Implementation of Web Based Collaborative Product
Development System using STEP/ XML / X3D
Emphasis on Mechanical Design and FE Analysis
Balakrishna Adavi
1,Dr D.Nageswara Rao
2,Prof V.Raja Rao
1,Suresh Babu
Ratnala
11 Mechanical Department, SRKR Engineering College Bhimavaram-534204
2 Mechanical Department, AU College of Engineering Vshikhapatnam
Abstract
The pressure on organizations to shorten product development cycle time, the key challenge is to extract important design information from their CAD system in a form of model data that enables it to be distributed and use by all the departments across their workgroup and extended enterprise. The CAD models not only provide visual confirmation of the product’s features and configuration, but also streamline the design process. The value of the Product Data Management (PDM) solution is largely determine by the ease with which it can be integrate with other applications, particularly CAD systems. The PDM solution should be tightly integrated not only with CAD system but also with every
application supports the product development process to meet the market needs as fast as possible. The integration between CAD and PDM systems at both application level and data level using toolkit of the CAD package and interface respectively is done for seamless data exchange. STEP (STandard for the Exchange of product model data) is the neutral format used for the data exchange. The data in PDM system database is further distribute to heterogeneous environment in the form of XML Schemas, which is key for inter-enterprise web based Collaborative Product Development system (CPDS). Hence, a framework to develop an interface program and web page to transfer the product data in the form of Extensible Markup Language (XML) for product data and FEA data and The eXtensible 3D (X3D) for visualization of 3D models through internet in anywhere in the enterprise especially from any CAD system to Ansys vice versa is presenting in the paper.
Introduction
Today’s industries face many challenges in this competitive world. In order to meet the competition in the market, the information technology and product’s innovative content has significant factors. The product makers expect to establish competitive advantage by introducing innovative product content that captures their customer’s imaginations and make their product offerings easier to sell. But competing on the basis of product innovation needs
• Develop your innovations at a reasonable cost. • Introduce new content ahead of the competition.
• Make certain that your breakthrough features comply with quality standards
To be enabling to meet these strategic objectives, visualizing and validating of product design is a collaborative solution that optimizes the early stages of the product lifecycle, which are crucial to product innovation. Hence, the product data exchange between the automation systems becomes a mandatory issue for an integrated product development scenario.
The increase in information sharing, led by multi site distribution of activities and by extended enterprise approaches implemented in many companies, emphasizes the requirements of means and tools supporting collaborative work in a remote organization [1]. Concurrent engineering and collaborative design methods and tools contribute widely to simplify the development of remote and distributed works [2]. Concurrency and distribution of tasks become synonymous with success because of the increasing needs for reactivity and competitiveness for companies. Web technologies represent one of the most powerful tools of exchange, pooling, and distribution of information between project’s team members [3, 4].
The aim of CPDS is the right information in the right format for the right people in the right location at the right time. The attempt of this paper is to present a web based collaborative product development system that would enhance the sharing of Computer Aided Design (CAD) and Finite Element Analysis (FEA) data. In the following section, the emphasis on using web technologies more widely in
mechanical product design is shown. Then the web based collaborative product development system and its main features are detailed.
Review of Web Based CPDS in Mechanical Design and FE
Analysis
Web-based product data exchanges have a strong development because of the interest shown by manufacturers, co-contractors, partners, and suppliers who find there the ideal support of concurrent engineering, extended enterprise, and collaborative design [5, 6]. Concurrent engineering introduced the need of tasks distribution and concurrency of activities between several project team members. Extended enterprise required remote work between project teams split up on worldwide units. Lastly, collaborative engineering reinforced the use of information and communication technologies in order to support communication, coordination, and cooperation between project teams in charge of product development.
The large range of software and computer systems and of, intrinsically, legacy file formats raises important difficulties in data exchange, reading, translation, and viewing, especially in a remote mode. To try to solve these matters especially in a web-oriented approach, numerous technologies or standards format come to maturity, such as PHP and XML [7] for dynamic processing of web based product data, VRML [8, 9, 10] or 3D XML [12] for 3D viewing within web applications, and STEP [12, 13] for product information exchanges.
