A Study of Structural Optimization Design System Based on Product Model in Shipbuilding

This paper presents a prototype for a structural analysis and design system by using the STEP for the representation and exchange of information on steel structures, by integrating the product model of steel framed structures of AP 230, the geometric and topological information of Part 42, and the detailed Finite Element Analysis information of Part 104 into an unified system. Thus, the STEP-based system makes engineering information more clearable and exchangeable between computer applications than any other conventional methods. This system may be further extended to incorporate such computer applications as detailed engineering and manufacturing information on steel structures.

Facing the escalating demands in both technical competence and financial accountability, practicing structural engineers are being forced into an ever-intensified fast-pace working environment. With more and more structural design codes becoming lengthy and cumbersome and, meanwhile, the time allocated for structural engineering design being drastically reduced, the quality assurance of the structural engineering design has been becoming more critical than ever for practicing structural engineers to succeed. Structural engineering design errors and failures have been observed in a variety of design phases and categories. Among them, there are several typical problems needed to be discussed and a systematical procedure of quality assurance of the structural engineering design shall be studied and developed. As a part of our collective professional effort to assure the quality of the structural engineering design, this paper will discuss following eight typical aspects related to quality control and assurance of structural engineering design and a number of real world practical examples will be presented to assist in illustrating the importance of the quality control and assurance for real world structural engineering design projects.

Structural system design is the process of giving form to a set of interconnected components subjected to loads and design constraints while navigating a complex design space. While safe designs are relatively easy to develop, optimal designs are not. Modern computational optimization approaches employ population based metaheuristic algorithms to overcome challenges with the system design optimization landscape. However, the choice of the initial population, or ground structure, can have an outsized impact on the resulting optimization. This paper presents a new method of generating such ground structures, using a combination of topology optimization (TO) and a novel system extraction algorithm. Since TO generates monolithic structures, rather than systems, its use for structural system design and optimization has been limited. In this paper, truss systems are extracted from topologies through morphological analysis and artificial intelligence techniques. This algorithm, and its assessment, constitutes the key contribution of this paper. The structural systems obtained are compared with ground truth solutions to evaluate the performance of the algorithms. The generated structures are also compared against benchmark designs from the literature. The results indicate that the presented truss generation algorithm produces structures comparable to those generated through metaheuristic optimization, while mitigating the need for assumptions about initial ground structures.

An approach to automate the design of fixed offshore structures

Building-focused structural engineering has been an advanced user of computational technologies over the last 3 decades. During this time, there was still a lack of integration among the participants involved in the structural design, which obstructs advancements in the structural design process. To address this, the creation of an integrated structural process model (ISPM) was formulated to promote advances in the design of structural systems through collaboration and integration among participants. The resulting ISPM is overarching in nature in that it is not specific to a structural material or system, but its scope is comprehensive because it encompasses a project from planning through construction. Within the ISPM are tasks to complete the structural processes, data-driven information exchanges among participants, and holistic representations and descriptions for methods and tools to perform the processes. The broad architectural/engineering/construction (A/E/C) impact of the structural level...

This paper proposes a new integrated design method to simultaneously optimize the coupled structural parameters and controllers of mechanical systems by combining decentralized control techniques and Riccati-based control theories. The proposed integrated design method aims at minimizing the closed-loop H2 norm from the disturbance to the system cost. In this paper, the integrated design problems have been formulated in the cases of full state-feedback controllers and full order output-feedback controllers. We extend the current linear time invariant (LTI) control system to a more general framework suitable for the needs of integrated design, where the structural design is treated as a passive control optimization tackled by decentralized control techniques with static output feedback, while the active controller is optimized by solving modified Riccati equations. By using this dual-loop control system framework, the original integrated design problem is transferred to a constrained structural design problem with some additional Riccati-equation based constraints simultaneously integrating the controller synthesis. This reduces the independent design variables from the structural design parameters and the parameters of the controller to the structural design parameters only. As a result, the optimization efficiency is significantly improved. Then the constrained structural design problem is reformed as an unconstrained optimization problem by introducing Lagrange multipliers and a Lagrange function. The corresponding optimal conditions for the integrated design are also derived, which can be efficiently solved by gradient-based optimization algorithms. Later, two design examples, an active–passive vehicle suspension system and an active–passive tuned mass damper (TMD) system, are presented. The improvement of the overall system performance is also presented in comparison with conventional design methods.

