scholarly journals COMPUTATIONAL-EXPERIMENTAL STUDY OF CONTACT INTERACTION OF BODIES WITH NEARLY FORM SURFACES

2021 ◽  
pp. 23-32
Author(s):  
Andrey Grabovskiy ◽  
Mykola А. Tkachuk ◽  
Natalia Domina ◽  
Ganna Tkachuk ◽  
Olha Ishchenko ◽  
...  
Keyword(s):  
Contact Pressure ◽  
Contact Interaction ◽  
Strain State ◽  
The Body ◽  
Contact Pressure Distribution ◽  
Interaction Method ◽  
Stress Strain ◽  
Stress Strain State ◽  
Flat Shape ◽  
Keywords Stress

  In many constructions, their elements are in contact with nominally matching (congruent) surfaces. In reality, this contact is disturbed due to deviations in the shape of these surfaces from the nominal. To study the effect of this perturbation on the distribution of contact pressure, the analysis of the stress-strain state of the body system of punched sheet-die is carried out. The middle element of this system deviates from the nominally flat shape. This causes a change in the contact pressure distribution. The proportionality between the clamping force and the level of contact pressure is also lost. The reliability and accuracy of the results obtained by numerical calculation have been experimentally confirmed. Keywords: stress-strain state; contact pressure; contact interaction; method of variational inequalities; Kalker variational principle; finite element method

scholarly journals NUMERCNAL ANALYSIS OF CONTACT INTERACTION OF BODIES WITH NEARLY FORM SURFACES

2021 ◽  
pp. 29-38
Author(s):  
Andrey Grabovskiy ◽  
Mykola А. Tkachuk ◽  
Natalia Domina ◽  
Ganna Tkachuk ◽  
Olha Ishchenko ◽  
...  
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Contact Interaction ◽  
Strain State ◽  
Contact Pressure Distribution ◽  
Stress Strain ◽  
Stress Strain State ◽  
Stamping Dies ◽  
The Impact ◽  
Element Method

Contact interaction of structural elements has been studied in the case of nominally close (nearly matching) surfaces. A non uniform gap is present between the contacting parts. Contact pressure and contact spot depend on the shape of this gap. Correspondingly so does the stress-strain state of the contacting bodies too. Since the problem is essentially nonlinear, the contact pressure distribution and the contact zones change with the growing loads. The solution is qualitatively different to the case of perfectly matching bodies. For the latter case, the contact pressure is linearly proportional to the load and the contact zone is predefined. Hence for the real structures for which the deviation from the nominal shape is unavoidable the impact of these inaccuracies on the contact pressure distribution and the stress-strain state need to be taken into account. This problem is addressed in the paper by example of elements of stamping dies. Keywords: element of stamping dies, stress-strain state, contact pressure, contact interaction, variational inequalities, Kalker’s variational principle, finite element method, boundary element method

scholarly journals MODELING THE ACTION OF THE SHOCK-WAVE LOAD ON THE HULLS ELEMENTS OF VEHICLES

2021 ◽  
pp. 5-16
Author(s):  
Anton Vasiliev ◽  
Serhii Kutsenko ◽  
Mykola А. Tkachuk ◽  
Andrey Grabovskiy ◽  
Oleg Shatalov ◽  
...  
Keyword(s):  
Shock Wave ◽  
Strain State ◽  
Moving Load ◽  
Element Model ◽  
The Body ◽  
Wave Load ◽  
Stress Strain ◽  
Stress Strain State ◽  
Dynamic Formulation ◽  
Keywords Stress

To study the effect of shock wave load on the body elements of vehicles, a setting has been developed that takes into account the mobile nature of this load. A specialized parametric finite-element model of the body layout has been created armored-carrier, taking into account the peculiarities of the studied process. The problem of determining the stress-strain state armored-hulls solved in static and dynamic formulation. The space-time distributions of components and characteristics of the stress-strain state of the investigated model armored-carrier of armored hulls are given. The results of research in the used formulations indicate the need to solve the problem in a complete dynamic formulation with account for plastic deformations. This  establishes a new methodology for the rational choice of engineering solutions. Keywords: stress-strain state; armored carrier; armored hulls; shock wave; moving load; sample; rational constructive decision

scholarly journals INVESTIGATION OF LOCAL UNLOADING OF AN ELEMENT IN A FINITE ELEMENT CONTINUUM