EVOLUTION OF MECHANICAL DESIGN ACTIVITIES
Based on the concepts issued from concurrent engineering, extended enterprise and CPDS approaches, the mechanical engineering activities, which were originally co-localized and mainly sequential, turn henceforth to distribution and concurrent planning of activities in order to reduce costs and lead times as well as to enhance reactivity ability. This evolution of working modes and organizations become one of the main strengths of business and corporate integration. This integration is now mainly based on right information for proper communication allowing taking advantage, remotely and at a lower cost, of skills and knowledge while they are physically far away. Regarding collaborative engineering, simultaneous carrying out of tasks by geographically distant project teams is henceforth enabling. This leads to the needs in improving the project management (tasks concurrency) and enabling the co-working of geographically distributed teams. However, it means numerous exchanges of information, which come along with further difficulties. Then, the teams also require the setting up of an efficient management and sharing of information, and remote viewing of data. The question of physical support to be chosen for data exchange security and for file format remains important. Regarding the method of data transferring, Internet stands out because of its universality in communication and exchange. For example, numerous systems of product lifecycle management (PLM) or collaborative engineering are either entirely Web-based, or they provide a thin Web client [14].
WEB TECHNOLOGIES INTEGRATION WITHIN MECHANICAL
DESIGN AND FE ANALYSIS FIELDS
By historical practice and organizational inheritance, mechanical companies often split up engineering design and FE analysis activities [15]. However, in collaborative engineering, these activities should be integrated and merged [16]. The departments involved in a project frequently have to exchange their own works in order to share or to comment on their respective issues. Furthermore, subcontracting development activities toward engineering consultancy companies create strong needs for information sharing between the original equipment manufacturer and its suppliers. On the contrary, to gain reactivity and quality in their performances, those late try to get customer validation as soon as possible on a 3D CAD file, on a preprocessing FEA model or on a preliminary analysis result. Computer Aided Design models are used as analysis input; then the post-processing results, sometimes, lead to the change of the original CAD model. Information transfer is thus bidirectional shown in figure 1. , and is generally made via a LAN or by Internet. Exchanged data between both fields often require adequate processing, standards, and software allowing the files translation. Regarding a simple viewing approach, it would be interesting to get these data available simply for the right users.
Figure 1. Bi-Directional data exchange
Boundary of Collaborative Product Development System
Collaborative Product Development system can be achieved by collaboration and sharing of the product data between different PDM/CAD and other systems. There are certain hurdles in achieving the Collaborative Product Development. As mentioned above the CAD data of a product provides required visual confirmation at any level of the product lifecycle. Such CAD data can be use by any product development systems in introducing the innovative product content at right time, which allows shortening the product lifecycle. Hence, the CAD data is to be made available to all the product development systems and different PDM systems as well in Collaborative Product Development shown in figure2.
Figure 2. Collaborative Product Development System.
Web Based Product Data Exchange in CPDS
To exchange the product data between a CAD system and a PDM system, the schema mapping on the conceptual level must be considered. Generally, any PDM system consists of schema. Assembly and component are considered as the part identification schemas in PDM system. The mapping between STEP entities and schemas of PDM system and generate XML data using interface program. To
transfer the product data created in a CAD system to a PDM system to Enterprise System shown in figure 3. This data can be transfer/extract easily by any CAD designer anywhere in the enterprise. Here we find some disadvantage for transferring the model data in the neutral format STEP.
• Each PDM system has maintain a server to/from transfer the data to individual CAD systems. Therefore, enterprise should maintain more than one PDM system. It is unnecessary to maintain more servers for STEP data translation.
• If CAD designer wants information other than product data, they send that query to PDM system that to enterprise system. It is a time taking process.
To overcome above said problems the best format for data exchange is XML (Extensible Markup Language). Now a days Internet is available at cheaper cost. If product data is in the form of XML tags, we can reduce the individual server systems by interacting CAD designer directly to the enterprise main server through internet see in figure 3.
