Online available since 2004Apr15 Development of a Knowledge-based Information Management Sy

Development of a Knowledge-based Information Management
System for Plant maintenance
Y. J. Park1, S. M. Lee1, H. S. Yim1, J. B. Choi1*,
Y. J. Kim1, E. C. Roh2 and B. I. Lee2
1 SAFE Research Centre, Sungkyunkwan University, Suwon, Kyonggi-do, Korea
2 Mechanical Engineering Dept., POSCO Gwangyang Works, Jeonnam, Korea Keywords: Plant Maintenance, Fatigue Life Evaluation, Fitness for Service, Plant Lifecycle Management, Knowledge-based Information System
ABSTRACT
In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. The system, which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance.
1. INTRODUCTION
Recently, the importance of plant maintenance(PM) was raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as risk-based inspection(RBI)[1], fitness for service guidelines(FFS)[2], plant lifecycle management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system, which was based on design data and regulation guides.
In this paper, a knowledge-based information system[3,4] for the plant operation of steel making company has been proposed. This system, which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP PM module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. K-VRS uses virtual plant, which provides 3-dimensional realistic information on each equipment. While the virtual plant is used for the management master of K-VRS, there are four engineering expert modules attached; engineering document management module, real time fatigue life estimation module, fitness for service module and risk-based inspection module. Each module
provides engineering knowledge based evaluation and judgment for more effective plant maintenance. K-VRS runs on internet WEB environment, and thus, provides collaborative and concurrent working interfaces to workers and relevant experts. Also, virtual reality environment, using 3D CAD data and virtual reality modeling language(VRML)[5], improves accessibility and recognizability of configurations of equipments. Fig.1 is the structural configuration of K-VRS. The system consists of 3 servers including application server, datawarehouse server and master server. The system connects engineering analysis module, technical data management module, ERP PM module together on the basis of VR plant.
Fig.1. The structural configuration of K-VRS Fig.2. The structure of virtual reality system
2. VIRTUAL REALITY BASED MANAGEMENT PLATFORM
2.1. 3D CAD Data
Most of plants consist of a great number of parts and assemblies. Therefore, it is difficult not only to search necessary informations including drawings and documents, but also to manage countless 2D drawings, 2D CAD data and related documents. In order to resolve these problems, a virtual plant is proposed. The developed VR models consist of 3 level structures as illustrated in Fig.
2. The upper group model is divided into sub models, and thus, a component can be managed efficiently by adapting this hierarchical structure.
The VR models have been produced by modifying 3-D CAD data. Currently, 3D-CAD softwares provide direct conversion of 3-D model data into a corresponding VR model and finite element mesh with slight modification. While the existing CAD data management system requires independent CAD data for 2-D drawings[6], 3-D VR models and 3-D CAD, the proposed system manages all CAD data generated from the same 3D-CAD model[7]. This system provides not only simple data management but also consistency among all CAD data.
2.2. Virtual Reality Plant
The VR plant has been developed by using an application program, Autodesk VIZ 4.0[8]. The virtual space was created in accordance with the structure of steel-making factory, and 3-D models were placed in corresponding positions. In order to provide virtual reality effect, light effects, mapping, camera views and events were assigned on the VR plant model. The camera views provide walk through navigation through major equipments. In this system, total of 8 camera views were installed covering converter part, ladle crane part and exterior of factory. The installed camera views use proxy sensor and thus operators can experience a walk through simulation from inside to outside of factory. Applying events on VR models, each model is designed to be connected into a more detail model, related database, and/or application programs. All VR models were translated into VRML(Virtual Reality Modeling Language) so that they can be assessed through internet. And also, each VR model can be connected independently into corresponding events by clicking
the
model on web browser. Fig. 3 shows 8 different camera views of virtual plant observed through internet web browser.
The VR plant is built on web environment, and provides menus for equipment maintenance on the web browser without extra program installation. The proposed VR plant manages all information on the server, and thus guarantees the data consistency. Informations on equipment maintenance include engineering analysis data, 2-D drawings, documents and knowledge-based expert application programs.
Fig.3. Camera views of virtual reality plant on a web browser
3. ENGINEERING KNOWLEDGE MODULES
3.1 Fatigue Life Evaluation
One of the most major components in steel-making factory is a ladle crane. It is critical to evaluate the fatigue lifetime of ladle crane, which carries melted iron. For this reason, an on-line fatigue life monitoring system for ladle crane was developed based on 3-D finite element analysis. As illustrated in Fig. 1, the proposed system connects to engineering knowledge modules including on-line fatigue life monitoring, fitness for service and risk based inspection modules.
