scholarly journals Scientifically substantiated technology for reverse extrusion of products made of anisotropic tubular billets

2019 ◽  
Vol 2019 (10) ◽  
pp. 12-18
Author(s):  
Сергей Ларин ◽  
Sergey Larin ◽  
В. Булычев ◽  
V. Bulychyov
Keyword(s):  
Orthotropic Material ◽  
Theoretical Research ◽  
Stress Strain ◽  
Cylindrical Anisotropy ◽  
Research Results ◽  
Tubular Billet

The theoretical research results of the reverse extrusion of a heavy-walled tubular billet made of orthotropic material having a cylindrical anisotropy of stress-strain properties are presented. The assessment of force modes and limiting potentialities of the reverse extrusion of anisotropic tubular billets is carried out.

scholarly journals Identification of orthotropic material parameters for acute, necrotic, fibrotic and remodelling myocardial infarcts in the rat

2019 ◽  
Author(s):  
Mazin S. Sirry ◽  
Laura Dubuis ◽  
Neil H. Davies ◽  
Jun Liao ◽  
Thomas Franz
Keyword(s):  
Constitutive Model ◽  
Orthotropic Material ◽  
Constitutive Models ◽  
Biaxial Stress ◽  
Percentage Error ◽  
Fe Model ◽  
Stress Strain ◽  
Material Parameters ◽  
Strain Data ◽  
Tensile Experiment

AbstractFinite element (FE) models have been effectively utilized in studying biomechanical aspects of myocardial infarction (MI). Although the rat is a widely used animal model for MI, there is a lack of material parameters based on anisotropic constitutive models for rat myocardial infarcts in literature. This study aimed at employing inverse methods to identify the parameters of an orthotropic constitutive model for myocardial infarcts in the acute, necrotic, fibrotic and remodelling phases utilizing the biaxial mechanical data developed in a previous study. FE model was developed mimicking the setup of the biaxial tensile experiment. The orthotropic case of the generalized Fung constitutive model was utilized to model the material properties of the infarct. The parameters of Fung model were optimized so that the FE solution best fitted the biaxial experimental stress-strain data. A genetic algorithm was used to minimize the objective function. Fung orthotropic material parameters for different infarct stages were identified. The FE model predictions best approximated the experimental data of the 28 days infarct stage with 3.0% mean absolute percentage error. The worst approximation was for the 7 days stage with 3.6% error. This study demonstrated that the experimental biaxial stress-strain data of healing rat infarcts could be successfully approximated using inverse FE methods and genetic algorithms. The material parameters identified in this study will provide an essential platform for FE investigations of biomechanical aspects of MI and the development of therapies.

scholarly journals Autodyne signal features of frequency-locked microwave oscillators

2019 ◽  
Vol 30 ◽  
pp. 12012 ◽  
Author(s):  
Vladyslav Ya. Noskov ◽  
Kirill A. Ignatkov ◽  
Kirill D. Shaidurov
Keyword(s):  
Experimental Data ◽  
Signal Analysis ◽  
Gunn Diode ◽  
Theoretical Research ◽  
Research Results ◽  
Microwave Oscillators ◽  
Signal Features ◽  
External Frequency ◽  
Autodyne Signal ◽  
The Impact

The research results on the autodyne signal formation in microwave oscillators, which are exposed under the impact of the proper reflected emission and, at the same time, of the external frequency-locked signal are presented. The basic relations are obtained for signal analysis under the condition of the quasistatic target movements. The theoretical research results are confirmed by experimental data obtained on the example of an oscillator made on the basis of the 8mm-range Gunn diode.

scholarly journals MODEL OF ACOUSTIC EMISSION SIGNAL AT THE PREVAILING MECHANISM OF COMPOSITE MATERIAL MECHANICAL DESTRUCTION

Aviation ◽  
2010 ◽  
Vol 14 (4) ◽  
pp. 95-103 ◽  
Author(s):  
Sergey Filonenko ◽  
Tatiana Nimchenko ◽  
Alexandr Kosmach
Keyword(s):  
Acoustic Emission ◽  
Composite Material ◽  
Acoustic Emission Signal ◽  
Theoretical Research ◽  
Variable Velocity ◽  
Destruction Process ◽  
Mechanical Destruction ◽  
Research Results ◽  
Emission Signal ◽  
Signal Modelling

A model of acoustic emission signal formation at the prevailing mechanism of the destruction of composite materials is considered. The results of acoustic emission signal modelling are presented, taking into account the variable velocity of loading change. Acoustic emission signal experimental research results corresponding to theoretical research results are considered in this paper. It is shown that irregularity of the trailing edge of the acoustic emission signal is influenced by the change in the rate of the destruction process in composites. Santrauka Išnagrinetas akustines emisijos signalo modelis su vyraujančiu kompozitiniu medžiagu irimo mechanizmu. Pateikti akustines emisijos signalu modeliavimo rezultatai, ivertinant skirtinga apkrovos pasikeitimo greiti. Taip pat pateikti eksperimentinio akustines emisijos signalu tyrimo rezultatai, kurie sutampa su teoriniais tyrimais. Parodyta, kad akustines emisijos signalo galinio fronto netolygumas atsiranda tuomet, kai kinta kompozitines medžiagos irimo greitis.

