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Article
Publication date: 1 March 1999

W.J. Roux, R.J. du Preez and N. Stander

A general approach for the construction of global approximations to structural behaviour using response surface methodology is presented. The computation and use of these…

370

Abstract

A general approach for the construction of global approximations to structural behaviour using response surface methodology is presented. The computation and use of these approximations are demonstrated using a semi‐solid tyre example. The use of these global approximations to the responses made it viable to utilise the capabilities of non‐linear analysis software in design optimisation. The insight gained from a preliminary low fidelity model was utilized in a two‐stage approach to achieve the maximum benefit from a more expensive high fidelity model. The resulting high‐accuracy approximations greatly reduced the cost of subsequent design calculations such as multidisciplinary and discrete optimisation.

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Engineering Computations, vol. 16 no. 2
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 January 2007

J. Sun and S. Ekwaro‐Osire

The paper focuses on two topics, optimizing the proposed triangular tube for crashworthiness and solving a non‐linear programming problem by a “mapping” technique, which the…

143

Abstract

The paper focuses on two topics, optimizing the proposed triangular tube for crashworthiness and solving a non‐linear programming problem by a “mapping” technique, which the condition of Lagrange Multiplier Theorem is violated within the feasible region. The purpose of studying optimized triangular tubes is to prepare them for redesigning vehicle bumpers. The dimension optimization of triangular tube is carried out for its thickness and lateral length, based on the accomplished shape optimization under an impact. The load uniformity is taken as the objective function, which is defined as the ratio of maximum peak force and means crushing force. Meanwhile the mean crushing force and absorbed energy are treated as constraints. Based on FEA analysis, the regression functions for load uniformity, mean crushing force, and absorbed energy are formulated by RSM. The result has shown that triangular tube possesses an optimization region, under which the better‐integrated property can be achieved to supply a more safety environment for vehicular occupants.

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Multidiscipline Modeling in Materials and Structures, vol. 3 no. 1
Type: Research Article
ISSN: 1573-6105

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Book part
Publication date: 10 November 2023

Catherine Brentnall

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Nurturing Modalities of Inquiry in Entrepreneurship Research: Seeing the World Through the Eyes of Those Who Research
Type: Book
ISBN: 978-1-80262-186-0

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Book part
Publication date: 6 September 2023

Verena Tandrayen-Ragoobur

Climate change and the COVID-19 pandemic are complex and have multifaceted effects on countries in an unpredictable and unprecedented manner. While both COVID-19 and the climate…

Abstract

Climate change and the COVID-19 pandemic are complex and have multifaceted effects on countries in an unpredictable and unprecedented manner. While both COVID-19 and the climate crisis share similarities, they also have some notable differences. Being both systemic in nature with knock-on and cascading effects that propagate due to high connectedness of countries, COVID-19, however, presents imminent and directly visible dangers, while the risks from climate change are gradual, cumulative and often distributed dangers. Climate change has more significant medium and long-term impacts which are likely to worsen over time. There is no vaccine for climate change compared to COVID-19. In addition, those most affected by extreme climatic conditions have usually contributed the least to the root causes of the crisis. This is in fact the case of island economies. The chapter thus investigates into the vulnerability and resilience of 38 Small Islands Developing States (SIDs) to both shocks. Adopting a comprehensive conceptual framework and data on various indices from the literature and global databases, we assess the COVID-19 and climate change vulnerabilities of SIDs on multiple fronts. The results first reveal a higher vulnerability across all dimensions for the Pacific islands compared to the other islands in the sample. There is also evidence of a weak correlation between climate change risk and the COVID-19 pandemic confirming our premise that there are marked differences between these two shocks and their impacts on island communities.

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Achieving Net Zero
Type: Book
ISBN: 978-1-83753-803-4

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Book part
Publication date: 3 June 2024

Asmae Ourkiya, Todd Jared LeVasseur and Paul M. Pulé

This chapter approaches issues of ecospirituality through Gender and the Environment analytical lenses. We propose the need to actively queer human/Nature relations and…

Abstract

This chapter approaches issues of ecospirituality through Gender and the Environment analytical lenses. We propose the need to actively queer human/Nature relations and understandings by exploring studies related to ecospirituality, Earth relations, and gender dynamics. The chapter considers ecospirituality as ritual practices, material cultures, codified ethics, and/or cosmological structures related to a category of “the sacred,” which influence how various gendered and sexed bodies interact with the non-human world. Here, we propose that ecospiritual categories can shape the ways that humans conceive of their humanness and their sexed and gendered bodies. Within the context of religion/Nature interactions white evangelical masculinist subcultures in the United States are considered as an example that demonstrates the paradoxical characteristics of the gender binary and human/Nature dualisms. The chapter proceeds to offer queered ecologies as alternative narratives that can assist the larger Gender and Environment discourse in better understanding ecospiritual practices and worldviews, and how the latter can contribute to prosustainable lifeways as a viable alternative to masculinist hegemonies that are continuing to predominate the ways that many humans – especially those in the Global North – understand and relate to the natural world at great cost to life on the planet.

