Papers by Author: Gang Zhao

Abstract: Experimental, analytical and finite element techniques are commonly known methods used in determining highly localized stress occurring in the body under loading as a result of geometric discontinuities. In this study, we use NURBS-based isogeometric analysis (IGA) to investigate the stress concentration factor (SCF) on three-dimensional geometry with discontinuity feature. The results show that IGA technique is in good agreement with analytical values, thus providing a more effective realistic way of determining SCF.

Abstract: Assembly Sequence Planning (ASP) is an essential question for aircraft assembly process design. Modern aircraft assembly contains plenty of complex shape components, which have so many assembly features to ensure, this leads to a large number of feasible assembly sequences using traditional sequence planning algorithms; and it is hard to evaluate the contribution to assembly quality for every sequence. A methodology called Key Characteristics Based ASP is proposed in this paper, which can significantly reduce unavailable sequences and ensure key features for quality in assembly process designing compared with previous methods. The methodology focuses on the final assembly quality and considers it as Assembly Key Characteristics (AKCs) in the beginning of assembly process design. With tools such as AKCs decomposition, Datum Flow Chain, precedence constraint matrix, the methodology describes the main process for ASP. To verify the technologys effectiveness, this paper presents an application of the algorithm in an aircraft component assembly by an 863 program.

Abstract: The design process comprises the Conceptual Phase, the Embodiment Phase and the Detail Design Phase in which commercial PLM/CAD systems mainly support the latter ones. This situation causes the discontinuity in the overall design information flow: Customer Needs (CNs) - Functional Requirements (FRs) – Design Parameters (DPs) – Key Characteristics (KCs) – Geometric Parameters (GPs). There is also a lack of knowledge reuse in routine design process, resulting in large cost-waste of the overall design process. Aiming to enhance the continuity of the design information flow and facilitate the knowledge reuse, this paper makes use of a knowledge-based framework to integrate conceptual design tools: Quality Function Deployment (QFD), Axiomatic Design (AD), Failure Mode and Effects Analysis (FMEA) and the MOKA methodology into CATIA v5 system. A knowledge-based application (KBA) on the large aircraft y-bolt component design is presented as a case study to validate the proposed framework. The result shows how this novel integrated framework and KBA system could benefit designers in a practical way.

Abstract: The aircraft parts contain the information of a great number of curves and surfaces, which makes it a big challenge for the aircraft components’ Assembly Sequence Planning (ASP) processes. The traditional interference matrix has limitation of expressing the assembly direction and can easily lead to the failure of ASP optimization. Hence, an improved interference matrix is provided in this paper to deal with the aircraft ASP problem based on the Genetic Algorithms (GA). With the mainly consideration of assembly time according to the assembly sequence evaluation criteria, the objective function is established and evaluated. This paper presents an application of the method in the aircraft cabin door assembly process supported by an 863 program. Meanwhile, the verification of the approach is shown in the practical example on MATLAB platform.