An Unexpected Feature of a Class of Damage Evolution Models

2016 ◽  
Vol 713 ◽  
pp. 195-198
Author(s):  
Sergei Alexandrov
Keyword(s):  
Metal Forming ◽  
Damage Evolution ◽  
Plastic Material ◽  
Closed Form Solution ◽  
Material Model ◽  
Form Solution ◽  
Friction Condition ◽  
Rigid Plastic ◽  
Damage Evolution Equation ◽  
Rigid Plastic Material

The main objective of the present paper is to demonstrate, by means of a boundary value problem permitting a closed-form solution, that no solution exists under certain conditions in the case of a rigid/plastic material model including a damage evolution equation. The source of this feature of the solution is the sticking friction condition, which is often adopted in the metal forming literature.

Rigid-Plastic Meshfree Method for Metal Forming Simulation

2003 ◽  
Author(s):  
Young H. Park
Keyword(s):  
Metal Forming ◽  
Plastic Material ◽  
Meshfree Method ◽  
Large Plastic Deformation ◽  
Rigid Plastic ◽  
Mesh Distortion ◽  
Forming Simulation ◽  
Rigid Plastic Material ◽  
Plastic Analysis ◽  
Main Variable

In this paper, material processing simulation is carried out using a meshfree method. With the use of a meshfree method, the domain of the workpiece is discretized by a set of particles without using a structured mesh to avoid mesh distortion difficulties which occurred during the course of large plastic deformation. The proposed meshfree method is formulated for rigid-plastic material. This approach uses the flow formulation based on the assumption that elastic effects are insignificant in the metal forming operation. In the rigid-plastic analysis, the main variable of the problem becomes flow velocity rather than displacement. A numerical example is solved to validate the proposed method.

A Theoretical Analysis of the Bending into Cylindrical Dies of Metal Strips

1984 ◽  
Vol 198 (2) ◽  
pp. 99-108 ◽  
Author(s):  
T X Yu ◽  
W Johnson
Keyword(s):  
Theoretical Analysis ◽  
Metal Forming ◽  
Plastic Material ◽  
Forming Process ◽  
Rigid Plastic ◽  
Rigid Plastic Material ◽  
Punch Load ◽  
Theoretical Predictions ◽  
Metal Forming Process ◽  
Good Agreement

Based on experiments on the bending of metal strips into cylindrical dies using a semi-circular ended punch (1) a theoretical analysis of this metal forming process is presented to predict the punch load—punch travel characteristic and the clearance between the punch pole and the mid-point of the strip. Elastic/plastic and rigid/plastic material idealizations are employed, and the effect of friction between the strip and the die is also considered. The theoretical predictions show good agreement with the experimental results and are useful for designers.

AXIAL CRUSHING OF TRIANGULAR TUBES

2013 ◽  
Vol 05 (01) ◽  
pp. 1350008 ◽  
Author(s):  
Z. FAN ◽  
G. LU ◽  
T. X. YU ◽  
K. LIU
Keyword(s):  
Plastic Material ◽  
Progressive Collapse ◽  
Material Model ◽  
Acute Angle ◽  
Rigid Plastic ◽  
Element Analysis ◽  
Axial Crushing ◽  
Rigid Plastic Material ◽  
Theoretical Predictions ◽  
New Type

In the present paper, the mechanical behavior of large deformation of a regular equilateral triangular tube under quasi-static axial crushing is reported, which is a polygon with an acute angle and odd number of sides. Based on the results from nonlinear finite element analysis (FEA), a new type of inextensional basic plastic collapse folding element is proposed to describe the plastic progressive collapse. The progressive folding around the stationary horizontal hinges and inclined traveling hinges are involved to develop the new basic folding element. Two types of inextensible deformation modes are discovered, i.e., diamond mode and rotational symmetrical mode. The average crushing load for each mode is predicted from the super-folding element theory, which was proposed from the previous investigation on the axial crushing of square columns. A rigid-plastic material model and a kinematically admissible model are involved in this theory. The results are further validated against experiments. The approximate quasi-static theoretical predictions for the mean crushing loads of triangular tubes provide reasonable agreement with the corresponding experimental results.

Numerical Study of Metal Forming Simulation Using Elasto-Plastic and Rigid-Plastic Meshfree Analysis

2005 ◽  
Author(s):  
Young H. Park
Keyword(s):  
Metal Forming ◽  
Reproducing Kernel ◽  
Numerical Study ◽  
Plastic Material ◽  
Meshfree Method ◽  
Material Model ◽  
Reproducing Kernel Particle Method ◽  
Rigid Plastic ◽  
Plastic Model ◽  
Forming Simulation

In this paper, material processing simulation is carried out using a meshfree method. The domain of the workpiece is discretized using the Lagrangian Reproducing Kernel Particle Method (RKPM) where no external meshes are used. The meshfree method is formulated for elasto-plastic material model as well as rigid-plastic model. For elasto-plastic model, a finite plasticity theory is formulated based on the multiplicative decomposition to handle large deformation problems. A rigid-plastic material model is also employed using flow formulation based on the assumption that elastic effects are insignificant in the metal forming operation. A comparative study between elasto-plastic and rigid-plastic RKPM methods was conducted to demonstrate consistency of the results from elasto-plastic and rigid-plastic simulations for a metal forming application.

scholarly journals A mixed elastoplastic/rigid-plastic material model

1999 ◽  
Vol 46 (9) ◽  
pp. 1421-1434 ◽  
Author(s):  
J. Hu�tink ◽  
A. H. Van den Boogaard ◽  
A. D. Rietman ◽  
J. Lof ◽  
T. Meinders
Keyword(s):  
Plastic Material ◽  
Material Model ◽  
Rigid Plastic ◽  
Rigid Plastic Material

Stamping Rectangular Plates into Doubly-Curved Dies

1984 ◽  
Vol 198 (2) ◽  
pp. 109-125 ◽  
Author(s):  
T X Yu ◽  
W Johnson ◽  
W J Stronge
Keyword(s):  
Plastic Material ◽  
Rectangular Plates ◽  
Rigid Plastic ◽  
Punch Force ◽  
Plate Buckling ◽  
Rigid Plastic Material ◽  
Force Contact ◽  
Curvature Distribution ◽  
Doubly Curved ◽  
Deformation Modes

Shallow spheroidal shell segments have been press formed from rectangular plates by stamping between a die and matching punch that have two degrees of curvature. Experiments on mild steel, copper and aluminium plates that were not clamped in the die have measured the punch force, contact regions and final curvature distribution; and have observed plate buckling for a range of die curvature ratios and plate sizes. An analysis based on a rigid/plastic material idealization and decoupled in-plane forces and bending moments has been correlated with these experiments. The sequence of deformation modes has been identified; initially these are bending but in later stages, in-plane forces predominate.

Theory of compression of a compressible rigid-plastic material

1974 ◽  
Vol 10 (3) ◽  
pp. 323-326
Author(s):  
I. S. Degtyarev ◽  
V. L. Kolgomorov
Keyword(s):  
Plastic Material ◽  
Rigid Plastic ◽  
Rigid Plastic Material
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