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The problem of optimal design of pressure vessel heads to maximize limit load behaviour is presented. Incremental elasto‐plastic analysis is used and a formulation based on the finite element method is presented whereby an approximate design model is generated which can be optimized via sequential programming. Results are presented for torispherical head shapes and tables are provided in order to evaluate the influence of different geometrical forms on limiting pressure loads. The method is generally applicable and can be applied to the design of components which are required to exhibit limited plastification under increasing load.

Pressure vessel is a closed cylindrical vessel for storing gaseous, liquids or solid products. The stored medium is at a particular pressure and temperature. The cylindrical vessel is closed at both ends by means of dished head, which may be hemispherical, ellipsoidal. The pressure vessels may be horizontal or vertical. The supporting system of this vertical vessel plays an important role in the performance of the equipment. Proper supporting system gives better efficiency. The bottom supports are critical components since they are to be designed with much care to avoid failure due to internal pressure with temperature. In this analysis, skirt support for vertical vessel was analyzed as per the guidelines given in the ASME (American Society of Mechanical Engineering) section VIII division 2 and IBR (Indian Boiler Regulations) standards. The stress analysis was carried out for this support using a general purpose FEM code, ANSYS macros. The coupled field (Structural and Thermal) Analysis was carried out for skirt support to find out the stresses in the support. The analysis’s results were compared with ASME code allowable stress values.

The purpose of this paper is to develop an autoclave that can be used to assess corrosion behaviour of suitable material in high-pressure–high-temperature (HPHT) environments. Many new discoveries of oil and gas field are in HPHT environments. The development of such fields requires appropriate selection of materials that are able to withstand not just the service loads but also corrosive production fluids in the HPHT environment.

The exposure of material samples to elevated pressure and temperature is usually done using an autoclave. The suitability of an existing autoclave for HPHT corrosion studies is provided together with suggestions on necessary design modifications. An alternative design of the autoclave is proposed based on functionality requirements and life cycle cost assessment.

It is concluded that the existing autoclave was unsuitable for HPHT corrosion tests, and modifications were very expensive to implement and/or not foolproof. A new autoclave was designed, manufactured, tested and successfully used to study the effect of aqueous solution on the corrosion of a pipe subject to a combination of axial tension, internal pressure and elevated temperature.

The maximum design pressure of 15 MPa is more than sufficient for high-pressure corrosion studies in aqueous solution where partial pressure of the dissolved gas is one of the main controlling parameters. However, the design pressure is only suitable for corrosion studies in a seawater environment of up to 1,500 m water depth.

A new design of autoclave together with all the necessary piping, assembly and control system is proposed for HPHT corrosion studies. The autoclave can be used as standalone or integrated with a mechanical testing machine and thus enables corrosion studies under a wide range of loading.

Finite element analysis (FEA) has been carried out utilizing the ANSYS software package to assess the failure of thick and thin‐walled steel cylindrical pressure vessels. A simple experimental stress analysis (ESA) procedure is described to evaluate the stress components on inner and outer surfaces of the vessels under internal pressure from the measured surface strains. The procedure is validated considering the strain values of FEA for the applied pressure as measured quantities and obtained the corresponding stress components considering the stress‐strain data of the material from ESA and compared with those of FEA results. Failure pressure estimates from FEA (based on the global plastic deformation) were found to be in good agreement with test results of thin as well as thick‐walled cylindrical vessels made of ductile steel materials.

The purpose of this paper is to present a combined framework for system design using Six Sigma and Lean concepts. Systems Engineering has evolved independently and there are numerous tools and techniques available to address issues that may arise in the design of systems. In the context of systems design, the application of Six Sigma and Lean concepts results in a flexible and adaptable framework. A combined framework is presented here that allows better visualization of the system-level components and their interactions at parametric level, and it also illuminates gaps that make way for continuous improvement. The Deming’s Plan-Do-Check-Act is the basis of this framework. Three case studies are presented to evaluate the application of this framework in the context of Systems Engineering design. The paper concludes with a summary of advantages of using a combined framework, its limitations and scope for future work.

Six Sigma, Lean and Systems Engineering approaches combined into a framework for collaborative product development.

The present framework is not rigid and does not attempt to force fit any tools or concepts. The framework is generic and allows flexibility through a plug and play type of implementation. This is important, as engineering change needs vary constantly to meet consumer demands. Therefore, it is important to engrain flexibility in the development of a foundational framework for design-encapsulating improvements and innovation. From a sustainability perspective, it is important to develop techniques that drive rationality in the decisions, especially during tradeoffs and conflicts.

