The defects in friction stir welding (FSW) of aluminum alloy, e.g., tunnel defect, lack of penetration (LOP) and kissing bond, are with complex shape and narrow gap by inappropriate welding parameters. Firstly, the characteristics of FSW welding and typical defects were briefly described, and the difficult points in ultrasonic testing were summarized from the low time resolution, incomplete characterization of irregular defects, close acoustic impedance between kissing bond and Al alloy and the reduction of detection sensitivity. Subsequently, the research work on the ultrasonic testing for FSW of aluminum alloy were reviewed from the following four aspects, including conventional ultrasonic testing, time-of-flight diffraction (TOFD), phased array ultrasonic testing and other ultrasonic testing techniques. Finally, the research on the ultrasonic signal processing methods and machine learning methods was prospected. The signal characteristics were analyzed and extracted to further improve the resolution and signal-to-noise ratio of ultrasonic testing and realize the accurate identification and quantification for complex shape defects and subtle defects.
LIU M , LI H Q , CHEN J Z , et al. Corrosion resistance of 7475-T7351 alloy plate for aviation[J]. Journal of Materials Engineering, 2017, 45 (9): 129- 135.
2
WANG G Q , ZHAO Y H , HAO Y F . Friction stir welding of high-strength aerospace aluminum alloy and application in rocket tank manufacturing[J]. Journal of Materials Science & Technology, 2018, 34 (1): 73- 91.
3
KANG M , YOON J , KIM C . Hook formation and joint strength in friction stir spot welding of Al alloy and Al-Si-coated hot-press forming steel[J]. The International Journal of Advanced Manufacturing Technology, 2020, 106 (5/6): 1671- 1681.
4
KIM S J , JANG S K , HAN M S , et al. Mechanical and electrochemical characteristics in sea water of 5052-O aluminum alloy for ship[J]. Transactions of Nonferrous Metals Society of China, 2013, 23 (3): 636- 641.
doi: 10.1016/S1003-6326(13)62510-8
5
SUN Y S , XUAN L , DU Q . Finite element analysis of welding pressing force for aluminum alloy middle roof plate of urban rail transit train[J]. Journal of Mechanical Science & Technology, 2017, 31 (3): 1357- 1363.
LIU M D . Research status and advances in cryogenic crack propagation of aeronautic aluminum-alloys[J]. Advances in Aeronautical Science and Engineering, 2020, 11 (1): 10- 19.
7
KULEKCI M K , KALUÇ E , ŞIK A , et al. Experimental comparison of MIG and friction stir welding processes for EN AW-6061-T6 (AlMg1SiCu) aluminum alloy[J]. Arabian Journal for Science and Engineering, 2010, 35 (1): 321- 330.
WANG C S , XIONG J T , LI J L , et al. Temperature evolution in fatigue test of 2024 aluminum alloy weld fabricated by friction stir welding[J]. Journal of Materials Engineering, 2015, 43 (9): 53- 59.
9
MEYGHANI B , AWANG M , EMAMIAN S . A mathematical formulation for calculating temperature dependent friction coefficient values: application in friction stir welding (FSW)[J]. Defect and Diffusion Forum, 2017, 379, 73- 82.
doi: 10.4028/www.scientific.net/DDF.379.73
10
ÇAM G , MISTIKOGLU S . Recent developments in friction stir welding of Al-alloys[J]. Journal of Materials Engineering and Performance, 2014, 23 (6): 1936- 1953.
doi: 10.1007/s11665-014-0968-x
11
KAID M , ZEMRI M , BRAHAMI A , et al. Effect of friction stir welding (FSW) parameters on the peak temperature and the residual stresses of aluminum alloy 6061-T6: numerical modelisation[J]. International Journal on Interactive Design and Manufacturing, 2019, 13 (2): 797- 807.
doi: 10.1007/s12008-019-00541-2
12
AZIZ S B , DEWAN M W , HUGGETT D J , et al. A fully coupled thermomechanical model of friction stir welding (FSW) and numerical studies on process parameters of lightweight aluminum alloy joints[J]. Acta Metallurgica Sinica (English Letters), 2018, 31 (1): 1- 18.
