Controlling Subcritical Crack Growth at Epoxy/Glass Interfaces

2002 ◽  
Vol 124 (4) ◽  
pp. 328-333 ◽  
Author(s):  
John E. Ritter ◽  
G. S. Jacome ◽  
J. R. Pelch ◽  
T. P. Russell ◽  
T. J. Lardner
Keyword(s):  
Stress Corrosion ◽  
Crack Growth ◽  
Fatigue Resistance ◽  
Subcritical Crack Growth ◽  
Cyclic Fatigue ◽  
Distilled Water ◽  
Silane Coupling Agents ◽  
Bonding Density ◽  
Low Humidity ◽  
Static And Cyclic Loading

The resistance of silane bonded epoxy/glass interfaces to subcritical crack growth was studied as a function of the density of primary bonds between the silane and epoxy using the double-cleavage drilled compression test (DCDC). The silane coupling agents propyltriethoxysilane (PES), 3-aminopropyltriethoxysilane (3-APES) and various mixtures of 3-APES and PES were used to systematically control the bonding density since 3-APES can form primary bonds with both the glass and the epoxy, while PES forms primary bonds only with the glass. The resistance of these interfaces to crack growth was tested under both static and cyclic loading in high and low humidity test environments. These tests allowed the separation of the effects on crack growth due to stress corrosion and cyclic fatigue. Experimental results showed that the density of primary bonding between the silane layer and the epoxy controls the cyclic fatigue resistance of the silanized interfaces. Additionally, for 3-APES bonded epoxy/glass interfaces cyclic fatigue crack growth predominates at both high and low humidities but for PES bonded interfaces, crack growth by stress corrosion dominates at high humidity and by cyclic fatigue at low humidities. For a 50% 3-APES/50% PES bonded interface, stress corrosion effects are somewhat greater than cyclic fatigue effects at high humidities but at low humidities the two effects are comparable. When testing the interfaces for durability, PES bonded interfaces showed spontaneous delamination when aged in distilled water for 36h at 94°C. On the other hand, 3-APES and mixtures of 3-APES bonded interfaces did not show any detrimental effect of the cyclic fatigue resistance when aged in distilled water at temperatures up to 98°C.

Fracture Toughness and Subcritical Crack Growth in CVD Diamond

1995 ◽  
Vol 383 ◽  
Author(s):  
A. Kant ◽  
M. D. Drory ◽  
R. O. Ritchie
Keyword(s):  
Fracture Toughness ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Chemical Vapor ◽  
Cyclic Fatigue ◽  
Cvd Diamond ◽  
Compact Tension ◽  
Fatigue Properties ◽  
Free Standing

ABSTRACTThe fracture toughness, stress corrosion and cyclic fatigue properties of polycrystalline chemical vapor deposited (CVD) diamond have been investigated on thick (˜100 to 300 μm) free-standing films. Specifically, the fracture toughness, Kc, of diamond was determined using indentation methods and for the first time by the tensile testing of pre-notched fracture-mechanics type compact-tension samples. Measured Kc values were found to be between 5 and 7 MPa-m1/2 by either method and to be apparently independent of grain size and shape. Studies on subcritical crack growth (i.e., at stress intensities less than Kc) indicated that CVD diamond is essentially immune to stress-corrosion cracking under sustained loads in room air, water and acid environments. Corresponding experiments to examine susceptibility to cyclic fatigue are currently being performed using indentation-precracked cantilever beams cycled in three-point bending.

scholarly journals Contributions of stress corrosion and cyclic fatigue to subcritical crack growth in a dental glass-ceramic

2014 ◽  
Vol 30 (8) ◽  
pp. 884-890 ◽  
Author(s):  
Gaurav V. Joshi ◽  
Yuanyuan Duan ◽  
Alvaro Della Bona ◽  
Thomas J. Hill ◽  
Kenneth St. John ◽  
...  
Keyword(s):  
Stress Corrosion ◽  
Crack Growth ◽  
Glass Ceramic ◽  
Subcritical Crack Growth ◽  
Cyclic Fatigue

scholarly journals Interaction of Cyclic Loading (Low-Cyclic Fatigue) with Stress Corrosion Cracking (SCC) Growth Rate

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Rehmat Bashir ◽  
He Xue ◽  
Rui Guo ◽  
Yueqi Bi ◽  
Muhammad Usman
Keyword(s):  
Growth Rate ◽  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Nuclear Power ◽  
Power Plants ◽  
Structural Integrity ◽  
Cyclic Fatigue ◽  
Joint Effect ◽  
Corrosion Cracking

The structural integrity analysis of nuclear power plants (NPPs) is an essential procedure since the age of NPPs is increasing constantly while the number of new NPPs is still limited. Low-cyclic fatigue (LCF) and stress corrosion cracking (SSC) are the two main causes of failure in light-water reactors (LWRs). In the last few decades, many types of research studies have been conducted on these two phenomena separately, but the joint effect of these two mechanisms on the same crack has not been discussed yet though these two loads exist simultaneously in the LWRs. SCC is mainly a combination of the loading, the corrosive medium, and the susceptibility of materials while the LCF depends upon the elements such as compression, moisture, contact, and weld. As it is an attempt to combine SCC and LCF, this research focuses on the joint effect of SCC and LCF loading on crack propagation. The simulations are carried out using extended finite element method (XFEM) separately, for the SCC and LCF, on an identical crack. In the case of SCC, da/dt(mm/sec) is converted into da/dNScc (mm/cycle), and results are combined at the end. It has been observed that the separately calculated results for SCC da/dNScc and LCF da/dNm of crack growth rate are different from those of joint/overall effect,  da/dNom. By applying different SCC loads, the overall crack growth is measured as SCC load becomes the main cause of failure in LWRs in some cases particularly in the presence of residual stresses.

