Elastic Stress Distribution in Layered Spherical Shells With Gaps Caused by Internal Pressure

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Shugen Xu ◽  
Chao Chen
Keyword(s):  
Finite Element ◽  
Spherical Shell ◽  
Elastic Stress ◽  
Outer Wall ◽  
Wall Surface ◽  
The Finite Element Method ◽  
Spherical Shells ◽  
Calculation Results ◽  
The Difference ◽  
Stress Discontinuity

An interlayer gap is inevitable in layered spherical shells. Therefore, the classic formulae for the monobloc spherical shell can no longer be used. In this paper, the formulae for the elastic stress calculation of layered spherical shells were proposed and the difference between the proposed formulae and ASME formulae was clarified. Interlayer gaps induce stress redistribution and stress discontinuity in the layered spherical shell. The hoop stress in the inner wall surface becomes higher than that in the monobloc spherical shell, and the stress in the outer wall surface is lower. Calculation results obtained from the proposed formulae were compared to those obtained by the finite element method (FEM) and ASME formulae. It was shown that the results from the proposed formulae are in accordance with finite element results.

Finite Element Analysis of Creep Damage Behavior Near the Cavity on Bimaterial Interface

2006 ◽  
Vol 324-325 ◽  
pp. 951-954 ◽  
Author(s):  
Qing Min Yu ◽  
Zhu Feng Yue ◽  
Yong Shou Liu
Keyword(s):  
Finite Element ◽  
Elastic Moduli ◽  
Elastic Stress ◽  
Creep Damage ◽  
Ductile Material ◽  
Bimaterial Interface ◽  
Modulus Ratio ◽  
Element Analysis ◽  
Damage Law ◽  
The Difference

Fracture along an interface between materials plays a major role in failure of material. In this investigation, finite element calculations with Kachanov–Rabotnov damage law were carried out to study the creep damage distribution near the interface cavity in bimaterial specimens. The specimens with central hole were divided into three types. The material parameters of K-R law used in this paper were chosen for a brittle material and ductile material. All calculations were performed under four load cases. Due to the difference between elastic moduli of the bounded materials, the elastic stress field as a function of the Young’s modulus ratio (R=E1/E2) was determined. At the same time, the influence of model type on elastic stress distribution near the cavity was considered. Under the same conditions, the material with larger modulus is subjected to larger stress. The creep damage calculations show that the location of the maximum damage is different for each model. The distributions of creep damage for all three models are dependent on the material properties and load cases.

scholarly journals The Search of Spatial Functions of Pressure in Adjustable Hydrostaticradial Bearing

2015 ◽  
Vol 9 (1) ◽  
pp. 23-26 ◽  
Author(s):  
Dmytro Fedorynenko ◽  
Sergiy Boyko ◽  
Serhii Sapon
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Elastic Deformation ◽  
Tangential Direction ◽  
The Finite Element Method ◽  
Radial Bearing ◽  
Operational Characteristics ◽  
Service Conditions ◽  
The Difference ◽  
Element Method

Abstract The analysis of spatial functions of pressure considering the geometrical deviations and the elastic deformation of conjugate surace have been considered. The analysis of spatial functions of pressure is performed by the finite element method. The difference of the size of pressure in a tangential direction of a pocket of a support under various service conditions has been investigated. A recommendation for improving of operational characteristics in regulated hydrostatic radial bearing has been developed.

scholarly journals INFORMATIZATION OF CONSTRUCTION MANAGEMENT AS A BASIS FOR PREVENTING MAN-MADE ACCIDENTS

2021 ◽  
Vol 4 (4) ◽  
pp. 11-31
Author(s):  
S. Koryagina
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
The Finite Element Method ◽  
Calculation Results ◽  
Definition Of ◽  
Deep Pits ◽  
Geotechnical Problems ◽  
Seismic Impacts ◽  
Base Structure ◽  
Element Method

the article presents the principles and algorithms of the finite element method in solving geotechnical prob-lems taking into account seismic impacts for determining the stress-strain state of structures and slope stabil-ity, implemented in the Midas GTS NX software package. GTS NX allows you to perform calculations of various types of geotechnical problems and solve complex geotechnical problems in a single software envi-ronment. GTS NX covers the entire range of engineering and geotechnical projects, including calculations of the "base-structure" system, deep pits with various mounting options, tunnels of complex shape, consolida-tion and filtration calculations, as well as calculations for dynamic actions and stability calculations. At the same time, all types of calculations in GTS NX can be performed both in 2D and in 3D. The author does not claim to be the author of the finite element method, but he cannot do without pointing out the basic equa-tions, as this affects the definition of the boundaries of use, the formulation of algorithms for constructing calculation schemes and the analysis of calculation results.