doi: 10.1007/s40195-017-0658-4
MAO Y Q , JIANG Z M , KE L M , et al. Material flow behavior of friction stir welding aluminum alloy thick plate joint[J]. Journal of Netshape Forming Engineering, 2018, 10 (5): 1- 15.
doi: 10.3969/j.issn.1674-6457.2018.05.001
14
QIN D Q , FU L , SHEN Z K . Visualisation and numerical simulation of material flow behaviour during high-speed FSW process of 2024 aluminium alloy thin plate[J]. The International Journal of Advanced Manufacturing Technology, 2019, 102 (5/8): 1901- 1912.
15
SONG S W , KIM B C , YOON T J , et al. Effect of welding parameters on weld formation and mechanical properties in dissimilar Al alloy joints by FSW[J]. Materials Transactions, 2010, 51 (7): 1319- 1325.
doi: 10.2320/matertrans.M2010032
YAN K , MA Z X , ZHANG J . Effect of alclad on mechanical property of FSW joint[J]. Journal of Materials Engineering, 2008, (9): 44- 47.
doi: 10.3969/j.issn.1001-4381.2008.09.012
LI Y , LI G , ZHOU Y F . Research progresses of non-destructive testing techniques for friction stir welding defects[J]. Welding Technology, 2020, 49 (2): 1- 4.
19
KINCHEN D G , ALDAHIR E . NDE of friction stir welds in aerospace applications[J]. Inspection Trends, 2002, 7, 1- 7.
WU Z C , LI L P , TU J , et al. Testing of friction stir welding joint of aluminum alloy based on eddy current array[J]. Nondestructive Testing, 2018, 40 (1): 25- 28.
21
ROSADOA L S , CARDOSO F A , CARDOSO S , et al. Eddy currents testing probe with magneto-resistive sensors and differential measurement[J]. Sensors and Actuators A, 2014, 212 (6): 58- 67.
22
HUGGETT D J , DEWAN M W , WAHAB M A , et al. Phased array ultrasonic testing for post-weld and on-line detection of friction stir welding defects[J]. Research in Nondestructive Evaluation, 2017, 28 (4): 187- 210.
doi: 10.1080/09349847.2016.1157660
GONG L H. A study on ultrasonic testing technology of friction stir welded joints of 2A70 aluminum alloy[D]. Harbin: Harbin Institute of Technology, 2010.
24
SUBBARATNAM R , ABRAHAM S T , VENKATRAMAN B , et al. Immersion and TOFD (I-TOFD): a novel combination for examination of lower thicknesses[J]. Journal of Nondestructive Evaluation, 2011, 30 (3): 137- 142.
doi: 10.1007/s10921-011-0101-0
25
AL-ATABY A , AL-NUAIMY W , BRETT C R , et al. Automatic detection and classification of weld flaws in TOFD data using wavelet transform and support vector machines[J]. Insight-Non-Destructive Testing and Condition Monitoring, 2010, 52 (11): 597- 602.
doi: 10.1784/insi.2010.52.11.597
MA T T , LIN L , ZHANG D H , et al. Accurate quantification of inclined cracks in thick-walled pipes based on TOFD circumferential scanning[J]. Chinese Journal of Scientific Instrument, 2019, 40 (3): 23- 29.
27
YUAN C , XIE C Z , LI L C , et al. Ultrasonic phased array detection of internal defects in composite insulators[J]. IEEE Transactions on Dielectrics and Electrical Insulation, 2016, 23 (1): 525- 531.
doi: 10.1109/TDEI.2015.005225
LIN L , YANG P H , ZHANG D H , et al. Review of phased array ultrasonic testing for thick wall cast austenitic stainless steel pipeline welds[J]. Journal of Mechanical Engineering, 2012, 48 (4): 12- 20.
ZHOU Z G , PENG D , LI Y , et al. Research on phased array ultrasonic total focusing method and its calibration[J]. Journal of Mechanical Engineering, 2015, 51 (10): 1- 7.