3.1.1 Finite Element Analyses
In order to obtain stress distribution on a ladle crane during the normal operation, 3-D finite element analyses were performed. Ladle cane is manufactured by assembling thin plates in a box shape to produce high stiffness against high bending load. The finite element model, and thus, was prepared by applying shell elements. The verification pre-analysis showed a good agreement with theoretical solution[9]. Fig. 4 shows the finite element model for ladle crane. Boundary conditions were applied by considering rail-carrying conditions. Fig. 5 shows the applied constraints on main Fig.4. FE model of ladle crane using shell
elements Fig.5. Applied constraints on main and
auxiliary girder
girder and auxiliary girder. Loading conditions were adapted from the Korean standard. The total load was obtained by applying following equation:
)
(
)]
(
)
(
)
(
6.1[
2.1load
heat
load
horizontal
weight
load
lift
load
Total+
+
+
×
×
=(1) Analyses were performed for 7 different loading conditions considering the trolley’s movement. Fig. 6 shows the stress distributions of main and auxiliary girders, and Fig. 7 shows the calculated stress amplitude at a sampling point.
(a) Main girder (b) Auxiliary girder
Fig.6. Stress distribution of main girder and aux. girder
Fig.7. Stress amplitude at a sampling point
3.1.2 Verification Measurement
In order to verify the finite element analysis results, a strain measurement on a ladle crane was performed. Strain measurement was achieved at 3 points as illustrated in Fig. 8. Three axial strain gages and rosette gages were used respectively. The measurement data were obtained during the ladle crane operation. Fig. 9 shows a comparison between finite element analysis results and verification measurement at point #1. Both results showed a good agreement[10].
3.1.3 On-line Fatigue Life Monitoring Module
Using maximum stress amplitude obtained from finite element analyses, fatigue life evaluation
on the basis of Goodman method was performed. As shown in Fig. 10, the calculated stress amplitude values were located under the Goodman line[11]. However, most of highly stressed locations were appeared to be influenced by residual stress due to welding process. For this reason, residual stress was applied in the fatigue life evaluation. The amount of residual stress was determined in accordance with SINTAP[12]. Fig. 11 shows the fatigue life evaluation considering residual stress[13,14]. The most highly stressed location showed a finite fatigue lifetime. On the basis of resulting life time, an on-line fatigue monitoring system has been developed as illustrated in Fig. 12. The strain amplitude is monitored through an on-line monitoring system. Then, the remaining life is calculated by applying S-N curve. The remaining operation cycle is displayed on
the web browser, and is connected on the VR plant.
Fig.8. Strain measurement locations
Fig.9. Comparison between measurement and analysis results (point #1)
3.2 Technical Document Management System
Technical documents are crucial in the process of plant maintenance. The proposed system has been developed by applying PHP(Professional Hypertext Preprocessor), Linux-based MySQL database. The system provides technical document management through internet using a web browser. The database includes equipment codes, inspection schedule, maintenance records, drawings and engineering reports. All documents are connected to corresponding VR model, and
thus, users can assess required information through internet with intuitive graphic images. The proposed system is expected to provide real-time collaborative and cooperative working
environment
Fig.10. Fatigue assessment result using a
Goodman fatigue diagram(SS400)
Fig.11. Fatigue assessment results considering residual stress
Fig.12. Structure of on-line fatigue life
monitoring system
Fig.13. The connection between PM module
and VR environment using ERP database
4. INTERFACE TO ERP
The steel-making factory is currently running the business on ERP. The ERP PM module, however, only manages 2D based text informations such as equipment code, drawing number, equipment name, etc. The developed system connects ERP(Oracle) and ERP PM module(MAXIMO) by sharing equipment code number as illustrated in Fig. 13. Users, therefore, assess engineering informations, such as virtual model, CAD data, analysis report, etc. during the maintenance process assigned by ERP PM module. It also uses web browser to assess all informations, and thus, provides cooperative and concurrent virtual working environment for entire maintenance process.
5. CONCLUSIONS
In this paper, an engineering knowledge based information system for steel-making factory is
proposed. The developed system provides cooperative and collaborative working environment through internet by applying advanced information technologies. It consists of engineering knowledge modules, technical document management module and VR plant module. All modules are integrated on the basis of VR plant and the developed system is assessable through internet. The system also provides a connection to ERP. The proposed system is expected to be well suited for the knowledge based information society.
ACKNOWLEDGEMENT
The authors are grateful for the support provided by a grant from Safety and Structural Integrity Research Centre at Sungkyunkwan University
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