2021 ◽  
pp. 86-96
Author(s):  
A.Yu. Burtsev ◽  
◽  
V.V. Glagolev ◽  
A.A. Markin ◽  
◽  
...  
Keyword(s):  
Finite Element ◽  
Failure Criterion ◽  
Strain State ◽  
Plastic Region ◽  
Elastoplastic Problem ◽  
The Body ◽  
Stress Strain ◽  
Adjacent Element ◽  
Stress Strain State ◽  
Ansys Workbench

The subcritical elastoplastic deformation and the fracturing of an element of a finite element continuum in the Ansys Workbench complex are considered. When solving the elastoplastic problem of the subcritical deformation, a finite element with the failure criterion reached is selected. In a pre-fracture state of the element, the nodal forces provided by the interaction with an adjacent element are determined using the Ansys Workbench internal procedure. The following step is the consideration of the varying stress-strain state of the body during the element destruction. The elastoplastic problem is solved in the conditions of simple unloading of the body surface adjacent to the destructible element while maintaining the external load corresponding to the destruction initiation. When implementing the local unloading, a possibility of the new plastic region formation and the partial unloading are studied. As a result, the stress-strain state of the body at the beginning of local unloading is not the same as that at the end of the process. The proposed approach differs from the “element killing” procedure when the element stiffness after the failure criterion reached is assumed to be close to zero. The paper provides solutions to the problems of deformation of elastic and elastoplastic plates with a side cut taking into account their element destruction.

scholarly journals Stress-strain state of a combined toroidal baromembrane apparatus

2021 ◽  
Vol 21 (2) ◽  
pp. 123-132
Author(s):  
S. I. Lazarev ◽  
О. V. Lomakina ◽  
V. Е. Bulanov ◽  
I. V. Khorokhorina
Keyword(s):  
Strain State ◽  
Liquid Waste ◽  
The Body ◽  
Transmembrane Pressure ◽  
Toroidal Shell ◽  
Outer Diameter ◽  
Stress Strain ◽  
Load Bearing ◽  
Stress Strain State ◽  
Membrane Apparatus

Introduction. Currently, the purification of wastewater and technological solutions by membrane methods is considered a promising way to neutralize liquid waste. Therefore, the task of developing an engineering method for calculating baromembrane devices is a challenge. Studies on methods involving calculation of design and process variables, membrane equipment design, research of technological features of membrane devices, selection of design schemes, as well as methods of strength and rigidity analysis, are investigated.Materials and Methods. Basic elements of the body of the combined membrane apparatus are considered, a design scheme is proposed, and a method for calculating the strength and rigidity of the main load-bearing element, the cover, is described.  Results. The methods determine the required dimensions of shells and plates for the development of a combined membrane apparatus, and evaluate the strength properties of the devices of this class. The construction elements of the apparatus (primarily, the load-bearing covers) must meet not only the requirements of efficiency and quality of separation and cleaning of solutions, but also the conditions for safe operation. Therefore, the design of the device covers should be based on the optimal design dimensions (thicknesses of round plates, toroidal shells, and support rings). To test the method, the stress-strain state of the membrane apparatus structure was calculated for strength and rigidity. As an example, we consider one cover presented in the form of an open toroidal shell. The evaluation of the application of this technique, taking into account the fact that the shell is mated with a round plate in the inner diameter, and with a ring in the outer diameter, has provided the determination of the required parameters.Discussion and Conclusions. The obtained method of analytical description of the mechanical impact on the elements of the combined apparatus and the example of calculating the toroidal shell and plate, enables to evaluate the stressstrain state of the structure for strength and rigidity. The results of the calculation of covers made of various materials at different pressures are presented. Loading the combined apparatus with transmembrane pressure made it possible to determine the required dimensions of the shells and plates for its design and development. 

The stress-strain state at the junction of a jacket shell to the body of a vessel

1971 ◽  
Vol 7 (3) ◽  
pp. 205-207
Author(s):  
V. D. Babanskii ◽  
V. F. Kurylev ◽  
S. M. Kutepov
Keyword(s):  
Strain State ◽  
The Body ◽  
Stress Strain ◽  
Stress Strain State

scholarly journals Peculiarities of the stress-strain state of the “excavation – geo-environment” and “embankment – geo-environment” systems in the process of erecting them (part II)