HE D Q , LUO W , WU H G . Microstructure and mechanical property analysis on double-sided friction stir welding joints of 60 mm 6061-T6 aluminum alloy plate[J]. Journal of Materials Engineering, 2011, (9): 20- 24.
doi: 10.3969/j.issn.1001-4381.2011.09.004
ZHAO X M. Ultrasonic signal features and quality evaluation method of friction stir welded joint of aluminum alloy[D]. Harbin: Harbin Institute of Technology, 2010.
ZHOU P , DAI Q L , ZHANG Y J . Microscopic characteristics of root defects in friction stir welded joints of 6082 aluminum alloy[J]. Materials for Mechanical Engineering, 2019, 43 (12): 29- 33.
doi: 10.11973/jxgccl201912006
33
AZIZ S B , DEWAN M W , HUGGETT D J , et al. Impact of friction stir welding (FSW) process parameters on thermal modeling and heat generation of aluminum alloy joints[J]. Acta Metallurgica Sinica (English Letters), 2016, 29 (9): 869- 883.
doi: 10.1007/s40195-016-0466-2
XU W F , LIU J H , LUAN G H , et al. Microstructures and mechanical properties of friction stir welded aluminum alloy thick plate[J]. Acta Metallurgica Sinica, 2008, 44 (11): 1404- 1408.
doi: 10.3321/j.issn:0412-1961.2008.11.022
ZHANG L L , WANG X J , LIU X . Crystal orientation evolution during friction stir welding of 6082 aluminum alloys[J]. Journal of Materials Engineering, 2018, 46 (10): 55- 59.
doi: 10.11868/j.issn.1001-4381.2017.001011
36
FENG A H , CHEN D L , MA Z Y . Microstructure and cyclic deformation behavior of a friction-stir-welded 7075 Al alloy[J]. Metallurgical and Materials Transactions A, 2010, 41 (4): 957- 971.
doi: 10.1007/s11661-009-0152-3
DONG P , SUN D Q , LI H M , et al. Microstructure and mechanical characteristics of friction stir welded 6005A-T6 aluminum alloy[J]. Journal of Materials Engineering, 2012, (4): 27- 31.
doi: 10.3969/j.issn.1001-4381.2012.04.006
38
MOVAHEDI M , KOKABI A H , REIHANI S M S , et al. Effect of tool travel and rotation speeds on weld zone defects and joint strength of aluminum steel lap joints made by friction stir welding[J]. Science and Technology of Welding and Joining, 2012, 17 (2): 162- 167.
doi: 10.1179/1362171811Y.0000000092
ZOU Q F , QIAN W , AN L , et al. Effect of stir pin shapes on microstruction and tensile properties of friction stir welded joint[J]. Materials for Mechanical Engineering, 2015, 39 (5): 37- 41.
40
BARLAS Z , OZSARAC U . Effects of FSW parameters on joint properties of AlMg3 alloy[J]. Welding Journal, 2012, 91 (1): 16- 22.
KE L M , PAN J L , XING L , et al. Physical mechanism of friction stir weld formation of aluminum alloy[J]. Journal of Materials Engineering, 2008, (4): 33- 37.
doi: 10.3969/j.issn.1001-4381.2008.04.009
HE D Q , LUO J W , WANG H J , et al. Study on relationship between process parameters and welding force of friction stir welding[J]. Hot Working Technology, 2016, 45 (19): 232- 234.
LI B , SHEN Y F , HU W Y . Friction-stir welded defects and repairing weld process of thick aluminum plates with telescopic stir-pin[J]. The Chinese Journal of Nonferrous Metals, 2012, 22 (1): 62- 71.
LIU S P , LIU F F , LI L G , et al. Nondestructive evaluation methods for aluminum alloy friction stir welding[J]. Aeronautical Manufacturing Technology, 2006, (3): 81- 84.
doi: 10.3969/j.issn.1671-833X.2006.03.014
45
LIU X C , WU C S . Elimination of tunnel defect in ultrasonic vibration enhanced friction stir welding[J]. Materials & Design, 2016, 90, 350- 358.
