Finite Element Analysis of Plastic Strain Distribution in Multipass ECAE Process of High Density Polyethylene

2009 ◽  
Vol 131 (3) ◽  
Author(s):  
B. Aour ◽  
F. Zaïri ◽  
M. Naït-Abdelaziz ◽  
J. M. Gloaguen ◽  
J. M. Lefebvre
Keyword(s):  
Finite Element Analysis ◽  
Plastic Deformation ◽  
Finite Element ◽  
Plastic Strain ◽  
High Density Polyethylene ◽  
Strain Distribution ◽  
High Density ◽  
Element Analysis ◽  
Die Geometry ◽  
Plastic Strain Distribution

Equal channel angular extrusion (ECAE) is a relatively novel forming process to modify microstructure via severe plastic deformation without modification of the sample cross section. In this study, an optimized design of die geometry is presented, which improves homogeneity of the plastic deformation and decreases the pressing force required for extrusion. Then, a typical semicrystalline polymer (high density polyethylene) was subjected to multipass ECAE using two different processing routes: route A where the sample orientation is kept constant between passes and route C where the sample is rotated by 180 deg. Compression tests at room temperature and under different strain rates were used to identify the material parameters of a phenomenological elastic-viscoplastic model. Two-dimensional finite element analysis of ECAE process was carried out, thus allowing to check out the homogeneity of the plastic strain distribution. The effects of die geometry, number of passes, processing route, and friction coefficient on the plastic strain distribution were studied. The simulations were performed for three channel angles (i.e., 90 deg, 120 deg, and 135 deg), considering different corner angles. According to simulation results, recommendations on the angular extrusion of the polymer are provided for improving die and process performance.

Finite Element Analysis of β-Titanium during Equal Channel Angular Extrusion

2011 ◽  
Vol 399-401 ◽  
pp. 1702-1707
Author(s):  
Jia Yong Si ◽  
Ze Hao Hu ◽  
Li Ping Zhong
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plastic Strain ◽  
Strain Distribution ◽  
Equal Channel Angular Extrusion ◽  
Equivalent Plastic Strain ◽  
Element Analysis ◽  
Die Geometry ◽  
Plastic Strain Distribution ◽  
Angular Extrusion

The finite element analysis was applied to evaluate the respective influences of die geometry and process conditions on plastic strain distribution for β-titanium (Ti-13V11Cr3Al) during the equal channel angular extrusion. It was found that optimum ECAE die geometry is strongly material dependent. Optimal strain homogeneity in the Ti-13V11Cr3Al alloy may be achieved at r (inner radius) =5mm, R (outer radius) =3mm. The equivalent plastic strain increases with increasing friction coefficient. And the better homogeneity of the equivalent plastic strain distribution can be achieved when m=0.1. The faster is the ram speed, the lower is the homogeneity of the equivalent plastic strain distribution. The back-pressure can increase the strain level across the workpiece and prevent the problem of surface cracking induced by tensile stresses. The distribution of the plastic strain is not temperature sensitive between 400°C and 600°C.

FINITE ELEMENT ANALYSIS OF CONSTRAINED GROOVE PRESSING OF PURE ALUMINUM SHEETS

2013 ◽  
Vol 02 (01) ◽  
pp. 1350001 ◽  
Author(s):  
S. S. SATHEESH KUMAR ◽  
I. BALASUNDAR ◽  
T. RAGHU
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Plastic Strain ◽  
Deformation Behavior ◽  
Strain Distribution ◽  
Pure Aluminum ◽  
Detailed Examination ◽  
Deformation Characteristics ◽  
Element Analysis ◽  
Aluminum Sheets

