Back-Calculated Indentation Stress-Strain Curves from Small Scale Testing and Verification Using Finite Element Models: Application to Nanoindentation and Micropillar Compression Study of a Heavy Ion Irradiated Zr-2.5Nb Alloy

2021 ◽  
pp. 294-318
Author(s):  
Qiang Wang ◽  
Mark R. Daymond
Keyword(s):  
Finite Element ◽  
Heavy Ion ◽  
Small Scale ◽  
Finite Element Models ◽  
Stress Strain ◽  
Micropillar Compression

Accuracy of Failure Criteria Commonly Used for Ship Collision Simulations

2018 ◽  
Author(s):  
R. Villavicencio ◽  
Bin Liu ◽  
Kun Liu
Keyword(s):  
Finite Element ◽  
Failure Criteria ◽  
Small Scale ◽  
Finite Element Models ◽  
Impact Loads ◽  
Large Scatter ◽  
Element Analysis ◽  
Advantages And Disadvantages ◽  
Ship Collision ◽  
Double Hull

The paper summarises observations of the fracture response of small-scale double hull specimens subjected to quasi-static impact loads by means of simulations of the respective experiments. The collision scenarios are used to evaluate the discretisation of the finite element models, and the energy-responses given by various failure criteria commonly selected for collision assessments. Nine double hull specimens are considered in the analysis so that to discuss the advantages and disadvantages of the different failure criterion selected for the comparison. Since a large scatter is observed from the numerical results, a discussion on the reliability of finite element analysis is also provided based on the present study and other research works found in the literature.

scholarly journals REGULARITIES OF THE LINING STRESS-STRAIN STATE DURING OF THE PYLON METRO STATION CONSTRUCTION

2021 ◽  
pp. 19-27
Author(s):  
D. O. BANNIKOV ◽  
V. P. KUPRII ◽  
D. YU. VOTCHENKO
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Elements ◽  
Strain State ◽  
Finite Element Models ◽  
Bending Moments ◽  
Stress Strain ◽  
Normal Forces ◽  
Stress Strain State ◽  
Station Structure

Purpose. Perform numerical analysis of the station structure. Take into account in the process of mathematical modeling the process of construction of station tunnels of a three-vaulted station. Obtain the regularities of the stress-strain state of the linings, which is influenced by the processes of soil excavation and lining construction. Methodology. To achieve this goal, a series of numerical calculations of models of the deep contour interval metro pylon station was performed. Three finite-element models have been developed, which reflect the stages of construction of a three-vaulted pylon station. Numerical analysis was performed on the basis of the finite element method, implemented in the calculation complex Lira for Windows. Modeling of the stress-strain state of the station tunnel linings and the soil massif was performed using rectangular, universal quadrangular and triangular finite elements, which take into account the special properties of the soil massif. Station tunnel linings are modeled by means of rod finite elements. Findings. Isofields of the stress-strain state in finite-element models reflecting the stages of construction are obtained. The vertical displacements and horizontal stresses that are characteristic of a three-vaulted pylon station are analyzed. The analysis of horizontal stresses proved that at the stage of opening of the middle tunnel the scheme of pylon operation is rather disadvantageous. The analysis of bending moments and normal forces was also carried out and the asymmetry of their distribution was noted. Originality. Based on the obtained patterns of distribution of stress-strain state and force factors, it is proved that numerical analysis of the station structure during construction is necessary to take measures to prevent or reduce deformation of frames that are in unfavorable conditions. Practical value. In the course of research, the regularities of changes in stresses, displacements, bending moments and normal forces in the models of the pylon station, which reflect the sequence of its construction, were obtained.