46
PAPADOPOULOS M , PANTELAKIS S . Fatigue testing of 2198 T8 FSW aluminum alloy with and without LOP defect[J]. International Journal of Structural Integrity, 2017, 8 (4): 496- 504.
doi: 10.1108/IJSI-04-2016-0015
47
ZHOU N , SONG D F , QI W J , et al. Influence of the kissing bond on the mechanical properties and fracture behaviour of AA5083-H112 friction stir welds[J]. Materials Science and Engineering: A, 2018, 719, 12- 20.
doi: 10.1016/j.msea.2018.02.011
48
SATO Y S , TAKAUCHI H , PARK S H C , et al. Characteristics of the kissing-bond in friction stir welded Al alloy 1050[J]. Materials Science and Engineering: A, 2005, 405 (1/2): 333- 338.
49
KADLEC M , RŮŽEK R , NOVÁKOVÁ L . Mechanical behaviour of AA 7475 friction stir welds with the kissing bond defect[J]. International Journal of Fatigue, 2015, 74 (5): 7- 19.
50
RAGUPATHY V D , BHAT M R , PRASAD M V N . An experimental study of discontinuities in friction stir welded joints through nondestructive testing[J]. Materials Evaluation, 2017, 75 (3): 406- 412.
51
TAHERI H , KILPATRICK M , NORVALLS M , et al. Investigation of nondestructive testing methods for friction stir welding[J]. Metals, 2019, 9 (6): 624- 644.
doi: 10.3390/met9060624
52
ZHAO Y , LIN L , LI X M , et al. Simultaneous determination of the coating thickness and its longitudinal velocity by ultrasonic nondestructive method[J]. NDT & E International, 2010, 43 (7): 579- 585.
53
MA Z Y , ZHAO Y , LUO Z B , et al. Ultrasonic characterization of thermally grown oxide in thermal barrier coating by reflection coefficient amplitude spectrum[J]. Ultrasonics, 2014, 54 (4): 1005- 1009.
doi: 10.1016/j.ultras.2013.11.012
WANG L , XIE L Y . Measurement and analysis of temperature in friction stirring welding process[J]. Light Alloy Fabrication Technology, 2011, 39 (4): 54- 59.
doi: 10.3969/j.issn.1007-7235.2011.04.012
55
JOSHIA V, BALASUBRAMANIAMA K, PRAKASH R V. Optimization of friction stir welding parameter for AA 5083 by radiography and ultrasonic technique[C]// 2011 IEEE International Ultrasonics Symposium. Orlando: IEEE, 2011: 1920-1923.
HU B W. Ultrasonic phased array detection and recognition of image features for defects in friction stir welded aluminum alloy joints[D]. Nanchang: Nanchang Hangkong University, 2018.
57
JOHNSTON P H. Addressing the limit of detectability of residual oxide discontinuities in friction stir butt welds of aluminum using phased array ultrasound[C]// American Institute of Physics. Hampton: AIP Conference Proceedings, 2009: 1902-1909.
HU H H. Study of signal characteristic and near surface defect recognition of friction stir welding based on ultrasonic TOFD technology[D]. Nanchang: Nanchang Hangkong University, 2014.
59
BIRD R C . Ultrasonic phased array inspection technology for the evaluation of friction stir welds[J]. Insight-Non-Destructive Testing and Condition Monitoring, 2004, 46 (1): 31- 36.
doi: 10.1784/insi.46.1.31.52658
60
董剑. 铝合金搅拌摩擦焊缝超声波检测仿真研究[D]. 长春: 吉林大学, 2014.
60
DONG J. Ultrasonic simulation of friction stir welded joints of aluminum alloy[D]. Changchun: Jilin University, 2014.
