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PHYSICS AND MATHEMATICS / «ШУУШШШУМ-ЛШТМак» #5(92), 2021
УДК 693.3
Дьомiчев К.,
Кшвський мiжнародний утверситет,
Петров О.,
Днтровський нацюнальний yHieepcumem iM. О.Гончара,
Стеблянко П. yHieepcumem митно'1 справи та фтанЫв DOI: 10.24412/2520-6990-2021-592-6-8 МОДЕЛЮВАННЯ ПОВЕД1НКИ ПСЕВДО-ПРУЖНО-ПЛАСТИЧНОГО NiTi СПЛАВУ ПРИ
ВЕЛИКИХ ДЕФОРМАЦ1ЯХ
Domichev K.,
Kyiv International University, Petrov A.,
Dnieper National University named after Oles Honchar,
Steblyanko P. University of Customs and Finance
SIMULATION OF BEHAVIOR OF PSEUDO-ELASTIC-PLASTIC NiTi ALLOY AT LARGE
DEFORMATIONS
АнотацЫ.
В po6omi до^джуеться вплив великих деформацш (приблизно до 15%), як виникають з пластично'1 деформацИмартенситу, на мехатчну повeдiнкy псевдо-пружно-пластичного NiTi сплаву. Задача розгля-даеться в геометрично нeлiнiйнiй поcmановцi. Екcпepuмeнmальнi результати показують, що 3i збшьшен-ням пластично'1 деформацИ залuшковi збшьшення деформацИ i фазовi ^rni деформацИ напруження пере-творення вiд мартенситу до аустенту стають бшьш крутими i менш очевидними.
В pо6оmi пропонуеться аналтично-числовий пiдхiд для описання дiагpамu маmepiалy при розванта-жeннi починаючи з довшьног точки активно'1 дшянки. Апpокcuмацiя криво'1 на вiдповiднuх дтянках дiагpам peалiзyеmьcя за допомогою напруженого сплайну.
Abstract.
The paper investigates influence of large deformations (up to about 15%) arising from the plastic deformation of martensite on mechanical behavior of pseudo-elastic-plastic NiTi alloy. The problem is considered in a geometrically nonlinear formulation.
Experimental results show that with increasing plastic deformation, the residual deformation increases and the phase deformation curves of the conversion stress from martensite to austenite become steeper and less obvious.
The paper proposes an analytical-numerical approach to describe diagram of material during unloading starting from an arbitrary point of the active site. The approximation of the curve on the corresponding sections of the diagrams is realized by means of a stressed spline.
Ключевi слова: велик деформацИ] псевдо-пружно-пластичтсть, сплайн-функцИ, фyнкцiональнi ма-mepiалu, геометрична нелтттсть.
Keywords: large deformations, pseudo-elastic-plasticity, spline functions, functional materials, geometric nonlinearity.
The work is devoted to the study of structural elements made of functionally inhomogeneous materials at large deformations. Functionally inhomogeneous materials or intellectual materials are widely used in science and technology. One of the representatives of this class of materials are materials with shape memory or materials with the property of pseudo-elastic-plasticity. Their physical or mechanical properties are very different from the behavior of conventional structural, heat-resistant or tool materials. Mechanical behavior largely depends on external conditions (temperature, pressure) and the history of their change.
Materials with shape memory (MPF) are able to accumulate deformation at low temperatures under load, and after heating to fully or partially restore it. Such materials include primarily alloys in which re-
verse martensitic transformations develop under thermal or mechanical action. These alloys can be the basis of composite materials, to a greater or lesser extent capable of restoring shape.
A similar phenomenon of shape change is observed in polymeric materials. However, the nature of deformation in them and the conditions of its creation and implementation are significantly different from alloys with shape memory.
The main mechanism in these processes is the inverse martensitic transformation between the phases of the solid, which can occur with a relatively small change in temperature. This conversion can be caused by a change in temperature or a change in voltage.
Materials that have the properties of shape memory, pseudo-elasticity and pseudo-elastic-plasticity usually include the following: NiTi AgCd, AuCd,
«coyyomum-jmtmail» #592)), 2©21 / PHYSICS and mathematics
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CuAlNi, CuSn, CuZn, FePt, MnCu, FeMnSi, CoNiAl, CoNiGa, NiPe , NiTiNb, NiMnGa.
Investigation of the influence of large deformations (up to about 15%), which arise from plastic deformation of martensite, on the mechanical behavior of pseudo-elastic-plastic NiTi alloy. The schematic diagram of the material before and after the phase transformation is shown in Figure 1. Note that in [1] the behavior of pseudo-elastic-plastic material at deformations up to 6% was studied. In this case, residual deformations during unloading were absent. The corresponding problems of thermomechanics for shape memory alloys were considered in a geometrically linear formulation.
In [4], the issue of modeling pseudo-elastic-plastic bodies with deformations up to 6% using geometric nonlinearity was investigated.
Experimental results show that with increasing plastic deformation, the residual deformation increases and the phase deformation curves of the transformation stress from martensite to austenite become steeper and less obvious [2].
Analytical-numerical approach to describe the diagram of the material during unloading starting from an arbitrary point of the active site. The experimental results shown in Figure 2 were used as a basis. The curve was approximated in the corresponding section by means of a stressed spline [3].
