scholarly journals Finite element analysis of long-term performance of buried high density polyethylene pipes

2006 ◽  
Author(s):  
Raj Kumar Gondle
1996 ◽  
Vol 23 (2) ◽  
pp. 395-407 ◽  
Author(s):  
Ian D. Moore ◽  
Fuping Hu

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).


2017 ◽  
Vol 54 (12) ◽  
pp. 1623-1636 ◽  
Author(s):  
R. Kerry Rowe ◽  
Mohamad Shoaib

The effect of a synthetic municipal solid waste leachate on the long-term performance of dual-wedge welds in a 1.5 mm thick high-density polyethylene geomembrane (GMB) is reported based on 4 years of testing at 40, 65, 75, and 85 °C. The effect of leachate on the GMB well away from the weld, in the heat-affected zone (HAZ) beside the weld, and in the welded zone are investigated. The slowest antioxidant depletion rate was in the weld itself and the fastest rate for the HAZ adjacent to the weld. The shear break and peel break properties started to decrease after the standard oxidative induction time had depleted to residual, but before the high-pressure oxidative induction time had reached residual. Failures occured at the HAZ adjacent to weld in both the shear and peel tests. No failure of the seam itself was observed. The times to nominal failure of the GMB in the critical HAZ are predicted. The rate of degradation in the weld and sheet are compared.


Polymer ◽  
1994 ◽  
Vol 35 (7) ◽  
pp. 1442-1451 ◽  
Author(s):  
Min-Diaw Wang ◽  
Eiji Nakanishi ◽  
Sadao Hibi

Author(s):  
B. Aour ◽  
F. Zaïri ◽  
M. Naït-Abdelaziz ◽  
J. M. Gloaguen ◽  
J. M. Lefebvre

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.


2020 ◽  
Vol 57 (8) ◽  
pp. 1130-1152 ◽  
Author(s):  
R.S. McWatters ◽  
R.K. Rowe ◽  
V. Di Battista ◽  
B. Sfiligoj ◽  
D. Wilkins ◽  
...  

An Antarctic biopile using a composite liner (high-density polyethylene geomembrane (GMB) over a geosynthetic clay liner (GCL)) was constructed on a coarse granular subgrade to contain hydrocarbon-contaminated soil and leachate. The soil was remediated after 4 years and the biopile was decommissioned. The liner was exhumed to assess the properties and performance of the GMB and GCL. There was no significant change in the GMB index properties. Although cobbles and coarse gravel of the subgrade had left indentations in the GMB, implying tensile strains that could impact long-term performance, there were no holes. There was significant variability in the hydration of the GCL (from 10% to 220%) and in the underlying subgrade soil water content (from 5% to 30%). This reflects the complexity of the subgrade and groundwater flow in the Antarctic environment. The exhumed GCL specimens had low hydraulic conductivity (1 × 10−11 to 7 × 10−11 m/s) at 13 kPa. Soil samples from below the composite liner showed no detectable hydrocarbons and confirmed no migration through the barrier. It is concluded that the composite barrier contained the leachate and biopile soil over the 4 years in service in the extreme Antarctic conditions.


Author(s):  
Vikram Venkatadri ◽  
Mark Downey ◽  
Xiaojie Xue ◽  
Dipak Sengupta ◽  
Daryl Santos ◽  
...  

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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