EXPERIMENTAL STUDY OF THE CRACK BRANCHING SPEED IN POLYMERS
https://doi.org/10.26896/1028-6861-2018-84-4-60-65
Abstract
One of the little-studied problems of modern mechanics and the physics of fracture is the branching of the crack, which is observed in materials of a different nature. For his research, an analysis of the criteria and mechanisms for crack branching. The investigations of crack branching in polymers and steel, fractographic investigation of the fracture surface are considered; criteria for crack branching as a dynamic stress intensity factor, crack speed. It is established that the crack at branching in brittle plastics reaches the limiting propagation speed V* = 500 – 800 m/sec. Tensile tests of flat samples from polymethylmethacrylate (PMMA) at temperatures of +20 and –60°C were carried out, with measurement of crack speed by the method of rupture of conducting strips. A measuring device based on a precision converter of signals of resistance thermometers and thermocouples «TERCON», connected to a computer, was created. Measured crack speed for rectilinear crack propagation in the mirror, matte, and feather zones of fracture surface of the PMMA; with single branching of the crack; with multiple branching of cracks with parallel movement of the front of several cracks. A hypothesis is proposed for the physical mechanism of fracture branching.
About the Authors
A. A. Alexeev
V. P. Larionov Institute of the Physical-Technical Problems of the North of the Siberian Branch of Russian Academy of Sciences
Russian Federation
Russian Federation
Anisiy A. Alexeev
Yakutsk
K. N. Bolshev
V. P. Larionov Institute of the Physical-Technical Problems of the North of the Siberian Branch of Russian Academy of Sciences
Russian Federation
Russian Federation
Konstantin N. Bolshev
Yakutsk
V. A. Ivanov
V. P. Larionov Institute of the Physical-Technical Problems of the North of the Siberian Branch of Russian Academy of Sciences
Russian Federation
Russian Federation
Vasiliy A. Ivanov
Yakutsk
A. S. Syromyatnikova
V. P. Larionov Institute of the Physical-Technical Problems of the North of the Siberian Branch of Russian Academy of Sciences
Russian Federation
Russian Federation
Aytalina S. Syromyatnikova
Yakutsk
A. M. Bolshakov
V. P. Larionov Institute of the Physical-Technical Problems of the North of the Siberian Branch of Russian Academy of Sciences
Russian Federation
Russian Federation
Alexander M. Bolshakov
Yakutsk
A. S. Andreev
V. P. Larionov Institute of the Physical-Technical Problems of the North of the Siberian Branch of Russian Academy of Sciences
Russian Federation
Russian Federation
Alexander S. Andreev
Yakutsk
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Review
For citations:
Alexeev A.A., Bolshev K.N., Ivanov V.A., Syromyatnikova A.S., Bolshakov A.M., Andreev A.S. EXPERIMENTAL STUDY OF THE CRACK BRANCHING SPEED IN POLYMERS. Industrial laboratory. Diagnostics of materials. 2018;84(4):60-65. (In Russ.) https://doi.org/10.26896/1028-6861-2018-84-4-60-65
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