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Mikhail Krasnov ◽  
Nikolay Gorshkov ◽  
Yuan Jingwen ◽  
Svetlana Jdanova
Keyword(s):  
Finite Elements ◽  
Strain State ◽  
Common Ground ◽  
Displacement Vector ◽  
Limit State ◽  
The Body ◽  
Volume Deformation ◽  
Stress Strain ◽  
Stress Strain State ◽  
The Stability

Excavations and embankments are the most common ground transport structures, operational reliability and durability of which is determined by the stability of their sides and slopes. The first article deals with the features of stress-strain state and changes in stability of ground transport structures (excavations) based on modeling according to the certified program of finite element method GenIDE32. At modeling the layer-by-layer excavation of homogeneous soil from excavations with finite geometrical sizes was carried out. In the excavation edge array, in the field of displacement vector ui, appeared are poorly studied phenomena in the form of «rotation circles» or short vortices. These phenomena, discovered in model experiments (Yu.I. Soloviev, 1956), require detailed research in the future. Graphic results of the calculations performed allow one to see the appearance and development of zones of «plasticity» or limit state in the form of zones of «shift-compression», «compression-shift» and «stretching». Shift-compression zones and vice versa are shown as shaded finite elements at an angle crosswise, while stretch zones are shown as shaded vertically, horizontally and vertically, and horizontally finite elements. These zones, in the process of modeling, are drawn in the edges of the projections of a slide with vertical and horizontal cracks. The contours of the landslide prisms show themselves well when the average relative volume deformation values of ε are displayed on the screen. The display of this value in two colors defines the landslide contours in this figure. Sliding lines with the minimum value of the stability coefficient kst min pass near the borders, where values of this parameter are equal to zero. In this figure, in the upper part of the array, you can see the places where vertical cracks are formed. The analysis also uses graphs of stress-strain state trajectories in the space of stress tensor invariants σij and relative deformations εij in significant nodes and finite elements, located, including, in places of sliding lines with kst min. They make it possible to see from the volume and shape deformation graphs where the system with the calculated condition is located, for example, from the condition at which the body of the landslide was formed.

scholarly journals CONTACT INTERACTION OF A TORSION SHAFT WITH A SPLINED BUSH IN ELASTICALLY PLASTIC DEFORMATIONS

2021 ◽  
pp. 34-46
Author(s):  
Andrey Grabovskiy ◽  
Mykola M. Tkachuk ◽  
Anton Zavorotnii ◽  
Serhii Kutsenko S ◽  
Mariia Saverska ◽  
...  
Keyword(s):  
Contact Interaction ◽  
Strain State ◽  
Design Parameters ◽  
Stress Strain ◽  
Plastic Deformations ◽  
Suspension Systems ◽  
Stress Strain State ◽  
Manufacturing Operations ◽  
Contact Loads ◽  
Interaction Stress

Torsion shafts are the main elastic element of the suspension systems of a large number of vehicles. To simulate their reaction to the action of torque, the stress-strain state is analyzed taking into account the contact interaction with the spline sleeve. The features of the distribution of contact pressure between these bodies are established. The nature of stress concentration in the splined hollows of the shaft head is determined. Models and research methods have been developed that make it possible to develop recommendations for design decisions in the design of vehicle suspension systems. The factors are determined that ensure the strength of the torsion shaft at the values of its head diameters close to the diameters of the torsion shaft stem. In the case under consideration, this factor is firstly strength of the torsion shaft head. In particular, it was found that during manufacturing operations there are significant plastic deformations and contact loads in the heads of torsion shafts. This factor is decisive in substantiating the design parameters of torsion shafts. Keywords: torsion shaft; contact interaction; stress-strain state; elastically plastic deformation; suspension system

scholarly journals Research of stress-strain state and stability of a rokfill dam under seismic actions

Vestnik MGSU ◽  
2015 ◽  
pp. 157-166
Author(s):  
Vyacheslav Valentinovich Orekhov
Keyword(s):  
Strain State ◽  
Initial Conditions ◽  
The Body ◽  
Cohesionless Soil ◽  
Soil Base ◽  
Stress Strain ◽  
Stress Strain State ◽  
Soil Skeleton ◽  
Water Saturated ◽  
Seismic Impacts

