Fracture Behavior of Polypropylene /Elastomer Blends

2008 ◽  
Vol 47-50 ◽  
pp. 278-281 ◽  
Author(s):  
M. Hernández ◽  
M.N. Ichazo ◽  
J. González ◽  
C. Albano ◽  
Orlando Santana
Keyword(s):  
Fracture Toughness ◽  
Plastic Deformation ◽  
Energy Dissipation ◽  
Fracture Resistance ◽  
Fracture Behavior ◽  
Thermoplastic Elastomer ◽  
Test Results ◽  
Essential Work ◽  
Dynamic Vulcanization ◽  
Injection Molded

In this paper, effort has been undertaken to study the fracture behavior of thermoplastic/elastomer (PP/SBS) dynamically vulcanized blends by analyzing the EWF test results. PP/SBS blends were prepared with concentrations of SBS of 15, 30 and 40 wt%. Deeply double edged notched tension (DDENT) specimens were cut from injection molded plaques for fracture testing. It should be noted that the incorporation of SBS to PP seems to enhance fracture toughness, thus the specific essential work (we) increases with elastomer content. The elastomer particles contribute to the energy dissipation at the fracture surface and in the outer plastic zone in which various types of deformation might have been at work. Also, it seems that the fracture toughness value levels-off from 30 wt% rubber on. In addition, the incorporation of SBS triggers a considerable plastic deformation, since the non-essential work ( βwp) increases compared to the value of pure PP. Nonetheless, a decrease in βwp is present with increasing amount of rubber. So the EWF method revealed that the dynamic vulcanization method can impair fracture resistance to PP/SBS blends.

Thermal Effects of Cracked Piezoelectric Materials under Cycling Electric-Loading

2006 ◽  
Vol 312 ◽  
pp. 35-40 ◽  
Author(s):  
Ning Ning Du ◽  
Shou Wen Yu
Keyword(s):  
Fracture Toughness ◽  
Energy Dissipation ◽  
Temperature Rise ◽  
Open Problem ◽  
Thermal Effects ◽  
Fracture Behavior ◽  
Piezoelectric Materials ◽  
Electric Loading ◽  
Dissipation Mechanism ◽  
Piezoelectric Solids

It is still an open problem how the thermal effect influences the fracture behavior of piezoelectric materials especially under cycling electrical loading. Experimental observations have found that the fracture toughness of piezoelectric solids under electric loading may be greatly different from that under mechanical loading. A pronounced rise of temperature may be caused either by mechanical or by electric loading. In this paper, the thermal effects and energy dissipation mechanism in cracked piezoelectric materials under cyclic-electric-loading have been studied. The temperature rise is derived under the assumption of decoupling between thermal and electromechanical fields and the influences of frequency and the shape of electric wave on the temperature rise are quantitatively analyzed.

Unusual fracture behavior of nanoporous polymeric thin-films

2005 ◽  
Vol 880 ◽  
Author(s):  
Andrew V. Kearney ◽  
Reinhold H. Dauskardt ◽  
Carol E. Mohler ◽  
Michael E. Mills
Keyword(s):  
Fracture Toughness ◽  
Pore Size ◽  
Fracture Resistance ◽  
Fracture Behavior ◽  
Volume Fraction ◽  
Porous Solids ◽  
Void Size ◽  
Polymeric Thin Films ◽  
Arylene Ether ◽  
Ductile Polymer

AbstractWe present surprising evidence that the fracture resistance of porous forms of poly(arylene) ether (PAE) films exhibit increasing fracture resistance with increasing porosity. Such behavior is in stark contrast to the fracture toughness of porous solids, which typically decrease markedly with increasing porosity. A fracture mechanics based model is presented to rationalize the increase in fracture toughness of the voided polymer film and explain the behavior in terms of the pore size and volume fraction. It is shown that a certain dependence of pore size and volume fraction is required to increase rather than decrease the fracture resistance. The research has implications for the optimum void size and volume fraction needed to enhance the fracture resistance of porous ductile polymer films.

J-R Fracture Toughness of Nuclear Piping Materials Under Excessive Seismic Loading Condition

2016 ◽  
Author(s):  
Jin Weon Kim ◽  
Myung Rak Choi ◽  
Sang Bong Lee ◽  
Yun Jae Kim
Keyword(s):  
Fracture Toughness ◽  
Cyclic Loading ◽  
Fracture Resistance ◽  
Cyclic Load ◽  
Fracture Behavior ◽  
Loading Rate ◽  
Seismic Loading ◽  
Monotonic Loading ◽  
Rate Effect ◽  
Loading Conditions