LU H , XING L W , ZHAO X Y . Visual scanning inspection of welding defects by high frequency ultrasonic[J]. Welding & Joining, 2014, (9): 19- 23.
doi: 10.3969/j.issn.1001-1382.2014.09.005
62
ADAMUS K , LACKI P . Assessment of aluminum FSW joints using ultrasonic testing[J]. Archives of Metallurgy and Materials, 2017, 62 (4): 2399- 2404.
doi: 10.1515/amm-2017-0353
LIU S P , LIU F F , LI L G , et al. Investigation of ultrasonic method based on different incident angles for evaluation of friction stir welding[J]. Nondestructive Testing, 2006, (5): 225- 228.
doi: 10.3969/j.issn.1000-6656.2006.05.001
64
GHIDINI T , VUGRIN T , DONNE C D . Residual stresses, defects and non-destructive evaluation of FSW joints[J]. Welding International, 2005, 19 (10): 783- 790.
doi: 10.1533/wint.2005.3493
65
孟永乐. 搅拌摩擦焊缺陷的无损检测技术研究[D]. 南昌: 南昌航空大学, 2011.
65
MENG Y L. Investigation on non-destructive testing technology in friction stir welding defects[D]. Nanchang: Nanchang Hangkong University, 2011.
XU J M , KE L M , XING L , et al. Study on ultrasonic dynamic waveform of weld defects in friction stir welding[J]. Nondestructive Testing Technology, 2008, 32 (1): 5- 8.
doi: 10.3969/j.issn.1671-4423.2008.01.002
67
WEGLOWSKI M S . Ultrasonic tests of FSW joints of thicknesses below 8 mm[J]. Biuletyn Instytutu Spawalnictwa, 2018, (2): 7- 14.
68
YEH F W T , LUKOMSKI T , HAAG J , et al. An alternative ultrasonic time of flight diffraction (TOFD) method[J]. NDT & E International, 2018, 100, 74- 83.
69
HABIBPOUR-LEDARI A , HONARVAR F . Three dimensional characterization of defects by ultrasonic time-of-flight diffraction (TOFD) technique[J]. Journal of Nondestructive Evaluation, 2018, 37 (1): 14- 24.
doi: 10.1007/s10921-018-0465-5
SUN X , JIN S J , ZHANG D H , et al. Suppression of dead zone in TOFD with autoregressive spectral extrapolation[J]. Materials for Mechanical Engineering, 2018, 54 (22): 15- 20.
SHI J W , LIU S P . Ultrasonic TOFD inspection and evaluation of weld seam defects in friction stir welding[J]. Nondestructive Testing, 2011, 33 (11): 1- 3.
CHI D Z , GANG T , YUAN Y , et al. Feature and recognition of signal and image of ultrasonic TOFD method for surface defect[J]. Transactions of the China Welding Institution, 2005, 26 (11): 1- 5.
doi: 10.3321/j.issn:0253-360X.2005.11.001
73
TABATABAEIPOUR M , HETTLER J , DELRUE S , et al. Non-destructive ultrasonic examination of root defects in friction stir welded butt-joints[J]. NDT & E International, 2016, 80 (6): 23- 34.
CHI D Z , GANG T , ZHAO L B . Identification of welding defects by linear focusing ultrasonic method[J]. Transactions of the China Welding Institution, 2015, 36 (5): 29- 32.
75
JIN S J , SUN X , MA T T , et al. Quantitative detection of shallow subsurface defects by using mode-converted waves in time-of-flight diffraction technique[J]. Journal of Nondestructive Evaluation, 2020, 39 (2): 33.
doi: 10.1007/s10921-020-00676-3
76
CHEN T L , QUE P W , ZHANG O , et al. Ultrasonic nondestructive testing accurate sizing and locating technique based on time-of-flight-diffraction method[J]. Russian Journal of Nondestructive Testing, 2005, 41 (9): 594- 601.
doi: 10.1007/s11181-006-0006-7
77
陶京新. 薄板焊缝缺陷超声散射检测方法的研究[D]. 南昌: 南昌航空大学, 2014.
77
TAO J X. Study of the ultrasonic scattering detection method for thin planar welds[D]. Nanchang: Nanchang Hangkong University, 2014.
