Browsing by Subject "FMI"

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    Integrated System Architecture Development and Analysis Framework Applied to a District Cooling System
    (2020-12) Dalvi, Akshay Satish; El-Mounayri, Hazim; Razban, Ali; Anwar, Sohel
    The internal and external interactions between the complex structural and behavioral characteristics of the system of interest and the surrounding environment result in unpredictable emergent behaviors. These emergent behaviors are not well understood, especially when modeled using the traditional top-down systems engineering approach. The intrinsic nature of current complex systems has called for an elegant solution that provides an integrated framework in Model-Based Systems Engineering. A considerable gap exists to integrate system engineering activities and engineering analysis, which results in high risk and cost. This thesis presents a framework that incorporates indefinite and definite modeling aspects that are developed to determine the complexity that arises during the development phases of the system. This framework provides a workflow for modeling complex systems using Systems Modeling Language (SysML) that captures the system’s requirements, behavior, structure, and analytical aspects at both problem definition and solution levels. This research introduces a new level/dimension to the framework to support engineering analysis integrated with the system architecture model using FMI standards. A workflow is provided that provides the enabling methodological capabilities. It starts with a statement of need and ends with system requirement verification. Detailed traceability is established that glues system engineering and engineering analysis together. Besides, a method is proposed for predicting the system’s complexity by calculating the complexity index that can be used to assess the complexity of the existing system and guide the design and development of a new system. To test and demonstrate this framework, a case study consisting of a complex district cooling system is implemented. The case study shows the framework’s capabilities in enabling the successful modeling of a complex district cooling system. The system architecture model was developed using SysML and the engineering analysis model using Modelica. The proposed framework supports system requirements verification activity. The analysis results show that the district chiller model developed using Modelica produces chilled water below 6.6 degrees Celsius, which satisfies the system requirement for the district chiller system captured in the SysML tool. Similarly, many such requirement verification capabilities using dynamic simulation integration with the high-level model provides the ability to perform continuous analysis and simulation during the system development process. The systems architecture complexity index is measured for the district cooling case study from the black-box and white box-perspective. The measured complexity index showed that the system architecture’s behavioral aspect increases exponentially compared to the structural aspect. The systems architecture’s complexity index at black-box and white-box was 4.998 and 67.3927, respectively.
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    Integrated System Architecture Development Framework and Complexity Assessment
    (ASME, 2021-11-01) Dalvi, Akshay S.; El-Mounayri, Hazim; Mechanical and Energy Engineering, School of Engineering and Technology
    Systems engineering is the popular top-down systematic approach to understand and develop complex systems. There is a gap between the systems engineering activities and engineering analysis in major system development processes. This paper presents an integrated MBSE development framework with definite and indefinite modeling capabilities to bridge this gap. The framework uses SysML, a system modeling language, to describe its elements from the system architecture’s perspective. A detailed workflow is presented that guides the engineer throughout the modeling process. The workflow establishes traceability throughout the framework. This research uses Functional Mock-up Interface (FMI) standards to integrate system engineering activities and engineering analysis. A district cooling system case study is presented to demonstrate the framework’s capabilities in enabling the system into existence. The system architecture model was developed using SysML language in the Cameo Enterprise Architecture environment. The engineering analysis model used object-oriented Modelica language in the Dymola environment. The analysis results show that the district chiller model developed using Modelica produces chilled water below 6.6 degrees Celsius, satisfying the district chiller’s system requirement. The exponential trend in the system architecture’s complexity pattern is measured and analyzed using complexity assessment techniques. The results show that the structural complexity of the system increases steadily from 2.7080 to 8.1241. However, the behavioral complexity increases drastically from 1.7915 to 59.2686 in the problem domain.