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1 – 10 of 138Mehdi Mcharek, Toufik Azib, Moncef Hammadi, Cherif Larouci and Jean-Yves Choley
Within the current industrial context, companies aim to decrease the design process time and cost. The multidisciplinary design optimization (MDO) appears as a solution to…
Abstract
Purpose
Within the current industrial context, companies aim to decrease the design process time and cost. The multidisciplinary design optimization (MDO) appears as a solution to accelerate the process and support designers in different stages of the design cycle. However, this relatively new concept needs to be integrated efficiently in the industrial environment and issues related to collaboration, data management, traceability and reuse need to be overcome.
Design/methodology/approach
The aim of this work is to efficiently integrate the MDO in the industrial design cycle by means of knowledge management (KM) techniques. To take into account the industrial environment, the methodology was applied in a collaborative software.
Findings
An example of collaborative design and optimization of an electronic throttle body (ETB) controller is presented with industrial requirements. The design problem was solved successfully and demonstrates the efficiency of the methodology in collaborative environments.
Originality/value
The contributions of this work lie in the structuration of the knowledge to support MDO and the definition of a general way to connect the existent MDO tools to the knowledge base. This methodology will enable to freely link different steps of the design process and reduce considerably the setting time of MDO in industries.
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Debiao Meng, Shiyuan Yang, Chao He, Hongtao Wang, Zhiyuan Lv, Yipeng Guo and Peng Nie
As an advanced calculation methodology, reliability-based multidisciplinary design optimization (RBMDO) has been widely acknowledged for the design problems of modern complex…
Abstract
Purpose
As an advanced calculation methodology, reliability-based multidisciplinary design optimization (RBMDO) has been widely acknowledged for the design problems of modern complex engineering systems, not only because of the accurate evaluation of the impact of uncertain factors but also the relatively good balance between economy and safety of performance. However, with the increasing complexity of engineering technology, the proposed RBMDO method gradually cannot effectively solve the higher nonlinear coupled multidisciplinary uncertainty design optimization problems, which limits the engineering application of RBMDO. Many valuable works have been done in the RBMDO field in recent decades to tackle the above challenges. This study is to review these studies systematically, highlight the research opportunities and challenges, and attempt to guide future research efforts.
Design/methodology/approach
This study presents a comprehensive review of the RBMDO theory, mainly including the reliability analysis methods of different uncertainties and the decoupling strategies of RBMDO.
Findings
First, the multidisciplinary design optimization (MDO) preliminaries are given. The basic MDO concepts and the corresponding mathematical formulas are illustrated. Then, the procedures of three RBMDO methods with different reliability analysis strategies are introduced in detail. These RBMDO methods were proposed for the design optimization problems under different uncertainty types. Furtherly, an optimization problem for a certain operating condition of a turbine runner blade is introduced to illustrate the engineering application of the above method. Finally, three aspects of future challenges for RBMDO, namely, time-varying uncertainty analysis; high-precision surrogate models, and verification, validation and accreditation (VVA) for the model, are discussed followed by the conclusion.
Originality/value
The scope of this study is to introduce the RBMDO theory systematically. Three commonly used RBMDO-SORA methods are reviewed comprehensively, including the methods' general procedures and mathematical models.
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Ping Jiang, Qi Zhou, Xinyu Shao, Ren Long and Hui Zhou
The purpose of this paper is to present a modified bi-level integrated system collaborative optimization (BLISCO) to avoid the non-separability of the original BLISCO. Besides, to…
Abstract
Purpose
The purpose of this paper is to present a modified bi-level integrated system collaborative optimization (BLISCO) to avoid the non-separability of the original BLISCO. Besides, to mitigate the computational burden caused by expensive simulation codes and employ both efficiently simplified and expensively detailed information in multidisciplinary design optimization (MDO), an effective framework combining variable fidelity metamodels (VFM) and modified BLISCO (MBLISCO) (VFM-MBLISCO) is proposed.
Design/methodology/approach
The concept of the quasi-separable MDO problems is introduced to limit range of applicability about the BLISCO method and then based on the quasi-separable MDO form, the modification of BLISCO method without any derivatives is presented to solve the problems of BLISCO. Besides, an effective framework combining VFM-MBLISCO is presented.
Findings
One mathematical problem conforms to the quasi-separable MDO form is tested and the overall results illustrate the feasibility and robustness of the MBLISCO. The design of a Small Waterplane Area Twin Hull catamaran demonstrates that the proposed VFM-MBLISCO framework is a feasible and efficient design methodology in support of design of engineering products.
Practical implications
The proposed approach exhibits great capability for MDO problems with tremendous computational costs.
Originality/value
A MBLISCO is proposed which can avoid the non-separability of the original BLISCO and an effective framework combining VFM-MBLISCO is presented to efficiently integrate the different fidelities information in MDO.
