Fracture Toughness of Structural Members

2012 ◽  
Vol 726 ◽  
pp. 195-202 ◽  
Author(s):  
Andrzej Neimitz
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Reference State ◽  
Finite Strains ◽  
Structural Members ◽  
Local Approach ◽  
Strain Fracture ◽  
Out Of Plane ◽  
Plain Strain

Abstract. In the paper several formulae to compute the fracture toughness are presented. The formulae include either parameter characterizing the in-plane constraint or out-of-plane constraint or both. The formulae are based on different assumptions and approaches to fracture mechanics. Namely, small or finite strains were assumed, global or local approach was adopted. In all cases the standard, plain strain fracture toughness was used as a reference state.

Fracture Toughness and Fatigue Behavior of T7451 Al-Zn-Mg-Cu Alloy Thick Plate

2014 ◽  
Vol 788 ◽  
pp. 223-230 ◽  
Author(s):  
Li Li Wei ◽  
Qing Lin Pan ◽  
Yi Lin Wang ◽  
Lei Feng
Keyword(s):  
Mechanical Property ◽  
Fracture Toughness ◽  
Fatigue Resistance ◽  
Fatigue Behavior ◽  
Plate Thickness ◽  
Transgranular Fracture ◽  
Cu Alloy ◽  
Tensile Fatigue ◽  
Strain Fracture ◽  
Plain Strain

The mechanical property, fracture toughness and fatigue behavior of T7451 Al-Zn-Mg-Cu alloy thick plates in different orientations and with various thicknesses were investigated by means of tensile, fatigue and plain strain fracture toughness testing. And the microstructures and fracture morphologies were analyzed with optical microscopy and scanning electron microscopy. The results showed that the samples in longitudinal (L)-transversal (T) orientation possessed better mechanical property, fracture toughness and fatigue resistance than that in T-L orientation. Fractography and optical microanalysis clearly demonstrated that the feature of recrystallized grains is the decisive factor for this anisotropy. On the other hand, values of strength and fracture toughness decreased with the increase of plate thickness, but their fatigue crack growth rate became slower. Combined with the fractography analysis, the increase of recrystallization degree and the coarser grains in the thicker plate should be the main reason for the detrimental to the strength and toughness properties since the main fracture mechanism changes from ductile transgranular fracture to intergranular failure. However, these coarse recrystallized grains play an advantageous role for fatigue resistance from crack deflection and closure perspectives.

scholarly journals The impact of the temperature and exploitation time on the tensile properties and plain strain fracture toughness, KIc in characteristic areas of welded joint

2018 ◽  
Vol 12 (46) ◽  
pp. 371-382 ◽  
Author(s):  
Simon Sedmak ◽  
Ivica Čamagić ◽  
Aleksandar Sedmak ◽  
Zijah Burzić ◽  
Mihajlo Aranđelović
Keyword(s):  
Fracture Toughness ◽  
Tensile Properties ◽  
Welded Joint ◽  
Strain Fracture ◽  
Plain Strain ◽  
The Impact

scholarly journals Effect of temperature and exploitation time on tensile properties and plain strain fracture toughness, KIc, in a welded joint

2018 ◽  
Vol 9 ◽  
pp. 279-286
Author(s):  
Ivica Čamagić ◽  
Simon Sedmak ◽  
Aleksandar Sedmak ◽  
Zijah Burzić ◽  
Mladen Marsenić
Keyword(s):  
Fracture Toughness ◽  
Tensile Properties ◽  
Welded Joint ◽  
Effect Of Temperature ◽  
Strain Fracture ◽  
Plain Strain

The Effects of In-Plane and Out-of-Plane Dimensions of a Curved Wide-Plate on Crack-Tip Constraint for Pipeline Fracture Assessment

2014 ◽  
Author(s):  
Hwee-Seung Lee ◽  
Nam-Su Huh ◽  
Ki-Seok Kim
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Crack Tip ◽  
Standard Test ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Out Of Plane ◽  
Dimensional Finite Element ◽  
Crack Tip Constraint ◽  
Crack Tip Opening

