Failure by stress corrosion of bundles of fibres

1981 ◽  
Vol 374 (1759) ◽  
pp. 475-489 ◽  
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Corrosion ◽  
Applied Load ◽  
Time To Failure ◽  
Corrosive Environment ◽  
Dominant Feature ◽  
Rate Of Failure ◽  
Two Parameter

Bundles of fibres loaded from their ends and immersed in a corrosive environment show times to failure that are extremely sensitive to the value of the applied load. This behaviour is accounted for by using the empirically established relation between rate of crack growth ( v ) and stress intensity-factor ( K I ) found for many brittle materials ( v ∝ K n 1 ) and by using a two-parameter Weibull distribution for the initial lengths of the cracks in the fibres. The theory accounts well for the time to failure of the bundle and for the rate of failure of individual filaments during stress corrosion. The dominant feature of the results is that time to failure depends on applied load to the power – n .

Analysis of HDPE Failure Data in Support of Development of Flaw Acceptance Criteria for Butt Fusion Joints

2020 ◽  
Author(s):  
Cheng Liu ◽  
Douglas Scarth ◽  
Douglas P. Munson ◽  
Ryan Wolfe
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Failure Time ◽  
Slow Crack Growth ◽  
Time To Failure ◽  
Acceptance Criteria ◽  
Failure Data ◽  
Criteria For Evaluation ◽  
Hdpe Pipes

Abstract There is a need for ASME B&PV Code procedures and acceptance criteria for evaluation of flaws detected by inspection of high density polyethylene (HDPE) piping items in safety Class 3 systems. To support the development of flaw acceptance criteria for butt fusion joints in HDPE pipes, a series of coupon tests have been completed for specimens cut from butt fused HDPE pipes with surface or subsurface flaws placed in the joints prior to fusion process. Specimens containing known flaw sizes were tested under axial load at accelerated stresses and temperatures until failure; or until a prescribed number of test hours was reached. The failure time from the tests has been correlated to the net section stress and the stress intensity factor, and the results showed that the failure time can be better represented by the stress intensity factor. The test results were then used to fit the Brown and Lu formula that predicts the time to failure due to the slow crack growth of flaws as a function of stress intensity factor and temperature. With the developed Brown and Lu equation, the allowable stress intensity factors for a piping lifetime of 50 years at the maximum code allowable temperature of 60°C have been proposed for both surface and subsurface flaws in HDPE butt fusion joints. Examples of what might be corresponding allowable flaw sizes in the butt fusion joints of piping are also provided.

Stress-Corrosion Cracking in Unidirectional GFRP Composites

2010 ◽  
Vol 430 ◽  
pp. 101-113
Author(s):  
Hideki Sekine ◽  
Peter W.R. Beaumont
Keyword(s):  
Growth Rate ◽  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Crack Growth Rate ◽  
Intensity Factor ◽  
Glass Fiber ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Matrix Crack

A micromechanical theory of macroscopic stress-corrosion cracking in unidirectional glass fiber-reinforced polymer composites is proposed. It is based on the premise that under tensile loading, the time-dependent failure of the composites is controlled by the initiation and growth of a crack from a pre-existing inherent surface flaw in a glass fiber. A physical model is constructed and an equation is derived for the macroscopic crack growth rate as a function of the apparent crack tip stress intensity factor for mode I. Emphasis is placed on the significance of the size of inherent surface flaw and the existence of matrix crack bridging in the crack wake. There exists a threshold value of the stress intensity factor below which matrix cracking does not occur. For the limiting case, where the glass fiber is free of inherent surface flaws and matrix crack bridging is negligible, the relationship between the macroscopic crack growth rate and the apparent crack tip stress intensity factor is given by a simple power law to the power of two.

Prevention of Stress Corrosion Cracking of SUS304 by Tensile Overload

2010 ◽  
Author(s):  
Hayato Sano ◽  
Koji Takahashi ◽  
Kotoji Ando
Keyword(s):  
Stress Intensity Factor ◽  
Stainless Steel ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Threshold Stress ◽  
Threshold Stress Intensity ◽  
Threshold Stress Intensity Factor ◽  
Tensile Overload

The effects of overload on the threshold stress intensity factor (KISCC) for stress corrosion cracks (SCC) in stainless steel were studied. Tensile overload was applied to a wedge opening loaded specimen of SUS304, and SCC tests were carried out to determine the resultant KISCC. The value of KISCC was found to increase with increasing stress intensity caused by tensile overload. Comparison of the effects of tensile overload on KISCC of SUS304 and SUS316 revealed that the effect on KISCC of SUS304 was smaller than that of SUS316.