Ship and Ocean Foundation has been conducting the feasibility study on CIM for shipbuilding and its committee has been establishing a conceptual framework for the CIM for shipbuilding. Now the committee has finished the conceptual design to develop a pilot model and has been prototyping it. The pilot model consists of the systems which will hold the keys to the success of the CIM for shipbuilding. One of the systems being prototyped is a structural design system. This paper reports about an expert system which has one of the functions of the structural design system and which incorporates the design method well-known to hull structural designers as “narai design”. This expert system is applied to the transverse sections in hold part of an oil tanker. The result indicates that the system is applicable to generate the design information necessary to production planning earlier in the CIM for shipbuilding.

"The main aims of this thesis were to investigate the main aspects of the design and implementation of rubble-mound structures as a form of shoreline stabilisation and coastal defence. An emphasis has been placed on the Irish context of how these structures have been implemented in the past. The intention was that this work would improve the understanding of the use of these structures for future projects both in Ireland and internationally. This work required a literature review which investigated the general aspects of rubble-mound structures, the coastal environment, and the theory of designing the structures’ layout, cross-section and impact upon the local shoreline as well as the subsequent environmental, economic and social impacts such a project might have. Furthermore detailed case studies have been undertaken on beaches in Ireland where rubble-mound beach stabilisation structures have been proposed or implemented. A computer programme has been developed capable of designing the structural layout and cross section for two forms of rubble-mound shoreline stabilisation structures, namely offshore breakwaters and groynes. The Rubble-mound Structure Analysis and Design System is also capable of predicting the shoreline response and the carbon footprint and cost of both structural systems. This system is based on the information presented in the literature review. RSADS has facilitated a detailed study into the sizing of Rubble-mound structure armour units which are the primary structural element of this form of coastal defence. This work has culminated in a detailed study of Youghal Beach in County Cork. This study has involved a beach level survey, and a detailed review of the coastal processes and existing coastal structures. Coastal structures which have been proposed for Youghal by Malachy Walsh & Partners have also been reviewed. Finally RSADS has been implemented to carry out a full design for the shoreline at Youghal resulting in a final proposal of a rock armoured rubble-mound groyne field. Finally the conclusions on the work carried out, future work and the topic in general are presented in the final chapter of this thesis."

An optimization method is proposed for the simultaneous design of structural and control systems using the equivalent static loads. The two structural and control systems are not completely independent and need to be considered in a unified fashion. Furthermore, an integrated system design is unavoidable to exhibit a good performance in the time domain. The analysis for the integrated system is conducted for the transient-state in a dynamic manner. The constraints for the structural and control systems are defined in the time domain as well. Therefore, a physically small scale problem in structural analysis easily becomes quite a large scale in an optimization problem. A new equivalent static loads (ESLs) method, which deals with the structural design variables as well as the control design variables, is proposed to solve physically large scale problems. A finite element dynamic equation is defined with control forces and a dynamic response optimization problem is formulated. Linear static response optimization is carried out with the ESLs. The control forces for the linear static response optimization are considered as design variables. Shape variables are utilized to handle the design variables for the control forces. Several examples are solved to validate the proposed method.

Building Information Modeling: Framework for Structural Design introduces a structure and architecture synergy (SAS) framework that helps develop and enhance the understanding of the fundamental principles of architectural analysis using building information modeling (BIM) tools. Based upon three main components: namely, the structural melody, structural poetry, and structural analysis, along with the BIM tools as the frame enabler, this new framework allows users to explore structural design as an art while also factoring in the principles of engineering. The framework stresses the influence structure can play in form generation and in defining spatial order and composition. By highlighting the interplay between architecture and structure, the book emphasizes the conceptual behaviors of structural systems and their aesthetic implications and enables readers to thoroughly understand the art and science of whole structural system concepts. Key Features: Is updated throughout Adds new exercises; cutting‑edge information on the use of AI, Machine Learning (ML), and modelling; and issues of sustainability. Presents the use of BIM technology as part of a design process or framework that can lead to a more comprehensive, intelligent, and integrated building design. Places special emphasis on the application of BIM technology for exploring the intimate relationship between structural engineering and architectural design. Includes a discussion of current and emerging trends in structural engineering practice and the role of the structural engineer in building design using new BIM technologies.