Constrained groove pressing (CGP) is an attractive severe plastic deformation technique capable of processing ultrafine grained/nanostructured sheet materials. The deformation behavior of pure aluminum during constrained groove pressing is investigated by carrying out a two-dimensional finite element analysis (FEA). FEA predicted deformation behavior observed during each stages of pressing indicated almost negligible deformation in flat regions, whereas the inclined shear regions revealed diverse deformation characteristics. The plastic strain distributions unveiled inhomogeneous strain distribution at the end of one pass. Detailed examination of plastic strain evolution during CGP along various sections divulged superior strain distribution along middle surfaces when compared to top and bottom surfaces. The degree of strain homogeneity is evaluated quantitatively along different regions of the sheet and is correlated to the deformation characteristics. Load–stroke characteristics obtained during corrugating and flattening of sheets exhibited three stages and two stages behavior, respectively. The results obtained from the analysis are experimentally validated by processing pure aluminum sheets by CGP and the measured deformation homogeneity is benchmarked with FEA results.

Finite element analysis of single-edgecracked rolled high-density polyethylene

Polymer ◽  
1994 ◽  
Vol 35 (7) ◽  
pp. 1442-1451 ◽  
Author(s):  
Min-Diaw Wang ◽  
Eiji Nakanishi ◽  
Sadao Hibi
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Density Polyethylene ◽  
High Density ◽  
Element Analysis

Linear viscoelastic modelling of profiled high density polyethylene pipe

1996 ◽  
Vol 23 (2) ◽  
pp. 395-407 ◽  
Author(s):  
Ian D. Moore ◽  
Fuping Hu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Density Polyethylene ◽  
Parallel Plate ◽  
High Density ◽  
Time Dependent ◽  
Element Analysis ◽  
Vertical Diameter ◽  
Polyethylene Pipes ◽  
Linear Viscoelastic

Rheological model parameters for a linear viscoelastic finite element analysis are developed for corrugated polyethylene pipes. Relaxation test data from parallel plate load tests on lined corrugated high density polyethylene pipes are used, for pipes deflected to 5% and 10% vertical diameter decrease. Three-dimensional time-dependent finite element analysis is then used to estimate the time-dependent response of a 610 mm diameter pipe subjected to a constant rate of vertical diameter decrease with time. Predictions are obtained for deflection rates varying over three orders of magnitude, for direct comparison with laboratory test results. Small deflection (5%) relaxation rheology leads to good predictions of measured response up to 3% vertical pipe deflection. Large deflection (10%) rheology yields reasonable predictions for pipe response between 3% and 10% vertical deflection. Levels of strain are examined in the pipe profile, and a peak local tensile strain of 0.6% is estimated for the pipe deflected to 3% vertical diameter decrease. The rheological models should permit prediction of response under parallel plate loading for other pipe profiles. These models might also be used for estimation of pipe response under other loading conditions (such as deep burial in the field).

Optimizing System-on-Film (SOF) Design Using Finite Element Analysis

2011 ◽  
Author(s):  
Vikram Venkatadri ◽  
Mark Downey ◽  
Xiaojie Xue ◽  
Dipak Sengupta ◽  
Daryl Santos ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Flip Chip ◽  
Flexible Substrate ◽  
High Density ◽  
Design Solution ◽  
Design Parameters ◽  
Optimized Design ◽  
Element Analysis ◽  
Bonding Parameters

System-On-Film (SOF) module is a complex integration of a fine pitch high density die and surface mounted discrete devices on a polyimide (PI) film laminate. The die is connected to the film using a thermo-compression flip-chip bonding (TCB) process which is capable of providing a very high density interconnect at less than 50um pitch. Several design and bonding parameters have to be controlled in order to achieve a reliable bond between the Au bumps on the die and the Sn plated Cu traces on the PI film. In the current work, the TCB process is studied using Finite Element Analysis (FEA) to optimize the design parameters and assure proper process margins. The resultant forces acting on the bump-to-trace interfaces are quantified across the different potential geometrical combinations. Baseline simulations showed higher stresses on specific bump locations and stress gradients acting on the bumps along the different sides of the die. These observations were correlated to both the failures and near failures on the actual test vehicles. Further simulations were then utilized to optimize and navigate design tradeoffs at both the die and flexible substrate design levels for a more robust design solution. Construction analysis performed on parts built using optimized design parameters showed significant improvements and correlated well with the simulation results.

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