ISSN 0020-1685, Inorganic Materials, 2012, Vol. 48, No. 15, pp. 1369–1378. © Pleiades Publishing, Ltd., 2012. Original Russian Text © S.V. Panin, A.V. Byakov, P.S. Lyubutin, O.V. Bashkov, V.V. Grenke, I.V. Shakirov, S.A. Khizhnyak, 2011, published in Zavodskaya Laboratoriya. Diagnostika materialov, 2011, Vol. 77, No. 9, pp. 50–59. 1369 In monitoring of the material state of construc- tions, the combination of various methods has been used for quite long. This is caused, in particular, by the fact that the elastic properties of materials correlate with the parameters of elastic waves propagating in them. As a result, for example, the ultrasound meth- ods can be applied to characterize the structure and reveal defects. For this, the acoustic microscope was created [1]. During its development and following control (adjustment), the traditional methods of opti- cal microscopy were used. One more leading investi- gation in this direction is induction of acoustic waves in material analyzed by laser radiation (by means of the thermal effect) [2]. With the use of excited US impulses not only the Young and shear moduli and the Poisson ratio can be measured, but also, in particular limits, the chemical composition of the material under investigation can be analyzed. The other evident reason of combination of various methods lies in the lack of information obtained with the use of only one of them. So the ultrasound meth- ods give quite complete information about the mate- rial volume, but for the visualization of the defects, the use, for example, of optical methods is required. How- ever, the optical methods can be used to estimate deformation, but mainly only the surface under obser- vation. During analysis of the stages of the σ–ε curve and change in the US propagation rate in various met- als and alloys [3], it was detected that between them a distinct correlation is observed. In [4], as a result of combination of fiberglass and AE methods, an acousto-fiberglass method of diagnosis is proposed. Its calibration allows one to increase the informativeness and reliability of investigation of the deformation pro- cesses. A whole series of papers dedicated to the combina- tion of the AE method and strain measurements were performed in SibNIA [5–8]. In this case, samples of D16 aluminum alloy and also composite materials were primarily investigated under conditions of cyclic loading. The main attention is drawn to processing of the analysis techniques of AE signals, and strain mea- surement is used for estimation of the deformation in the AE source region revealed. The method of AE reg- istration for interconnection of its parameters with the character of the strain–stress state at the stage of the fatigue crack growth was used in [9, 10]. The author [9] introduces the term “prefracturing state,” which corresponds to formation of the main crack. The anal- Investigation of Deformation and Fracture by Acoustic Emission Data, Correlation of Digital Images, and Strain Measurements S. V. Panin a , A. V. Byakov a , P. S. Lyubutin b , O. V. Bashkov b , V. V. Grenke a , I. V. Shakirov a , and S. A. Khizhnyak c a Institute of Strength Physics and Materials Science, Siberian Branch, Russian Academy of Sciences, Akademicheskii pr. 2/1, Tomsk, 634055 Russia b Komsomol’sk-on-Amur State Technical University, pr. Lenina 27, Komsomol’sk-on-Amur, 681013 Russia c JSC Sukhoi Company, ul. Polikarpova 23B, Moscow, 125284 Russia e-mail: svp@ispms.tsc.ru, bashkov_ov@mail.ru, elk@okb.sukhoi.org Received December 29, 2010 Abstract—To analyze the deformation of solid bodies, it was proposed to use simultaneously three in situ methods of data registration, including loading diagram (macroscale level), correlation of digital images (mesoscale level), and acoustic emission (microscale level). The complex for multiscale in situ investigation of deformation and fracture processes, the operating principle of which is based on interconnection of dura- tion of the characteristic stages of change in the informative parameters and their ratios with the leading scale level, was implemented. By the example of stretching of the samples of aluminum alloy D16 with cut of dif- ferent depth, the characteristic stages of change in the derivative of the load applied, AE activity, and intensity of shear deformation on the degree of deformation were revealed. It was shown that the characteristic stages marked on graphs of changes in all informative parameters on time agree well between each other and refer to elastic deformation, parabolic strengthening, and crack propagation. Keywords: acoustic emission, deformation, fracture, loading diagram, analysis of optical images; micro– meso–macroscale levels of deformation DOI: 10.1134/S0020168512140117