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A description of experimental complexes, methodological and hardware means for determining the mechanical properties of materials under high-speed deformation and fracture is given in the report. Determination of mechanical properties in the strain rate range 5•102÷103 s-1 is the first direction of work in the laboratory of “Dynamic Materials Testing”. These tests are done using automated complexes based on the Kolsky method and its modifications for compression, tension and shearing. It is also possible to determine the fracture toughness, the characteristics of dynamic crack resistance, as well as to obtain stressstrain curves of low-density materials under uniaxial strain. Original gas guns with a caliber of 10, 20 and 57 mm are used for creation a dynamic load. The study of the behavior of materials at strain rates of 105 s-1 and higher is the second direction of work. In this case, the methods of a planewave shock experiment based on gas guns of 57 and 85 mm caliber are used. Manganine and dielectric pressure sensors, as well as laser interferometry are used for measuring the parameters of elastoplastic waves and for determining such important characteristics as impact compressibility, Hugoniot yield strength, spall strength.

We discuss experimental and numerical studies of the deformation and destruction of fine-grained concrete B22.5 under dynamic loading. The experiments were carried out using the Kolsky (or split-Hopkinson pressure bar) method, and its modifications in the strain rate range from 400 to 2000 s−1. The rate dependences of ultimate stresses and fracture energy in tension and compression are obtained. Based on experimental data, the identification of the dynamic component of two models from the LS-DYNA computational complex was carried out: *MAT_CONCRETE_DAMAGE and *MAT_CSCM. The results of a comparative analysis of the identified models based on single-element modeling and comparison with experimental data are presented. It is shown that the obtained experimental strain rate dependences of the fracture characteristics can significantly improve the predictive ability of the model compared to the default parameter set. Information about the rate dependence of the fracture energy in *MAT_CSCM model makes it possible to more realistically simulate the behavior of the material beyond the ultimate stress. [ABSTRACT FROM AUTHOR]

The results of dynamic compression tests of aspen under elevated temperature up to +60°C are presented. The tests were carried out based on the Kolsky method using the split Hopkinson pressure bar. To study the anisotropy of properties, aspen samples were fabricated and tested by cutting along and across the fibers direction. Dynamic stress-strain curves were obtained as well as the average values of modulus of active loading sites. The greatest steepness of the loading branches and the highest breaking stresses are observed for the samples loaded along the fiber direction, while the smallest values are noted under loading across the fiber direction. Also the effect of elevated temperature on strength and deformation properties of aspen is estimated. [ABSTRACT FROM AUTHOR]

This paper presents the features of a method for determining the dynamic properties of brittle materials using the split Hopkinson bar technique on mortar as an example. Experiments were conducted both with and without a loading pulse shaper, a deformable copper disc (pad) placed on the impacted end of the input bar. Experimental data from the experiments without the pad were processed with and without dispersion correction based on a direct solution of the Pochhammer–Chree frequency equation of pulses in the measuring bars. There were compared both the deformation graphs and mechanical characteristics of the tested material for three variants of the split Hopkinson pressure bar experiments: with and without a loading pulse shaper, and with the dispersion correction procedure for pulses in the measuring bars. The phenomena observed during these experimental schemes and the processing of obtained data are described and discussed; further, the effect of the nature of the load increase is revealed. [ABSTRACT FROM AUTHOR]

Results of experimental studies and numerical modeling of high strain rate of aluminum alloy AK4-1 (analog AU2GN) have been presented. Using Split Hopkinson Pressure Bar (SHPB) method stress-strain curves under compression and tension have been obtained. On the basement of these results appropriate parameters of some constitutive equations have been calculated. Strength and deformation material failure properties, dynamic crack resistance, dynamic friction factor for material pair aluminum-titanium have been obtained by carrying out of modificated SHPB tests. A verification of the constitutive equations has been realized by dynamic indentation method and modified Taylor test. [ABSTRACT FROM AUTHOR]

Dynamic tests of fine-grained fired dioxide-zirconia ceramics under compression under uniaxial stress conditions were carried out. The influence of the specimen length on the obtained strength and deformation properties of ceramics is investigated. The thickness of the specimen has a significant impact on the course of the obtained dynamic stress–strain diagrams: short specimens have a much more sloping area of active loading branch. The main contribution to the modulus of the load branch resulting from tests of brittle porous media is made by the geometry of the specimens and the porosity of the material. When choosing the length of specimens for dynamic tests, the optimal geometry of the tested specimens is preferable in accordance with the Davies–Hunter criterion, when the contributions of axial and radial inertia are mutually compensated, and the contribution of the effects of friction in the resulting diagram is minimal. When choosing the geometry of specimens of brittle porous media, the structure of the material should be taken into account so that the size of the specimen (both length and diameter) exceeds the size of the internal fractions of the material by at least five times. [ABSTRACT FROM AUTHOR]

A new method has been developed for determining the main laws of the deformation of soft soils under conditions of dynamic loading with amplitudes of up to several gigapascals. The method is based on the results of high-strain-rate tests under uniaxial deformation conditions, which were obtained using a modified Kolsky method and the plane shock wave technique. The possibilities of the proposed method are illustrated by determining the dynamic properties of sand. © 2005 Pleiades Publishing, Inc. [ABSTRACT FROM AUTHOR]