摘要 :
Multi-disciplinary analysis and optimization (MDAO) has been a long-standing goal in the aerospace community. In order to employ MDAO effectively, one needs to be able to compute the sensitivity of the objective function with resp...
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Multi-disciplinary analysis and optimization (MDAO) has been a long-standing goal in the aerospace community. In order to employ MDAO effectively, one needs to be able to compute the sensitivity of the objective function with respect to the driving parameters in a robust and efficient manner. Over the past decade there have been considerable efforts towards the generation of "adjoint" versions of flow solvers in order to help in this process. Unfortunately, the corresponding efforts have not been expended in the geometry and grid generation processes, especially when the geometries are generated parametrically with a modern computer-aided design (CAD) or CAD-like system. Contained herein is a pair of complementary techniques for computing configuration sensitivities directly on parametric, CAD-based geometries. One technique computes the configuration sensitivity analytically by differentiating the geometry-generating process; the other employs a new finite-difference technique that overcomes the difficulties previously encountered. Modifications to the Engineering Sketch Pad (ESP) (which is built on top of OpenCSM, EGADS, and OpenCASCADE) are described. Then the use of these configuration sensitivities in the computation of the sensitivity of grid-points is discussed. The results of these new techniques are shown on several configurations.
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摘要 :
Multi-disciplinary analysis and optimization (MDAO) has been a long-standing goal in the aerospace community. In order to employ MDAO effectively, one needs to be able to compute the sensitivity of the objective function with resp...
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Multi-disciplinary analysis and optimization (MDAO) has been a long-standing goal in the aerospace community. In order to employ MDAO effectively, one needs to be able to compute the sensitivity of the objective function with respect to the driving parameters in a robust and efficient manner. Over the past decade there have been considerable efforts towards the generation of "adjoint" versions of flow solvers in order to help in this process. Unfortunately, the corresponding efforts have not been expended in the geometry and grid generation processes, especially when the geometries are generated parametrically with a modern computer-aided design (CAD) or CAD-like system. Contained herein is a pair of complementary techniques for computing configuration sensitivities directly on parametric, CAD-based geometries. One technique computes the configuration sensitivity analytically by differentiating the geometry-generating process; the other employs a new finite-difference technique that overcomes the difficulties previously encountered. Modifications to the Engineering Sketch Pad (ESP) (which is built on top of OpenCSM, EGADS, and OpenCASCADE) are described. Then the use of these configuration sensitivities in the computation of the sensitivity of grid-points is discussed. The results of these new techniques are shown on several configurations.
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摘要 :
Aerospace vehicle design can be described as an evolutionary process of gathering information to make informed decisions. Meticulous application of this process involves numerous simulations covering many disciplines and fidelity ...
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Aerospace vehicle design can be described as an evolutionary process of gathering information to make informed decisions. Meticulous application of this process involves numerous simulations covering many disciplines and fidelity levels. A design team needs to be able to easily increase or decrease fidelity as they gather more information about a particular design. To this end a geometry system that can support multi-disciplinary, multi-fidelity analysis from a single source is required. The Computational Aircraft Prototype Syntheses (CAPS), which is a part of the Engineering Sketch Pad (ESP), satisfies the above by combining proven computational geometry, meshing, and analyses model generation techniques into a complete browser-based, client-server environment that is accessible to the entire design team of an aerospace vehicle. CAPS links analysis and meshing disciplines to any ESP geometry model via dynamically-loadable Analysis Interface Module (AIM) plugins. CAPS is accessed from either a browser-based user interface and or Multi-Disciplinary Analysis and Optimization (MDAO) framework through a programing interface. In this paper we describe the fundamental building blocks of CAPS and ESP. The paradigm shift of creating geometry for multi-fidelity design is described in detail and represented in ESP scripts. We then demonstrate the use of this multi-fidelity geometry to support multi-fidelity, multi-physics analysis including discipline coupling.
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摘要 :
Aerospace vehicle design can be described as an evolutionary process of gathering information to make informed decisions. Meticulous application of this process involves numerous simulations covering many disciplines and fidelity ...