Figure3. Data exchange in CPDS
Web Based CPDS between Mechanical Design and FE
Analysis
Nowadays, products lead times are a key factor of competitiveness. In product development cycle, many companies practice iterative exchanges: a 3D CAD model is issued and updated during the whole project lifecycle; decisions are made during technical meetings and project reviews until the
manufacturing launch. In collaborative engineering, these iterative exchanges have to be minimized and project times reduced. Generally, various project team members have to check the design changes (project manager, designers, mechanical engineers, etc.). In such a context, many data exchanges and information sharing are required [16]. Three main needs are generally mentioned: right
communication, right coordination, and right cooperation.
• management of projects and distributed teams members (right coordination), • Remote viewing of CAD models and FEA results (right cooperation).
CPDS provides a friendly web page interaction with a project management workspace (teams, schedule and shared documents) and 3D visualization web page for CAD models.
Architecture
CPDS is developed based on three-tier client– server architecture [7] and on Open Sources technologies: IBM main server, VB and Java script interpreter, and MS Access database (Figure 4). CPDS consists of a set of VB and Java scripts, which allows structuring and storing information in the database. The software is only implemented on one server connected to the Internet or through the company Intranet, on which all the user workspaces are centralized via the database. Currently, users access the system by simply opening a Web browser. They visualize the features of 3D CAD models with a 3D XML plug-in [17]. This kind of architecture is especially relevant for CAD and FEA activities regarding collaborative engineering context [18].
Figure 4. Three tier architecture of CPDS
Main Functionalities
Regarding the basic needs for right communication, right coordination, and right cooperation, CPDS provides several functionalities in the form of Web pages. The interface program has been developed in VB-6. This interface program provides the web page for information display in 3D XML and the features for management in the form of XML, for various users’ access rights (administrator, co-worker, project manager, etc.).
Messages and Shared Files
As regards communication needs, each team member can create, publish, and erase messages as for ‘post-it’. These messages are shown on the web page via a selection of addressees to whom they are sent. The shared file module allows the exchange of files while they are under working version. This module can be compared to an interfaced FTP application or simply to a remote disk space.
Projects and Documents Management
In a virtual organization made up of numerous team members involved in many projects, data management can be difficult [21]. CPDS allows team members to have a very easy sharing of the required information. Projects and documents management provide useful functionalities for coordination between team members. Knowing the project title, schedule and tasks distribution, they can download necessary documents for their assigned activities.
DOCUMENTS BASE
Documents download/upload within the base can be carried out in two ways: (1) by closing a task for which a deliverable is required, or (2) by creating a new document index card. Several attributes are necessary for document download/upload in the base: project name, author, revision, document type, file, and description. The document management functionality allows team members to have concurrent data access and then carry their tasks simultaneously. When a document is used, its access for other team members is then read only; no overwriting is possible. Synchronous access is possible but document changes can only be asynchronous.
CAD and FEA Data Visualization
Lastly, concerning cooperation needs (currently with a free downloadable 3D XML plug-in), users can visualize 3D CAD models within the support of web page for checking design changes and carrying out asynchronous project review.
CAD MODEL
Browsing in CAD model is ensured by a hierarchical organization of the models, which allows selection of the parts for which visualization is needed. Then models can be handled in 3D with useful features, such as rotation, zoom, pan, and refit. Furthermore, information associated with CAD models, such as part names, comments, author name, and native version is available via respected web pages.
FEA MODEL
CPDS integrates viewing functionalities of FEA models in order to allow team members to read all information linked to FE analysis without having to implement FEA post-processor. Figure 5 shows the model of F1 Race Car shape displayed within the CPDS environment. Considering the need for remote review of FE analysis issues, all pre-processing information is available in the FEA viewing web page, meshing, strains, and boundary conditions applied to the model, material, and properties.