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Elizabeth Spruin, Tara Dunleavy, Chloe Mitchell and Belinda Siesmaa
This study aims to evaluate the utility and reliability of the Psychological Inventory of Criminal Thinking Styles (PICTS) to investigate the criminal cognitions of mentally…
Abstract
Purpose
This study aims to evaluate the utility and reliability of the Psychological Inventory of Criminal Thinking Styles (PICTS) to investigate the criminal cognitions of mentally disordered offenders (MDOs) from the UK.
Design/methodology/approach
The reliability and validity of the PICTS scales were investigated within an MDO sample from the UK (N = 45) and compared to PICTS data from the USA and general offenders in the UK.
Findings
The findings showed that the PICTS functioned in a similar way when used in MDO and non-MDO populations, indicating that from a psychometric perspective, the PICTS scales produce consistent results across both populations. Evidence is further provided to indicate that MDOs from the UK endorse criminal cognitions at a similar level to those in the USA and at a significantly higher level than general UK offenders.
Practical implications
The implications and insight that these findings provide into the criminal cognitions of MDOs are discussed, with specific focus on the significant difference between general offenders and offenders with serious mental illness.
Originality/value
To the best of the authors’ knowledge, this study is the first to use the PICTS with MDOs in the UK, comparing the criminal thinking styles of MDOs and non-MDOs.
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The treatment of substance use amongst mentally disordered offenders (MDOs) remains a challenge for secure forensic mental health services. The purpose of this paper is to present…
Abstract
Purpose
The treatment of substance use amongst mentally disordered offenders (MDOs) remains a challenge for secure forensic mental health services. The purpose of this paper is to present an integrated three-stage substance use treatment programme (SUTP) for male and female MDO’s in medium security.
Design/methodology/approach
In total, 45 (72.6 per cent) MDO’s were referred (39 males/6 females). Standardised outcome measures were administered pre-SUTP, post-SUTP and at one year follow-up. Abstinence rates and location was determined via case notes at three year follow-up.
Findings
All MDO’s had a past history of substance use, approximately three-quarters reporting problematic use prior to admission. Over half completed all three SUTP stages, less than 5 per cent dropping out during active treatment. The SUTP supported abstinence throughout the one year follow-up period and significantly improved MDO’s adaptive beliefs about substances and craving by one year follow-up amongst attendees. At three years, most MDO’s were in the community and almost three-quarters were abstinent. There was no significant difference in abstinent rates between community and hospital. There was a non-significant trend suggesting SUTP attendance supported abstinence. Both male and female participants appear to have benefited from treatment and satisfaction was high, reflecting the specific aims and objectives of treatment.
Research limitations/implications
The small non-randomised sample from one area limits the generalisability of findings and statistical power.
Originality/value
Findings indicate further support for the limited evidence base that small but clinically meaningful and maintained changes to problematic substance use are possible following integrated substance use treatment for male and female MDO’s.
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Qing Hua, Jiang He‐fu, Wen Wei‐dong and Wu Chang‐bo
In this paper, a turbine blade was optimized by multidisciplinary design optimization (MDO) method. This turbine blade optimization is based on the optimization frame software…
Abstract
In this paper, a turbine blade was optimized by multidisciplinary design optimization (MDO) method. This turbine blade optimization is based on the optimization frame software iSIGHT, in which four disciplines (aerodynamics, thermal dynamics, structural mechanics and structural dynamics) have been integrated. Two commercial discipline analysis soft wares, NUMECA and ANSYS, are coupled in the platform iSIGHT. The three dimensional (3‐D) model of a blade was firstly parameterized. And then a set of parameters are chosen to optimize the blade to obtain the better overall properties. The result shows that the overall performances of the turbine blade have been improved remarkably after it is optimized by using the MDO method.
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Zheng Jiang, Haobo Qiu, Ming Zhao, Shizhan Zhang and Liang Gao
In multidisciplinary design optimization (MDO), if the relationships between design variables and some output parameters, which are important performance constraints, are complex…
Abstract
Purpose
In multidisciplinary design optimization (MDO), if the relationships between design variables and some output parameters, which are important performance constraints, are complex implicit problems, plenty of time should be spent on computationally expensive simulations to identify whether the implicit constraints are satisfied with the given design variables during the optimization iteration process. The purpose of this paper is to propose an ensemble of surrogates-based analytical target cascading (ESATC) method to tackle such MDO engineering design problems with reduced computational cost and high optimization accuracy.
Design/methodology/approach
Different surrogate models are constructed based on the sample point sets obtained by Latin hypercube sampling (LHS) method. Then, according to the error metric of each surrogate model, the repeated ensemble of surrogates is constructed to approximate the implicit objective functions and constraints. Under the framework of analytical target cascading (ATC), the MDO problem is decomposed into several optimization subproblems and the function of analysis module of each subproblem is simulated by repeated ensemble of surrogates, working together to find the optimum solution.