Improvement of Plate’s Shape for Ingots Upsetting

2015 ◽  
Vol 806 ◽  
pp. 141-150
Author(s):  
Oleg E. Markov ◽  
Natalia A. Rudenko ◽  
Igor A. Grachov ◽  
Aleksandar Ristovski ◽  
Vladimir Radojičić
Keyword(s):  
Strain State ◽  
Theoretical Research ◽  
Uniform Stress ◽  
Flat Plates ◽  
Stress Strain ◽  
Stress Strain State ◽  
Axial Defects ◽  
Cylindrical Steel ◽  
Axial Defect ◽  
Main Influence

A stress-strain state and a resize of an axial defect during upsetting have been investigated in the article. Theoretical research based on a FEM has been conducted. The upsetting of cylindrical steel workpieces which had the axial defect equal to 10 % of the workpiece diameter has been simulated. Upsetting has been carried out by flat, concave-conical and convex plates (solid or with hole). The result of the studies showed that the main influence on the workpiece shape had a ratio of dimensions. The maximal closure of the axial defect provides upsetting by concave-conical solid plates. Upsetting by flat plates does not provide the closure of axial defects. Convex plates provide the uniform stress-strain state along the workpiece cross section. The hole in the plates increases the non-uniformity of strain distribution and also does not provide the axial defects closure.

Laboratory Triaxial Test Study on Soil Reinforced with Roots of Manilagrass

2011 ◽  
Vol 250-253 ◽  
pp. 1366-1370 ◽  
Author(s):  
Kai Fu Liu ◽  
Xiang Ru Yang ◽  
Xin Yu Xie ◽  
Chang Fu Wu ◽  
Yong Hai Liu
Keyword(s):  
Shear Strength ◽  
Triaxial Test ◽  
Triaxial Tests ◽  
Stress Strain ◽  
Research Results ◽  
Test Study ◽  
Strain Relationship ◽  
Optimal Quantity ◽  
Better Than

Laboratory triaxial tests of the soil reinforced with roots of Manilagrass were carried out in order to understand the stress-strain relationship. The change of shear strength indexes of the soil reinforced with roots of Manilagrass was investigated with the quantity of grassroots planted in the soil specimens. The results of laboratory triaxial tests show that the strength and capacity for resisting the deformation of soil reinforced with roots are better than those of unreinforced soil. And under the certain number of grassroots layers, the strength and capacity for resisting the deformation of soil reinforced with roots increase firstly and then reduce with the increasing of Manilagrass roots quantity. In other words, there is an optimal quantity of Manilagrass roots affecting the strength and capacity for resisting the deformation of soil reinforced with roots. The research results are important for understanding the mechanism and use of vegetation protection for slope.

scholarly journals Compressive Behavior for Surface-Nanocrystallized Al-Alloy Material

2002 ◽  
Vol 740 ◽  
Author(s):  
Yueguang Wei ◽  
Chen Zhu ◽  
Xiaolei Wu
Keyword(s):  
Compressive Stress ◽  
Cell Model ◽  
Material Behavior ◽  
Theoretical Research ◽  
Al Alloy ◽  
Compressive Behavior ◽  
Stress Strain ◽  
Alloy Material ◽  
Ultrasonic Shot Peening ◽  
Theoretical Results

ABSTRACTMechanical behavior of the surface-nanocrystallized material fabricated by the ultrasonic shot peening method is investigated experimentally and theoretically. In the experimental research, based on microscopic observations, the compressive specimens are designed and machined considering the material features, and the compressive experiments are performed. Furthermore the compressive stress-strain curves are measured. In the theoretical research, a microstructure cell model is presented considering the material microscopic organization observed from experiments, and the compressive stress-strain relations are simulated. Both experimental and theoretical results display the strong size effect on the material behavior.