Contact Analysis of the Rotor in a Variable Capacitance Micro-Motor

2005 ◽  
Author(s):  
Wen-Ming Zhang ◽  
Guang Meng
Keyword(s):  
Finite Element ◽  
Contact Problem ◽  
Contact Stress ◽  
Numerical Solutions ◽  
Ground Plane ◽  
Contact Process ◽  
Nonlinear Phenomena ◽  
Finite Element Models ◽  
Stress Strain ◽  
Variable Capacitance

The most widely known nonlinear phenomena in Micro-electro-mechanical systems (MEMS) are probably the contact instabilities. Contact problem is an important topic in the research of micro-motors. While the micro-motor is in operation, the rotor is intended to be in electrical contact with the ground plane, and the rotor and bearing hub form a pair of contact bodies. In the paper, a mathematic model is proposed to describe the contact process and two simplified contact finite element models of the rotor, bearing and ground plane are presented to simulate the contact. The effects on the contact stress, strain and pressure are analyzed in micro-scale. The rotor-to-bearing-hub and the hemispherical-bushing-on-ground-plane configurations finite element models (FEM) are established and the implementation of the contact problem is introduced to provide the numerical solutions acted as a guide to solution of contact problems in a variable capacitance micromotor. The numerical results of the contact stress, strain and pressure and the effects of the coefficient of friction and the surface roughness of the contact pairs on contact characteristics are studied and discussed in detail. It is indicated that the nonlinear effects should not be ignored and these results must be evaluated on a relative scale to compare different design options.

scholarly journals ANALYSIS OF FEATURES OF APPLIED SOFTWARE “LIRA” IN CALCULATIONS OF NON-CIRCULAR TUNNEL LININGS

2019 ◽  
pp. 41-50
Author(s):  
V. P. KUPRIY ◽  
O. L. TIUTKIN ◽  
P. YE. ZAKHARCHENKO
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Finite Element Model ◽  
Software Package ◽  
Strain State ◽  
Element Model ◽  
Finite Element Models ◽  
Stress Strain ◽  
Stress Strain State ◽  
The Finite Element Model

Purpose. The article examines the effect on the stress-strain state of the parameters of the finite-element model created in the “Lira” software package in a numerical analysis of non-circular outlined tunnels. Methodology To achieve this goal, the authors developed finite element models of the calotte part of the mine during the construction of a double track railway tunnel using “Lira” software. In each of the models in the “Lira” software package, the interaction zone with temporary fastening was sampled in a specific way. After creation of models, their numerical analysis with the detailed research of his results was conducted. Findings. In the finite element models, the values of deformations and stresses in the horizontal and vertical axes, as well as the maximum values of the moments and longitudinal forces in the temporary fastening were obtained. A comparative analysis of the obtained values of the components of the stress-strain state with a change in the parameters of the finite element model was carried out. The graphs of the laws of these results from the discretization features of the two models were plotted. The third finite element model with a radial meshing in the zone of interaction of temporary support with the surrounding soil massif was investigated. Originality It has been established that in the numerical analysis of the SSS of a tunnel lining of a non-circular outline, its results substantially depend on the shape, size and configuration of the applied finite elements, on the size of the computational area of the soil massif, and also on the conditions for taking into account the actual (elastic or plastic) behavior of the soil massif.  Practical value. The features of discretization and the required dimensions of the computational area of the soil massif were determined when modeling the “lining – soil massif” system, which provide sufficient accuracy for calculating the parameters of the stress-strain state of the lining.

scholarly journals Elaboration of testing technique of flat slabs on punching shear strength using finite element modeling

2018 ◽  
Vol 196 ◽  
pp. 02048
Author(s):  
Valery Filatov ◽  
Zulfat Galyautdinov ◽  
Alexander Suvorov
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Cross Section ◽  
Strain State ◽  
Concrete Slabs ◽  
Finite Element Models ◽  
Bending Moments ◽  
Stress Strain ◽  
Stress Strain State ◽  
Reinforced Concrete Slabs

The results of researches on finite-element models of stress-strain state of flat reinforced concrete slabs of beamless frame under punching by columns of square and rectangular cross-section are presented. The purpose of the study was to develop a technique for testing samples plates for punching in the presence of bending moments in a column. The results of the study of deflections of reinforced concrete slabs, the distribution of bending moments in the punching zone of the plate under various loading schemes are presented. Variable parameter was the ratio of the sides of the column cross-section. Comparative analysis of studies results on finite element models has made it possible to choose the optimal variant of applying the load to the test samples, depending on the aspect ratio of rectangular section of column. Results of the conducted research will allow simulating the stress-strain state in the punching zone of natural reinforced concrete slabs of monolithic beamless frame during the test of samples.

scholarly journals Development of 3-D Finite Element Models for Geo-Jute Reinforced Flexible Pavement

