Calculation of the stress-strain state and time for the start of failure for structural elements taking account of material damage vulnerability during creep

1983 ◽  
Vol 15 (1) ◽  
pp. 68-74 ◽  
Author(s):  
A. F. Nikitenko ◽  
V. A. Zaev
Keyword(s):  
Strain State ◽  
Material Damage ◽  
Structural Elements ◽  
Stress Strain ◽  
Stress Strain State

Designing of Details Taking into Account Degradation of Structural Ceramics at Exploitation

2015 ◽  
Vol 752-753 ◽  
pp. 268-271 ◽  
Author(s):  
Valery V. Kuzin ◽  
Stanislav Grigoriev ◽  
Marina Volosova ◽  
Mike Fedorov
Keyword(s):  
Rational Choice ◽  
Strain State ◽  
Structural Elements ◽  
Structural Ceramics ◽  
Stress Strain ◽  
Stress Strain State ◽  
New Generation

Composite character of ceramics is a base for creating new generation materials. It is established that the rational choice of the basic structural elements allows to control stress-strain state of the "loaded" ceramics and to slow down process of its degradation. The developed method of designing of details taking into account ceramics degradation at exploitation is described.

scholarly journals THEORETICAL BASIСS OF PROVIDING THE TECHNICAL CHARACTERISTICS OF MILITARY AND CIVIL VEHICLES BY JUSTIFICATION OF THE FORM AND PROPERTIES OF THE MATERIALS OF CONTACTING ELEMENTS

2021 ◽  
pp. 17-22
Author(s):  
Andrey Grabovskiy ◽  
Iryna Hrechka ◽  
Mykola M. Tkachuk ◽  
Mariia Saverska ◽  
Serhii Kutsenko ◽  
...  
Keyword(s):  
Strain State ◽  
Variational Principles ◽  
Technological Factor ◽  
Interaction Strength ◽  
Structural Elements ◽  
Stress Strain ◽  
Strength Criteria ◽  
Stress Strain State ◽  
Contact Loads ◽  
World Class

Elements of constructions of modern military and civil vehicles usually work in conditions of high contact loads. Аt the stage of their creation, strength studies are carried out using traditional models of contact of bodies of nominal shape. Нowever, the real structural elements have deviations from such models, which are due to design and technological factors: macrodeviation of the shape, surface roughness, strengthening etc. Such perturbations of nominal parameters have a significant effect on the distribution of contact pressure between the elements of military and civil vehicles, however, traditional methods for studying the stress-strain state of contacting bodies do not make it possible to take such factors into account fully, collectively and exhaustively. To eliminate the existing contradiction, a semi-analytical method is proposed, which is based on the development of variational principles and boundary-element sampling. The created models make it possible to take into account the regularities of the influence of shape perturbations and properties of the surface layers of contacting bodies on the stress-strain state. As a result, it becomes possible to justify favorable perturbations by strength criteria. Such models and methods are offered to the work, and on their basis it’s proposed the implementation of research elements of military and civil vehicles for appointment to ensure world class the technical and tactically technical characteristics. Ключові слова: military and civilian vehicles; design and technological factor; stress-strain state; contact interaction; strength

scholarly journals Influence of stresses on deformation process under the irradiation creep and swelling

2021 ◽  
pp. 23-28
Author(s):  
Dmytro Breslavsky
Keyword(s):  
Numerical Modelling ◽  
Strain State ◽  
Strain Tensor ◽  
Complex Stress ◽  
Complex Stress State ◽  
Structural Elements ◽  
Stress Strain ◽  
Radiation Creep ◽  
Stress Strain State ◽  
Radiation Swelling

Approaches for describing the deformation of structural elements made from the material, in which radiation creep and swelling strains develop simultaneously, are discussed. The technique for description of irradiation swelling strains, which is used for calculational analysis of stress-strain state arising in structural elements under the joint action of irradiation and thermal-stress fields, is regarded. A complete system of equations of the boundary –initial value problem is presented, in which elastic and thermal strains, strains of radiation creep and swelling are taken into account. Numerical modelling was carried out using the specialized software FEM Creep, in which the boundary value problem is solved by the Finite Element Method, and the initial one is integrated in time by the difference predictor-corrector method. Two forms are given for the equation of state describing the radiation swelling strains: first is for the components of the strain tensor as well as second is prepared for their rates. The hypothesis about the linear correspondence of the received radiation dose and the deformation time, during which radiation swelling strains develop, are analyzed. A number of questions that require answers when using equations with a complex stress state in which the radiation swelling strains are directly depend on stresses, are discussed. Based on the processing of experimental data on the swelling of tubes made of steel 316Ti in the temperature range of 450-460 °С, a form of the equation for the radiation swelling strain rate is proposed, and the constants included in it are determined. Using the example of numerical modelling of the deformation of tubes were made of steel 316Ti and loaded by inner pressure, the applicability of the classical approach for the analysis of the stress-strain state in the presence of radiation swelling strains is shown.

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