scholarly journals Determination of Stress Intensity Factor Value for Chevron-Notched Specimens – Pilot Study

2017 ◽  
Vol 17 (2) ◽  
pp. 125-130 ◽  
Author(s):  
Jakub Sobek ◽  
Stanislav Seitl
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Material Behavior ◽  
Bending Test ◽  
Layer Width ◽  
Test Configuration ◽  
Three Point Bending ◽  
Loading Mode ◽  
Chevron Notch

Abstract The description of material behavior is one of important information for its application in civil engineering. One area is covering fracture mechanical properties. For evaluation of the fracture toughness values, the knowledge of calibration curve is important. The paper is aimed on the numerical modelling of the test specimens with a chevron notch serving as an initiator of the stress distribution at the crack tip. The three-point bending test configuration with a chevron notch is used for the simulation given by plane model with different layer width of cross section part and output is given by the value of the stress intensity factor KI for tension loading mode.

Crack Growth Resistance of Carbide Reinforced Composite Ceramics Based on Alumina

2009 ◽  
Vol 409 ◽  
pp. 231-236
Author(s):  
Magdalena Szutkowska ◽  
Marek Boniecki
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Length ◽  
Crack Growth ◽  
Slow Crack Growth ◽  
Crack Growth Resistance ◽  
Bending Test ◽  
Special Device ◽  
Three Point Bending

The relationship of KR versus crack length c (R curve) for Al2O3-30wt.% Ti(C,N).and for comparison alumina ceramics has been examined. The R-curve has been evaluated using pronounced long-crack formed during the three point bending (3PB) of the double edge notched beam. A combination of in situ microscopic crack growth observation and mechanical testing enabled measurement of crack growth resistance curves. The special device consisting of light microscope coupled with CCD camera, was fitted to Zwick 1446 testing machine. These observations reveal the existence of flat R-curve for Al2O3-30wt.% Ti(CN) and increasing R-curve for pure alumina. A study of slow-crack-growth (SCG) in tested materials was carried. The load-relaxation technique was used for observation at slow-crack-growth. The crack length was evaluated by linear-elastic analysis from the compliance of single-edge-notched specimen in three-point bending test. Parameters of stable crack growth n and logA, work-of fracture (WOF), stress intensity factor at the moment of crack initiation KI0 and maximum values of stress intensity factor KImax were determined. Mechanism of grain bridging responsible for occurrence of R-curve was observed by SEM and TEM.

Numerical Modelling of a Chevron Notched Bend Specimen - Plane Model

2017 ◽  
Vol 754 ◽  
pp. 198-201 ◽  
Author(s):  
Jakub Sobek ◽  
S. González Menéndez ◽  
Stanislav Seitl
Keyword(s):  
Numerical Modelling ◽  
Stress Condition ◽  
Bending Test ◽  
Plane Model ◽  
Plane Stress Condition ◽  
Three Point Bending ◽  
Loading Mode ◽  
Chevron Notch ◽  
Geometry Configuration ◽  
Tension Loading

The paper focuses on a numerical modelling of the initial chevron notch in test specimens subjected to the three-point bending test geometry configuration. The plane model is used with variable thicknesses of the layers with plane stress condition. The number of layers is being investigated and the influence of some input parameters like relative crack length, breadth of initial notch, etc. is evaluated by value of the stress intensity factor for tension loading mode.

Study on the Stress Intensity Factor for Mixed Mode Surface Crack under Three Point Bending

2008 ◽  
Vol 33-37 ◽  
pp. 85-90
Author(s):  
Wei Xie ◽  
Qi Qing Huang ◽  
Masanori Kikuchi
Keyword(s):  
Stress Intensity Factor ◽  
Finite Element ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Energy Release Rate ◽  
Crack Closure ◽  
Release Rate ◽  
Mixed Mode ◽  
Three Point Bending ◽  
Closure Method

In the virtual crack closure method (VCCM), the energy release rate is computed based on the results of finite element calculation, and the stress intensity factor (SIF) is computed from the energy release rate. In this paper, the stress intensity factor of mixed-mode surface cracks under three point bending is studied by using the three dimensional modified virtual crack closure method (MVCCM). The modified virtual crack closure method is required to open one element face area whose shape is arbitrary and finite element widths are unequal across the crack front. The effect of the distance between the location of load and crack face, crack shape and crack depth to the stress intensity factor is also discussed, along with practical results and conclusions.

Examination of the mode I critical stress intensity factor of wood obtained by single-edge-notched bending test

Holzforschung ◽  
2010 ◽  
Vol 64 (4) ◽  
Author(s):  
Hiroshi Yoshihara
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Length ◽  
Critical Stress ◽  
Initial Crack ◽  
Critical Stress Intensity Factor ◽  
Bending Test ◽  
Mode I ◽  
Single Edge

Abstract The critical stress intensity factor of mode I (K Ic) obtained by single-edge-notched bending (SENB) tests of wood was experimentally and numerically analyzed. A double cantilever beam (DCB) test was also conducted and the results were compared with those of SENB tests. The K Ic value was obtained by introducing an additional crack length into the equations used for analyzing the SENB test of isotropic material when the initial crack length ranged from 0.1 to 0.6 times the depth of the specimen.