Figure 5. Model of F1 Race Car in Web page
Technology Survey for Developing a Dynamic User Interface
Creating dynamic Web pages interacting with the customized information display is the kernel of Web application, based on three-tier architecture. For the development of Web applications, several script languages are frequently used. For example, Active Server Page (ASP), Person Home Page (PHP),VB Script, Java Server Pages (JSP), Applet, Servlet, and JavaScript. Regarding the application needs, the use of a Server side scripting language to reduce the client side charge has been chosen. As the Applets and JavaScript scripts processing part are implemented on the client side, they do not meet thespecifications of the above-mentioned needs. Sun Microsystems developed the Java Server Pages (JSP) technology based entirely upon Java programming language. JSP is a better solution to generate dynamic Web pages in comparison to ASP (not compatible with all platforms), PHP (poor database
access functions, undeveloped library mechanism), JavaScript scripts, and Applets. Together, the JSP and Servlet technologies seem the most attractive alternative to develop dynamic Web
scripting/programming. Indeed, these solutions provide platform independence, enhanced
performances, splitting up of logic from display, and easier administration and use. Hence, all these elements validate the choice of the JSP and Servlet to develop a dynamic user interface. Figure 4 describes classical three-tier architecture with the possible technology implementations.
Survey of 3D Data Visualization Technology
The next step is to identify the most suitable technology for implementing the visualization module. This module must be able to create a virtual world to support a high interaction level with the user regarding collaborative engineering needs. Considering a 3D FEA model, the minimum interactivity is to be able to view this model from various perspectives. One of the main objectives is to use a viewer, which does not need huge hardware requirements and can run on a common personal computer (desktop or laptop). Last, the software must be portable and platform independent. The preliminary version of the CPDS visualization module was based on VRML, but the interactivity with users was satisfying. Then a survey was necessary to assess available technologies for improving the viewer.
Technology Review for 3D Viewing
VRML
Virtual Reality Modeling Language is a file format for describing interactive 3D objects and worlds. VRML is designed to be used on the Internet, intranet, and local client systems. VRML is also intended to be a universal exchange format for integrated 3D graphics and multimedia. The richness of VRML is due to its interaction and navigation capabilities and the fact that VRML objects can be hyperlinked to multimedia (image, text, video and audio) or HTML files, as well as to other VRML objects. However, it was not widely accepted and used as HTML because of the limitations and the rigidity of the standard. These limitations naturally led to the development of new Web3D formats including X3D, and legacy format, which are less rigid and thus more expandable [19].
X3D
The eXtensible 3D alias X3D aims to be the successor of the VRML. It is developed to solve the VRML problems while taking up the VRML functionalities and integrating new features and new possibilities for data visualization and data exchange (www.web3d.org). X3D is a significant step in the VRML evolution, defined to ensure the best functionalities of VRML and to be fully integrated with XML. In fact, XML seems to be the future file exchange standard for all applications over the Web. Currently, X3D lack programming language possibilities. Although it provides some means for data description, X3D is limited regarding data modification.
Choice of X3D
A growing number of engineers in the 3D modeling and design communities are using this technology for cross-platform, 3D graphics application development and deployment. The advantages of X3D are portability, efficient programming, and easy code modification, Advantages of browsing X3D models versus VRML ones are that they are faster, have significant improvement in visualization quality, interactivity, better ability for data storing.
Interface Program
Here we develop an interface program in VB-6 executed in server side that converts STEP file data, which can be generated in any modeling package like CATIA, PROE, IDEAS, UNIGRAPHICS, SOLIDWORKS and SOLIDEDGE, into valid XML data file, valid means including XML Scheme and XSLT file. This xml file directly link to the web page. This interface program we divided into two categories. One for product data (includes organization name, designer info and assembly data, analysis preprocessor data etc.) and second for 3D XML for browsing 3D models in web page. For converting STEP file to XML file we maintain the Express entity info as database in SQL shown in figure6.To enhance FEA data sharing and transfer via Internet developing a translator between ANSYS and X3D formats is under process. The chosen language for implementing this translator is VB-6 because of many implemented functionalities, appropriateness to Internet through VB Script.
Figure 6. Interface Program Developed in VB-6
Conclusion
Mainly this paper presents available web technologies in CAD and FEA. Using Internet as
communication support allows the implementation of new methods and tools enabling collaborative engineering in a remote and distributed design project approach. The implementation of CPDS is fully based on Internet and OpenSource features. It offers a fast and efficient access to the issues of Computer aided design and FE analysis. Another important subject is X3D format. If ANSYS upcoming versions include X3D as redirect plot controls option then the documentation is too easy because X3D file can easily attach to word document as well as power point presentation slide so that we can present our analysis in better. Our interface program concentrated on neutral format STEP so it is a generalized solution.
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