Numerical Analysis of Crack Propagation in Cyclic-Loaded Structures

1967 ◽  
Vol 89 (3) ◽  
pp. 459-463 ◽  
Author(s):  
R. G. Forman ◽  
V. E. Kearney ◽  
R. M. Engle
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Crack Extension ◽  
Load Ratio ◽  
Stress Intensity Factor Range ◽  
Time To Failure ◽  
Excellent Correlation ◽  
Extensive Experimental Data

An improved theory is proposed for the crack-growth analysis of cyclic-loaded structures. The theory assumes that the crack tip stress-intensity-factor range, ΔK, is the controlling variable for analyzing crack-extension rates. The new theory, however, takes into account the load ratio, R, and the instability when the stress-intensity factor approaches the fracture toughness of the material, Kc. Excellent correlation is found between the theory and extensive experimental data. A computer program has been developed using the new theory to analyze the crack propagation and time to failure for cyclic-loaded structures.

Fracture Toughness Assessment of the Susceptibility for Sulfide Stress Corrosion Cracking in High Strength Carbon Steels: A review

CORROSION ◽  
10.5006/3610 ◽  
2020 ◽  
Author(s):  
Raymundo Case ◽  
Bostjan Bezensek
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
High Strength ◽  
Carbon Steels ◽  
Sulfide Stress ◽  
Sulfide Stress Corrosion Cracking

High strength carbon steels typically used as oil country tubular goods can be susceptible to sulfide stress corrosion cracking (SSC) when in service in environments that contain H2S. In the last 25 years, linear-elastic fracture mechanics has been used to understand both the mechanistic aspects of this form of cracking and to quantify the susceptibility to SSC of different OCTG steel grades. This paper presents a review on the evolution of the Double Cantilever Method (DCB) as a standard practice to assess the threshold stress intensity factor KISSC. The paper evaluates the capabilities and limitations of this testing method to describe the conditions associated with crack propagation. The review study indicates that new fracture parameters based on the energy required for crack propagation such as J-integral JIc might be required to overcome the limitations of the static conditions implied in the stress intensity factor KIc evaluation approach

Effects of Overloads on the Incubation Time for Stress Corrosion Cracking of 7075 Aluminum

CORROSION ◽  
1982 ◽  
Vol 38 (6) ◽  
pp. 330-335 ◽  
Author(s):  
A. H. Hanisch ◽  
L. H. Burck
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Incubation Time ◽  
High Strength ◽  
Critical Stress Intensity Factor ◽  
Corrosion Cracking ◽  
Cracking Behavior

Abstract A series of tests was conducted on precracked high strength aluminum alloy 7075-T651 plate to determine the effects of overstressing on the short-transverse stress corrosion cracking behavior. Fatigue precracked wedge-opening-loading specimens were preloaded in air to various percentages of the critical stress intensity factor, unloaded, and reloaded statically to lower stress intensity factor levels. The samples were then alternately immersed in an aqueous 3.5% sodium chlorine solution for stress corrosion testing. The incubation time which preceded crack extension by stress corrosion cracking was found to increase substantially for higher percentages of preloading. Furthermore, for a given percentage of prestress overload, greater effects were observed for higher applied stress intensity factor levels. The increase in incubation period produced by stress overloading is attributed primarily to the effects of residual compressive stresses at the crack tips.

scholarly journals Effect of T-stress on Fracture of a Long Cracked Plate in Unsteady Heat Transfer

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Shaoqing Zhou ◽  
Limin Li
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Temperature Difference ◽  
Thermal Load ◽  
Crack Tip ◽  
Maximum Tensile Stress ◽  
T Stress ◽  
Structural Fracture ◽  
Two Parameter

In order to accurately predict the structure fracture caused by thermal load, a modified maximum tensile stress (MTS) criterion combined with T-stress is proposed. The modified MTS uses a two-parameter model (stress intensity factor K and T-stress) to describe the fracture behavior under thermal load. The T-stress and stress intensity factor at the crack tip are solved by using J-integral in the theoretical calculation of a cracked strip with temperature difference. The results show that T-stress can affect the fracture toughness and the stress at the crack tip of the cracked strip with temperature difference. This provides a basis for the simulation of structural fracture under thermal load.

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