One important element of fracture mechanics assessment in pipelines is how to determine the relevant fracture toughness (J-resistance or CTOD-resistance (crack-tip opening displacement)) for nonlinear fracture mechanics analysis. The general practice using a standard fracture mechanics specimen is known to often provide conservative estimates of toughness due to differences in crack-tip constraints between standard specimens and actual components. To improve the accuracy of predicting pipeline failure, various non-standard fracture mechanics specimens have been suggested over the past few decades. Among the several non-standard test specimens, a curved wide-plate in tension is often employed to predict fracture behavior of cracked components, for instance, in gas transportation pipelines. In order to show validity of a curved wide-plate in tension, the fracture toughness values from a full-scale pipeline test have been compared with those from a curved wide-plate in tension, and crack-tip constraints of a curved wide-plate in tension have also been compared with those of actual pipelines or other specimens during last decades. It is well known that a crack-tip constraint of test specimens, including curved wide-plates in tension, depends on many geometric and material parameters, for instance, crack length, thickness and width of specimen and material’s hardening characteristic. Thus, in order to obtain relevant fracture resistance from a curved wide-plate in tension representing accurate crack-tip constraint of pipeline of interest, variations of crack-tip constraints of curved wide-plates in tension according to various in-plane and out-of-plane constraint conditions should systematically be quantified. In the present study, systematic 3-dimensional finite element analyses attempt to investigate the effect of in-plane and out-of-plane parameters on crack-tip constraints of a curved wide-plate in tension.

Fracture Toughness of AZ61 Magnesium Alloy with Various Thickness

2015 ◽  
Vol 761 ◽  
pp. 479-483
Author(s):  
Mohd Ahadlin Mohd Daud ◽  
Nurulhilmi Zaiedah Nasir ◽  
Mohd Zulkefli Selamat ◽  
Sivakumar Dhar Malingam
Keyword(s):  
Fracture Toughness ◽  
Magnesium Alloy ◽  
Stress Intensity Factor Range ◽  
Critical Crack ◽  
Critical Crack Length ◽  
Az61 Magnesium Alloy ◽  
Critical Fracture ◽  
Strain Fracture ◽  
Plain Strain ◽  
Different Thickness

The critical fracture toughness parameterKΙCof AZ61 magnesium alloy was determined on the three point bent specimens with notch designed according to ASTM E399 standard. Five specimens having different thickness, i.e., 2, 4, 6, 8 and 10 mm were considered in order to evaluate the effect on fracture toughness. The stress intensity factor rangeΔKwas constant ~1x 10-8for every specimen until the critical crack length reached half of the width of the specimens. The fracture test was done with the speed rate 0.12-0.15 MPa√m/sec until the specimens broke. The experimental results showed that the critical plain strain fracture toughnessKΙCis 12.6 MPa√m and the highest plain stress fracture toughnessKCis 16.5 MPa√m.

Development of Fracture Toughness Testing of Thin-Width SEN(B) Specimens

2011 ◽  
Author(s):  
R. S. Kulka
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Test Specimen ◽  
Stress Triaxiality ◽  
Crack Tip ◽  
Element Analysis ◽  
Fracture Toughness Testing ◽  
Out Of Plane ◽  
Toughness Testing ◽  
Crack Tip Constraint

During fracture toughness testing of SEN(B) specimens, an important assumption is that the test specimen is highly constrained. This assumption is ensured by the testing of a deeply cracked specimen, with in-plane and out-of-plane dimensions that are sufficient to guarantee an appropriate level of crack tip stress triaxiality. This condition guarantees that high-constraint fracture toughness values are derived, conservative for use in standard fracture mechanics assessments. In reality, many components have small in-plane or out-of-plane dimensions. It is considered that this could cause a reduction in crack tip constraint of a sufficient amount to increase the effective fracture toughness of the components. However, there is currently limited understanding as to the magnitude of the benefits that could be claimed. Finite element analysis of various thin-width SEN(B) specimens has been undertaken. The knowledge gained can be used to develop fracture mechanics methodology for the testing of thin-width specimens and the subsequent derivation of appropriate toughness values.

CORONA 5 Alloy

Alloy Digest ◽  
1978 ◽  
Vol 27 (5) ◽  
Keyword(s):  
Fracture Toughness ◽  
Tensile Strength ◽  
Corrosion Resistance ◽  
Density Ratio ◽  
Heat Treating ◽  
Steel Company ◽  
Specific Strength ◽  
Strain Fracture ◽  
Crucible Steel ◽  
Chloride Stress Corrosion Cracking

Abstract CORONA 5 is a titanium alloy developed for applications in fracture-controlled aircraft components. Plane strain fracture toughnesses of 110,000 to 150,000 psi sq.rt. in. (120 to 165 MPa sq.rt. m) have been produced in this alloy at 135,00 psi (930 MPa) tensile strength through a variety of different process histories. The specific strength (strength/density ratio) is superior to that of the Ti-6A1-4V alloy. Resistance to fatigue crack propagation and resistance to chloride-stress-corrosion cracking are comparable to those of Ti-6A1-4V. This datasheet provides information on composition, physical properties, microstructure, elasticity, and tensile properties as well as fracture toughness and fatigue. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ti-70. Producer or source: Crucible Steel Company of America, Titanium Division.

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