Scalability of the approach for large systems where complex interactions exist. Besides, the application of negotiation techniques for more than three persons poses a challenge from a mathematical context. Future research should address these in the context of systems design using Six Sigma and Lean techniques.

This paper provides a flexible framework for combining the three techniques based on Six Sigma, Lean and Systems Engineering.

This paper will influence the construction of agent-based systems, particularly the ones using the Habermas’s theory of social action as the basis for product development.

This paper has not been published in any other journal or conference.

This paper aims to represent an improved whale optimization algorithm (WOA) based on a Lévy flight trajectory and called the LWOA algorithm to solve engineering optimization problems. The LWOA makes the WOA faster, more robust and significantly enhances the WOA. In the LWOA, the Lévy flight trajectory enhances the capability of jumping out of the local optima and is helpful for smoothly balancing exploration and exploitation of the WOA. It has been successfully applied to five standard engineering optimization problems. The simulation results of the classical engineering design problems and real application exhibit the superiority of the LWOA algorithm in solving challenging problems with constrained and unknown search spaces when compared to the basic WOA algorithm or other available solutions.

In this paper, an improved WOA based on a Lévy flight trajectory and called the LWOA algorithm is represented to solve engineering optimization problems.

It has been successfully applied to five standard engineering optimization problems. The simulation results of the classical engineering design problems and real application exhibit the superiority of the LWOA algorithm in solving challenging problems with constrained and unknown search spaces when compared to the basic WOA algorithm or other available solutions.

An improved WOA based on a Lévy flight trajectory and called the LWOA algorithm is first proposed.

SYNOPSIS DURING the last ten years or more an outwardly unnoticeable change has been taking place on board a variety of ships, in that the traditional method of heating cargo, engine room services and accommodation by steam, has been replaced by a thermal fluid which remains in the liquid phase throughout the entire heating system.

This paper aims to propose a novel nature-inspired optimization algorithm, called whirlpool algorithm (WA), which imitates the physical phenomenon of whirlpool.

The idea of this algorithm stems from the fact that the whirlpool has a descent direction and a vertex.

WA is tested with two types of models: 29 typical mathematical optimization models and three engineering problems (tension/compression spring design, welded-beam design, pressure vessel design).

The results shown that the WA is vying compared to the state-of-art algorithms likewise conservative approaches.

The purpose of this paper is to investigate the performance of chaotic gravitational search algorithm (CGSA) in solving mechanical engineering design frameworks including welded beam design (WBD), compression spring design (CSD) and pressure vessel design (PVD).

In this study, ten chaotic maps were combined with gravitational constant to increase the exploitation power of gravitational search algorithm (GSA). Also, CGSA has been used for maintaining the adaptive capability of gravitational constant. Furthermore, chaotic maps were used for overcoming premature convergence and stagnation in local minima problems of standard GSA.

The chaotic maps have shown efficient performance for WBD and PVD problems. Further, they have depicted competitive results for CSD framework. Moreover, the experimental results indicate that CGSA shows efficient performance in terms of convergence speed, cost function minimization, design variable optimization and successful constraint handling as compared to other participating algorithms.

The use of chaotic maps in standard GSA is a new beginning for research in GSA particularly convergence and time complexity analysis. Moreover, CGSA can be used for solving the infinite impulsive response (IIR) parameter tuning and economic load dispatch problems in electrical sciences.

The hybridization of chaotic maps and evolutionary algorithms for solving practical engineering problems is an emerging topic in metaheuristics. In the literature, it can be seen that researchers have used some chaotic maps such as a logistic map, Gauss map and a sinusoidal map more rigorously than other maps. However, this work uses ten different chaotic maps for engineering design optimization. In addition, non-parametric statistical test, namely, Wilcoxon rank-sum test, was carried out at 5% significance level to statistically validate the simulation results. Besides, 11 state-of-the-art metaheuristic algorithms were used for comparative analysis of the experimental results to further raise the authenticity of the experimental setup.

THE Structural Integrity Centre (SIC) had its origins in the 1970s when major integrity issues arose on the UKAEA's plant in service, eg weld cracking in the prototype fast reactors (PFR) steam generator units, and safety concerns led to a rigorous assessment of the integrity of the civil pressurised water reactors (PWR) pressure vessel (the Marshall committee report). In both cases engineers and scientists from various disciplines throughout the authority were involved in the consideration and resolution of these issues, and it was demonstrated that assurance of plant integrity could no longer be provided by the plant designer or operator alone.