Fracture Toughness of Freshwater Ice—Part I: Experimental Technique and Results

1996 ◽  
Vol 118 (2) ◽  
pp. 135-140 ◽  
Author(s):  
L. J. Weber ◽  
W. A. Nixon
Keyword(s):  
Fracture Toughness ◽  
Experimental Technique ◽  
Test Temperature ◽  
Significant Variation ◽  
Loading Rate ◽  
Companion Paper ◽  
Fractographic Analysis ◽  
Linear Elastic ◽  
Freshwater Ice ◽  
Crack Tip Plasticity

Experiments have been performed to determine the effect of loading rate and temperature on the fracture toughness of both granular and S2 columnar freshwater ice. Loading rate was varied from 0.04 to 40.0 kPam s-1, and over this range the fracture toughness was observed to decrease from 201 to 109 kPam. Examination of load—CMOD curves indicate that at a loading rate of 40 kPam s-1, the crack tip plasticity was sufficiently limited that the specimen behavior can be considered linear elastic, thus providing a valid Kq measurement. When test temperature was varied from −5 to −45°C for the S2 columnar ice, no significant variation in toughness was observed. In contrast, for granular ice, a higher toughness (144 kPam) was observed in the −5 to −20°C range than for the S2 columnar ice. However, the toughness of the granular ice at−45°C is not significantly different from that of the S2 columnar ice. A companion paper (Weber and Nixon, 1996) analyzes the results in greater detail comparing them with previous work, and presents a detailed fractographic analysis of the failure surfaces.

Fracture Toughness of Freshwater Ice—Part II: Analysis and Micrography

1996 ◽  
Vol 118 (2) ◽  
pp. 141-147 ◽  
Author(s):  
L. J. Weber ◽  
W. A. Nixon
Keyword(s):  
Fracture Toughness ◽  
Fracture Surface ◽  
Experimental Technique ◽  
Loading Rate ◽  
Process Zone ◽  
Crack Tip ◽  
Simple Method ◽  
Dislocation Activity ◽  
Freshwater Ice

Experiments have been performed to determine the effect of loading rate and temperature on the fracture toughness of freshwater ice. A first paper (Weber and Nixon, 1996) presents the experimental technique and results, while this paper focuses on discussion of the crack tip process zone and fracture surface micrography. A simple method to estimate the size of the process zone will be presented. Also, fracture surface micrography will be used to interpret the results of the temperature experiments by considering evidence of dislocation activity in preferentially oriented grains.

Applicability of Master Curve Method to Japanese Reactor Pressure Vessel Steels

2006 ◽  
Author(s):  
Naoki Miura ◽  
Naoki Soneda ◽  
Taku Arai ◽  
Kenji Dohi
Keyword(s):  
Fracture Toughness ◽  
Test Temperature ◽  
Pressure Vessel ◽  
Master Curve ◽  
Loading Rate ◽  
Specimen Size ◽  
Master Curves ◽  
Master Curve Method ◽  
Curve Method ◽  
Reactor Pressure

The Master Curve method has been proposed and recognized worldwide as an alternative approach to evaluate fracture toughness of reactor pressure vessel (RPV) steels in brittle-to-ductile transition temperature range. This method theoretically provides the confidence levels of fracture toughness in consideration of the statistical distribution, which is an inherent property of fracture toughness. In this study, a series of fracture toughness tests was conducted for typical Japanese RPV steels, SFVQ1A and SQV2A, to identify the effects of test temperature, specimen size, and loading rate, and the applicability of the Master Curve method was experimentally validated. The differences in test temperature and specimen size did not affect master curves. In contrast, increasing loading rate significantly shifted master curves to higher temperatures. The lower bound curve based on the master curve could conservatively envelop all of the experimental fracture toughness data. The present rule, in which the lower limit of fracture toughness is indirectly determined by Charpy impact test results, can be too conservative, while the application of the Master Curve method may significantly reduce the conservativity of the allowable level of fracture toughness.

Effects of Temperature and Loading Rate on Fracture Toughness

2005 ◽  
Vol 297-300 ◽  
pp. 2397-2402
Author(s):  
Tetsuya Murakami ◽  
Hiroyuki Toda ◽  
Toshiro Kobayashi
Keyword(s):  
Fracture Toughness ◽  
Test Temperature ◽  
Loading Rate ◽  
Type Specimen ◽  
Specimen Size ◽  
Specimen Thickness ◽  
Rate Parameter ◽  
Rate Dependency ◽  
Round Bar ◽  
Circular Notch

