Feature Extraction of Gear Fault Signal Based on Sobel Operator and WHT

Taking Wigner-Ville distribution of gear fault signal as a picture, Sobel operator was applied for edge detection of picture and then Hough transform was used to extract signal feature. Some simulated and measured signals have been processed to demonstrate the effectiveness of new method, which was compared with traditional Wigner-Hough transform and SPWD-Hough transform. The results show that the proposed method can suppress cross term which is produced from using Wigner-Ville distribution to analyze multi-component signal, especially under the condition of low signal to noise ratio. The improved Wigner-Hough transform can effectively suppress the influence of noise and has a good real-time performance because its algorithm is fast. The proposed method provides an effective method to determine the state of gear accurately

Integration of Failure Modes and Effects Analysis (FMEA) in the Engineering Design Process

ABSTRACT Integration of Failure Modes and Effects Analysis (FMEA) in the Engineering Design Process Hua-wei Wen Failure modes and effects analysis (FMEA) is one of the most practical design tools implemented in the product design to analyze the potential failures and to improve the design. The practice of FMEA is diversified and different approaches are proposed by different organizations and researchers from one application to another. Yet, the question is how to systematically utilize the features of FMEA along with the design process. This thesis aims to integrate different types of FMEA in the design process, which is considered as the mapping between customer requirements, product functions, and design components. These three design elements are the foundation of the integration model proposed in this thesis. The objective of this thesis is to develop an integration approach of FMEA in the design process. Particularly, an integration framework is developed to integrate FMEA and design process. Then, a step-by-step FMEA-facilitated design process is proposed to apply FMEA along with the design process. In the end, a detailed case study of a smartphone model is conducted to demonstrate and verify the proposed methodology. The expectedly benefits of the proposed methodology are the consistency of failure analysis information, and the utilization of the failure analysis information from one stage to the later stages of the design process