INVESTIGATION OF DEPENDENCE IMPACT OF TOOL GEOMETRICAL PARAMETERS AND CUTTING SPEED UPON SHAPING EFFORT AT HELICAL GROOVE CUTTING ON INTERNAL SURFACE OF CYLINDRICAL SHELL

2020 ◽  
Vol 2020 (10) ◽  
pp. 22-28
Author(s):  
Vadim Kuc ◽  
Dmitriy Gridin
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Contact Interaction ◽  
Cutting Speed ◽  
Internal Surface ◽  
Geometrical Parameters ◽  
Software Complex ◽  
Helical Groove ◽  
Groove Cutting

The work purpose was the investigation of dependence impact of tool geometrical parameters upon shaping effort during internal groove cutting. As a realization for the fulfillment of the helical groove processing investigation there was used a software complex based on a finite element method and a computer mathematic system. As a result of the investigations carried out there was obtained a regression equation manifesting the dependence of factors impact upon axial force falling on one tooth of the tool in the set scale of factor parameters. The scientific novelty consists in that in the paper there is considered a new method for helical groove cutting in which a shaping motion is carried out at the expense of the contact interaction of a tool and a billet performing free cutting. The investigation results obtained allowed determining the number of teeth operating simultaneously, that can be used further at cutting mode setting, and also as recommendations during designing tool design.

Local Hydrostatic Pressure Test for Cylindrical Vessels

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
H. Al-Gahtani ◽  
A. Khathlan ◽  
M. Sunar ◽  
M. Naffa'a
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Hydrostatic Pressure ◽  
Cylindrical Vessel ◽  
Geometrical Parameters ◽  
The Finite Element Method ◽  
Wide Range ◽  
Pressure Test ◽  
Local Test ◽  
Alternative Test

The juncture of a small cylindrical nozzle to a large cylindrical vessel is very common in the pressure vessel industry. Upon fabrication, it is required that the whole structure is subjected to pressure testing. The test can be expensive as it necessitates pressurizing the whole structure typically having a large volume. Hence, it is proposed to make a “local test,” which is considerably simpler as it involves capping the small nozzle and testing only a relatively small portion of the structure. This paper investigates the accuracy and reliability of such an alternative test, using the finite-element method. Two different finite-element types are used in the study, specifically a shell-based element and a solid-based element. The verification of the finite-element results for two different cases shows that the models used in the study are valid. It also proves that the two element types yield very similar stress results. In addition, the study includes a numerical investigation of more than 40 different nozzle-to-vessel junctures with a wide range of parameters for the nozzle and vessel. The results indicate that the use of cylindrical caps that are slightly larger than the nozzle is not recommended as it produces stresses that are significantly different from those for the original required pressure test. As such, the study provides an estimate of the smallest size of the cap that may be used in the local test to generate stresses that agree with the full test. For most practical geometries, it is shown that the size of the cap needs to be at least 2–30 times larger than that of the nozzle, depending on the geometrical parameters of the juncture.

scholarly journals Combined Semianalytical and Numerical Static Plate Analysis. Part 2: Resultant Multipoint Boundary Problem

2018 ◽  
Vol 196 ◽  
pp. 01011
Author(s):  
Oleg Negrozov ◽  
Pavel Akimov ◽  
Marina Mozgaleva
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Boundary Problem ◽  
Thin Plates ◽  
Geometrical Parameters ◽  
Element Mesh ◽  
Multipoint Boundary ◽  
Basic Dimension ◽  
Plate Analysis ◽  
Element Method

The distinctive paper is devoted to solution of multipoint boundary problem of plate analysis (Kirchhoff model) based on combined application of finite element method (FEM) and discrete-continual finite element method (DCFEM). As is known the Kirchhoff-Love theory of plates is a two-dimensional mathematical model that is normally used to determine the stresses and deformations in thin plates subjected to forces and moments. The given domain, occupied by considering structure, is embordered by extended one. The field of application of DCFEM comprises fragments of structure (subdomains) with regular (constant or piecewise constant) physical and geometrical parameters in some dimension (“basic” dimension). DCFEM presupposes finite element mesh approximation for non-basic dimension of extended domain while in the basic dimension problem remains continual. FEM is used for approximation of all other subdomains (it is convenient to solve plate bending problems in terms of displacements). Coupled multilevel approximation model for extended domain and resultant multipoint boundary problem are constructed. Brief information about software systems and verification samples are presented as well.

