Modeling method and basic structure design of the

2022-10-02
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Dassault V5 product modeling method and basic structure design

Abstract

in the increasingly competitive shipbuilding industry, shipyards have been committed to improving their design process. Now, the progress of it software tools and it industry infrastructure has provided the functionality of friction coefficient that can be measured to break through the early market bottleneck of product utilization and improve the efficiency of ship design process. Therefore, while improving the design quality, it can also greatly reduce the cost and deliver the ship on schedule

in this article, we will focus on the "basic design" structural engineering stage. It extends from signing the "preliminary design" contract with the ship owner to the "detailed design" of the first segment to be assembled

we will introduce and describe in detail the following basic features and concepts of scientific and technological innovation through the engineering management functions provided by Dassault V5 shipbuilding solutions

· engineering management

· 3D rapid modeling and modification (modeling concept, design template reuse and Collaborative Engineering)

· weight and cost calculation (report extraction)

· strength analysis (grid generation)

· classification engineering drawing drawing (automatic annotation and graphic replacement)

· collaborative design with other departments (machine equipment layout, distribution system interference inspection)

· automatically transfer to the preparation of detailed design

this paper describes how V5 shipbuilding solutions support different methods and their related results (CAD, reports, etc.); And explain how these methods are connected with the upper and lower processes, and how to manage a large amount of data generated in collaborative operations and ship engineering design

introduction

in the past few years, the unpredictable economic situation of the shipbuilding industry has been hindering the commercial and technical realization of the process of shipyard globalization. In order to solve this difficulty, shipyards have to transform their construction process from two aspects: Management (subcontracting, collaborative design, etc.) and pure technology. Nowadays, this spontaneous enthusiasm to take countermeasures with the progress of science and technology is frustrated by the extremely fixed computer architecture and the diverse information system in the production field. In the past, these two aspects required a lot of investment to ensure that they are completely complete, and even today, this is an important part of the maintenance budget. Therefore, we can easily understand why shipyards are extremely reluctant to abolish those systems that have major defects and are unstable in themselves (lack of collaborative management, data duplication, outdated information, errors, etc.)

if the goal is to greatly improve the three factors inherent in any engineering project itself (namely, development cycle, cost and quality), then a complete solution based on the product model method and the evolving computer architecture is one of the key success factors. This article will focus on the benefits of this method by describing "basic design", a relatively important stage in the ship design process

hull design and macro

due to the characteristics and inherent differences of various types of ships, it is difficult to clearly describe the unique complexity of the ship design process in a few words, especially to define a general process that can be applied to the whole ship in advance. However, a certain number of macro processes can be determined in the value-added chain. The application boundary and time schedule of these macro processes change significantly with the changes of shipyard conditions and ship types

each macro process is defined by a group of product design states and represents the progress state of a project

· conceptual design

· basic design

· detailed design

· product, inspection and testing

· sea trial and delivery

· warranty period

in fact, because these macros overlap in a specific period of time, it is difficult to clearly define the boundary between them. The sequence and timing of these macros are described in a method in top down, which is specific to ship design. This method divides the hull into a certain number of system modules and can carry out the whole ship analysis. When these system modules can be further divided, they can be divided into some sub modules in turn, and finally parts or components installed on the deck. Finally, as the design continues, the number of molded objects and participants increases exponentially

basic structural design

basic design is a key stage in the ship design process. It is after the overall design (specify the specification stage proposed by the ship owner) and before the detailed design (generate the necessary through holes and prepare the overall structure stage of the product). In fact, the basic design has already started before the general layout plan is determined. This alternation in the production process requires the personnel of different departments of the shipyard to cooperate closely in adjusting the labor distribution, especially in this stage of the design process, the adjustment is numerous and very important

the goal of this stage is to determine the size of steel structural members and ensure that the construction process meets the existing classification society specifications. The steel structure includes all members bearing the overall strength of the ship (primary and secondary members) and structural elements bearing local strength and connecting members (openings, brackets, etc.)

at this stage, The main tasks are:

· study the midship cross-section

· draw the general structural drawing to be submitted to the Classification Society for review

· weight estimation

· hull overall and local structural modeling (beam model, finite element analysis, load, result post-processing)

· collaborative design with the shipyard design department (such as checking and approving the perforation information)

