone. The purpose of this paper is to automate this translation. This paper uses Maple and Mathematica as the CAS, and LaTeX as the DPS.

Design/methodology/approach

Bruce Miller at the National Institute of Standards and Technology (NIST) developed a collection of special LaTeX macros that create links from mathematical symbols to their definitions in the NIST Digital Library of Mathematical Functions (DLMF). The authors are using these macros to perform rule-based translations between the formulae in the DLMF and CAS. Moreover, the authors develop software to ease the creation of new rules and to discover inconsistencies.

Findings

The authors created 396 mappings and translated 58.8 percent of DLMF formulae (2,405 expressions) successfully between Maple and DLMF. For a significant percentage, the special function definitions in Maple and the DLMF were different. An atomic symbol in one system maps to a composite expression in the other system. The translator was also successfully used for automatic verification of mathematical online compendia and CAS. The evaluation techniques discovered two errors in the DLMF and one defect in Maple.

Originality/value

This paper introduces the first translation tool for special functions between LaTeX and CAS. The approach improves error-prone manual translations and can be used to verify mathematical online compendia and CAS.

Details

Aslib Journal of Information Management, vol. 71 no. 3
Type: Research Article
ISSN: 2050-3806

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Article
Publication date: 1 April 1966

D.F. BALL and T.H. WISE

There have been large changes in the content of chemistry courses during the post‐war period, particularly at an advanced level. It is believed that the relevance of the…

Abstract

There have been large changes in the content of chemistry courses during the post‐war period, particularly at an advanced level. It is believed that the relevance of the existing mathematics course to the changing chemistry syllabus and to what industry expects of the trained chemist is sometimes neglected. This has led (in Constantine College) to a reconsideration of the adequacy of syllabuses in mathematics for existing advanced chemistry courses and to a consideration of the type of course which would be attractive to the industrial chemist. The authors have been supported by a working party and the ideas suggested here result largely from its findings. The object of this paper is to put forward some views as a first approximation in the hope that this will stimulate discussion and criticism of the existing situation. In November of 1964 a two‐day course was held in Newcastle on the teaching of physical chemistry. The lecturers at this meeting were mainly from university departments plus one industrialist and one former university lecturer now at a government research institute. Letters were sent to seven of these lecturers, who were asked what mathematics they considered appropriate for a modern undergraduate chemistry course. Most of the replies indicated what mathematics was being taught to chemistry undergraduates in the department with which the writer was concerned. In addition some information was volunteered by one other university department. In the non‐industrial replies topics were mentioned with a frequency indicated by the number following each topic — calculus (6), matrices and determinants (6), group theory and symmetry (4), vectors (4), differential equations (4) and probability (3). The industrial reply was quite different and discussed the need for the chemist to have an understanding of more industrial mathematics.

Details

Education + Training, vol. 8 no. 4
Type: Research Article
ISSN: 0040-0912

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Article
Publication date: 31 July 2021

Shi Zhao, Tien-Fu Lu, Larissa Statsenko, Benjamin Koch and Chris Garcia

In the mining industry, a run-of-mine (ROM) stockpile is a temporary storage unit, but it is also widely accepted as an effective method to reduce the short-term…

Abstract

Purpose

In the mining industry, a run-of-mine (ROM) stockpile is a temporary storage unit, but it is also widely accepted as an effective method to reduce the short-term variations of ore grade. However, tracing ore grade at ROM stockpiles accurately using most current fleet management systems is challenging, due to insufficient information available in real time. This study aims to build a three-dimensional (3D) model for ROM stockpiles continuously based on fine-grained grade information through integrating data from a number of ore grade tracking sources.

Design/methodology/approach

Following a literature review, a framework for a new stockpile management system is proposed. In this system, near real-time high-resolution 3D ROM stockpile models are created based on dump/load locations measured from global positioning system sensors. Each stockpile model contains a group of layers which are separated by different qualities.

Findings

Acquiring the geometric shapes of all the layers in a stockpile and cuts made by front wheel loaders provides a better understanding about the quality and quality distribution within a stockpile when it is stacked/reclaimed. Such a ROM stockpile model can provide information on predicating ore blend quality with high accuracy and high efficiency. Furthermore, a 3D stockyard model created based on such ROM stockpile models can help organisations optimise material flow and reduce the cost.

Research limitations/implications

The modelling algorithm is evaluated using a laboratory scaled stockpile at this stage. The authors expect to scan a real stockpile and create a reference model from it. Meanwhile, the geometric model cannot represent slump or collapse during reclaiming faithfully. Therefore, the model is expected to be reconcile monthly using laser scanning data.

Practical implications

The proposed model is currently translated to the operations at OZ Minerals. The use of such model will reduce the handling costs and improve the efficiency of existing grade management systems in the mining industry.

Originality/value

This study provides a solution to build a near real-time high-resolution multi-layered 3D stockpile model through using currently available information and resources. Such novel and low-cost stockpile model will improve the production rates with good output product quality control.

