Papers by Author: Dong Xing Cao

Abstract: This paper proposes an improved computational algorithm for structure topology optimization. It integrates the merits of Evolutionary Structure Optimization and Level Set Method (LSM) for structure topology optimization. Traditional LSM algorithm has some drawbacks, for instance, its optimal topology configuration is largely dependent on the structural topology initialization. Additionally, new holes cannot be evolved within the updated topology during the optimization iteration. The method proposed in this paper combines the merits of ESO techniques with the LSM scheme, allowing new holes to be automatically inserted in regions with low deformation energy at prescribed iterations of the optimization. The nodal neighboring region is a good selection. For complex structures in which holes cannot be properly inserted in advance, the proposed method considerably improves the ability of LSM to search the optimal topology. In addition to achieving more accurate results, the proposed method also yields higher efficiency during optimization. Benchmark problems are presented to show the effectiveness and robustness of the new proposed algorithm.

Abstract: Existing conceptual design methods mainly focus on component modeling and representation, which makes them insufficient to help in the conceptual design stage. Port ontology, as an approach to formally expressing product design, has been effectively applied to concept description of a product. An incidence matrix support for product conceptual design based on port ontology is given in this paper. It formally represents and organizes product information in both functional ontology and physical domain in a hierarchy. Port compatibilities are used to map and link the two components. This makes it possible to build incidence matrix and decompose it into an independence matrix, and allow designers from different backgrounds with various interests to access the design ontology. A multilevel matrix is constructed to generate principle schemes of products at different levels of abstraction, which facilitates design decision-making through the whole conceptual design stage. A case study is also given to demonstrate the proposed approach.

Abstract: In today’s highly volatile global market, design activities become more and more important in the whole lifecycle of product. The process of different developments should adopt appropriate modeling approaches at each stage. Different modeling technologies exert a great impact on different design stages. Therefore, modeling design is crucial to achieve success in the process of product development. This paper presents an integrated modeling of design process for product development. Its objective is to realize concurrent design towards ever-growing demands of market that has already integrated design process and production activities. It can manage to develop product towards early design activities. Different design stage model relations and activities are presented for product development. At first, the characteristics of different development stages are analyzed. The performances and attributes of product are established through considering component, constraints and environment. Second, the process of product modeling is described in detail for early design, and the time interval between the two activities is evaluated for concurrent engineering during the design modeling. Third, a promising framework is given to describe the process of design. Finally, an application example and knowledge are presented to illustrate the process of product development.

Abstract: Configuration design lies in the later stage of the conceptual design. It affects the downstream of design process and decides product structure. Therefore, it is necessary to pursue an approach to support such design stage activities. Port, as the location of intended interaction, plays an important role in the configuration design, which abstractly represents the intended exchange of signals, energy or material in a convenient way. Ontology is an unambiguous and flexible semantic specification corresponding entities, and it can effectively describe the function of port. In this paper, we firstly give port concept and port functional description, and their semantic synthesis is used to describe port ontology. Second, we build an ontology repository which contains the assorted primitive concepts and primitive knowledge to map the component connections and interactions. Meanwhile we provide a model of port-based multi-views which contains functional view, behavior view and configuration view, and gives the attributes and taxonomy of ports. Next, a port-based ontology language (PBOL) is described to represent the process of port ontology refinement, and a port-based FBS modeling framework is presented to describe system configuration. Finally, a revised tape case is given to show the application of the port-based ontology.