scholarly journals Uniaxial equivalent of stress and stress intensity factor in Mode I crack opening for fatigued metals subjected to multi parametric external loading

2018 ◽  
Vol 165 ◽  
pp. 13003
Author(s):  
Andrey Shanyavskiy
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Opening ◽  
Equivalent Stress ◽  
Material Behavior ◽  
Correction Function ◽  
External Loading ◽  
Mode I ◽  
Mode I Crack

The principles of physical mesomechanics and synergetics, provides for a measure of energy involved in the ability of a material to resist deformation and fatigue cracking used for introducing a concept of equivalent stress and stress intensity factor in Mode I crack opening of fatigued metals. Acquired under the standard test conditions, the curves of unidirectional tension and those of fatigue duration and of crack-growth kinetics show themselves applicable as universal master-diagrams descriptive of the material behavior though under multiparametric loading. Specimen patterns of fracture, revealed by the test pieces of metallic alloys given to asymmetrical biaxial loading or multiparametric loading, passed careful research. In the biaxial case, this research facilitated finding of the view of the correction function for the level of equivalent stress and, in the multi-axial case, employing of the above subject ideas to ascertain the very level of equivalent stress.

Evaluation of Three-Point Bending Fracture Tests of Concrete Specimens with Polypropylene Fibres via Double-K Model

2013 ◽  
Vol 592-593 ◽  
pp. 185-188 ◽  
Author(s):  
Ivana Havlíková ◽  
Romana Viktória Majtánová ◽  
Hana Šimonová ◽  
Jaromír Láník ◽  
Zbyněk Keršner
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Lightweight Concrete ◽  
Crack Tip Opening Displacement ◽  
Polypropylene Fibres ◽  
Three Point Bending ◽  
Fracture Tests ◽  
Parameter Values ◽  
Bending Fracture

The fracture-mechanical parameter values of concrete, a quasi-brittle composite material, are determined via evaluation of records of experiments on specimens with stress concentrators. One of the fracture models applicable to concrete is the double-K model. This model combines the concept of cohesive forces acting on the effective crack increment with a criterion based on the stress intensity factor. The outputs of the model are critical crack tip opening displacement and fracture toughness values, including the initiation stress intensity factor value corresponding to the beginning of stable crack propagation. Outputs of three-point bending fracture tests of fibre reinforced concrete obtained using double-K fracture model are presented in this paper. The main aim is the determination and comparison of the above-mentioned parameter values of two types of the composite both without and with polypropylene fibres. Both types of tested composite had the same basic matrix consisting of cement, sand and water. In one case, gravel was used for normal weight concrete, in the other case lightweight aggregates were used for lightweight concrete. Both types of the testing matrix were designed with a similar value of compressive strength. Concretes were reinforced by spread polypropylene fibres of three lengths. There were made eight sets of testing concrete specimens: without fibres, and with fibres of 19 mm, 38 mm and 54 mm length. Dosage of fibres was 9 kg/m3 in all six cases.

Study on Stress Intensity Factor of PMMA with Double Cracks Using Coherent Gradient Sensing (CGS) Technique

2011 ◽  
Vol 109 ◽  
pp. 114-119 ◽  
Author(s):  
Ling Tao Mao ◽  
Cai Ping Liu ◽  
Ke Chen ◽  
Li Qian An ◽  
Xin Xin Zhu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Intensity Factors ◽  
Fracture Behaviour ◽  
Intensity Factors ◽  
Gradient Sensing ◽  
Coherent Gradient Sensing ◽  
Three Point Bending ◽  
Fringe Patterns

In this paper, the principle of coherent gradient sensing (CGS) technology is briefly introduced. Fracture behaviour of the PMMA specimens with single or double cracks under three-point-bending are studied using the CGS optical method. A series of CGS fringe patterns under different loading are abtained. With these fringes, stress intensity factors are caculated. The influences of the different spacing on stress intensity factors are discussed. These results will be useful for researching on strength of PMMA materials.

Crack Growth Evaluation of Induction Quenched JIS-S45C Steel Based on Stress Intensity Factor Simulation

2021 ◽  
Vol 1020 ◽  
pp. 126-130
Author(s):  
Takahiro Matsueda ◽  
Ayumu Tamura ◽  
Koshiro Mizobe ◽  
Katsuyuki Kida
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Fracture Surface ◽  
Fatigue Cracks ◽  
Optical Microscope ◽  
Bending Test ◽  
Test Machine ◽  
Low Carbon ◽  
Rotating Bending

Problems lived with fatigue fracture for the safe design of the members and structures. In this study, rotating bending tests were performed to investigate the fatigue crack propagation behavior of induction quenched and tempered JIS S45C low carbon steel. Hardness distribution was checked by the Vickers hardness test machine and the microstructure in cross section and fracture surface were observed with an optical microscope and a scanning electron microscope. The depth of the hardened boundary was approximately 1 mm from the surface and formation into martensite occurred at the surface of the specimen. It was ascertained that fracture surface of notched specimens consisted of the five fracture types. In addition, the maximum stress intensity factor of fatigue cracks increased during rotating bending test on notched specimen. The relation between SIF and the fracture surface is discussed.

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