scholarly journals Predicting and Measuring Surface Enlargement in Forward Rod Extrusion

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Deniz Duran ◽  
İzzet Özdemir
Keyword(s):  
Metal Forming ◽  
Deformation Gradient ◽  
Lubricant Layer ◽  
Finite Element Program ◽  
Numerical Predictions ◽  
Comparison Of Experiments ◽  
Measuring Surface ◽  
Element Program ◽  
Gradient Based ◽  
General Deformation

Surface enlargement during bulk metal forming processes is one of the key parameters controlling the tribology at the tool-workpiece interface. Not only the surface roughness evolution but also the integrity of the lubricant layer critically reposes on surface enlargement. As an attempt to address this issue, in the first part of this work, a general, deformation gradient based surface enlargement description is implemented in a commercial finite element program. In the second part, forward rod extrusion tests with different area reductions are conducted using customized steel workpieces in which cylindrical copper rods are embedded through the depth. By sectioning the extruded parts and by identifying the position of the copper rods on the lateral surface, average surface enlargement values could be measured locally at different positions along the extrudate. Comparison of experiments and numerical predictions reveal that the deformation gradient based description performs reasonably well in capturing surface enlargement profiles both qualitatively and quantitatively.

Finite Element Analysis of Metal Forming Processes on Personal Computers

1991 ◽  
Vol 113 (4) ◽  
pp. 441-445 ◽  
Author(s):  
Li-lai Yan ◽  
Song-qing Xu ◽  
Guo-ji Li
Keyword(s):  
Finite Element ◽  
Metal Forming ◽  
Industrial Applications ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Finite Element Program ◽  
Forming Analysis ◽  
Element Program ◽  
Linear Problems ◽  
Shape Complexity

The main difficulty in running a rigid-plastic finite element program for metal forming analysis on a personal computer lies in the lengthy computation, typical of non-linear problems. To make the PC more acceptable for forming analyses in industrial applications, some measures have been proposed, such as using a higher order IVP solver and modifying the generation of the initial velocity field to account for the existence of rigid zones, if any. As a result, 2-D metal forming problems with moderate shape complexity can be solved on PCs within a reasonable length of time.

Some Aspects of Spar Platform Buoyancy Can Loads

2002 ◽  
Author(s):  
Hugh Thompson ◽  
Mehemosh B. Irani ◽  
Lyle D. Finn
Keyword(s):  
Finite Element ◽  
Field Measurements ◽  
Element Model ◽  
Scale Model ◽  
Spar Platform ◽  
Finite Element Program ◽  
Numerical Predictions ◽  
Element Program ◽  
Actual Field ◽  
The Time Domain

A finite element program is developed to analyze the dynamics of buoyancy cans within the centerwell of Spar platforms. The time domain non-linear finite element model includes the effects of the hydrodynamics of the water within the centerwell, and, the gap between the buoyancy cans and guides. The forces on the buoyancy can guide structure due to Spar motions is studied in the present paper. The theoretical results are validated with experimental and field measurements. 1:20.89 scale model tests are conducted to measure the buoyancy can motions and guide reaction forces for a range of gap sizes and specified Spar motions. A Spar platform is also instrumented to measure the guide forces in actual field conditions. The prototype field data is analyzed and compared with the numerical predictions.

Friction Force and Stresses Analysis for Contact of Assembled Details

2006 ◽  
Vol 113 ◽  
pp. 334-338
Author(s):  
Z. Dreija ◽  
O. Liniņš ◽  
Fr. Sudnieks ◽  
N. Mozga
Keyword(s):  
Mechanical Properties ◽  
Surface Roughness ◽  
Plastic Deformation ◽  
Friction Force ◽  
Sliding Friction ◽  
Friction Model ◽  
Contact Interface ◽  
Finite Element Program ◽  
Elastic Plastic ◽  
Element Program

The present work deals with the computation of surface stresses and deformation in the presence of friction. The evaluation of the elastic-plastic contact is analyzed revealing three distinct stages that range from fully elastic through elastic-plastic to fully plastic contact interface. Several factors of sliding friction model are discussed: surface roughness, mechanical properties and contact load and areas that have strong effect on the friction force. The critical interference that marks the transition from elastic to elastic- plastic and plastic deformation is found out and its connection with plasticity index. A finite element program for determination contact analysis of the assembled details and due to details of deformation that arose a normal and tangencial stress is used.

scholarly journals The impact of drilling and slitting construction on damage field: evolution characteristics in low-permeability coal seam

2021 ◽  
Vol 37 ◽  
pp. 205-215
Author(s):  
Heng Chen ◽  
Hongmei Cheng ◽  
Aibin Xu ◽  
Yi Xue ◽  
Weihong Peng
Keyword(s):  
Finite Element ◽  
Rock Mass ◽  
Damage Mechanics ◽  
Effective Strain ◽  
Secondary Development ◽  
Distribution Area ◽  
Finite Element Program ◽  
Element Program ◽  
Mining Face ◽  
The Impact

ABSTRACT The fracture field of coal and rock mass is the main channel for gas migration and accumulation. Exploring the evolution law of fracture field of coal and rock mass under the condition of drilling and slitting construction has important theoretical significance for guiding efficient gas drainage. The generation and evolution process of coal and rock fissures is also the development and accumulation process of its damage. Therefore, based on damage mechanics and finite element theory, the mathematical model is established. The damage variable of coal mass is defined by effective strain, the elastoplastic damage constitutive equation is established and the secondary development of finite element program is completed by FORTRAN language. Using this program, the numerical simulation of drilling and slitting construction of the 15-14120 mining face of Pingdingshan No. 8 Mine is carried out, and the effects of different single borehole diameters, different kerf widths and different kerf heights on the distribution area of surrounding coal fracture field and the degree of damage are studied quantitatively. These provide a theoretical basis for the reasonable determination of the slitting and drilling arrangement parameters at the engineering site.

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