Grant P. Steven

Grant P. Steven
Strand7

BSc, DPhil, FTSE, FRAeS
Structural and Multidisciplinary Optimization, Finite Element Analysis, Computational Mechanics

About

249
Publications
47,840
Reads
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12,172
Citations
Introduction
My main research area is Structural and Multidisciplinary Optimization my published work as over 20000 citation with the initial ESO paper in 1993 attracting 2500 citations. I am still working with Qing Li and his students at the University of Sydney.
Additional affiliations
March 2004 - present
Strand7 Pty Ltd
Position
  • Founding director
Description
  • Strand7 makes Finite Element Analysis easier. We have over 4000 commercial clients worldwide.
November 1985 - December 2014
Strand7
Position
  • Research and Devopment at Strand7 FEA.
Description
  • Strand7 is a world leader in cost effective FEA code. We have many 1000s of users worldwide.
Education
June 1966 - June 1970
University of Oxford
Field of study
  • Engineering Science

Publications

Publications (249)
Article
This study proposes a novel topology optimization approach for design of continuous steering fiber path for composite structures using a level set method. The radial basis function (RBF) is employed to construct the level set function (LSF). Fiber orientations are parameterized by LSF and fiber paths can be determined instinctively for the inherent...
Article
Phase field approaches have been developed to analyze the failure behavior of ductile materials. In the previous phase field models, a constant critical energy or strain threshold is commonly introduced to the formulation of the driving force, aiming to avoid damage initiation at a low level of elastic and plastic deformations. However, it may not...
Article
Full-text available
Periodic topology optimization has been suggested as an effective means to design efficient structures which address a range of practical constraints, such as manufacturability, transportability, replaceability and ease of assembly. This study proposes a new approach for design of finite periodic structures by allowing variable orientation states o...
Article
Full-text available
This study proposes a machine learning (ML) based approach for optimizing fiber orientations of variable stiffness carbon fiber reinforced plastic (CFRP) structures, where neural networks are developed to estimate the objective function and analytical sensitivities with respect to design variables as a substitute for finite element analysis (FEA)....
Article
Full-text available
Computational modeling methods combined with non-invasive imaging technologies have exhibited great potential and unique opportunities to model new bone formation in scaffold tissue engineering, offering an effective alternate and viable complement to laborious and time-consuming in vivo studies. However, existing numerical approaches are still hig...
Article
In this paper, a recently-developed phase-field damage model is incorporated into the topology optimization framework to take into account crack initiation and propagation in a path-dependent fashion. The proposed topological design can enhance fracture resistance of structures made of brittle materials such as advanced ceramics. For the first time...
Article
This study proposes a robust and effective evolutionary shape optimization methodology for bell design. Axisymmetric bell profiles are defined within a 2D-half-cross-sectional design space, from which a 3D finite element model is constructed. An objective function is formulated with respect to a desired tuning spectrum and evaluated through a modal...
Article
This study develops a topology optimization approach for design of carbon fiber reinforced plastic (CFRP) laminated components with different failure criteria to reduce the risk of structural failure. The discrete material and thickness optimization (DMTO) method is presented to parameterize the design variables of thickness and orientation of CFRP...
Article
Scaffold-based bone tissue engineering has been extensively developed as a potential means to treatment of large bone defects. To enhance the biomechanical performance of porous tissue scaffolds, computational design techniques have gained growing popularity attributable to their compelling efficiency and strong predictive features compared with ti...
Article
Full-text available
Design of engineering structures may benefit from reduction in assembly complexity through use of periodic components, in which uniform sub-structures combine to form a relatively simple topology. The benefits of periodic structures include lower manufacture costs as well as ease of assembly. Recent developments in periodic topology optimization ha...
Article
Full-text available
Fracture is one of the most common failure modes in brittle materials. It can drastically decrease material integrity and structural strength. To address this issue, we propose a level-set (LS) based topology optimization procedure to optimize the distribution of reinforced inclusions within matrix materials subject to the volume constraint for max...
Article
Bone plates have been widely used for the treatment of bone defects and trauma. These fixation plates can stabilize or replace bone tissue to restore appropriate load-bearing functionality. Nevertheless, the use of bone plates may lead to the stress shielding, thereby weakening prosthetic bone substitutes (e.g. bone graft or scaffolds) due to signi...
Article
Full-text available
To date, topology optimization has proven to be the most beneficial, yet most complex, structural optimization technique available to engineers and scientists. However, particularly in the aerospace industry, there exists little application to real-world design problems, including all the complexities required to ensure that the resulting design co...
Article
The performance of countless engineering systems usually depends on various physical phenomena belonging to different disciplines, such as solid mechanics, fluid mechanics, and heat transfer. Such problems are normally referred to as multiphysics. Topology optimization provides a promising approach to systematically solve multiphysics problems, whi...