Analysis by the mixed method of statically indeterminate frames with elements of increased rigidity and numerical verification of the calculation results using the finite element method

2021 ◽  
Vol 14 (2) ◽  
pp. 54-66
Author(s):  
Svetlana Sazonova ◽  
Viktor Asminin ◽  
Alla Zvyaginceva
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Initial Data ◽  
Mixed Method ◽  
Numerical Verification ◽  
Bending Moments ◽  
The Finite Element Method ◽  
Calculation Results ◽  
Internal Forces ◽  
Element Method

The sequence of application of the mixed method for calculating internal forces in statically indeterminate frames with elements of increased rigidity is given. The main system is chosen for the frame with one kinematic and one force unknown. The canonical equations of the mixed method are written, taking into account their meaning. Completed the construction of the final diagram of the bending moments and all the necessary calculations and checks. When calculating integrals, Vereshchagin's rule is applied. The solution of the problem is checked by performing the calculation using the computer program STAB12.EXE; the results of the calculations are numerically verified using the finite element method. An example of the formation of the initial data for the STAB12.EXE program and the subsequent processing of the calculation results, the rules for comparing the numerical results and the results obtained in the calculation of the frame by the mixed method are given.

Pipeline On-Bottom Stability Analysis Based on FEM Model

2011 ◽  
Author(s):  
Yong Bai ◽  
Zhimeng Yu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Design Procedure ◽  
Element Model ◽  
The Finite Element Method ◽  
Fem Model ◽  
Engineering Software ◽  
Calculation Results ◽  
Pipeline Design ◽  
Element Method

Pipeline on-bottom stability is one of the sophisticated problems in subsea pipeline design procedure. Due to the uncertainty of the pipe-soil interaction and environment loads, including wave, current, or earthquake, etc., it is classified as the typical nonlinear problem. The Finite Element Method is introduced into pipeline engineering several years ago. More and more special engineering software such as AGA, PONDUS are available in market. However, when doing a project, some abnormal data was found when compared the DnV calculation results and AGA. In order to know the behavior of pipeline on seabed under wave and current load, finite element method – ABAQUS is introduced to do this analysis. The ABAQUS/explicit is used to simulate 600s pipeline dynamic response. The pipeline is supposed to be exposed on seabed and the selected seabed model is large enough to avoid the edge effect. ABAQUS calculation results are compared with the requirements in DnV rules to verify the validity of finite element model.

scholarly journals Numerical simulation of the stress state of the layered gas-bearing rocks in the bottom of mine working

2019 ◽  
Vol 109 ◽  
pp. 00043 ◽  
Author(s):  
Oleksandr Krukovskyi ◽  
Viktoriia Krukovska
Keyword(s):  
Mine Working ◽  
Physical And Mechanical Properties ◽  
Coupled Processes ◽  
The Finite Element Method ◽  
Gas Filtration ◽  
Calculation Results ◽  
The Difference ◽  
The Mathematical Model ◽  
Gas Bearing ◽  
Brittle Destruction

The mathematical model has been developed for the coupled processes of the rock massif deformation and gas filtration in a disturbed area around mine working, in the bottom of which there are hard and soft gas-bearing rocks. When solving the problem, the finite element method was used. The calculation results of the displacements, stresses and pressures of methane in the studied area are represented in the paper. It is shown that the difference in the physical and mechanical properties of the bottom rocks of mine working causes the non-uniform distribution of geomechanics and filtration parameters. In more strong sandstone, the stresses concentration increases. Therewith, an intensive process of fractures formation takes place in the argillite and the coal. Methane from the upper part of the gas-bearing sandstone is filtered into the mine working, the destruction of the coal interlayer is accompanied by release of methane and its accumulation under the layer of a strong sandstone. The development of a zone of inelastic deformations leads to the destruction of sandstone. In case of brittle destruction, with the formation of fractures of a certain length, a breakthrough of methane may occur out of the bottom into mine working.

Piezoelectric “Kumihimo-gumi” sensor fabricated by braiding method using piezoelectric poly-L-lactic acid fiber

2020 ◽  
Vol 557 (1) ◽  
pp. 43-57 ◽  
Author(s):  
Y. Tajitsu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Lactic Acid ◽  
Polyethylene Terephthalate ◽  
Wearable Sensor ◽  
The Finite Element Method ◽  
Complex Motion ◽  
Calculation Results ◽  
New Type ◽  
Plla Fiber

We have developed a piezoelectric braided cord consisting of a conducting fiber yarn core, piezoelectric poly-l-lactic acid (PLLA) fiber yarn and a polyethylene terephthalate (PET) middle sheath, and a conducting fiber outer shield (piezoelectric PLLA braided cord). Actually, we made various types of piezoelectric PLLA braided cords using Japanese traditional braiding method called as Kumihimo-gumi in Japanese. Furthermore, by optimization based on the calculation results for each type of piezoelectric PLLA Kumihimo-gumi obtained by the finite element method (FEM), we were able to develop a new type of piezoelectric PLLA braided cord with a sensing function for complex motion (piezoelectric PLLA Kumihimo-gumi). Finally, we developed a new wearable sensor for a selfie stick which is a popular smartphone accessory, fabricated from a piezoelectric PLLA Kumihimo-gumi.