This study investigated the loading rate effect on the fracture resistance under cyclic loading conditions to clearly understand the fracture behavior of piping materials under excessive seismic conditions. J-R fracture toughness tests were conducted under monotonic and cyclic loading conditions at various displacement rates at room temperature (RT) and the operating temperature of nuclear power plants (NPPs), i.e., 316°C. SA508 Gr. 1a lo w-alloy steel (LAS) and SA312 TP316 stainless steel (SS) piping materials were used for the tests. The fracture resistance under a reversible cyclic load was considerably lower than that under monotonic load regardless of test temperature, material, and loading rate. Under both cyclic and monotonic loading conditions, the fracture behavior of SA312 TP316 SS was independent of the loading rate at both RT and 316°C. For SA508 Gr. 1a LAS, the loading rate effect on the fracture behavior was appreciable at 316°C under both cyclic and monotonic loading conditions. However, the loading rate effect diminished when the cyclic load ratio (R) was −1. Thus, it was recognized that the fracture behavior of piping materials, including seismic loading characteristics, can be evaluated when tested under a cyclic load of R = −1 at a quasi-static loading rate.

Fracture Properties of Epoxy Asphalt Mixture

2009 ◽  
Vol 417-418 ◽  
pp. 917-920
Author(s):  
Xian Hua Chen ◽  
Hong Tao Li ◽  
Zhen Dong Qian
Keyword(s):  
Fracture Toughness ◽  
Fracture Resistance ◽  
Asphalt Mixture ◽  
J Integral ◽  
Test Results ◽  
High Tensile Strength ◽  
Fracture Properties ◽  
Epoxy Asphalt ◽  
Scb Test ◽  
Good Repeatability

The fracture properties of the thermo-setting materials of epoxy asphalt mixture were evaluated based on J-integral concept and ultimate strength and compared to that of HMA with thermo-plastic binder materials. Totally 60 specimens cored from SGC with different notches were tested with SCB test under a temperature of -10°C and 20°C. The experimental results reveals that epoxy asphalt mixture has a super higher resistance of fracture at low temperature than thermo-plastic HMA due to its super high tensile strength and flexibility, and the influences of temperature on the fracture resistance of EAM is not so significant as that of thermo-plastic HMA. Good repeatability of SCB test results indicates the capability of the SCB test to be useful for measuring the fracture toughness of epoxy asphalt mixture.

scholarly journals Fracture Resistance of Advanced High-Strength Steel Sheets for Automotive Applications

2021 ◽  
Author(s):  
D. Frómeta ◽  
A. Lara ◽  
L. Grifé ◽  
T. Dieudonné ◽  
P. Dietsch ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fracture Resistance ◽  
High Strength ◽  
Tensile Tests ◽  
Essential Work ◽  
Automotive Applications ◽  
Advanced High Strength Steel ◽  
Thickness Strain ◽  
Essential Work Of Fracture ◽  
Work Of Fracture

AbstractThe fracture resistance of different advanced high-strength steel (AHSS) sheets for automotive applications is investigated through conventional tensile tests, fracture toughness measurements, and hole expansion tests. Different fracture-related parameters, such as the true fracture strain (TFS), the true thickness strain (TTS), the fracture toughness at crack initiation (w e i ), the specific essential work of fracture (we), and the hole expansion ratio (HER), are assessed. The specific essential work of fracture (we) is shown to be a suitable parameter to evaluate the local formability and fracture resistance of AHSS. The results reveal that fracture toughness cannot be estimated from any of the parameters derived from tensile tests and show the importance of microstructural features on crack propagation resistance. Based on the relation fracture toughness-local formability, a new AHSS classification mapping accounting for global formability and cracking resistance is proposed. Furthermore, a physically motivated fracture criterion for edge-cracking prediction, based on thickness strain measurements in fatigue pre-cracked DENT specimens, is proposed.

Fracture Mechanisms in NiAlCr Eutectic Composites

1992 ◽  
Vol 273 ◽  
Author(s):  
Keh-Minn Chang
Keyword(s):  
Fracture Toughness ◽  
Fracture Resistance ◽  
Fracture Behavior ◽  
Room Temperature ◽  
Ternary Systems ◽  
Fracture Mechanisms ◽  
Fracture Properties ◽  
Intermetallic Matrix ◽  
Binary Eutectic ◽  
Ternary Eutectics

ABSTRACTSelected eutectic compositions in Ni-Al-Cr ternary systems were processed by directional solidification (DS) with various growth rates. Fracture toughness tests were performed at room temperature and 400 °C; fracture surfaces of broken specimens were examined using SEM to investigate fracture behavior of each alloy. The alignment of eutectic phases was found to play an important role in composite toughening for the intermetallic matrix. Binary eutectic composites consisting of bcc α-Cr and B2 β-NiAl phases with a directional, well-aligned structure showed improved fracture properties over NiAl single crystals. Ternary eutectics, which contain an fcc γ-Ni phase, offered an excellent fracture resistance at room temperature.

