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Duan, Da-Ming; Williams, J. G.

doi:10.1023/a:1004369107748

Cited by 33 publications

(10 citation statements)

References 11 publications

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“…, rectangular specimen bars of 50x10x10 mm were compression molded following the same process as for the PENT specimens. Afterwards, a deep circumferential notch was introduced maintaining the remaining ligament equal to 1/10 of the cross sectional area , the test being carried out under applied stress of 1 MPa at 80°C. At least three specimens were tested for both PENT and CDNT geometries in order to have an accurate result.…”

Section: Methodsmentioning

confidence: 99%

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The effect of microstructure on the slow crack growth resistance in polyethylene resins

Adib

Domı́nguez

Rodrı́guez

et al. 2014

Polymer Engineering & Sci

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The slow crack growth (SCG) in high density polyethylene (HDPE) is a phenomenon dominated by crazing. In this work, the crazing was analyzed from a microstructural point of view. PENT (Pennsylvania Edge Notched Tensile) test was chosen to study the evolution of the craze with time for different resins from PE‐80 up to PE‐100 grades. Two different geometries, the standard and an alternative named CDNT (Circumferentially Deep Notched Tensile), were employed. Failure times were correlated with intercrystalline parameters like tie molecules and the molecular weight between entanglements. Experimental results showed good correlations using both direct SCG test (standard PENT and CDNT geometries). Finally, the strain hardening modulus was correlated with PENT failure times. The results disclosed an outstanding correlation for several polyethylene grades from blow molding up to PE‐80, PE‐100, and higher resistant to crack grades. These results permitted an easy‐classifying and ranking method as much to the old polyethylene grades as to the new generation of HDPE resins with a very high SCG resistance. POLYM. ENG. SCI., 55:1018–1023, 2015. © 2014 Society of Plastics Engineers

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Section: Methodsmentioning

confidence: 99%

“…Williams introduced a highly constrained specimen, namely circumferentially deep notched tensile (CDNT) to study crazing . In this article, this specimen has been used together with the standard PENT geometry to determine SCG resistance.…”

Section: Introductionmentioning

confidence: 99%

The effect of microstructure on the slow crack growth resistance in polyethylene resins

Adib

Domı́nguez

Rodrı́guez

et al. 2014

Polymer Engineering & Sci

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“…K,c(t) = (ScE(t)%(t))1/2 (23) where S , is the critical crack opening displacement required for unstable fracture (assumed to be constant), and E, and uyo are the short-term Young's modulus and yield stress of the pipe material respectively. Assuming that material visco-elasticity can be described by:…”

Section: Is0lai-q the Effect Offracture Toughnessmentioning

confidence: 99%

“…The crack tip process zone: Currently a Dugdale craze is assumed to operate at the uniaxial yield stress of the pipe material. Recent work has indicated that increased constraint in a fibrillated craze zone merits the use of an independently defined craze stress (23).…”

Section: Od-i14mmmentioning

confidence: 99%

Lifetime prediction for ABS pipes subjected to combined pressure and deflection loading

Davis

Burn

2003

Polymer Engineering & Sci

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As part of an investigation into the performance of acrylonitrile-butadiene-styrene (ABS) systems for water transportation, this paper presents a method for predicting the service lifetimes of buried pipes under in-service loading conditions. A linear fracture mechanics approach was used to analyze brittle failure initiating from adventitious flaws located at the bore surface of pipe. Failure criteria were determined using the time-dependent, quasistatic, plane strain fracture toughness of the ABS material, combined with empirical parameters that describe slow, steady crack growth. The expected operating conditions of a buried pipe were then separated into static loading contributions from internal pressure, diametrical deflection and residual stress. Idealized stress intensity factors associated with mode-I crack opening under each of these components were determined using a finite element analysis and superposed to describe the general case in service. The computed nett stress intensity factor was then combined with the previously determined fracture toughness and slow crack growth data in an algorithm to simulate incremental radial crack growth from the pipe bore. Predicted failure times compared well with an experimental model of expected operating conditions, which combined hydrostatic pressure and parallel-plate deflection loading of an internally notched pipe. The prediction method was also used to identify the factors that control the lifetime of a pipe in service. The influence of material visco-elasticity was investigated by simulating variations in fracture toughness and slow crack growth resistance. It was proposed that, in practice, these variations are governed by opposing changes in visco-elasticity. The effect of changing diametrical deflection and residual stress distribution were also simulated, allowing recommendations on pipe manufacture and installation conditions to be made.

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“…This involves fatigue of material in the process zone that can fail (i.e. failure of fibrils in the craze zone) leading to an increased rate of crack tip advance [75,79]. This process can be environmentally assisted and detailed stress, time, and temperature models have been developed [80].…”

Section: Vib Introductionmentioning

confidence: 99%

The Dynamic Response of Polymers Interrogated by 3rd Generation X-ray Light Sources

Abbott

Branch

Brown

et al. 2019

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Cellular silicones reinforced with silica filler and prepared using additive manufacturing (AM) have been used widely for vibrational damping and shockwave mitigation. The two most commonly printed cellular silicone structures-simple cubic (SC) and face-centered tetragonal (FCT)-display distinctly different static and dynamic mechanical responses. In this work, the relationship of filler size and composition with mechanical response is investigated using polydimethylsiloxane-based silicones filled with aluminum oxide (alumina, Al 2 O 3), graphite, or titanium dioxide (titania, TiO 2). SC and FCT structures of porous, periodic silicone pads were printed using new DIW resin formulations containing up to 25 wt.% of functional filler. All AM pads were characterized using chemical, thermal (TGA, DSC), and mechanical techniques (DMA, compression). Dynamic compression experiments coupled with time-resolved X-ray imaging were performed to obtain insights into the role of filler interactions in the in situ evolution of shockwave coupling in these functional, periodic, and porous polymers. Understanding the kinetics of phase transition and decomposition during extreme condition events is not a trivial undertaking. Capturing these processes require: 1) diagnostics that probe on the timescales and at energies capable of interacting with the dynamically evolving products, penetrating the opaqueness of the changing system; and 2) detectors sensitive enough to observe these events. Synchrotrons provide access to keV X-ray beams capable of penetrating the opaqueness of the dynamic event with a wavelength adept at interacting with the evolved or compressed crystal structures. At the Dynamic Compression Sector at the Advanced Photon Source, gas guns produce planar shocks at a myriad of projectile velocities while capturing in situ X-ray diffraction of the evolving material under dynamic compression. Specifically, we shocked high density polyethylene to 7.45 GPa observing compression and orientation of the polymer chains.

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Untitled

Cited by 33 publications

References 11 publications

The effect of microstructure on the slow crack growth resistance in polyethylene resins

The effect of microstructure on the slow crack growth resistance in polyethylene resins

Lifetime prediction for ABS pipes subjected to combined pressure and deflection loading

The Dynamic Response of Polymers Interrogated by 3rd Generation X-ray Light Sources

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