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Aerospace vehicle design can be described as an evolutionary process of gathering information to make informed decisions. Meticulous application of this process involves numerous simulations covering many disciplines and fidelity levels. A design team needs to be able to easily increase or decrease fidelity as they gather more information about a particular design. To this end a geometry system that can support multi-disciplinary, multi-fidelity analysis from a single source is required. The Computational Aircraft Prototype Syntheses (CAPS), which is a part of the Engineering Sketch Pad (ESP), satisfies the above by combining proven computational geometry, meshing, and analyses model generation techniques into a complete browser-based, client-server environment that is accessible to the entire design team of an aerospace vehicle. CAPS links analysis and meshing disciplines to any ESP geometry model via dynamically-loadable Analysis Interface Module (AIM) plugins. CAPS is accessed from either a browser-based user interface and or Multi-Disciplinary Analysis and Optimization (MDAO) framework through a programing interface. In this paper we describe the fundamental building blocks of CAPS and ESP. The paradigm shift of creating geometry for multi-fidelity design is described in detail and represented in ESP scripts. We then demonstrate the use of this multi-fidelity geometry to support multi-fidelity, multi-physics analysis including discipline coupling.
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摘要 :
There has been a tendency in the last decade to transition from single-discipline to multi-disciplinary analysis and design; this trend has been hastened by the increased availability of analysis and optimization frameworks that m...
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There has been a tendency in the last decade to transition from single-discipline to multi-disciplinary analysis and design; this trend has been hastened by the increased availability of analysis and optimization frameworks that manage the workflow. But one of the enabling technologies that is needed has not received much attention: that is, the need to transfer information from the surface of one representation to another, with particular emphasis on transferring the data conservatively. Described herein is a new method for performing such transfers. It is based upon two key technologies: a universal view of solver discretizations and a new optimization-enabled conservative fitting technique. The scheme is fully described and demonstrated in one dimension; then the extension to two dimensions is discussed along with results.
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摘要 :
There has been a tendency in the last decade to transition from single-discipline to multi-disciplinary analysis and design; this trend has been hastened by the increased availability of analysis and optimization frameworks that m...
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There has been a tendency in the last decade to transition from single-discipline to multi-disciplinary analysis and design; this trend has been hastened by the increased availability of analysis and optimization frameworks that manage the workflow. But one of the enabling technologies that is needed has not received much attention: that is, the need to transfer information from the surface of one representation to another, with particular emphasis on transferring the data conservatively. Described herein is a new method for performing such transfers. It is based upon two key technologies: a universal view of solver discretizations and a new optimization-enabled conservative fitting technique. The scheme is fully described and demonstrated in one dimension; then the extension to two dimensions is discussed along with results.
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摘要 :
Within the multi-disciplinary analysis and optimization community, there is a strong need for browser-based tools that provide users with the ability to visualize and interact with complex three-dimensional configurations. This ne...
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Within the multi-disciplinary analysis and optimization community, there is a strong need for browser-based tools that provide users with the ability to visualize and interact with complex three-dimensional configurations. This need is particularly acute when the designs involve shape- and/or feature-based optimizations. Described herein is a family of open-sources software products that provides such a capability. At the top is a browser-based system, called the Engineering Sketch Pad (ESP), which provides the user the ability to interact with a configuration by building and/or modifying the design parameters and feature tree that define the configuration. ESP is built both upon the Web Viewer (which is a WebGL-based visualizer for three-dimensional configurations and data) and upon OpenCSM (which is a constructive solid modeler; it in turn is built upon the EGADS and OpenCASCADE systems). Each of these open-source software components are described as well as the interactions amongst them.
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摘要 :
Within the multi-disciplinary analysis and optimization community, there is a strong need for browser-based tools that provide users with the ability to visualize and interact with complex three-dimensional configurations. This ne...