Influence of Top Slag on the Plasticity of CaO-SiO2-Al2O3 Inclusions in 42CrMoA Crankshaft Steel

2014 ◽  
Vol 804 ◽  
pp. 285-288
Author(s):  
Jian Tao Ju ◽  
Sen Yang ◽  
Yan Ping Guo ◽  
Yuan She ◽  
Zhao Hui Zhang
Keyword(s):  
Molten Steel ◽  
Good Choice ◽  
Oxygen Activity ◽  
Theoretical Research ◽  
Calcium Activity ◽  
Research Results ◽  
Mass Percent ◽  
Top Slag

In order to control the plasticity of CaO-SiO2-Al2O3system inclusions so as to reduce the harm to the quality of 42CrMoA crankshaft steel, the target controlling ranges of CaO-SiO2-Al2O3inclusions is put forward. On the basis, influence of CaO-SiO2-Al2O3and CaO-SiO2-Al2O3-MgO system top slag on the content of calcium and aluminum in molten steel is contrasted. Theoretical research results show that, calcium activity should be controlled in the range of (90~3300)×10-10, oxygen activity should be below 7×10-6, the mass percent of calcium should be controlled more than 75ppm. And CaO-SiO2-Al2O3-MgO should be a good choice to obtain the plastic inclusions of CaO-SiO2-Al2O3.

Study of the stress-strain state of joints made of an orthotropic material

1990 ◽  
Vol 25 (4) ◽  
pp. 480-484
Author(s):  
V. I. Grishin ◽  
T. K. Begeev ◽  
V. B. Litvinov
Keyword(s):  
Orthotropic Material ◽  
Strain State ◽  
Stress Strain ◽  
Stress Strain State

Research on the Propagation of the Crack Parallel to and Lying on the Interface in the Cermet Cladding Part

2012 ◽  
Vol 426 ◽  
pp. 287-292
Author(s):  
J.R. Yang ◽  
X.F. Wang ◽  
Y.K. Zhang ◽  
Z.Q. Li ◽  
C.Z. Huang
Keyword(s):  
Crack Propagation ◽  
Interface Crack ◽  
Propagation Direction ◽  
Theoretical Research ◽  
Propagation Property ◽  
Research Results ◽  
Object A ◽  
Crack Propagation Direction ◽  
Propagation Law ◽  
Crack Propagation Criterion

Taking the interface crack in the cermet cladding part as the study object, a new comparative propagation property parameter (CPPP) CP suitable to judge the interface crack propagation direction in the cladding part is proposed. The interface crack propagation criterion is established. Based on it, the theoretical research on the parameters (CP1, CP2 and CPi) for the crack parallel to and lying on the interface propagating to the clad, to the substrate, and along the interface is carried out. The interface crack propagation law is investigated with an example. The research results show that the crack will more easily deflect to the clad.

scholarly journals Digital Radio Networks Centralized Elements Synchronization Model with Random Multiple Access to the CSMA/CA Type Medium

2020 ◽  
pp. 128-154
Author(s):  
Maksim Peregudov ◽  
Anatoliy Steshkovoy
Keyword(s):  
Communication Networks ◽  
Analytical Model ◽  
Multiple Access ◽  
Radio Networks ◽  
Packet Transmission ◽  
Theoretical Research ◽  
Radio Network ◽  
Radio Communication ◽  
Digital Radio ◽  
Research Results

Currently, there is a great interest in digital radio network centralized elements synchronization with random multiple access to the CSMA/CA type , the effectiveness of which determines the process of establishing a communication session. At the same time, there was no assessment effectiveness digital radio communication network centralized elements synchronization with random multiple access to the CSMA/CA type. Also, there was no assessment made the contribution of potential destructive actions by the attacker to the reduction in the effectiveness of such synchronization. This paper presents digital radio networks centralized elements synchronization analytical model with random multiple access to the CSMA/CA type medium. In this model the theoretical resulting indicator is the probability of successful delivery of a synchronization package, and a package frequency of successful delivery is used in experimental indicator evaluation . The model takes into account the potential destructive effects of the attacker in analytical expressions for known probabilistic indicators. An digital radio network  centralized elements synchronization with random multiple access to a CSMA/CA type experimental study an environment is also presented. The most common network of digital radio standard IEEE 802.11 (Wi-Fi) is considered as such network. The experimental research results differ from the theoretical research results slightly, which indicates the adequacy of the developed analytical model. It was established, firstly, that the successful delivery probability of a synchronization packet does not depend on number of subscriber terminals in digital radio communication networks, secondly, with an average duration of a data packet transmission by such terminal less than 0.85 ms, it is advisable to use non-random, and the reserved multiple access to the environment, and, thirdly, centralized synchronization is resistant to destructive influences. The model is applicable in the design of digital radio networks with random multiple access to the medium such as CSMA/CA, as well as in optimizing the operation of such networks.

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