Fig. 1. Schematic diagram of the material before and after the phase transformation.
Fig. 2. Macroscopic diagram of the material in the active area and during unloading from a given point
Conclusions. The influence of large deformations (up to about 15%) arising from plastic deformation of martensite on the mechanical behavior of pseudo-elastic-plastic NiTi alloy is studied in this work. A schematic diagram of the material before and after the phase transformation is constructed.
Similar problems were solved in a geometrically linear formulation with deformations up to 6%. Experimental results show that with increasing plastic deformation, the residual deformation increases and the
phase strain curves of the conversion stress from martensite to austenite become steeper and less obvious.
The paper proposes an analytical-numerical approach to describe the diagram of the material during unloading starting from an arbitrary point of the active site. The experimental results shown in Figure 2 and the approximation of the curve in the corresponding section by means of a stressed spline were used as a basis [3].
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PHYSICS AND MATHEMATICS / «ШУУШШШУМ-ЛШТМак» #5(92), 2021
References
1. Steblyanko P. Phenomenological Model of Pseudo-Elastic-Plastic Material Under Nonstationary Combining Loading/ P.Steblyanko, Y.Chernyakov, A.Petrov, V.Loboda // Structural Integrity, Volume 8, Theoretical, Applied and Experimental Mechanics, Springer Verlag, 2019.- P. 205-208.
2. Wang X.M. Micromechanical modelling of the effect of plastic deformation on the mechanical behaviour in pseudoelastic shape memory alloys. / X.M.Wang, B.X.Xu, Z.F.Yue // International Journal of Plasticity 24, 2008. - P. 1307-1332.
3. Стеблянко П.А. Мeтоды расщепления в пространственных задачах теории пластичности / П.А. Сгеблянко. - Киев: Наукова думка, 1998. -304с.
4. Petrov A. Development of the method with enhanced accuracy for solving problems from the theory of thermo-psevdoelastic-plasticity / A.Petrov, Yu.Chernyakov, P.Steblyanko, K.Demichev, V.Hay-durov // Eastern-European Journal of Enterprise Technologies. 2018. Vol. 4/7 (94). P. 25-33.
Sadigova N.,
Institute of Radiation Problems, Baku, Azerbaijan
Isayev K.,
National Nuclear Research Center, Baku, Azerbaijan National Research Nuclear University MEPHI, Moscow, Russia
Sadigov A.,
Institute of Radiation Problems, Baku, Azerbaijan National Nuclear Research Center, Baku, Azerbaijan
Ahmadov F.,
Institute of Radiation Problems, Baku, Azerbaijan National Nuclear Research Center, Baku, Azerbaijan
Yilmaz E.,
The Center for Radiation Detector Research and Applications -iBU, Bolu, Turkey
Mammadli A.,
Institute of Radiation Problems, Baku, Azerbaijan
Gerayeva A.
Institute of Radiation Problems, Baku, Azerbaijan DOI: 10.24412/2520-6990-2021-592-8-11 IMPROVEMENT OF BURIED PIXEL AVALANCHE PHOTODETECTORS
Abstract
The paper presents the results of a study of the latest MAPD-3NMphotodiodes based on silicon with a deeply buried pixel structure. The working parameters of the developed photodiode were determined. The results were compared with the parameters of previously manufactured samples. It was found that this structure has a high photon detection efficiency and internal avalanche amplification at a lower operating voltage.
Keywords: SiPM; MAPD; silicon photomultiplier; avalanche photodiode; buried pixel.
Introduction
Rapid progress in the physics and technology of semiconductors in the last century led to the creation of solid-state analogs of almost all vacuum devices, except for photomultiplier tubes (PMTs). Although, after the discovery in the early 50s of the last century of the effect of increasing the photocurrent in silicon and germanium avalanche photodiodes and the creation of the basic theory of impact ionization in semiconductors, certain prospects appeared, but the creation of adequate solid-state analogs of PMTs required many years of research. The avalanche photodiodes (APDs) known at that time were significantly inferior to PMTs in such basic parameters as the gain, the size of the working area, and the threshold sensitivity. In the 90s, Silicon Photoelectron Multipliers (SiPM) [1] detectors were developed and are now widely used, capable of registering single photons at room temperature. SiPM detectors operate in a mode above the breakdown voltage (or in the Geiger mode) and have a wide range of photore-sponse linearity in terms of the number of photons per pulse. Depending on the manufacturer, SiPMs are also
called Micro Pixel Avalanche Photodiodes (MAPD) or Micro Pixel Photon Counters (MPPC). At present, SiPM detectors in their main parameters, such as the efficiency of photon detection, gain, region of linearity of the photoresponse, and working area, significantly exceed SPAD and VLPC detectors. Therefore, the SiPM detector is considered the most adequate solidstate analog of the PMT [2-4]. During the past decade, mass production of SiPM detectors has been achieved. So far, the main consumers of SiPM detectors are large-scale projects in high-energy physics carried out in leading scientific centers of the world [5], including the NICA project (Dubna, Russia). Tests are being carried out with the aim of mass application of SiPM detectors in medical tomographs [6] of a new generation and in the automotive industry. You can notice the fact that the structures and designs of SiPM are constantly being modernized, thereby improving their operating parameters. It is required to carry out research on the parameters of new silicon photodiodes, and also to conduct an analytical study with other analogs.