Advanced Composite Materials (ACM), such as Carbon Fiber Reinforced Plastics (CFRP), have a big potential for achieving a light-weight marine structure. However material design, structural design and fabrication technology should closely be entangled in achieving a significant weight saving.The present paper aims at developing a computer aided design and manufacturing system for advanced composite marine structures. The term “marine structure” is defined here as a shell structure in which stiffness and strength for out-plane pressure and light-weight are required such as in the case of high speed boats and America's cup challenging yachts.First, this paper reports on design, manufacturing and evaluation of an ultra light-weight sailing dinghy with the use of ACM. Honeycomb sandwich structure, whose skin and core materials are angle-plied unidirectional carbon fiber reinforced epoxy and Nomex honeycomb, respectively, is adopted as the hull and deck structure. A successful application of CAD/CAE/CAM technology leads to remarkable weight reduction as large as 70 perecent of the conventional GFRP dinghy. The stiffness and strain distribution of the actual ship structure was measured and compared with the computational values and structural performance was confirmed.Second, a concept was proposed on the application of CAD/CAE/CAM technology to advanced composite marine structures. For example, definition of orientation angles, structural analysis of sandwich shells and material data base should be included in this system.

The present paper aims at developing a computer aided design and manufacturing system for advanced composite marine structures, that is, shell structures in which stiffness and strength for outplane pressure and lightweight are achieved by making efficient use of advanced composite materials.In the previous report, some specialized prototypes of CAD/CAE system for laminated materials were developed by means of object oriented language. However, a general-purpose finite element analysis program is used temporarily as analysis code. Such a general-purpose program has some problems in handling anisotropic laminated composites and not suitable for effective design and analysis in the developed systems.In this report, a finite element is formulated as a thick shell element, in which special attention is paid to anisotropic principal axes, which are one of the most important characteristic of composite materials. This formulation allows to change fiber direction in a element, by using shape function for anisotropic principal axes.Some examples are demonstrated, and it shows that the developed system is effective in analyzing anisotropic laminated materials.

A lower limb prosthetic knee joint based on MR damper is designed, and the designed lower limb prosthetic knee joint is parameterized. On this basis, build the knee joint test platform of lower limb prosthesis, collect the angle data of knee joint, and carry out the corresponding experimental research on the movement of knee joint of lower limb prosthesis. The test results show that the structural design and control system of lower limb prosthetic knee joint are reasonable, which can realize the normal walking gait of the disabled in daily life, and the designed lower limb prosthetic knee joint meets the normal needs of human body. It has certain significance and value in the field of motion control of medical equipment and lower limb prosthesis.

This note is a continuation of the work in [J. Comput. Math., 6 (1988), pp. 28–38]. The directional derivatives of multiple eigenvalues of a symmetric eigenproblem analytically dependent on several parameters are given. The result can be used to define the sensitivity of multiple eigenvalues, and it is useful for investigating structural vibration design and control system design.

Prepared on behalf of the Task Group 1 on Life-Cycle Performance of Structural Systems Under Uncertainty of the Technical Council on Life-Cycle Performance, Safety, Reliability and Risk of Structural Systems of the Structural Engineering Institute of the American Society of Civil EngineersStructural engineering is facing a profound change toward a life-cycle oriented design philosophy in order to address the continuously increasing societal, political, economic, and environmental demand for sustainable structural and infrastructural facilities that minimize risks arising from aging, deterioration, and natural and human-made hazards. Life-Cycle Design, Assessment, and Maintenance of Structures and Infrastructure Systems is a state-of-the-art comprehensive report outlining the current status and research needs in life-cycle of civil structure and infrastructure systems. This book examinesPhysical, chemical, and mechanical processes involved in the degradation mechanisms of concrete and steel structures located in severe environments; Methods and strategies for life-cycle design and assessment of deteriorating structural systems under uncertainty; Life-cycle management concepts for structures and infrastructure networks under uncertainty and the application of such concepts in management process; and Principles and implications associated with the scheduling and application of maintenance policies for deteriorating structures and infrastructure networks. This book serves as a valuable resource to engineers, managers, and government agencies concerned with life-cycle design and maintenance of civil structures and infrastructure systems.