78
CHEN Y , LUO Z B , ZHOU Q , et al. Modeling of ultrasonic propagation in heavy-walled centrifugally cast austenitic stainless steel based on EBSD analysis[J]. Ultrasonics, 2015, 59, 31- 39.
doi: 10.1016/j.ultras.2015.01.009
79
OIWA N , KIDA K , IWAKI T , et al. A test of phased array ultrasonic testing of aluminum alloy friction stir welded joints[J]. Welding International, 2008, 22 (8): 511- 517.
doi: 10.1080/09507110802351920
80
FORTUNATO J , ANAND C , BRAGA D F O , et al. Friction stir weld-bonding defect inspection using phased array ultrasonic testing[J]. The International Journal of Advanced Manufacturing Technology, 2017, 93 (9/12): 3125- 3134.
81
WANG F , TU J , WEI Q , et al. Ultrasonic phased array testing of friction stir welded thin-walled lock welds[J]. Nondestructive Testing, 2017, 39 (5): 17- 20.
SUN C L , GANG T , LIU B , et al. 3D visualization of FSW defects based on ultrasonic phased array[J]. Transactions of the China Welding Institution, 2015, 36 (4): 47- 50.
WANG C X , GANG T , YU P , et al. Ultrasonic method for rapid detection of the aluminum friction stir welding defects[J]. Materials for Mechanical Engineering, 2015, 51 (2): 7- 13.
84
LAMARRE A , DUPUIS O , MOLES M . Complete inspection of friction stir welds in aluminum using ultrasonic and eddy current arrays[J]. CINDE Journal, 2006, 27 (4): 14- 16.
85
OIWA N , IWAKI S , OKADA T , et al. Studies on characteristics of friction stir welded joints in structural thin aluminum alloys part 1: imperfections in friction stir welded zones and their precision non-destructive testing[J]. Welding in the World, 2005, 49 (3): 76- 82.
KANG J , LUAN G H , FU R D . Microstructures and mechanical properties of banded textures of friction stir welded 7075-T6 aluminum alloy[J]. Acta Metallurgica Sinica, 2011, 47 (2): 224- 230.
WANG B , GAO S S , MA M . Study of ultrasound nondestructive detection of friction stir welded joint of 2024 aluminum alloy sheet[J]. Machine Building Automation, 2019, 48 (5): 54- 56.
88
易冠英. 铝合金搅拌摩擦焊接头缺陷的无损检测研究[D]. 沈阳: 沈阳航空航天大学, 2016.
88
YI G Y. Nondestructive testing of defects in friction stir welded joints of aluminum alloy[D]. Shenyang: Shenyang Aerospace University, 2016.
YU L , CHEN Y H , HUANG C P , et al. Ultrasonic phased array inspection technology for defects in friction stir welded seam[J]. Transactions of the China Welding Institution, 2014, 35 (1): 21- 24.
90
屈祎昕. 铝合金搅拌摩擦焊接头的无损检测与缺陷表征[D]. 石家庄: 河北科技大学, 2019.
90
QU Y X. Nondestructive testing and defect characterization of friction stir welding joints of aluminum alloys[D]. Shijiazhuang: Hebei University of Science and Technology, 2019.
91
SAGAR S P , MIYASAKA C , GHOSH M , et al. NDE of friction stir welds of Al alloys using high-frequency acoustic microscopy[J]. Nondestructive Testing and Evaluation, 2012, 27 (4): 375- 389.
doi: 10.1080/10589759.2012.656638
92
JIANG Y , WANG H , CHEN S , et al. Quantitative imaging detection of additive manufactured parts using laser ultrasonic testing[J]. IEEE Access, 2020, 8, 186071- 186079.
doi: 10.1109/ACCESS.2020.3030307
93
LIU J , FENG X , YIN A , et al. Weld quality inspection of small-diameter thin-walled pipes by a laser ultrasonic method[J]. Applied Optics: Optical Technology and Biomedical Optics, 2020, 59 (12): 3538- 3542.
94
郑德根. 基于激光超声的铝合金搅拌摩擦焊缺陷评价[D]. 上海: 上海交通大学, 2014.
