Infrasonic wave accompanying a crack opening during the 2015 Hakone eruption

The problem of a mode I crack having multiple contacts between the crack faces is considered. In the case of small contact islands of arbitrary shapes, which are arbitrarily located inside the crack, the first-order asymptotic model for the crack opening displacement is constructed using the method of matched asymptotic expansions. The case of a penny-shaped crack has been studied in detail. A scaling hypothesis for the compliance reduction factor is formulated.

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Modeling of Bridging Law for Bundled Aramid Fiber-Reinforced Cementitious Composite and its Adaptability in Crack Width Evaluation

Materials ◽

10.3390/ma14010179 ◽

2021 ◽

Vol 14 (1) ◽

pp. 179

Author(s):

Daiki Sunaga ◽

Takumi Koba ◽

Toshiyuki Kanakubo

Keyword(s):

Fiber Orientation ◽

Crack Width ◽

Volume Fraction ◽

Characteristic Point ◽

Crack Opening ◽

Aramid Fiber ◽

Cementitious Composite ◽

Fiber Reinforced ◽

Cross Sectional ◽

Bridging Law

Tensile performance of fiber-reinforced cementitious composite (FRCC) after first cracking is characterized by fiber-bridging stress–crack width relationships called bridging law. The bridging law can be calculated by an integral calculus of forces carried by individual fibers, considering the fiber orientation. The objective of this study was to propose a simplified model of bridging law for bundled aramid fiber, considering fiber orientation for the practical use. By using the pullout characteristic of bundled aramid fiber obtained in the previous study, the bridging laws were calculated for various cases of fiber orientation. The calculated results were expressed by a bilinear model, and each characteristic point is expressed by the function of fiber-orientation intensity. After that, uniaxial tension tests of steel reinforced aramid-FRCC prism specimens were conducted to obtain the crack-opening behavior and confirm the adaptability of the modeled bridging laws in crack-width evaluation. The experimental parameters are cross-sectional dimensions of specimens and volume fraction of fiber. The test results are compared with the theoretical curves calculated by using the modeled bridging law and show good agreements in each parameter.

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The Fracture Toughness of Hardened Tool Steels

Journal of Engineering Materials and Technology ◽

10.1115/1.3225983 ◽

1987 ◽

Vol 109 (4) ◽

pp. 314-318 ◽

Cited By ~ 3

Author(s):

D. F. Watt ◽

Pamela Nadin ◽

S. B. Biner

Keyword(s):

Fracture Toughness ◽

Crack Growth ◽

Slow Crack Growth ◽

Crack Opening ◽

Compact Tension ◽

Testing Procedure ◽

Tool Steels ◽

Opening Displacement ◽

Tempering Temperature ◽

Toughness Testing

This report details the development of a three-stage fracture toughness testing procedure used to study the effect of tempering temperature on toughness in 01 tool steel. Modified compact tension specimens were used in which the fatigue precracking stage in the ASTM E-399 Procedure was replaced by stable precracking, followed by a slow crack growth. The specimen geometry has been designed to provide a region where slow crack growth can be achieved in brittle materials. Three parameters, load, crack opening displacement, and time have been monitored during the testing procedure and a combination of heat tinting and a compliance equation have been used to identify the position of the crack front. Significant KIC results have been obtained using a modified ASTM fracture toughness equation. An inverse relationship between KIC and hardness has been measured.

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Fatigue Crack Growth Tests on Glass Fibre Reinforced Polymer Matrix Composite

Materials Science Forum ◽

10.4028/www.scientific.net/msf.473-474.189 ◽

2005 ◽

Vol 473-474 ◽

pp. 189-194

Author(s):

Zilia Csomós ◽

János Lukács

Keyword(s):

Cyclic Loading ◽

Crack Opening Displacement ◽

Matrix Composite ◽

Glass Fibre ◽

Crack Opening ◽

Loading Conditions ◽

Opening Displacement ◽

Interfacial Cracks ◽

Glass Fibre Reinforced ◽

Number Of Cycles

E-glass fibre reinforced polyester matrix composite was investigated, which was made by pullwinding process. Round three point bending (RTPB) specimens were tested under quasi-static and mode I cyclic loading conditions. Load vs. displacement (F-f), load vs. crack opening displacement (F-v) and crack opening displacement range vs. number of cycles (ΔCOD-N) curves were registered and analysed. Interfacial cracks were caused the final longitudinal fracture of the specimens under quasi-static and cyclic loading conditions.

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Crack-Extension Force for a Part-Through Crack in a Plate

Journal of Applied Mechanics ◽

10.1115/1.3640649 ◽

1962 ◽

Vol 29 (4) ◽

pp. 651-654 ◽

Cited By ~ 507

Author(s):

G. R. Irwin

Keyword(s):

Stress Field ◽

Crack Extension ◽

Crack Opening ◽

Elliptical Crack ◽

Field Parameter ◽

Experimental Measurements ◽

Boundary Points ◽

Crack Extension Force ◽

Extension Force

The crack stress-field parameter K and crack-extension force G at boundary points of a flat elliptical crack may be derived from knowledge that normal tension produces an ellipsoidal crack opening. Rough correction procedures can be employed to adapt this result for application to a part-through crack in a plate subjected to tension. Experimental measurements suggest this adapted result has a useful range of accuracy.

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