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Within the multi-disciplinary analysis and optimization community, there is a strong need for browser-based tools that provide users with the ability to visualize and interact with complex three-dimensional configurations. This need is particularly acute when the designs involve shape- and/or feature-based optimizations. Described herein is a family of open-sources software products that provides such a capability. At the top is a browser-based system, called the Engineering Sketch Pad (ESP), which provides the user the ability to interact with a configuration by building and/or modifying the design parameters and feature tree that define the configuration. ESP is built both upon the Web Viewer (which is a WebGL-based visualizer for three-dimensional configurations and data) and upon OpenCSM (which is a constructive solid modeler; it in turn is built upon the EGADS and OpenCASCADE systems). Each of these open-source software components are described as well as the interactions amongst them.
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摘要 :
This paper examines the desirability and the challenges of incorporating high-fidelity geometry definition into the Multidisciplinary Design, Analysis and Optimization (MDAO) process earlier than currently practiced. A major objec...
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This paper examines the desirability and the challenges of incorporating high-fidelity geometry definition into the Multidisciplinary Design, Analysis and Optimization (MDAO) process earlier than currently practiced. A major objective is the ability to enable geometry definition for low-fidelity as well as high-fidelity analyses, in order to support the entire MDAO process from conceptual to detail design in a seamless manner. Another objective is the ability to support different disciplines such as both structural and aerodynamic analyses from the same geometry definition. Finally, there are the goals of ease of use and support for automation to minimize unnecessary or repetitive human effort. It is argued that Constructive Solid Geometry (CSG) is the natural foundation for attaining these goals. Two different current user-level approaches which employ CSG at low level are considered: 1) CAD systems and their "feature" based view of construction, and 2) Bottom-Up methods which generate solid "components". Although Bottom-Up methods do not have the turn-key features of commercial CAD systems, it is clear that their flexibility and potential open nature is an advantage in the long term, especially if geometric design-gradient information is required for optimization. To realize the MDAO objectives via the Bottom-Up approach, a new software suite, the Electronic Geometry Aircraft Design System (EGADS), has been developed. It is a relatively simple and compact Open-Source Object-Based API built on top of the extensive OpenCASCADE solid-modeling kernel. EGADS routines implement relatively high-level operations which insulate the user from OpenCASCADE's size and complexity, and for maximum flexibility can be driven by either C, C++, or FORTRAN user applications. The basic features and constructs of EGADS are described, and an example application is presented to demonstrate its capabilities and effectiveness.
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摘要 :
This paper examines the desirability and the challenges of incorporating high-fidelity geometry definition into the Multidisciplinary Design, Analysis and Optimization (MDAO) process earlier than currently practiced. A major objec...
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This paper examines the desirability and the challenges of incorporating high-fidelity geometry definition into the Multidisciplinary Design, Analysis and Optimization (MDAO) process earlier than currently practiced. A major objective is the ability to enable geometry definition for low-fidelity as well as high-fidelity analyses, in order to support the entire MDAO process from conceptual to detail design in a seamless manner. Another objective is the ability to support different disciplines such as both structural and aerodynamic analyses from the same geometry definition. Finally, there are the goals of ease of use and support for automation to minimize unnecessary or repetitive human effort. It is argued that Constructive Solid Geometry (CSG) is the natural foundation for attaining these goals. Two different current user-level approaches which employ CSG at low level are considered: 1) CAD systems and their "feature" based view of construction, and 2) Bottom-Up methods which generate solid "components". Although Bottom-Up methods do not have the turn-key features of commercial CAD systems, it is clear that their flexibility and potential open nature is an advantage in the long term, especially if geometric design-gradient information is required for optimization. To realize the MDAO objectives via the Bottom-Up approach, a new software suite, the Electronic Geometry Aircraft Design System (EGADS), has been developed. It is a relatively simple and compact Open-Source Object-Based API built on top of the extensive OpenCASCADE solid-modeling kernel. EGADS routines implement relatively high-level operations which insulate the user from OpenCASCADE's size and complexity, and for maximum flexibility can be driven by either C, C++, or FORTRAN user applications. The basic features and constructs of EGADS are described, and an example application is presented to demonstrate its capabilities and effectiveness.
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