94
ZHENG D G. Friction stir welding flaw evaluation of aluminum alloy by laser ultrasonic[D]. Shanghai: Shanghai Jiao Tong University, 2014.
95
LÉVESQUE D , DUBOURG L , BLOUIN A . Laser ultrasonics for defect detection and residual stress measurement of friction stir welds[J]. Nondestructive Testing and Evaluation, 2011, 26 (3/4): 319- 333.
96
FAN Z , LOWE M J S . Interaction of weld-guided waves with defects[J]. NDT & E International, 2012, 47, 124- 133.
TENG F. Time-reversal lamb wave used in defect detection of aluminum alloyed plates[D]. Harbin: Harbin University of Science and Technology, 2009.
98
SANTOS M J , SANTOS J B . Lamb waves technique applied to the characterization of defects in friction stir welding of aluminum plates: comparison with X-Ray and ultrasonic C-Scan[J]. Journal of Testing & Evaluation, 2010, 38 (5): 622- 627.
99
YU L Y , TIAN Z H , LECKEY C A C . Crack imaging and quantification in aluminum plates with guided wave wavenumber analysis methods[J]. Ultrasonics, 2015, 62, 203- 212.
doi: 10.1016/j.ultras.2015.05.019
100
FAKIH M A , MUSTAPHA S , TARRAF J , et al. Detection and assessment of flaws in friction stir welded joints using ultrasonic guided waves: experimental and finite element analysis[J]. Mechanical Systems and Signal Processing, 2018, 101 (1): 516- 534.
101
HAFEZI M H , ALEBRAHIM R , KUNDU T . Peri-ultrasound for modeling linear and nonlinear ultrasonic response[J]. Ultrasonics, 2017, 80, 47- 57.
doi: 10.1016/j.ultras.2017.04.015
102
DELRUE S , TABATABAEIPOUR M , HETTLER J , et al. Applying a nonlinear, pitch-catch, ultrasonic technique for the detection of kissing bonds in friction stir welds[J]. Ultrasonics, 2016, 68, 71- 79.
doi: 10.1016/j.ultras.2016.02.012
XIA N , TENG D P , LI D F , et al. Automatic identification system of rail vehicle aluminum alloy friction stir welding joint defects based on phased array images[J]. Welding Technology, 2019, 48 (9): 107- 109.
YUAN K Y , HAN Z D , SHI Q Y , et al. Ultrasonic nondestructive evaluation of friction stir welding joints based on independent component analysis[J]. Transactions of the China Welding Institution, 2015, 36 (12): 9- 12.
105
SANTOS T , VILAÇA P , QUINTINO L . Developments in NDT for detecting imperfections in friction stir welds in aluminium alloys[J]. Welding in the World, 2008, 52 (9): 30- 37.
106
LIU J , XU G C , REN L , et al. Defect intelligent identification in resistance spot welding ultrasonic detection based on wavelet packet and neural network[J]. The International Journal of Advanced Manufacturing Technology, 2017, 90 (9): 2581- 2588.
107
WEIMER D , THAMER H , SCHOLZ-REITER B . Learning defect classifiers for textured surfaces using neural networks and statistical feature representations[J]. Procedia CIRP, 2013, 7, 347- 352.
doi: 10.1016/j.procir.2013.05.059
108
DAS B , PAL S , BAG S . A combined wavelet packet and Hilbert-Huang transform for defect detection and modelling of weld strength in friction stir welding process[J]. Journal of Manufacturing Processes, 2016, 22 (4): 260- 268.
109
PASADAS D J , RAMOS H G , FENG B , et al. Defect classification with SVM and wideband excitation in multilayer aluminum plates[J]. IEEE Transactions on Instrumentation and Measurement, 2020, 69 (1): 241- 248.
doi: 10.1109/TIM.2019.2893009
XU J M , KE L M . Characteristic extraction based on wavelet packet and pattern recognition for ultrasonic inspection signals from defects in FSW joints using artificial neural network[J]. Nuclear Power Engineering, 2020, 41 (1): 163- 166.