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People, Spaces and Places in Gendered Environments
Type: Book
ISBN: 978-1-83797-894-6

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Article
Publication date: 1 June 2002

Nielen Stander and K.J. Craig

This paper evaluates a Successive Response Surface Method (SRSM) specifically developed for simulation‐based design optimization, e.g. that of explicit nonlinear dynamics in…

1084

Abstract

This paper evaluates a Successive Response Surface Method (SRSM) specifically developed for simulation‐based design optimization, e.g. that of explicit nonlinear dynamics in crashworthiness design. Linear response surfaces are constructed in a subregion of the design space using a design of experiments approach with a D‐optimal experimental design. To converge to an optimum, a domain reduction scheme is utilized. The scheme requires only one user‐defined parameter, namely the size of the initial subregion. During optimization, the size of this region is adapted using a move reversal criterion to counter oscillation and a move distance criterion to gauge accuracy. To test its robustness, the results using the method are compared to SQP results of a selection of the well‐known Hock and Schittkowski problems. Although convergence to a small tolerance is slow when compared to SQP, the SRSM method does remarkably well for these sometimes pathological analytical problems. The second test concerns three engineering problems sampled from the nonlinear structural dynamics field to investigate the method's handling of numerical noise and non‐linearity. It is shown that, despite its simplicity, the SRSM method converges stably and is relatively insensitive to its only user‐required input parameter.

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Engineering Computations, vol. 19 no. 4
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 January 2005

K.J. Craig, Nielen Stander, D.A. Dooge and S. Varadappa

The purpose of this paper is to provide a methodology with which to perform variable screening and optimization in automotive crashworthiness design.

3043

Abstract

Purpose

The purpose of this paper is to provide a methodology with which to perform variable screening and optimization in automotive crashworthiness design.

Design/methodology/approach

The screening method is based on response surface methodology in which linear response surfaces are used to create approximations to the design response. The response surfaces are used to estimate the sensitivities of the responses with respect to the design variables while the variance is used to estimate the confidence interval of the regression coefficients. The sampling is based on the D‐optimality criterion with over‐sampling to improve noise filtering and find the best estimate of the regression coefficients. The coefficients and their confidence intervals as determined using analysis of variance (ANOVA), are used to construct bar charts for the purpose of selecting the important variables.

Findings

A known analytical function is first used to illustrate the effectiveness of screening. Using the finite element method (FEM), a complex vehicle occupant impact problem and a full vehicle multidisciplinary problem featuring frontal impact and torsional modal analysis of the vehicle body are modeled and parameterized. Two optimizations are conducted for each FEM example, one with the full variable set and one with a screened subset. An iterative, successive linear approximation method is used to achieve convergence. It is shown that, although significantly different final designs may be obtained, an appropriately selected subset of variables is effective while significantly reducing computational cost.

Practical implications

The method illustrated provides a practical approach to the screening of variables in simulation‐based design optimization, especially in automotive crashworthiness applications with costly simulations. It is shown that the reduction of variables used in the optimization process significantly reduces the total cost of the optimization.

Originality/value

Although variable screening has been used in other disciplines, the use of response surfaces to determine the variable screening information is novel in the crashworthiness field.

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Engineering Computations, vol. 22 no. 1
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 10 October 2008

Ming Zhao, Zhengdong Huang and Liping Chen

The purpose of this paper is to introduce a new method to carry out the design optimization of the tool head system in the heavy‐duty machine tool where closed hydrostatic…

607

Abstract

Purpose

The purpose of this paper is to introduce a new method to carry out the design optimization of the tool head system in the heavy‐duty machine tool where closed hydrostatic guideways with multiple pockets are employed.

Design/methodology/approach

A more accurate method of pressure calculation for closed hydrostatic guideways is introduced. Then, a multidisciplinary design optimization (MDO) model is formulated for design of a tool head system, which minimizes the highest pocket pressure under some constraints from machining accuracy and vibration resistance requirements as well as constraints from ballscrew design specifications. Finally, a metamodel‐based design space alternation (DSA) strategy is proposed to solve the optimization problem.

Findings

The results show that the maximum pocket pressure in a tool head system can be reduced over 47 percent with a proper design while all the constraints are satisfied. As a consequence, the tool head system can safely work under the maximum output pressure of oil supply system.

Originality/value

This paper introduces a more accurate method of pressure calculation for multi‐pocket closed hydrostatic guideways, develops a metamodel‐based MDO model for the tool head system, and proposes a DSA strategy to solve the MDO problem.

Details

Engineering Computations, vol. 25 no. 7
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 24 July 2007

Ibrahim A. Sultan

This paper aims to replace the complicated iterative procedure used to prevent interference in limaçon‐to‐limaçon machines by a simplified mathematical equation which can be…

225

Abstract

Purpose

This paper aims to replace the complicated iterative procedure used to prevent interference in limaçon‐to‐limaçon machines by a simplified mathematical equation which can be solved by a straightforward substitution of the required clearance value.

Design/methodology/approach

The input data to the iterative procedure and the obtained results have been employed in regression models to construct the sought after equation. Searching for a proper form of this equation involved numerical experiments to study the effects of the various model parameters on the system response.

Findings

The numerical experiments conducted proved to be an effective model construction technique, and the regression model proposed has been found extremely accurate in the specified parameter space.

Research limitations/implications

The proposed equation is applicable within the parameter range chosen for the study. This range is the one often used for industrial applications. Should the parameters selected for a specific design fall outside the specified range, the proposed model structure may have to be varied to maintain a desirable level of accuracy.

Practical implications

The interference study is a part of the iterative procedure employed to design the dimensions of the limaçon‐to‐limaçon machine. This iterative procedure searches for the proper design amongst hundreds of various possible solutions. The results of this paper will ensure a much faster convergence for the design procedure, since the interference study will be eliminated from the iterative section of the analysis.

Originality/value

The paper offers a valid and accurate model that can be efficiently used for the intended purpose.

Details

Engineering Computations, vol. 24 no. 5
Type: Research Article
ISSN: 0264-4401

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Available. Content available
Book part
Publication date: 30 July 2018

Abstract

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Marketing Management in Turkey
Type: Book
ISBN: 978-1-78714-558-0

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