It is known that fracture toughness value is affected by test temperature, specimen thickness and loading rate. In the present study, specimen size and test temperature are varied widely with the obtained data then being analyzed using rate parameter. Additionally, the fracture toughness values are obtained using round bar-type specimen with a circular notch. This result is compared with the result of the CT specimens, and the advantage of using the round bar-type specimen with a circular notch to modify specimen size requirement is discussed. Sample material used is HT780 high tensile strength steel. The test specimens were 1T, 2T and 4T-CT that are described in ASTM E399. Notched round bar-type specimen with a diameter of 15mm and notch root radius of 0.25mm is also used. The test temperature is varied from a low temperature to room temperature, and loading rate is varied about the 1T-CT specimen and the notched round bar-type specimen between static and 1000mm/sec. The test temperature and the loading rate dependency of the fracture toughness values were arranged by the rate parameter. The fracture toughness value has decreased with the decrease in test temperature and with the increase in specimen thickness and loading rate. The fracture toughness value obtained from the notched round bar-type specimen indicated a value close to 2T-CT specimen. It is shown that valid fracture toughness value can be obtained with a small test specimen by the notched round bar-type specimen. The test temperature and the loading rate dependency of the fracture toughness values can be successfully arranged by the rate parameter that can express both temperature and strain rate dependencies. Feasibility of using round bar-type specimen to obtain valid fracture toughness values with less specimen mass was demonstrated.

Linear translaminar fracture characterization of additive manufactured continuous carbon fiber reinforced thermoplastic

2021 ◽  
pp. 089270572110214
Author(s):  
Weiller M Lamin ◽  
Flávio LS Bussamra ◽  
Rafael TL Ferreira ◽  
Rita CM Sales ◽  
José E Baldo
Keyword(s):  
Fracture Toughness ◽  
Carbon Fiber ◽  
Fracture Mechanics ◽  
Image Correlation ◽  
Fiber Reinforced ◽  
Fused Filament Fabrication ◽  
Critical Energy Release Rate ◽  
Linear Elastic ◽  
Continuous Carbon Fiber ◽  
Carbon Fiber Reinforced

This work presents the experimental determination of fracture mechanics parameters of composite specimens manufactured by fused filament fabrication (FFF) with continuous carbon fiber reinforced thermoplastic filaments, based on Linear Elastic Fracture Mechanics (LEFM). The critical mode I translaminar fracture toughness (KIc) and the critical energy release rate (GIc) are found for unidirectional and cross-ply laminates. The specimens were submitted to quasi-static tensile testing. Digital Image Correlation (DIC) is used to find the stress field. The stress fields around the crack tip are compared to linear elastic finite element simulations. The results demonstrate the magnitude of fracture toughness is in the same range as for polymers and some metals, depending on lay-up configuration. Besides, fractographic analyses show some typical features as river lines, fiber impression, fiber pulls-out and porosity aspects.

Investigation of loading rate and plate thickness effects in dynamic fracture toughness of PMMA

1997 ◽  
Vol 57 (4) ◽  
pp. 459-460
Author(s):  
H. Wada ◽  
M. Seika ◽  
T.C. Kennedy ◽  
C.A. Calder ◽  
K. Murase
Keyword(s):  
Fracture Toughness ◽  
Dynamic Fracture ◽  
Loading Rate ◽  
Plate Thickness ◽  
Dynamic Fracture Toughness

scholarly journals Evaluation of linear-elastic fracture toughness of the teeth restored with different post and core systems

2015 ◽  
Vol 7 (8) ◽  
pp. 125-129
Author(s):  
Lamartine De Moraes Melo Neto Clovis ◽  
Afonso Franciscone Paulo ◽  
Mondelli Jose ◽  
Sbeghen Sabio Silvia ◽  
Lorenzi Poluha Rodrigo ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Linear Elastic ◽  
Elastic Fracture ◽  
Post And Core

An Experimental Study on Stretchy and Tough PDMS/Fabric Composites

2018 ◽  
Vol 86 (1) ◽  
Author(s):  
Ruofei Chang ◽  
Zhou Chen ◽  
Cunjiang Yu ◽  
Jizhou Song
Keyword(s):  
Fracture Toughness ◽  
Low Cost ◽  
Elastic Response ◽  
Deformation Localization ◽  
Practical Applications ◽  
Damage Propagation ◽  
Linear Elastic ◽  
Nylon Fabric ◽  
Fabric Composite ◽  
Fabric Composites

Polydimethylsiloxane (PDMS) has a good elasticity but with a pretty low fracture toughness, which limits its use in practical applications. This paper presents a simple and low-cost approach to manufacture a PDMS/fabric composite through incorporating the commercially available stretchy plain weft-knitted nylon fabric into the PDMS matrix. The fracture toughness of the composite is much higher than that of pure PDMS with an increase up to 700%. The toughening mechanism, which can be attributed to the deformation localization induced fiber stretch and damage propagation in the PDMS matrix, is fully investigated. During cyclic loadings, the composite may exhibit a linear elastic response or a significant hysteresis depending on the stretch level. These results provide physical insights into the deformation mechanism of a soft fabric-reinforced composite and may offer practical routes to realize robust crack-insensitive PDMS.

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