New Solutions to Rigid-Plastic Deformation Problems Using a Matrix Method

1973 ◽  
Vol 95 (3) ◽  
pp. 865-873 ◽  
Author(s):  
C. H. Lee ◽  
S. Kobayashi
Keyword(s):  
Plastic Deformation ◽  
Plane Stress ◽  
Matrix Method ◽  
Stress Distributions ◽  
Planar Anisotropy ◽  
Rigid Plastic ◽  
Relative Slip ◽  
The Matrix ◽  
Simple Compression ◽  
Cylinder Compression

The matrix method for the analysis of rigid-plastic deformation problems was described and applied to simple compression of cylinders and plane-stress bore expanding and flange drawing. In cylinder compression new solutions were obtained with regard to the effect of specimen dimensions on the contact stress distributions, the effect of friction on the relative slip at the tool-workpiece interface, and bulging and “folding”. In plane-stress problems the planar anisotropy was taken into account and the application of the matrix method resulted in new solutions for nonaxisymmetric hole expansion and “earing” in flange drawing.

scholarly journals Cylinder plastic compression by the flat dies

2020 ◽  
pp. 101-120
Author(s):  
Ростислав Иванович Непершин
Keyword(s):  
Computer Simulation ◽  
Plastic Deformation ◽  
Limit Load ◽  
Contact Length ◽  
Contact Friction ◽  
Plastic Layer ◽  
Cylinder Surface ◽  
Initial Contact ◽  
Rigid Plastic ◽  
Cylinder Compression

Приведено численное моделирование пластического сдавливания цилиндра плоскими штампами по нормали к его оси на основе теории плоской деформации жесткопластического тела. Рассматриваются начальная пластическая деформация с выдавливанием материала на свободную поверхность цилиндра, переходящая в пластическое деформирование высокой заготовки и пластического слоя с конечным отношением длины контакта к толщине. Используются линии скольжения и скорости пластического течения по Прандтлю при изменении формы деформируемого сечения цилиндра с учетом контактного трения при сдавливании пластического слоя. Моделирование представляет практический интерес для оценки предельной нагрузки при контактной деформации цилиндра плоскими штампами и деформировании заготовки при ковке плоскими бойками. Computer simulation of the rigid-plastic cylinder compression by the flat dies is presented using plane strain ideal plastic theory. Initial contact plastic deformation with material lip forming on the free cylinder surface, followed by the high workpiece and the plastic layer with finite contact length to thickness relation plastic deformation are considered. Prandtl’s slip lines and velocity fields are used for the cylinder section form predictions and plastic layer compression with contact friction consideration. Computer simulation can be used for the limit load estimation with cylinder contact plastic flow, compressed by the flat rigid dies, and cylinder workpiece forging by the flat dies.

Effect of Interfacial Properties on the Mechanical Behavior of Bone-Like Materials: A Numerical Study

2017 ◽  
Vol 09 (01) ◽  
pp. 1750014 ◽  
Author(s):  
Xingguo Li ◽  
Bingbing An ◽  
Dongsheng Zhang
Keyword(s):  
Mechanical Properties ◽  
Plastic Deformation ◽  
Numerical Study ◽  
Element Model ◽  
Interfacial Behavior ◽  
Yield Behavior ◽  
Bonding Property ◽  
The Matrix ◽  
Bonding Properties ◽  
Superior Mechanical Properties

Interfacial behavior in the microstructure and the plastic deformation in the protein matrix influence the overall mechanical properties of biological hard tissues. A cohesive finite element model has been developed to investigate the inelastic mechanical properties of bone-like biocomposites consisting of hard mineral crystals embedded in soft biopolymer matrix. In this study, the complex interaction between plastic dissipation in the matrix and bonding properties of the interface between minerals and matrix is revealed, and the effect of such interaction on the toughening of bone-like biocomposites is identified. For the case of strong and intermediate interfaces, the toughness of biocomposites is controlled by the post yield behavior of biopolymer; the matrix with low strain hardening can undergo significant plastic deformation, thereby promoting enhanced fracture toughness of biocomposites. For the case of weak interfaces, the toughness of biocomposites is governed by the bonding property of the interface, and the post-yield behavior of biopolymer shows negligible effect on the toughness. The findings of this study help to direct the path for designing bioinspired materials with superior mechanical properties.