scholarly journals Efficient Improvement in Fracture Toughness of Laminated Composite by Interleaving Functionalized Nanofibers

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2509
Author(s):  
Seyed Mohammad Javad Razavi ◽  
Rasoul Esmaeely Neisiany ◽  
Moe Razavi ◽  
Afsaneh Fakhar ◽  
Vigneshwaran Shanmugam ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Fracture Behavior ◽  
Laminated Composite ◽  
Carbon Phase ◽  
Reinforced Composite ◽  
Reinforcing Agent ◽  
The Matrix ◽  
As Stress ◽  
Double Cantilever Beam Test ◽  
Pan Nanofiber

Functionalized polyacrylonitrile (PAN) nanofibers were used in the present investigation to enhance the fracture behavior of carbon epoxy composite in order to prevent delamination if any crack propagates in the resin rich area. The main intent of this investigation was to analyze the efficiency of PAN nanofiber as a reinforcing agent for the carbon fiber-based epoxy structural composite. The composites were fabricated with stacked unidirectional carbon fibers and the PAN powder was functionalized with glycidyl methacrylate (GMA) and then used as reinforcement. The fabricated composites’ fracture behavior was analyzed through a double cantilever beam test and the energy release rate of the composites was investigated. The neat PAN and functionalized PAN-reinforced samples had an 18% and a 50% increase in fracture energy, respectively, compared to the control composite. In addition, the samples reinforced with functionalized PAN nanofibers had 27% higher interlaminar strength compared to neat PAN-reinforced composite, implying more efficient stress transformation as well as stress distribution from the matrix phase (resin-rich area) to the reinforcement phase (carbon/phase) of the composites. The enhancement of fracture toughness provides an opportunity to alleviate the prevalent issues in laminated composites for structural operations and facilitate their adoption in industries for critical applications.

Fracture Toughness Testing and its Implications to Engineering Fracture Mechanics Analysis of Energy Pipelines

2018 ◽  
Author(s):  
Sergio Limon ◽  
Peter Martin ◽  
Mike Barnum ◽  
Robert Pilarczyk
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Test Data ◽  
Fracture Mode ◽  
Fracture Process ◽  
Fracture Behavior ◽  
Fracture Initiation ◽  
Fracture Toughness Testing ◽  
Final Fracture ◽  
Toughness Testing

The fracture process of energy pipelines can be described in terms of fracture initiation, stable fracture propagation and final fracture or fracture arrest. Each of these stages, and the final fracture mode (leak or rupture), are directly impacted by the tendency towards brittle or ductile behavior that line pipe steels have the capacity to exhibit. Vintage and modern low carbon steels, such as those used to manufacture energy pipelines, exhibit a temperature-dependent transition from ductile-to-brittle behavior that affects the fracture behavior. There are numerous definitions of fracture toughness in common usage, depending on the stage of the fracture process and the behavior or fracture mode being evaluated. The most commonly used definitions in engineering fracture analysis of pipelines with cracks or long-seam weld defects are related to fracture initiation, stable propagation or final fracture. When choosing fracture toughness test data for use in engineering Fracture Mechanics-based assessments of energy pipelines, it is important to identify the stage of the fracture process and the expected fracture behavior in order to appropriately select test data that represent equivalent conditions. A mismatch between the physical fracture event being modeled and the chosen experimental fracture toughness data can result in unreliable predictions or overly conservative results. This paper presents a description of the physical fracture process, behavior and failure modes that pipelines commonly exhibit as they relate to fracture toughness testing, and their implications when evaluating cracks and cracks-like features in pipelines. Because pipeline operators, and practitioners of engineering Fracture Mechanics analyses, are often faced with the challenge of only having Charpy fracture toughness available, this paper also presents a review of the various correlations of Charpy toughness data to fracture toughness data expressed in terms of KIC or JIC. Considerations with the selection of an appropriate correlation for determining the failure pressure of pipelines in the presence of cracks and long-seam weld anomalies will be discussed.

Fracture behavior of 3-d Braided Nicalon/Silicon Carbide Composite

1988 ◽  
Vol 120 ◽  
Author(s):  
J.-M. Yang ◽  
J.-C. Chou ◽  
C. V. Burkland
Keyword(s):  
Fracture Toughness ◽  
Silicon Carbide ◽  
Thermal Shock Resistance ◽  
Fracture Behavior ◽  
Ceramic Composite ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Fiber Architecture ◽  
Structural Ceramic ◽  
Shock Resistance

AbstractThe fracture behavior of a 3-D braided Nicalon fiber-reinforced SiC matrix composite processed by chemical vapor infiltration (CVI) has been investigated. The fracture toughness and thermal shock resistance under various thermomechanical loadings have been characterized. The results obtained indicate that a tough and durable structural ceramic composite can be achieved through the combination of 3-D fiber architecture and the low temperature CVI processing.

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