2019 ◽  
Vol 5 (2) ◽  
pp. 437 ◽  
Author(s):  
Md Mostaqur Rahman ◽  
Sajib Saha ◽  
Amin Sami Amin Hamdi ◽  
Md Jobair Bin Alam
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Flexible Pavement ◽  
Reinforced Soil ◽  
Finite Element Models ◽  
Stress Strain ◽  
Element Analysis ◽  
Subgrade Soil ◽  
Cbr Test

In this study, three dimensional (3-D) finite element analysis are performed to evaluate the effect of geo-textile interlayer on the performance of flexible pavement. The main objective of this study is to evaluate the improvement in stress distribution of flexible pavement due to the application of geo-jute at three specific positions i.e., subgrade-base interface, base-asphalt layer interface, and within asphalt layers. Stress, strain and displacement values are investigated and compared for the application of geo-jute interlayer on various positions. Moreover, to better understand the mechanistic behavior of geo-jute on pavement subgrade, a separate 3-D finite element model is developed to simulate the California bearing ratio (CBR) test on geo-jute reinforced soil. Results showed that the inclusion of geo-jute on flexible pavement significantly improves the pavement performance by producing lower stress, strain, and displacement at top of the subgrade. Moreover, the bearing capacity of subgrade soil increased more than 20% due to the inclusion of geo-jute.

scholarly journals Load simulation of a base station chassis of the mobile transport and overloading rope complex

2021 ◽  
Vol 7 (2) ◽  
pp. 166-175
Author(s):  
V.I. Tarichko ◽  
◽  
P.I. Shalupina ◽  
Keyword(s):  
Finite Element ◽  
Strain State ◽  
Metal Structure ◽  
Base Station ◽  
Finite Element Models ◽  
Stress Strain ◽  
Grid Model ◽  
Stress Strain State ◽  
Load Simulation

The article deals with the issues of modeling the stress-strain state of a chassis designed to accommodate the equipment of a mobile transport and overloading rope complex. The main computational cases are determined. Geometric and computational finite element models are constructed, taking into account the features of the metal structure and suspension elements. The method of gluing elements of the grid model is applied. On the basis of the performed calculations, conclusions are drawn about the compliance of the developed structure with the requirements of strength and rigidity.

scholarly journals Stress-strain state of reinforced concrete structures of the LN-1 and LN-2 retaining walls of Zagorskaya PSPP taking into account the opening of interblock joints and the formation of secondary cracks

2021 ◽  
Vol 17 (4) ◽  
pp. 324-334
Author(s):  
Nartmir V. Khanov ◽  
Fedor A. Pashchenko
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Strain State ◽  
Retaining Walls ◽  
Transverse Reinforcement ◽  
Reinforced Concrete Structures ◽  
Finite Element Models ◽  
Computational Studies ◽  
Stress Strain ◽  
Stress Strain State

Relevance. The lower retaining walls of the water intake of the Zagorskaya PSPP perform the important function of protecting the pressure water conduits from the collapse of the soil massif. Two of them (LN-2 and LN-3) were reinforced with anchor rods. Considering the long period of operation (more than 25 years), certain deviations in the work during examinations and field observations were revealed. So, on the front face of the walls, extended horizontal cracks were recorded (opening of horizontal interblock joints and the emergence of secondary oblique cracks on the front surface of the walls). To carry out computational studies of the stress-strain state of the downstream retaining walls was required. The purpose of the work was to determine the stress-strain state of the lower retaining walls of the water intake of the Zagorskaya PSPP taking into account the opening of interblock joints and the formation of secondary oblique cracks. Methods. Computational studies of the stress-strain state of retaining walls were carried out within the framework of the method of numerical modeling of reinforced concrete structures of hydraulic structures based on finite element models. In finite element models, structural features of retaining walls were reproduced, including anchor rods, horizontal interblock joints, actual reinforcement, secondary oblique cracks. Results. The stress-strain state of the retaining walls was obtained. The stresses in the longitudinal and transverse reinforcement were determined, including when the structure was changed due to anchor rods. In horizontally transverse reinforcement, tensile stresses exceeding the yield point are recorded. It took the development of measures to strengthen the lower retaining walls.

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