A Research on the Forward Slip Coefficient in Alloyed Bar Rolling by the Round-Oval-Round Pass Sequence

2011 ◽  
Vol 413 ◽  
pp. 444-448
Author(s):  
Jian Feng Song ◽  
Yong Gang Dong
Keyword(s):  
Three Dimensional ◽  
Contact Boundary ◽  
Forward Slip ◽  
Slip Coefficient ◽  
Rigid Plastic ◽  
Bar Rolling ◽  
Effective Height ◽  
Rolling Experiment ◽  
Modified Formula ◽  
Round Pass

For predicting the forward slip coefficient and veocity of outgoing workpiece exactly during alloyed bar rolling by Round-Oval-Round pass sequence, the influence of the spred of the outgoing workpiece and its contact boundary condition was considered and the calculating formula for the effective height of outgoing workpiece and the mean roll radius was proposed individually. Moreover, the new parameters were substituted into the Shinokura and Takai Formula to modify it. Then a modified forward slip coefficient firmula was proposed. The validity of the theoretical model has been examined by the bar rolling experiment and the numerical simulation using three-dimensional rigid-plastic FEM. Compared with the Shinokura and Takai dormula, the predict accuracy of the modified formula was improved apparently. So, it can be applied in alloyed bar rolling to predict the the forward slip coefficient and veocity of outgoing workpiece exactly.

Numerical Investigation of the Drag and Lift Forces Acting on Impenetrable Rotating Spherical Nano-Particle

2008 ◽  
Author(s):  
M. R. Meigounpoory ◽  
A. Rahi ◽  
A. Mirbozorgi
Keyword(s):  
Lift Coefficient ◽  
Three Dimensional ◽  
Slip Boundary Condition ◽  
Slip Condition ◽  
Nano Particle ◽  
Slip Coefficient ◽  
Slip Boundary ◽  
Lift Forces ◽  
Drag And Lift ◽  
Drag And Lift Coefficient

The drag and lift forces acting on a rotating impenetrable spherical suspended nano-particle in a homogeneous uniform flow are numerically studied by means of a three-dimensional numerical simulation with slip boundary condition. The effects of both the slip coefficient and rotational speed of the nanosphere on the drag and lift forces are investigated for Reynolds numbers in the range of 0.1 < Re < 100. Increase of rotation increases the drag and lift force exerted by flow at the surface of nano-sphere. By increasing slip coefficient the values of drag and lift coefficients decreases. At full slip condition, rotation of the nano-sphere has not significant effects on the drag and lift coefficient values moreover the lift coefficient of flow around the rotating spherical particle will be vanished. Present numerical results at no-slip condition are in good agreements with certain results of flow around of rotating sphere.

Analyses of Full-Scale Tank Car Shell Impact Tests

2007 ◽  
Author(s):  
Y. H. Tang ◽  
H. Yu ◽  
J. E. Gordon ◽  
M. Priante ◽  
D. Y. Jeong ◽  
...  
Keyword(s):  
Finite Element ◽  
Test Data ◽  
Three Dimensional ◽  
Full Scale ◽  
Collision Dynamics ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Closed Form Solutions

This paper describes analyses of a railroad tank car impacted at its side by a ram car with a rigid punch. This generalized collision, referred to as a shell impact, is examined using nonlinear (i.e., elastic-plastic) finite element analysis (FEA) and three-dimensional (3-D) collision dynamics modeling. Moreover, the analysis results are compared to full-scale test data to validate the models. Commercial software packages are used to carry out the nonlinear FEA (ABAQUS and LS-DYNA) and the 3-D collision dynamics analysis (ADAMS). Model results from the two finite element codes are compared to verify the analysis methodology. Results from static, nonlinear FEA are compared to closed-form solutions based on rigid-plastic collapse for additional verification of the analysis. Results from dynamic, nonlinear FEA are compared to data obtained from full-scale tests to validate the analysis. The collision dynamics model is calibrated using test data. While the nonlinear FEA requires high computational times, the collision dynamics model calculates gross behavior of the colliding cars in times that are several orders of magnitude less than the FEA models.

Smooth 3D manifolds based on thin plates

2016 ◽  
Vol 22 (3) ◽  
pp. 477-490
Author(s):  
VA Grachev ◽  
YS Neustadt
Keyword(s):  
Degrees Of Freedom ◽  
3D Structure ◽  
Three Dimensional ◽  
Small Diameter ◽  
Thin Plates ◽  
Mechanics Of Solids ◽  
Dimensional Manifold ◽  
Initial State ◽  
Rigid Plastic ◽  
Definition Of

This paper demonstrates a fractal system of thin plates connected with hinges. The system can be studied using the methods of the mechanics of solids with internal degrees of freedom. The structure is deployable, and initially, it is similar to a small-diameter one-dimensional manifold, which occupies significant volume after deployment. The geometry of solids is studied using the method of the moving hedron. The relationships enabling the definition of the geometry of the introduced manifolds are derived based on the Cartan structure equations. The proof substantially makes use of the fact that the fractal consists of thin plates that are not long compared to the sizes of the system. The mechanics are described for solids with rigid plastic hinges between the plates, and the hinges are made of shape memory material. Based on the ultimate load theorems, estimates are performed to specify the internal pressure that is required to deploy the package into a three-dimensional (3D) structure and the heat input needed to return the system into its initial state. Some possible applications of the smooth 3D manifolds are demonstrated.

Forward Slip and Backward Slip in Radial Ring Rolling Process

2013 ◽  
Vol 423-426 ◽  
pp. 820-823 ◽  
Author(s):  
Yan Liu ◽  
Qiang Wang ◽  
Dong Mei Cai
Keyword(s):  
Rolling Process ◽  
Tangential Component ◽  
Ring Rolling ◽  
Forward Slip ◽  
Slip Coefficient ◽  
Relative Slip ◽  
Speed Difference ◽  
Slip Tendency ◽  
Ring Rolling Process

During the process of radial ring rolling, relative slip or relative slip tendency occurs on the interface between the ring and the rolls. Research on the relative slip or relative slip tendency plays an important role on reducing friction to ensure the ring rolling smoothly. In this paper, the reason of relative slip or relative slip tendency is investigated that there is speed difference between tangential component of the ring and linear velocity of the rolls. According to speed difference, slip types of the interface are classified. Forward slip coefficient and backward slip coefficient are defined and derived and relations between them are studied. Comparison between the new method and the previous one is conducted via case study, which proves the rationality and effectiveness.

Geometric Instabilities in Isotropic Plastic Solids Under Increasing Uniaxial Compression

1972 ◽  
Vol 39 (2) ◽  
pp. 431-437 ◽  
Author(s):  
J. B. Newman
Keyword(s):  
Shear Stress ◽  
Strain Hardening ◽  
Uniaxial Compression ◽  
Maximum Shear Stress ◽  
Three Dimensional ◽  
Rigid Plastic ◽  
Axisymmetric Mode ◽  
Plastic Materials ◽  
Compressive Flow ◽  
Shanley Theory

This analysis seeks three-dimensional instabilities of uniaxial compressive flow in isotropic, strain-hardening, rigid-plastic materials of the Mises and maximum shear stress types. No instabilities are found for Mises materials. Maximum shear materials display axisymmetric, “deflectional”, and “higher-order” buckling. For increasingly slender specimens, the deflectional buckling process merges into that of the Shanley theory. The axisymmetric mode raises the possibility that instabilities contribute to the double axial bulging of ductile compression specimens reported by Na´da´i.

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