Method for analyzing the kinetics of damage accumulation in the structure of polymer materials under tensile stresses

2021 ◽  
Author(s):  
Tatyana Nizina ◽  
Dmitriy Nizin ◽  
Nadezhda Kanaeva ◽  
Denis Artamonov
Keyword(s):  
Damage Accumulation ◽  
Polymer Materials ◽  
Tensile Stresses ◽  
Kinetics Of

Quantitative Assessment of the Kinetics of Damage Accumulation in the Polymer Matrix Structure Under Full-Scale Climatic Factors and Tensile Loads

2021 ◽  
pp. 93-102
Author(s):  
В. П. Селяев ◽  
Д. Р. Низин ◽  
Н. С. Канаева
Keyword(s):  
Damage Accumulation ◽  
Climatic Factors ◽  
Full Scale ◽  
Polymer Materials ◽  
Strength Performance ◽  
Deformation Curves ◽  
Epoxy Polymers ◽  
Specific Index ◽  
Accumulation Kinetics ◽  
Kinetics Of

Постановка задачи. Изучено изменение упруго-прочностных показателей и кинетики накопления повреждений в эпоксидных полимерах под действием растягивающих нагрузок в контрольном состоянии и после натурного климатического воздействия в течение одного календарного года. Расчет кинетики накопления повреждений осуществлялся на основе авторской методики, основанной на использовании методов фрактального анализа кривых деформирования образцов полимерных материалов при растяжении. Результаты. Предложен удельный показатель θ, позволяющий количественно оценивать суммарное число повреждений на единицу прочности, накопление которого приводит к разрушению полимеров. Получены аппроксимирующие зависимости, описывающие взаимосвязь между удельным показателем θ и пределом прочности эпоксидных полимеров при растяжении. Выводы. Установлено, что наибольшей стабильностью свойств под действием натурного климатического воздействия обладает полимер на основе эпоксидной смолы «Этал-247». Statement of the problem. In the current study we look at the change in the elastic-strength performance and kinetics of damage accumulation in epoxy polymers under tensile loads in the control state and after full-scale climatic exposure during one calendar year were studied. Damage accumulation kinetics was calculated based on the author's method using methods of fractal analysis of deformation curves for polymer materials samples under tension. Results. We proposed specific index θ to quantify the total number of damages per unit of strength where its accumulation leads to the destruction of polymers. The dependences have been obtained that describe the relationship between specific index θ and tensile strength of epoxy polymers. Consclusion. The study has shown that the Etal-247 epoxy resin-based polymer cured with Etal-1440 amine hardener has the most stable properties under the full-scale climatic exposure.

scholarly journals QUANTITATIVE ASSESSMENT OF THE KINETICS OF DAMAGE ACCUMULATION IN THE POLYMER MATRIX STRUCTURE UNDER FULL-SCALE CLIMATIC FACTORS AND TENSILE LOADS

2021 ◽  
pp. 63-71
Author(s):  
V. P. Selyaev ◽  
D. R. Nizin ◽  
N. S. Kanaeva
Keyword(s):  
Damage Accumulation ◽  
Climatic Factors ◽  
Full Scale ◽  
Polymer Materials ◽  
Strength Performance ◽  
Deformation Curves ◽  
Specific Index ◽  
Accumulation Kinetics ◽  
The Relationship ◽  
Kinetics Of

Statement of the problem. In the current study we look at the change in the elastic-strength performance and kinetics of damage accumulation in epoxy polymers under tensile loads in the control state and after full-scale climatic exposure during one calendar year were studied. Damage accumulation kinetics was calculated based on the author's method using methods of fractal analysis of deformation curves for polymer materials samples under tension.Results. We proposed specific index θ to quantify the total number of damages per unit of strength,where its accumulation leads to the destruction of polymers. We obtained approximating dependences that describe the relationship between specific index θ and tensile strength of epoxy polymers.Consclusion. The study has shown that the Etal-247 epoxy resin-based polymer cured withEtal-1440 amine hardener has the most stable properties under the full-scale climatic exposure.

Kinetics of diffusion and sorption in aging processes of polymer materials (Review)

2021 ◽  
pp. 1-14
Author(s):  
A. A. Dalinkevich ◽  
◽  
L. V. Fomin ◽  
V. V. Melnikov ◽  
T. A. Nenasheva ◽  
...  
Keyword(s):  
Polymer Materials ◽  
Kinetics Of

scholarly journals EVALUATION OF THE RESOURCE CHARACTERISTICS OF POLYCRYSTALLINE STRUCTURAL ALLOYS UNDER CYCLIC THERMOMECHANICAL LOADING

2021 ◽  
Vol 83 (4) ◽  
pp. 481-504
Author(s):  
I.A, Volkov ◽  
L.A. Igumnov ◽  
D.N. Shishulin ◽  
A.A. Belov
Keyword(s):  
Fatigue Damage ◽  
Damage Accumulation ◽  
Mechanical Characteristics ◽  
Stress Deviator ◽  
Thermomechanical Loading ◽  
Effective Stresses ◽  
Accumulation Of Damage ◽  
Resource Characteristics ◽  
Kinetics Of ◽  
Physical And Mechanical Characteristics