Article
This article presents an optimisation framework for the compliance minimisation of structures subjected to design-dependent pressure loads. A finite element solver coupled to a Lattice Boltzmann method is employed, such that the effect of the fluid-structure interactions on the optimised design can be considered. It is noted that the main computati...
Article
This article presents an optimisation framework for the compliance minimisation of structures subjected to design-dependent pressure loads. A finite element solver coupled to a Lattice Boltzmann method is employed, such that the effect of the fluid-structure interactions on the optimised design can be considered. It is noted that the main computati...
Article
Full-text available
Multi-cell thin-walled structures exhibit significant advantages in maximizing energy absorption and minimizing mass during vehicle crashes. Since the topological distribution of wall members has an appreciable effect on the crashworthiness, their design signifies an important area of research. As a major energy absorber, multi-cell tubes are more...
Article
This paper proposes the introduction of a connectivity constraint in the Bi-directional Evolutionary Structural Optimisation (BESO) method, which avoids the possibility of arriving at highly non-optimal local optima. By developing a constraint that looks at the usefulness of complete members, rather than just elements, local optima are shown to be...
Article
Full-text available
Multicell tubal structures have generated increasing interest in engineering design for their excellent energy-absorbing characteristics when crushed through severe plastic deformation. To make more efficient use of the material, topology optimization was introduced to design multicell tubes under normal crushing. The design problem was formulated...
Conference Paper
Full-text available
To date the design of structures via topology optimisation methods has mainly focused on single-objective problems. However, real-world design problems usually involve several different objectives, most of which counteract each other. Therefore, designers typically seek a set of Pareto optimal solutions, a solution for which no other solution is be...
Article
The optimum design of structures with frequency constraints is of great importance in the aeronautical industry. In order to avoid severe vibration, it is necessary to shift the fundamental frequency of the structure away from the frequency range of the dynamic loading. This paper develops a novel topology optimisation method for optimising the fun...
Article
Full-text available
Structural topology optimisation has mainly been applied to strength and stiffness objectives, due to the ease of calculating the sensitivities for such problems. In contrast, dynamic and buckling objectives require time consuming central difference schemes, or inefficient non-gradient algorithms, for calculation of the sensitivities. Further, soft...
Article
The optimum design of structures with frequency constraints is of great importance in the aeronautical industry. To avoid severe vibration, it is necessary to shift the fundamental frequency of the structure away from the frequency range of the dynamic loading. This paper develops a novel topology optimization method for optimizing the frequency of...
Article
Long before FEA was developed, people were participating in sports and as competition intensified is became clear that for many sports, the equipment plays as important a part in performance as does the athlete. With the use of modern materials and manufacturing processes there is always scope for maximizing the performance of sporting equipment. T...
Article
Topology optimization has evolved rapidly since the late 1980s. The optimization of the geometry and topology of structures has a great impact on its performance, and the last two decades have seen an exponential increase in publications on structural optimization. This has mainly been due to the success of material distribution methods, originatin...
Article
Purpose – To describe the mathematics, mechanics and computer code that are involved in deriving the mechanical properties of a 3D composite material with a complicated internal architecture. To inform the reader how an application programming interface (API) can be used with a commercial FEA code to undertake the task. Finally to validate the proc...
Article
Most structures in the real life are subject to multiple load cases. This paper aims at extending the evolutionary struc-tural optimization (ESO) algorithm to optimal contact shape design for elastic bodies under the multiple load cases. To evaluate the reference stresses of each contact node in a finite element framework, an extreme stress criteri...
Article
The success of GA-based topology optimisation methods for continuum structures has been limited. Though a number of methods exist, the results are far from comparable to solutions from more established methods in terms of quality and fidelity. This had led many structural optimisation researchers to dismiss the GA as a viable method for topology op...
Article
An automated 3D finite element (FE) modeling procedure for direct fiber reinforced dental bridge is established on the basis of computer tomography (CT) scan data. The model presented herein represents a two-unit anterior cantilever bridge that includes a maxillary right incisor as an abutment and a maxillary left incisor as a cantilever pontic bon...
Article
Evolutionary structural optimisation (ESO) method is based on the idea that by gradually removing inefficient materials, the structure evolves towards an optimum. Bi-directional ESO (BESO) allows for adding efficient materials in the evolution. This paper investigates the ESO and BESO methods in solving the topology optimisation of continua structu...
Article
This paper aims at developing an efficient finite element based computational procedure for the topology design of heat conducting fields. To evaluate the temperature change in a specific position, due to varying the conducting material distribution in other regions, a discrete temperature sensitivity is derived for an evolutionary topology optimiz...
Article
This experimental investigation aims at revealing the mechanical behaviour and failure pattern of direct fibre-reinforced resin-bonded dental bridge with various designs. To evaluate the overall effects of some newly developed dental materials, in the experiment, genuine composite dental bridge specimens are prepared and tested. The ultimate load,...