Findings
The proposed method shows better modeling accuracy and robustness than other individual surrogate model-based ATC method. A numerical benchmark problem and an industrial case study of the structural design of a super heavy vertical lathe machine tool are utilized to demonstrate the accuracy and efficiency of the proposed method.
Originality/value
This paper integrates a repeated ensemble method with ATC strategy to construct the ESATC framework which is an effective method to solve MDO problems with implicit constraints and black-box objectives.
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Sandeep W. Dahake, Abhaykumar M. Kuthe, Jitendra Chawla and Mahesh B. Mawale
The purpose of this paper is to develop a workflow for design and fabrication of customized surgical guides (CSGs) for placement of the bidirectional extraoral distraction…
Abstract
Purpose
The purpose of this paper is to develop a workflow for design and fabrication of customized surgical guides (CSGs) for placement of the bidirectional extraoral distraction instruments (EDIs) in bilateral mandibular distraction osteogenesis (MDO) surgery to treat the bilateral temporomandibular joint ankylosis with zero mouth opening.
Design/methodology/approach
The comprehensive workflow consists of six steps: medical imaging; virtual surgical planning (VSP); computer aided design; rapid prototyping (RP); functional testing of CSGs and mock surgery; and clinical application. Fused deposition modeling, an RP process was used to fabricate CSGs in acrylonitrile butadiene styrene material. Finally, mandibular reconstruction with MDO was performed successfully using RP-assisted CSGs.
Findings
Design and development of CSGs prior to the actual MDO surgery improves accuracy, reduces operation time and decreases patient morbidity, hence improving the quality of surgery. Manufacturing of CSG is easy using RP to transfer VSP into the actual surgery.
Originality/value
This study describes an RP-assisted CSGs fabrication for exact finding of both; osteotomy site and drilling location to fix EDI’s pins accurately in the mandible; for accurate osteotomy and placement of the bidirectional EDIs in MDO surgery to achieve accurate distraction.
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Amirhossein Adami, Mahda Mortazavi and Mehran Nosratollahi
For complex engineering problems, multidisciplinary design optimization (MDO) techniques use some disciplines that need to be run several times in different modules. In addition…
Abstract
Purpose
For complex engineering problems, multidisciplinary design optimization (MDO) techniques use some disciplines that need to be run several times in different modules. In addition, mathematical modeling of a discipline can be improved for each module. The purpose of this paper is to show that multi-modular design optimization (MMO) improves the design performances in comparison with MDO technique for complex systems.
Design/methodology/approach
MDO framework and MMO framework are developed to optimum design of a complex system. The nonlinear equality and inequality constrains are considered. The system optimizers included Genetic Algorithm and Sequential Quadratic Programming.
Findings
As shown, fewer design variables (optimization variables) are needed at the system level for MMO. Unshared variables are optimized in the related module when shared variables are optimized at the system level. The results of this research show that MMO has lower elapsed times (14 percent) with lower F-count (16 percent).
Practical implications
The monopropellant propulsion upper-stage is selected as a case study. In this paper, the efficient model of the monopropellant propulsion system is proposed. According to the results, the proposed model has acceptable accuracy in mass model (error < 2 percent), performance estimation (error < 6 percent) and geometry estimation (error < 10 percent).
Originality/value
The monopropellant propulsion system is broken down into the three important modules including propellant tank (tank and propellant), pressurized feeding (tank and gas) and thruster (catalyst, nozzle and catalysts bed) when chemical decomposition, aerothermodynamics, mass and configuration, catalyst and structure have been considered as the disciplines. The both MMO and MDO frameworks are developed for the monopropellant propulsion system.
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Ramzi Ben Ayed and Stéphane Brisset
The purpose of this paper is to investigate the use of multidisciplinary optimization (MDO) formulations within space‐mapping techniques in order to reduce their computing time.
Abstract
Purpose
The purpose of this paper is to investigate the use of multidisciplinary optimization (MDO) formulations within space‐mapping techniques in order to reduce their computing time.
Design/methodology/approach
The aim of this work is to quantify the interest of using MDO formulations within space mapping techniques. A comparison of three MDO formulations is carried out in a short time by using an analytical model of a safety transformer. This comparison reveals the advantage of two formulations in terms of robustness and computing time among the three MDO formulations. Then, the best formulations are investigated within output space mapping, using both analytical and FE models of the transformer.
Findings
A major computing time gain equal to 5.5 is achieved using the Individual Disciplinary Feasibility formulation within the output space‐mapping technique in the case of the safety transformer.
Originality/value
The MultiDisciplinary Feasibility formulation is the common formulation used within space‐mapping technique because it is the most conventional way to perform MDO. The originality of this paper is to investigate the Individual Disciplinary Feasibility formulation within output space‐mapping technique in order to allow the parallelization of calculation and to achieve a major reduction of computing time.
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