· prepare for the detailed design module

the repeated characteristics and various specifications of steel structures in the ship design process make them completely universal as long as they are defined accurately enough. Due to the limitation of outsourcing parts, all parallel steps need to be considered in advance, and these pragmatic restrictions on promoting bank enterprise cooperation and the combination of industry and finance will affect any decision to quickly find the best solution (for example, some large equipment, such as the main engine, must be ordered one year before it is installed on board, so it is very important to accurately calculate its volume in the engine room)

negotiate with classification society

classification society has been an extremely important service organization in the maritime industry since its establishment in the 18th century. In addition to their own work (ship classification and registration), in the past decade, classification societies have also developed computer-aided tools (veristar hull, ABS saferhull, primeship hull, etc.) to analyze structural stresses within the limits of allowable rules (yield, instability, fatigue, etc.)

these software are developed on the basis of the specifications and mathematical methods (direct strength calculation) of various classification societies to improve its performance and processability and become a special engineering plastic. The pre-treatment and post-treatment functions are developed to simplify its structural analysis. In short, ergonomics and ease of use have received special attention. The biggest defect of these software is that they are separated from the production process of the shipyard. Although CAD developers and classification societies have recently worked closely together and allowed the development of specific interfaces, these tools are still hardly universal with CAD

another important limitation is that different norms and rules are more or less different. Although IACS (International Federation of classification societies) recently issued a resolution on the unification of structural specifications for oil tankers and bulk carriers in the near future, standardization is still a long-term goal. After great efforts to adapt and haggling over various details, the shipyard must try to cope with this situation

shortening the preparation time in the early stage of ship delivery and being constrained by production tools make the optimization of this critical stage particularly important. The goal of this stage is to gradually reduce the number of negotiations with the classification society in order to reduce the time for approving the structural drawing

V5 PLM shipbuilding solution

overview

V5 PLM shipbuilding solution is a complete set of integrated application software covering many departments involved in the shipbuilding industry (such as structural design, cabin layout and outfitting equipment design, infrastructure design, mechanical equipment, pipeline design, ventilation pipeline design, electrical design and manufacturing). It supports collaborative design functions and can also provide fully integrated design processes and end-to-end solutions

v5 PLM shipbuilding solution is based on the database of components (Engineering Network Center), which integrates the relevant ship type data (detailed specifications, sketches, 3D components, documentation, rules, bill of materials, 2D engineering drawings, etc.) and even the data generated by third-party software (such as naval architect software) into the same engineering project folder. The engineering network center forms the product information center of the company, which can ensure the collaborative design, management, distribution and use of product definition information in a virtual extended enterprise

Figure 1 Composition of digital enterprise

in this method, the ship is described and decomposed into an aggregation of intelligent components, and each component contains a large amount of geometric and engineering information, including:

· component identification (such as creator, data, life cycle),

· classification (such as ship floor, elbow, pipeline, elbow, valve, pump),

· attributes

· graphical representation

· connectivity (such as the connection with the open deck and double bottom)

· reference documents (such as detailed specifications, engineering drawings)

· classification

· etc.

this system structure can ensure the creation of an accurate, meaningful and detailed hull virtual product model serving the whole life cycle. It can use a variety of flexible extraction methods (without introducing special pre-defined methods to divide the hull into segments, systems or regions) so that each functional department can easily access the database to obtain the data they need

product modeling and structural design process:

in most shipyards, the 3D representation of ships is generally limited to the detailed design module, while the basic structural design process is mainly based on 2D engineering drawings. In order to extract some data (such as weight calculation report, finite element analysis, etc.), 3D models generated based on 2D engineering drawing reference data are temporarily created

v5 PLM ship construction solution puts forward an important breakthrough from the perspective of implementation, and actually affects the whole process of ship structure design. In this method, every cycle of ship design is considered to be the completion of the given life cycle of the same and unique product model; Consistency and information flow are preserved in the engineering network, and constantly refined in order to avoid repetition, so it can improve production efficiency while reducing design errors

Figure 2 design process of hull structure

the accuracy of product model and the convenience of data acquisition by different design groups in ship projects help to raise some enlightening questions, which was usually too late in the past; On the other hand, it also accelerates the proposal of corrective measures

however, before shipyards or design institutes choose this method to organize production, they must first conduct an in-depth analysis of existing working methods, design and manufacturing processes and workflows. (end)

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