Prediction of tablet characteristics based on sparse modeling for residual stresses simulated by the finite element method incorporating Drucker-Prager cap model

2019 ◽  
Vol 52 ◽  
pp. 1021-1031
Author(s):  
Kozo Takayama ◽  
Tsubasa Sato ◽  
Kazuki Sato ◽  
Hiroaki Todo ◽  
Yasuko Obata ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
The Finite Element Method ◽  
Sparse Modeling ◽  
Cap Model ◽  
Element Method

Three-phase micromechanical analysis of residual stresses in reinforced fiber by carbon nanotubes

2016 ◽  
Vol 51 (12) ◽  
pp. 1783-1794 ◽  
Author(s):  
Ahmad Reza Ghasemi ◽  
Mohammad Mohammadi Fesharaki ◽  
Masood Mohandes
Keyword(s):  
Finite Element Method ◽  
Carbon Nanotubes ◽  
Finite Element ◽  
Carbon Fiber ◽  
Residual Stresses ◽  
Representative Volume Element ◽  
Volume Element ◽  
The Finite Element Method ◽  
Representative Volume ◽  
Element Method

In this study, circular disk model and cylinder theory for two dimension (2D) and three dimension (3D), respectively, have been used to determine residual stresses in three-phase representative volume element. The representative volume element is consisting of three phases: carbon fiber, carbon nanotubes, and polymer matrix, that carbon fiber is reinforced by carbon nanotube using electrophoresis method. Initially, the residual stresses analysis of two-phase representative volume element has been implemented. The two-phase representative volume element has been divided to carbon fiber and matrix phases with different volume fractions. In the three-phase representative volume element, although the volume fraction of carbon fiber is constant and equal to 60%, the volume fractions of carbon nanotubes for various cases are different as 0%, 1%, 2%, 3%, 4%, and 5%. Also, there are two different methods to reinforce the fiber according to different coefficients of thermal expansion of the carbon fiber and carbon nanotube in two longitudinal and transverse directions; carbon nanotubes are placed on carbon fiber either parallel or around it like a ring. Subsequently, finite element method and circular disk model have been used for analyzing micromechanic of the residual stresses for 2D and then the results of stress invariant obtained by the finite element method have been compared with the circular disk model. Moreover, for 3D model, the finite element method and cylinder theory have been utilized for micromechanical analysis of the residual stresses and the results of stress invariant obtained by them, have been compared with each other. Results of the finite element method and analytical model have good agreement in 2D and 3D models.

Prediction of Residual Stresses in Butt Welded Plates Using Inherent Strains

1993 ◽  
Vol 115 (4) ◽  
pp. 417-423 ◽  
Author(s):  
Y. Ueda ◽  
M. G. Yuan
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
The Finite Element Method ◽  
Butt Weld ◽  
Butt Welds ◽  
Plastic Analysis ◽  
Inherent Strain ◽  
Element Method

The source of residual stresses in the vicinity of a weld may be expressed in terms of inherent strains. The characteristics of the inherent strain distributions in butt welds are investigated. It is found that the patterns vary little with changes in the welding conditions and sizes of the welded plates. With some assumptions, simple formulas are derived for the distribution and magnitude of inherent strain in a butt weld. A method of predicting the residual stress in a butt-welded plate using the characteristics of inherent strain distributions is presented. The validity of the method is confirmed by thermal elasto-plastic analysis using the finite element method (FEM).

scholarly journals Modeling and Calculating of Residual Stress and Strain of Butt Welded Joint

2021 ◽  
Vol 31 (5) ◽  
pp. 58-67
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Welded Joint ◽  
The Finite Element Method ◽  
Force Method ◽  
Stress Components ◽  
Residual Stresses And Strains ◽  
Element Method

The non-uniform thermal expansion and contraction resulting from welding processes cause residual stresses and strains. Experimental studies on measuring welding residual stresses and strains of structure are costly and sometimes they are not possible. Previously, analytical methods with idealized models were developed to determine the welding residual stresses and strain. Recently, numerical methods are constructed to analyze the stresses and the strains in welded structures. This paper presents the calculation results of residual stress and welding strain in butt welded joint of S355J2G3 carbon steel of 5 mm thickness made by MAG welding process with a single pass. The calculation is performed by two methods: the imaginary force method and the finite element method. In the finite element method, the SYSWELD software is used to simulate and to determine residual stresses and strain of this welded joint. The results of finite element method are compared with those of imaginary force method to show the rationality and the advantages of finite element method. The study results have shown that in this welded joint, only the longitudinal and transverse stress components are important and the other stress components are negligible.

New Measuring Method of Axisymmetric Three-Dimensional Residual Stresses Using Inherent Strains as Parameters

1986 ◽  
Vol 108 (4) ◽  
pp. 328-334 ◽  
Author(s):  
Yukio Ueda ◽  
Keiji Fukuda ◽  
You Chul Kim
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Residual Stresses ◽  
Three Dimensional ◽  
Measuring Method ◽  
Basic Theory ◽  
The Finite Element Method ◽  
New Approach ◽  
Practical Procedure ◽  
Element Method

For the measurement of axisymmetric three-dimensional residual stresses, Sachs’ method is often used. The accuracy of this method is not high when even small errors are contained in observed strains. In 1975, the authors presented a new approach for the measurement of residual stresses in which inherent strains (the source of residual stresses) are dealt with as parameters and formulated a basic theory using the finite element method. In this paper, based on the new approach, a basic theory for the measurement of axisymmetric three-dimensional residual stresses is developed and a practical procedure of measurement is presented. This method is applied to determine the residual stresses in a quenched shaft and its reliability and practicability are also demonstrated.

Calculation of Residual Stresses in Plastic Deformation Processes

1973 ◽  
Vol 95 (1) ◽  
pp. 283-291 ◽  
Author(s):  
C. H. Lee ◽  
H. Iwasaki ◽  
S. Kobayashi
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Residual Stresses ◽  
Internal Pressure ◽  
Solid Cylinder ◽  
The Finite Element Method ◽  
Concentric Cylinders ◽  
Deformation Processes ◽  
Element Method

Three problems, namely, autofrettage process, plastic upsetting of a solid cylinder, and plane-strain and axisymmetric extrusion, are treated for residual stress calculation. A thick-walled cylinder consisting of two loosely fitted concentric cylinders of different materials is subjected to various levels of internal pressure. The residual stresses were calculated with an emphasis on the case where the inner surface of the cylinder yields again upon removal of the internal pressure. Comparison between the calculations and the measurements is given. The residual stresses in plastic upsetting of a solid cylinder were calculated by the finite-element method. An attempt was also made to simulate the real situation in extrusion by the finite-element method. An estimation of the residual stress distribution is then discussed for axisymmetric extrusion problems.

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