Development of Computer Aided Design and Manufacturing System for Advanced Composite Marine Structures

Recently, a structural optimization design system linked with a FEM analysis system is going to be useful for a structural design, by a radical development of a computer environment. But, when structural engineers use this design system in practice, complicated operations are required to make an input-data. So this design system is not “a Practical Tool” for designers, we have to develop the structural optimization design system which is used easily for designers.Authors research the CIM for shipbuilding and develop a prototype CIM system. We call this system SODAS (System Of Design and Assembling for Shipbuilding). In the SODAS, designers can design a ship structure by design parameters and evaluate a designed structure by FEM directly.In this study, authors try to integrate a commercial structural optimization design system (GENESIS : which is developed in NASA) with the SODAS. We make relations clear between design parameters in the SODAS and design variables in the structural optimization design system. And we propose the method of system integration used by these relations. In the concrete, we develop the structural optimization design system based on the Product Model which supports designers powerfully by presenting optimal design-values.

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.

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

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 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."

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.

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...

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 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.

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.

Zhangzhou Opera House adopts the complex structure system of petal shape. According to the building shape and architectural layout, the structure combines the steel truss for large-span space and the frame-shear wall structure surrounding. This article introduced its structural system, multi-line defense line arrangement and anti-seismic performance objectives, and summarized the structural characteristics of the overall structure, especially focusing on key issues such as setting the ring floor beam to resist the extroversive forces, anti-seismic performance of key components and the design of the junction between the steel truss and concrete structure. The results show that the structure has strong adaptability to the building shape with suitable seismic performance, and fulfilling both the requirements of seismic performance design and the structural safety.

A user-friendly software system, UNIQUIMER 3D, was developed to design DNA structures for nanotechnology applications. It consists of 3D visualization, internal energy minimization, sequence generation and construction of motif array simulations (2D tiles and 3D lattices) functionalities. The system can be used to check structural deformation and design errors under scaled-up conditions. UNIQUIMER 3D has been tested on the design of both existing motifs (holiday junction, 4 × 4 tile, double crossover, DNA tetrahedron, DNA cube, etc.) and nonexisting motifs (soccer ball). The results demonstrated UNIQUIMER 3D's capability in designing large complex structures. We also designed a de novo sequence generation algorithm. UNIQUIMER 3D was developed for the Windows environment and is provided free of charge to the nonprofit research institutions.

A new general-purpose computer program for optimum structural design synthesis is developed. Its principal components are, in general terms, optimizer and analyzer routines. The analyzer routine provides considerable flexibility and efficiency in the computational treatment of structural design problems. Special processor interfacing of the analyzer to the optimizer is composed in the system. By applying this programming system, an optimum design problem on the framed structure of the motor cycle to find the framed structure that will maximize the torsional rigidity subject to the constant volume, is studied.

Conceptual design of structural systems based on topology optimization and prefabricated components