Article
Motivated by the clinical success and limitations on experimental investigation of the fibre-reinforced composite dental bridge, this paper aims at providing a numerical investigation into the bridge structure. The finite element (FE) model adopted here is constructed from computer tomography images of a physical bridge specimen. The stress and str...
Chapter
This chapter describes a paper that elucidates the range of individual design sensitivities that have been used in an evolutionary design optimization algorithm and presents some applications using these design sensitivities, which involve multioptimality criteria and multiphysics. The process, the evolutionary structural optimization (ESO), has be...
Chapter
This chapter describes a paper that elucidates the range of individual design sensitivities that have been used in an evolutionary design optimization algorithm and presents some applications using these design sensitivities, which involve multioptimality criteria and multiphysics. The process, the evolutionary structural optimization (ESO), has be...
Article
Many real structures are made up of trusses and beams as are their computational models. It may be important to the designer to consider such structures to be in contact and if so, then to ensure that such contact does not produce high localized stress. This study is concerned with such an issue in truss/beam structures involving a unilateral conta...
Article
Full-text available
In previous work by the authors, a Genetic Algorithm (GA) based shape optimization technique was introduced. The method was shown to be capable of producing high-fidelity optimal shapes. However, the process was computationally expensive and required constant re-meshing due to distorted boundary elements resulting from large boundary movements. Thi...
Article
Shape optimization through a genetic algorithm (GA) using discrete boundary steps and the fixed‐grid (FG) finite‐element analysis (FEA) concept was recently introduced by the authors. In this paper, algorithms based on knowledge specific to the FG method with the GA‐based shape optimization (FGGA) method are introduced that greatly increase its com...
Article
This study examined the influence of ceramic coping thickness on the maximum stresses that arise in a first premolar all-ceramic crown. Axisymmetric finite element models with different In-Ceram Alumina coping thicknesses (0.3, 0.6, and 0.9 mm) were examined. Models with and without resin lute were constructed. To all models, an identical axial loa...
Article
Two different Finite Element Analysis studies were conducted to examine the influence of thickness of a relatively stiff (In-Ceram Alumina) ceramic core on an all-ceramic crown. The first study was that of a biaxial, bi-laminar disc with 5 different ratio thicknesses (where the overall thickness of the disc was maintained). The effect of different...
Article
The finite element method (FEM) has been extensively applied to explore contact stress distributions in multi-body mechanical systems. Uneven contact stresses are often one of the main concerns of mechanical design engineers. By adopting the evolutionary structural optimization (ESO) concept, this paper presents a non-gradient procedure for gradual...
Article
The principal stress based evolutionary structural optimisation method is presented herein for topology optimisation of arch, tied arch, cable-stayed and suspension bridges with both stress and displacement constraints. Two performance index formulas are developed to determine the efficiency of the topology design. A refined mesh scheme is proposed...
Article
The purpose of this study was to examine the influence of the elastic modulus of cement and luting thickness on the resulting stresses in an axially loaded crown cemented onto a first premolar. A comparison of these stresses was also made with the strength of the constituent materials making up the crown. Examination of the stresses on a restored c...
Article
Full-text available
1. Abstract The success of GA-based topology optimisation methods for continuum structures has been limited. Though a number of methods exist, the results are far from comparable to solutions from more established methods in terms of quality and fidelity. A new GA-based method for the continuum topology optimisation problem is herein presented whic...
Article
Full-text available
Evolutionary structural optimization (ESO) has been shown through much published research to be a simple and yet effective method for structural shape and topology optimization. However, attention has been drawn to shortcomings in the method related to the computational efficiency of the algorithm as well as the jagged edge representation of the Fi...
Article
The purpose of this study was to determine the influence of margin design and taper abutment angle on the stresses developed in all-ceramic first premolar crowns. Four margin designs and three taper abutment angles were independently incorporated into models examined by finite element analysis. A 600-N force was applied vertically downward. The tap...
Article
This study examined the stresses developed during loading in a first premolar metal-ceramic crown made of different metal cores, and used them to anticipate the locations and form of the most likely failure modes. The maximum principal stresses in the porcelain are indicators of fracture, and the von Mises stresses in the metal core are indicators...
Article
In presenting and discussing structural analysis and design an engineer/analyst is always emphasizing the importance of strength and stiffness and endeavoring to get a balance between them both that suits the design in hand. It seems logical therefore in presenting structural optimization that both these crucial items be objectives of the process r...
Article
An intuitive approach for the determination of voltage distribution in the application to shape control of smart structures using piezoelectric actuators is presented. This novel approach introduces slope as the fine-tuning criterion on top of the common displacement-based shape control. The algorithm, called the perturbation buildup voltage distri...