scholarly journals Survivability of the locomotive cabin at interval estimation of obstacle parameters

2018 ◽  
Vol 216 ◽  
pp. 02021
Author(s):  
Alexander Smolyaninov ◽  
Igor Emel'yanov ◽  
Vladimir Mironov ◽  
Alexei Kuznetsov ◽  
Vasily Lapshin
Keyword(s):  
Finite Element ◽  
Interval Estimation ◽  
Dynamic Strength ◽  
Elastic Interaction ◽  
Strength Criterion ◽  
Structural Elements ◽  
The Finite Element Method ◽  
Initial State ◽  
Calculation Results ◽  
Speed Regime

The article considers the multiparameter problem of the mechanical system behavior and its survivability when destructing individual elements. The technique for constructing the area of safe operation of the cabin of the GT1-h gas turbine locomotive was illustrated on the example of collision of a locomotive with an obstacle at a crossing. The main parameters determining the energy of interaction between the cabin and the obstacle was singled out, and their influence on the survivability of the structure was analyzed. The finite element method was used to calculate the load-bearing capacity of a power frame with a buffer device in the initial state and after the destruction of individual structural elements by the dynamic strength criterion. The force of elastic interaction between the locomotive and the obstacle was estimated through the spring, the rigidity of which was estimated on the basis of the finite element calculation results. As a result of the calculations, proposals were developed to strengthen the cabin frame to ensure the safety of the crew and the instrument part in case of unauthorized collision with an obstacle of considerable mass and violation of the speed regime.

scholarly journals Determining internal forces in modular building elements under action wind load

2018 ◽  
Vol 196 ◽  
pp. 02010
Author(s):  
Viacheslav Shirokov ◽  
Alexey Soloviev ◽  
Tatiana Gordeeva
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Section ◽  
Dynamic Characteristics ◽  
Wind Load ◽  
Wind Loads ◽  
Bending Moments ◽  
The Finite Element Method ◽  
Calculation Results ◽  
Internal Forces

The research paper focuses on internal forces determination in the elements of modular buildings under wind load. It provides a methodology for determining dynamic characteristics of a building and for calculating wind loads. This method is based on the following assumptions: coupling of the modules elements is rigid; coupling of block-modules with foundations is hinged-fixed; connection of blocks to each other is hinged in angular points; the floor disk in its plane is not deformed. On the basis of these assumptions the authors derived approximate and refined equations for determining forces in modules elements under static and pulsation components of wind load. The equation of bending moments determination in the pillar bearing cross-section is obtained by approximation of the graph of moments variation, calculated for the spectrum of the ratio of the pillar stiffness and the floor beam in the range from 1/64 to 64. The paper further introduces the calculation results of forces based on the proposed methodology and on the finite element method. The calculations were done while taking different values of wind load and different number of storeys in a building (from 1 to 4 floors). The obtained results are similar, the error does not exceed 5%.

scholarly journals INITIAL STRESS CORRECTION METHOD FOR THE MODELING OF FOLDED SPACE INFLATABLE STRUCTURES

Aviation ◽  
2014 ◽  
Vol 18 (4) ◽  
pp. 166-173 ◽  
Author(s):  
Yanan Zhan ◽  
Li Yu ◽  
Xue Yang ◽  
Han Cheng
Keyword(s):  
Finite Element ◽  
Initial Stress ◽  
Control Volume ◽  
Technical Problem ◽  
Correction Method ◽  
Numerical Calculations ◽  
Inflatable Structures ◽  
Initial Errors ◽  
Calculation Results ◽  
The Difference

Initial errors and mesh distortions are inevitable in the modelling of folded space inflatable structures. Aimed at this key technical problem, an initial stress correction method based on finite element theory is proposed in this paper. First, initial stress is calculated through the difference of mapping and reference configurations, the former with initial errors and the later without. Then the initial stress is imposed on the mapping configuration to correct initial errors. Through the correction, the accuracy of the inflation deployment numerical calculation is greatly improved. In order to validate the reliability of this correction method, a typical space inflatable structure-inflatable tube is studied as an example. First of all, the finite element models of both Z-folded and rolled tubes are established with the initial stress correction method. Then the inflation deployment numerical calculations of the folded tubes are carried out applying the segmented inflatable control volume method. Through comparative analysis of the calculation results with and without a correction, the method proposed in this paper is proved to be feasible and accurate. The correction method is a complement to the modelling of folded space inflatable structures and it has a great significance for the improvement of the accuracy of the inflation deployment numerical calculations of space inflatable structures.

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