Influence of Attachment Rigidity on Stress Analysis

2011 ◽  
Vol 138-139 ◽  
pp. 74-78
Author(s):  
Yue Qiang Qian ◽  
Fu Jun Liu ◽  
Zhang Wei Ling ◽  
Shuai Kong
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cylindrical Shell ◽  
Stress Analysis ◽  
Shell Thickness ◽  
Equivalent Stress ◽  
Local Stress ◽  
Pressure Vessels ◽  
Equivalent Stresses ◽  
Typical Method

In pressure vessels design, WRC107 provides a typical method of local stress analysis to supports and attachments. But influence of the rigidity of attachments on calculation is not considered. For fatigue analysis of round hollow attachment on cylindrical shell, equivalent stresses calculated by WRC107 were compared with those by finite element method. Three attachment thickness configurations, that half, equal, double of the shell thickness were tested. Results show that, in key point Au defined by WRC107 equivalent stress decreases while attachment rigidity increases, and in key point Cu, equivalent stress increases while attachment rigidity increases. When the thickness of attachment equals to that of shell, equivalent stress of WRC107 in Cu comes closest to FEM.

Pentamodal behaviors and acoustic bandgaps of asymmetric pentamode elastic metamaterials

2016 ◽  
Vol 30 (19) ◽  
pp. 1650118 ◽  
Author(s):  
Yan Huang ◽  
Xuegang Lu ◽  
Gongying Liang ◽  
Zhuo Xu
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Cross Section ◽  
Single Mode ◽  
Geometrical Parameters ◽  
Metamaterial Structure ◽  
Regular Triangle ◽  
Asymmetric Case ◽  
Elastic Metamaterials ◽  
Complete Bandgap

The asymmetric pentamode metamaterial structure which is built by connecting double-cones with different cross-section shapes (regular triangle, square, pentagon and hexagon) to form diamond lattice is proposed in this paper. Then its phonon band structure is calculated by finite-element method (FEM), and its pentamodal behaviors and acoustic bandgaps are studied in detail. Results show that in the process of adjusting geometrical parameters, the asymmetric case performs similar pentamodal behaviors [ratio of bulk modulus to shear modulus [Formula: see text] and single-mode bandgap (SBG)] with the symmetric cases. And the asymmetric case not only remains the intrinsic complete bandgap (CBG) of mode 12-13 like symmetric cases, but also opens new and wide CBG of mode 10-11 and mode 14-15 for appropriate parameters. Therefore, introducing structural asymmetry should be an effective way to open CBG in pentamode elastic metamaterials.

scholarly journals WAVELET-BASED DISCRETE-CONTINUAL FINITE ELEMENT PLATE ANALYSIS WITH THE USE OF DAUBECHIES SCALING FUNCTIONS

2019 ◽  
Vol 15 (3) ◽  
pp. 96-108
Author(s):  
Marina Mozgaleva ◽  
Pavel Akimov ◽  
Taymuraz Kaytukov
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thin Plate ◽  
Scaling Functions ◽  
Geometrical Parameters ◽  
Computer Implementation ◽  
Basic Direction ◽  
Piecewise Constant ◽  
Plate Analysis ◽  
Operational Formulation

The distinctive paper is detoded to special version of wavelet-based discrete-continual finite element method of plate analysis. Daubechies scaling functions are used within this version. Its field of application comprises plates with constant (generally piecewise constant) physical and geometrical parameters along one direction (so-called “basic” direction). Modified continual operational formulation of the problem with the use of the method of extended domain (proposed by A.B. Zolotov) is presented. Corresponding discrete-continual formulation is given as well. Brief information about computer implementation of the method with the use of MATLAB software is provided. Besides numerical sample of analysis of thin plate is considered.

scholarly journals Application of Finite Element Method for Analysis of Nanostructures

2017 ◽  
Vol 11 (2) ◽  
pp. 116-120 ◽  
Author(s):  
Jozef Bocko ◽  
Pavol Lengvarský
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Element Model ◽  
Geometrical Parameters ◽  
The Finite Element Method ◽  
Beam Elements ◽  
Stiffness Properties ◽  
Force Displacement ◽  
The Finite Element Model ◽  
Element Method

AbstractThe paper deals with application of the finite element method in modelling and simulation of nanostructures. The finite element model is based on beam elements with stiffness properties gained from the quantum mechanics and nonlinear spring elements with force-displacement relation are gained from Morse potential. Several basic mechanical properties of structures are computed by homogenization of nanostructure, e.g. Young's modulus, Poisson's ratio. The problems connecting with geometrical parameters of nanostructures are considered and their influences to resulting homogenized quantities are mentioned.

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