One of the main factors determining the safety of earth sea and river hydraulic structures erected on water-saturated grounds is the process of consolidation, manifested under the action of static and seismic loads. A feature of cohesionless soils located in the structure itself or in its base, is their potential ability to liquefaction under seismic impacts. This paper describes the method of calculating the saturated soil’s environments under seismic actions based on the numerical solution of differential equations of the theory of consolidation by finite element method. The results of the static problem solving for the phased construction of the installation are used as the initial conditions. In order to describe the deformability of soil materials mathematical model formed by the theory of plastic flow with hardening is used. The parameters of this model are determined by the results of triaxial testing of soils. As an example, we study the interaction of a sea rockfill dam with a sandy base under seismic impacts, determined by the synthetic accelerograms. The results of calculations of the stress-strain state of the two sections of the dam (shallow and deep) are presented, and assessment is made of the possibility of liquefaction of sandy soil base. It is shown that the pore pressure that occurs in water-saturated cohesionless soil base and the body of the dam under seismic impacts, unloads the soil skeleton, which leads to a decrease in local shear safety factors. And, in the less dense soil base of the shallow section of the dam, the soil skeleton is unloaded to a greater extent, which negatively affects its overall safety factor.

scholarly journals Numerical Study of Stress-Strain State of Workpiece in Contact Problem of Surface Mandrel Drilling

2021 ◽  
Vol 20 (3) ◽  
pp. 259-267
Author(s):  
N. S. Sivtsev ◽  
V. V. Tarasov
Keyword(s):  
Plastic Deformation ◽  
Friction Coefficient ◽  
Contact Interaction ◽  
Computational Experiment ◽  
Strain State ◽  
Numerical Study ◽  
Surface Plastic Deformation ◽  
Surface Plastic ◽  
Stress Strain ◽  
Stress Strain State

In recent years, the economic factor has played an increasingly important role in the selection of technologies for manufacturing machine parts with specified values of normalized parameters of geometric accuracy and quality of working surfaces. As applied to surface plastic deformation processes, this is noticeably manifested in the search for effective friction control methods in the “tool – workpiece” pair, which ultimately determines the distribution pattern and the magnitude of stresses and strains in the workpiece and the tool. It is not possible to obtain a rigorous analytical solution to the problem of establishing a connection between surface conditions, friction, and the stress-strain state of the contacted bodies. In this regard, the construction of mathematical models comes to the fore, the solution of which is possible by numerical methods. The paper presents the results of a numerical study (computational experiment) of a finite-element model of workpiece deformation under various conditions of contact interaction and friction by one of the methods of surface plastic deformation – surface mandrel drilling. The friction coefficient has been chosen as the criterion for assessing the conditions of contact interaction and friction. It is shown that a change in the friction coefficient in the process of surface mandrel has no noticeable effect on the formation of a stress field in the deformable workpiece both in the axial, and in the radial and circumferential directions. At the same time, with an increase in the value of the friction coefficient in the “tool – workpiece” pair and with the associated increase in the force of mechanical resistance to deformation of the workpiece, their growth is observed. A computational experiment has confirmed the presence of non-contact deformations of the workpiece and tool during surface mandrel drilling, as well as  as a decrease in the value of residual deformations in the workpiece with a decrease in the coefficient of friction. Balance assessment of contact surface displacements in the workpiece (the inner surface of the hole to be machined) and the tool (mandrel) has shown that the deformations of the tool in the elastic region can lead to a significant decrease in the real tightness of surface mandrel drilling.

scholarly journals DETERMINATION OF STRESS-STRAIN STATE OF THE BODY SURFACE OR ITS AREA IN CASE OF PERFECT PLASTICITY AT GIVEN STRESS AND DISPLACEMENT VECTORS

2020 ◽  
Vol 2 ◽  
pp. 201-209
Author(s):  
Anvar I. Chanyshev ◽  
Ilgizar M. Abdulin ◽  
Olga A. Lukyashko
Keyword(s):  
Body Surface ◽  
Strain State ◽  
Rapid Assessment ◽  
Strain Tensor ◽  
The Body ◽  
Plastic State ◽  
Cauchy Stress ◽  
Stress Strain ◽  
Stress Strain State ◽  
Displacement Vectors

Ideally plastic state of material under conditions of Mises plasticity, proportionality of stress and strain deviators (deformation theory of plasticity) and elastic volume change is considered. Given the Cauchy stress and displacement vectors specified on the body surface (with indicated state) or its area, all six components of the stress tensor, all six components of the strain tensor, and also three components of the rotation vector are restored on this surface. This method for determining the stress-strain state can be related to the methods of rapid assessment of the structure state (body surface), since differential equations inside the body are not involved.

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