The Mechanical Characteristics and Sealing Performance Evaluation of Bolted Pipe Flange Connections With Metallic Flat Gaskets Subjected to Internal Pressure

2016 ◽  
Author(s):  
Koji Kondo ◽  
Koji Sato ◽  
Satomi Takahashi ◽  
Toshiyuki Sawa
Keyword(s):  
Plastic Deformation ◽  
Mechanical Characteristics ◽  
Experimental Results ◽  
Leak Rate ◽  
Effect Of Temperature ◽  
Load Factor ◽  
Stress Distributions ◽  
Bolt Preload ◽  
Sealing Performance ◽  
Higher Temperature

Bolted pipe flange connections with metallic gaskets have been used under higher pressure as well as higher temperature. However, a few researches on the mechanical characteristics in connections with metallic gaskets have been carried out. It is necessary to examine the mechanical characteristics such as the contact gasket stress distributions which govern the sealing performance, the deformation of the metallic gaskets, changes in axial bolt forces and the hub stress under higher pressure and temperature. In the present paper, the objectives are to examine the changes in axial bolt forces, the hub stress and the contact gasket stress distributions and the sealing performance of the pipe flange connections with metallic flat gaskets. Firstly, the mechanical characteristics of the connections under higher pressure are analyzed using FEA. Then, experiments were carried out to measure the load factor, the hub stress and the leak rate (the sealing performance). The relationship between the average contact gasket stress and the leak rate was measured using platen device at room temperature. The FEA results are fairly coincided with the experimental results. It is shown that the leak rate decreases as the contact gasket stress increases and when the plastic deformation of gaskets occurs, the sealing performance increases. The leak rate was measured in the range of 10−4∼10−7 [Pa·m3/s]. It is found that the sealing performance increases as the gasket width increase in the elastic deformation range while it is independent of the gasket width when the plastic deformation occurs. The effect of temperature on the mechanical characteristics of the connection is also examined. The FEA results are in a fairly good agreement with the experimental results. It is found that the sealing performance increases as the temperature increases. In addition, a method how to determine the bolt preload for increasing the sealing performance is proposed.

Accurate Calculation of Stress Distributions in Multiholed Plates

1965 ◽  
Vol 87 (3) ◽  
pp. 331-335 ◽  
Author(s):  
L. E. Hulbert ◽  
F. W. Niedenfuhr
Keyword(s):  
Computer Program ◽  
Plane Stress ◽  
Symmetric Groups ◽  
Thin Plates ◽  
Stress Distributions ◽  
Accurate Calculation ◽  
Point Matching ◽  
Shallow Shells ◽  
Matching Technique ◽  
Stress Functions

This paper discusses the application of the point-matching technique in obtaining the solution of many problems involving multiholed thin plates undergoing generalized plane stress. The stress functions appropriate to plates with symmetric groups of holes are described. A large number of problems solved by a computer program are described and compared with published results. Problems are solved also for which there are no known published results. Two interesting new problems are discussed in detail. The results show the power and flexibility of the technique. The extension of the methods to permit the solution of problems in the deflection of thin, multiholed plates and shallow shells is discussed.

Determination of the Force Constants of Non-linear XY2 Molecules in the Gas-Phase by the GF Matrix Method

2004 ◽  
Vol 59 (9) ◽  
pp. 621-622 ◽  
Author(s):  
Fatih Ucun ◽  
Vesile Gūçlü
Keyword(s):  
Gas Phase ◽  
Condensed Phase ◽  
Matrix Method ◽  
Solid Phase ◽  
Force Constants ◽  
Matrix Solution ◽  
The Matrix ◽  
Newton Raphson ◽  
Raphson Method

The force constants of the internal coordinates of nonlinear XY2 molecules in the gas-phase were calculated by using the GF matrix method. The matrix solution was carried out by means a computer program built relative to the Newton-Raphson method and the calculations were listed in a table. The force constants of some molecules in the liquidand solid- phase were also found and compared with these ones, and it was seen that the force constants for more condensed phase are lower as in an agreement with having its lower frequency.

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