title: Ultrasonic test of resistance spot welds based on wavelet package analysis.
abstract: In this paper, ultrasonic test of spot welds for stainless steel sheets has been studied. It is indicated that traditional ultrasonic signal analysis in either time domain or frequency domain remains inadequate to evaluate the nugget diameter of spot welds. However, the method based on wavelet package analysis in time-frequency domain can easily distinguish the nugget from the corona bond by extracting high-frequency signals in different positions of spot welds, thereby quantitatively evaluating the nugget diameter. The results of ultrasonic test fit the actual measured value well. Mean value of normal distribution of error statistics is 0.00187, and the standard deviation is 0.1392. Furthermore, the quality of spot welds was evaluated, and it is showed ultrasonic nondestructive test based on wavelet packet analysis can be used to evaluate the quality of spot welds, and it is more reliable than single tensile destructive test.
authors.affiliation: Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science & Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Liu
authors.affiliation: Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science & Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025, PR China. Electronic address: jluliujing@126.com.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Xu
authors.affiliation: Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science & Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025, PR China.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Gu
authors.affiliation: Key Laboratory of Automobile Materials of Ministry of Education and Department of Materials Science & Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025, PR China.
authors.forename: Guanghao
authors.initials: G
authors.lastname: Zhou
keywords: Non-destructive testing; Nugget diameter; Resistance spot welding; Ultrasonic; Wavelet packet transform