Article
This study examined the effects of using four different core-ceramic materials on the stresses that developed in a single all-ceramic first premolar crown. This was done by analyzing models constructed in an axisymmetric fashion with finite element analyses. The model had a 600-N vertical load applied uniformly over a circular area on top of the cr...
Article
Full-text available
Conventional trial-and-error methods are not efficient in developing appropriate strut-and-tie models in complex structural concrete members. This paper describes a performance-based optimization (PBO) technique for automatically producing optimal strut-and-tie models for the design and detailing of structural concrete. The PBO algorithm utilizes t...
Article
In the field of topology optimization, increasing interest has been applied toward improving the practical applicability of the methods. Mechanically, a cavity in a structure introduces stress concentrations and, hence, structurally undesirable effects on the design. However, designs such as aircraft fuselages and wing ribs often require a specifie...
Article
A heuristic and intuitive algorithm is presented for the determination of the orientation of piezoelectric actuator patches in the application to shape control of smart structures. The fundamental concept of this approach is similar to another method developed by the same authors for voltage optimization, but the implementation of the current algor...
Article
In the past, we have seen extensive developments in computational applications in order to improve the efficiency of a design process — e.g. FEA; CAD/CAM; and virtual modelling. In more recent years, much research has been conducted in optimisation. The introduction of optimisation in design is revolutionary in that it aids both the efficiency and...
Article
A performance-based optimization (PBO) method for optimal topology design of linear elastic continuum structures with mean compliance constraints is presented in this paper. The performance-based design concept is incorporated in continuum topology optimization, which is treated as the problem of improving the performance of a continuum design doma...
Article
Group evolutionary structural optimisation (GESO) is a recent modification of evolutionary structural optimisation (ESO) which extends the topological method to configuration optimisation. This paper demonstrates the optimisation of an aircraft wing with ESO and GESO. The optimisation is conducted over some of the major areas involved in the design...
Chapter
The evolutionary structural optimization (ESO) and basic ESO (BESO) processes and given various illustrative examples are described. Such processes are based on the concept of slowly removing inefficient materials from a structures so that the residual structure evolves towards the optimum. It is shown that the simple ESO and BESO algorithms are ca...
Article
A curved beam model is presented for studying the effect of fiber yarn waviness on the tensile strength of woven composite materials. In the model, a curved beam is assumed to be supported, with an elastic tension or shear foundation in a woven composite material, either with the open-mode type or with the shear mode type. By using the maximum stre...
Article
A shape or topology design with the stiffness maximized and the maximum stress minimized is usually of practical significance in structural optimization. This paper proposes a thickness based evolutionary procedure for such multicriteria design problems. To make the multicriteria optimization suit to more realistic structural situations, multiple m...
Article
Full-text available
In continuation of the recent development of Evolutionary Structural Optimisation (ESO) applied to the simultaneous objective to maximise the natural frequency and to minimise the mean compliance, presents the Multicriteria ESO optimisation of two new criteria. This has been done with the use of four different multicriteria methods. Three examples...
Article
Full-text available
Checkerboard patterns are quite common in various fixed grid finite element based structural optimization methods. In the evolutionary structural optimization procedure, such checkerboard patterns have been observed under various design criteria. The presence of checkerboard patterns makes the interpretation of optimal material distribution and sub...
Article
The design of structures using evolutionary structural optimization (ESO) has previously been based on a single criterion. Multiple criteria are incorporated into the ESO process. This is done using a weighting method and a global criterion method. In the present work, two criteria are optimized simultaneously, namely, the maximization of the first...
Article
Full-text available
An intuitive algorithm for the determination of voltage distribution in the application to shape control of smart structures using piezoelectric actuators is presented here. This approach uses curvature as the fine-tuning criteria on top of the common displacement-based shape control, and is an extension of the slope–displacement method developed b...
Article
This paper presents a shear stress based evolutionary algorithm for the cross-section design of shafts subject to torsion. In this method, finite element analysis is employed to find the shear stress distribution throughout the cross-sectional area of the shaft. To seek a full stress or iso-strength design, two basic procedures are developed in thi...
Article
Full-text available
This paper presents a structural application of a shape optimization method based on a Genetic Al-gorithm (GA). The method produces a sequence of fixed-distance step-wise movements of the boundary nodes of a finite element model to derive optimal shapes from an arbitrary initial design space. The GA is used to find the optimal or near-optimal combi...
Article
Full-text available
This paper presents a performance index for topology and shape optimization of plate bending problems with displacement constraints. The performance index is developed based on the scaling design approach. This performance index is used in the Performance-Based Optimization (PBO) method for plates in bending to keep track of the performance history...
Article
In this study, an evolutionary procedure is developed for the shape optimization of indentors in two- and three-dimensional elastic contact problems. This evolutionary optimization procedure uses finite element analysis, in which contact profiles are iteratively and slowly modified based on the relative levels of contact stress. Through this proced...