The main physical regularities of complex thermoviscoplastic deformation and accumulation of damage in structural materials (metals and their alloys) under various modes of cyclic combined thermomechanical loading and mathematical models of these processes are considered. A mathematical model of the mechanics of a damaged medium has been developed, which makes it possible to simulate the cyclic viscoelastoplastic behavior and determine the resource characteristics of polycrystalline structural alloys under the combined action of degradation mechanisms that combine material fatigue and creep. The model is based on the joint integration of equations describing the kinetics of the stress-strain state and damage accumulation processes. The final relation to the model is the strength criterion, the fulfillment of which corresponds to the formation of a macrocrack. The plasticity equations are based on the basic principles of the flow theory. To describe the creep process in the stress space, a family of equipotential creep surfaces of the corresponding radius and having a common center is introduced. The relationship between the creep equations and the thermoplasticity equations describing “instantaneous” plastic deformations is carried out at the loading stage through the stress deviator and the corresponding algorithm for determining and at the loading stage by means of certain relationships between “temporary” and “instantaneous” scalar and tensor quantities. At the stage of development of damage scattered throughout the volume, the effect of damage on the physical and mechanical characteristics of the material is observed. This influence can be taken into account by introducing effective stresses. In the general case, stresses, plastic strains, and creep strains are determined by integrating the thermal creep equations by the four-point Runge-Kutta method with correction of the stress deviator and subsequent determination of stresses according to the thermoplasticity equations, taking into account the average creep strain rate at a new time. The relationships that simulate the accumulation of damage are based on the energy approach to determining the resource characteristics. The kinetics of fatigue damage accumulation is based on the introduction of a scalar parameter of damage to a structural material and a unified model form for representing the degradation mechanism under fatigue and creep conditions. The influence of scattered damage on the physical and mechanical characteristics of the material is taken into account by introducing effective stresses. The results of numerical simulation of cyclic thermoplastic deformation and accumulation of fatigue damage in heat-resistant alloys (Haynes188) under combined thermomechanical loading are presented. Particular attention is paid to the issues of modeling the processes of cyclic thermoplastic deformation and the accumulation of fatigue damage for complex deformation processes accompanied by the rotation of the main areas of stress and strain tensors.

Kinetics of damage accumulation in D16сh alloy specimens under static loading

2021 ◽  
pp. 18-26
Author(s):  
M.R. Tyutin ◽  
◽  
L.R. Botvina ◽  
V.P. Levin ◽  
E.N. Beletskii ◽  
...  
Keyword(s):  
Static Loading ◽  
Damage Accumulation ◽  
Kinetics Of

scholarly journals Kinetics of deformation and damage accumulation in concentration zones with nonisothermal low-cycle loading

1985 ◽  
Vol 17 (8) ◽  
pp. 1050-1056
Author(s):  
A. G. Kazantsev ◽  
A. P. Gusenkov ◽  
A. N. Chernykh
Keyword(s):  
Damage Accumulation ◽  
Cycle Loading ◽  
Kinetics Of

scholarly journals The Toxicological Testing and Thermal Decomposition of Drive and Transport Belts Made of Thermoplastic Multilayer Polymer Materials

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2232 ◽  
Author(s):  
Piotr Krawiec ◽  
Łukasz Warguła ◽  
Daniel Małozięć ◽  
Piotr Kaczmarzyk ◽  
Anna Dziechciarz ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Degradation Kinetics ◽  
Combustion Products ◽  
Polymer Materials ◽  
Toxic Substances ◽  
Butadiene Rubber ◽  
Different Temperatures ◽  
Increasing Temperature ◽  
In Fire ◽  
Kinetics Of

The article presents the potential impact of flat drive and transport belts on people’s safety during a fire. The analysis distinguished belts made of classically used fabric–rubber composite materials reinforced with cord and currently used multilayer polymer composites. Moreover, the products’ multilayers during the thermal decomposition and combustion can be a source of emissions for unpredictable and toxic substances with different concentrations and compositions. In the evaluation of the compared belts, a testing methodology was used to determine the toxicometric indicators (WLC50SM) on the basis of which it was possible to determine the toxicity of thermal decomposition and combustion products in agreement with the standards in force in several countries of the EU and Russia. The analysis was carried out on the basis of the registration of emissions of chemical compounds during the thermal decomposition and combustion of polymer materials at three different temperatures. Moreover, the degradation kinetics of the polymeric belts by using the thermogravimetric (TGA) technique was evaluated. Test results have shown that products of thermal decomposition resulting from the neoprene (NE22), leder leder (LL2), thermoplastic connection (TC), and extra high top cower (XH) belts can be characterized as moderately toxic or toxic. Their toxicity significantly increases with the increasing temperature of thermal decomposition or combustion, especially above 450 °C. The results showed that the belts made of several layers of polyamide can be considered the least toxic in fire conditions. The TGA results showed that NBR/PA/PA/NBR belt made with two layers of polyamide and the acrylonitrile–butadiene rubber has the highest thermal stability in comparison to other belts.

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