Details

Journal of Engineering, Design and Technology , vol. ahead-of-print no. ahead-of-print
Type: Research Article
ISSN: 1726-0531

Keywords

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Article
Publication date: 11 May 2015

Gonzalo Garcia, Shahriar Keshmiri and Thomas Stastny

Nonlinear model predictive control (NMPC) is emerging as a way to control unmanned aircraft with flight control constraints and nonlinear and unsteady aerodynamics…

Abstract

Purpose

Nonlinear model predictive control (NMPC) is emerging as a way to control unmanned aircraft with flight control constraints and nonlinear and unsteady aerodynamics. However, these predictive controllers do not perform robustly in the presence of physics-based model mismatches and uncertainties. Unmodeled dynamics and external disturbances are unpredictable and unsteady, which can dramatically degrade predictive controllers’ performance. To address this limitation, the purpose of this paper is to propose a new systematic approach using frequency-dependent weighting matrices.

Design/methodology/approach

In this framework, frequency-dependent weighting matrices jointly minimize closed-loop sensitivity functions. This work presents the first practical implementation where the frequency content information of uncertainty and disturbances is used to provide a significant degree of robustness for a time-domain nonlinear predictive controller. The merit of the proposed method is successfully verified through the design, coding, and numerical implementation of a robust nonlinear model predictive controller.

Findings

The proposed controller commanded and controlled a large unmanned aerial system (UAS) with unsteady and nonlinear dynamics in the presence of environmental disturbances, measurement bias or noise, and model uncertainties; the proposed controller robustly performed disturbance rejection and accurate trajectory tracking. Stability, performance, and robustness are attained in the NMPC framework for a complex system.

Research limitations/implications

The theoretical results are supported by the numerical simulations that illustrate the success of the presented technique. It is expected to offer a feasible robust nonlinear control design technique for any type of systems, as long as computational power is available, allowing a much larger operational range while keeping a helpful level of robustness. Robust control design can be more easily expanded from the usual linear framework, allowing meaningful new experimentation with better control systems.

Originality/value

Such algorithms allows unstable and unsteady UASs to perform reliably in the presence of disturbances and modeling mismatches.

Details

International Journal of Intelligent Unmanned Systems, vol. 3 no. 2/3
Type: Research Article
ISSN: 2049-6427

Keywords

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Article
Publication date: 15 July 2019

R.R. Kumar, P.K. Karsh, Vaishali , K.M. Pandey and S. Dey

The purpose of this paper is to investigate the first three stochastic natural frequencies of skewed sandwich plates, considering uncertain system parameters. To conduct…

Abstract

Purpose

The purpose of this paper is to investigate the first three stochastic natural frequencies of skewed sandwich plates, considering uncertain system parameters. To conduct the sensitivity analysis for checking the criticality of input parameters.

Design/methodology/approach

The theoretical formulation is developed based on higher-order-zigzag theory in accordance with the radial basis function (RBF) and stochastic finite element (FE) model. A cubic function is considered for in-plane displacement over thickness while a quadratic function is considered for transverse displacement within the core and remains constant in the facesheet. RBF is used as a surrogate model to achieve computational efficiency and accuracy. In the present study, the individual and combined effect of ply-orientation angle, skew angle, number of lamina, core thickness and material properties are considered for natural frequency analysis of sandwich plates.

Findings

Results presented in this paper illustrates that the skewness in the sandwich plate significantly affects the global dynamic behaviour of the structure. RBF surrogate model coupled with stochastic FE approach significantly reduced the computational time (more than 1/18 times) compared to direct Monte Carlo simulation approach.

Originality/value

The stochastic results for dynamic stability of sandwich plates show that the inevitable source uncertainties present in the input parameters result in significant variation from the deterministic value demonstrates the need for inclusive design paradigm considering stochastic effects. The present paper comprehensively establishes a generalized new RBF-based FE approach for efficient stochastic analysis, which can be applicable to other complex structures too.

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Article
Publication date: 1 January 2006

Herbert De Gersem, Mariana Ion, Markus Wilke, Thomas Weiland and Andrzej Demenko

To propose trigonometric interpolation in combination with both sliding‐surface and moving‐band techniques for modelling rotation in finite‐element electrical machine…

Abstract

Purpose

To propose trigonometric interpolation in combination with both sliding‐surface and moving‐band techniques for modelling rotation in finite‐element electrical machine models. To show that trigonometric interpolation is at least as accurate and efficient as standard stator‐rotor coupling schemes.

Design/methodology/approach

Trigonometric interpolation is explained concisely and put in a historical perspective. Characteristic drawbacks of trigonometric interpolation are alleviated one by one. A comparison with the more common locked‐step linear‐interpolation and mortar‐element approaches is carried out.

Findings

Trigonometric interpolation offers a higher accuracy and therefore can outperform standard stator‐rotor coupling techniques when equipped with an appropriate iterative solver incorporating Fast Fourier Transforms to reduce the higher computational cost.

Originality/value

The synthetic interpretation of trigonometric interpolation as a spectral‐element approach in the machine's air gap, the efficient iterative solver combining conjugate gradients with Fast Fourier Transforms. The unified application to both sliding‐surface and moving‐band techniques.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 1
Type: Research Article
ISSN: 0332-1649

Keywords

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