As a result of the research, formulas for calculating shear elastic constants of cubic crystals, based on the resonant frequency of torsional vibrations of samples c 44 and C' with square and rectangular cross-section in the method of the composite piezoelectric vibrator was obtained. Despite the fact that the resonance method does not need a large single crystals, the calculation formulas for the samples most simple to manufacture prismatic either incomplete or completely unknown. For example, there is data on the calculation of the c 44 and C' of the natural frequencies of torsional vibrations of the rods only circular cross-section. An exception is the ultrasonic pulse method for measuring the elastic constants, but it requires to measure single-crystal samples of sufficiently large size. The calculation is reduced to finding the proper expressions for rotating mechanical torque, which is more or less complex function of the cross-section and the elastic constants of the sample material. At the same time it takes into account the amendment to the warping of the cross-section of anisotropic samples under torsion. Then calculates the natural frequencies of torsional vibration samples of square and rectangular cross-section and the corresponding shear elastic constants. As an example, the calculation of shear considered constant C' on the basis of the pitch frequency of torsional vibrations of square cross-section sample of nickel-titanium NiTi.
Comparative analysis of the mode of deformation of hollow organs (extrahepatic bile ducts at the site of stricture) was carried out by the finite elements method during interventions in the lumen using stone extraction Dormia basket made of stainless steel and NiTi. Geometrical and physical models of the ducts and basket were created, strain and deformation fields in the choledochal walls were determined, criteria of traumaticity and medical technological requirements to the material and geometry of lithoextractors were formulated.
The measurement and calculation of the mechanical properties of silicone rubber used for the manufacture of a prosthesis for the auricle of patients based on dental CAD/CAM systems, using a hybrid technology that includes traditional and digital methods of manufacturing medical devices were performed. Mechanical tensile tests were carried out in a climatic chamber at various temperatures: -20; 0; 25; 40 °C. All mechanical characteristics of silicone rubber lay in a very limited range of values and monotonically decreased with increasing test temperature from -20 to + 45°C. At the same time, the elastic characteristics (elastic modulus) decreased by 1.55, deformation (fracture deformation) - by 1.98, strength (tensile strength) - by 2.37 times. The average values of tensile strength were 6.54 MPa, fracture deformation - 1480.61%, modulus of elasticity - 0.53 MPa, and temperature gradient: 0.08 MPa/deg, 14.8%/deg and 0.004 MPa/deg, respectively. In the framework of the Mooney - Rivlin hyperelastic model, the coefficients of the model C 01 and C 10 are determined, which can be used as parameters when performing simulation modeling of the stress-strain state of prostheses. Based on the data obtained, an assessment was made of the cross-linked density of the silicone rubber material as a synthetic polymer. It turned out to be equal to 0.49.
Совокупность уникальных свойств термомеханической памяти формы (ПФ) и сверхэластичности (СЭ) соединений на основе никелида титана (TiNi), механизм и природа этих явлений до сих пор вызывает несомненный интерес у физиков и инженеров. Данное сообщение посвящено выходу в свет очередной книги, в которой изложены научные аспекты исследований и практического применения интерметаллидов никелида титана в различных аспектах сферы жизнедеятельности человека.
The combination of unique properties of thermomechanical shape memory (SM) and superelasticity (SE) of compounds based on titanium nickelide (TiNi), the mechanism and nature of these phenomena are still of great interest to physicists and engineers. This message is dedicated to the publication of the book, which sets out the scientific aspects of research and the use of titanium nickelide intermetallic compounds in various aspects of human life.
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