scholarly journals Cyclical fatigue of annealed and of thermally tempered soda-lime-silica glass

2018 ◽  
Vol 165 ◽  
pp. 18003
Author(s):  
Jens Schneider ◽  
Jonas Hilcken
Keyword(s):  
Crack Growth ◽  
Silica Glass ◽  
Subcritical Crack Growth ◽  
Soda Lime ◽  
Cyclic Fatigue ◽  
Growth Exponent ◽  
Static Fatigue ◽  
Strength Increase ◽  
Soda Lime Silica Glass ◽  
Number Of Cycles

We present experimental and theoretical investigations on the cyclic fatigue of annealed and of thermally tempered soda-lime-silica glass. Static fatigue due to subcritical crack growth at micro cracks significantly decreases the macroscopic strength of soda-lime-silica glass and causes a time-dependent strength reduction. A subsequent thermal tempering process is typically used to induce residual surface compression stresses, which inhibit the crack growth of surface cracks, and corresponding bulk tension stresses. From the experimental results we show that the existing models for static fatigue used in linear elastic fracture mechanics can be used for the lifetime prediction of cyclically loaded annealed glass and thermally tempered glass, although the (static) crack growth exponent slightly decreases in cyclic loading. The equivalent duration of tensile stress at the crack tip of a micro crack governs the crack growths and not the number of cycles. The threshold for subcritical crack growth determined from the cyclic experiments was found to be in good agreement with data from literature. But unlike in strength tests with singular and quasi-static re-loading, it could be found that periodic loading with load free intervals does not lead to a strength increase by crack healing effects. Based on the results, an engineering design concept for cyclically loaded glass is presented.

Fracture mechanics in design and service: ‘living with defects’ - Subcritical crack growth: fatigue, creep and stress corrosion cracking

1981 ◽  
Vol 299 (1446) ◽  
pp. 31-44 ◽  
Keyword(s):  
Stress Corrosion ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Crack Extension ◽  
Subcritical Crack Growth ◽  
Practical Interest ◽  
Crack Tip ◽  
Corrosion Cracking ◽  
Time Dependent ◽  
Crack Advance

Subcritical crack growth can occur under steady or varying loads. In the former it is precipitated by specific environmental conditions that encourage the operation of time-dependent processes controlling crack advance. These include aggressive environments leading to stress corrosion cracking, or elevated temperature conditions leading to creep cavitation. The result is a time-dependent maintenance of a sharp crack profile during crack extension. Under varying loads such a sharp profile is readily achieved by plastic deformation on load reduction. Net crack advance in fatigue therefore occurs in each load cycle by this blunting-resharpening process, and empirical crack growth laws reflect this physical basis. Parameters such as K and J, which define crack tip deformation, are useful for correlating fatigue crack growth. In that they define crack tip stress-strain fields under load, they also partly describe crack advance for steady load creep and stress corrosion cracking. In particular they can define a threshold state for crack extension by all three processes. Under varying loads, if fatigue conditions are combined with an aggressive or high-temperature environment the description of crack growth can be complex. These areas of corrosion fatigue and creep fatigue are of considerable current practical interest.

Subcritical Crack Growth of α/β-Sialon Ceramics in Distilled Water

2008 ◽  
Vol 403 ◽  
pp. 129-132
Author(s):  
Marco Riva ◽  
Rainer Oberacker ◽  
Michael J. Hoffmann ◽  
Theo Fett
Keyword(s):  
High Pressure ◽  
Life Cycle ◽  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Testing Procedure ◽  
Fatigue Tests ◽  
Static Fatigue ◽  
Distilled Water

Environmental-assisted subcritical crack growth on two different /-sialon ceramics is determined in static fatigue tests. The goal of these investigations was to determine the influence of delivering medium of high pressure pumps on their durability (life cycle). Therefore 4-point-bending bars were statically loaded in distilled water and subcritical crack growth was analyzed. The large number of spontaneous failure and survivals made the development of a modified testing procedure necessary in order to obtain a significant database.

Adhesion and Reliability of Epoxy/Glass Interfaces

2000 ◽  
Vol 123 (4) ◽  
pp. 401-404 ◽  
Author(s):  
John E. Ritter ◽  
Armin Huseinovic
Keyword(s):  
Fatigue Crack ◽  
Cyclic Loading ◽  
Fatigue Crack Growth ◽  
Crack Growth ◽  
Slow Crack Growth ◽  
Cyclic Fatigue ◽  
Aqueous Environments ◽  
Crack Tip Plasticity ◽  
Static And Cyclic Loading ◽  
Microelectronic Components

The reliability of microelectronic components is profoundly influenced by the fracture resistance of the polymer/inorganic interfaces and by the progressive debonding of these interfaces in aqueous environments. Consequently, fatigue (slow) crack growth in epoxy/glass interfaces bonded with the silane coupling agent 3-aminopropyltriethoxysilane (3-APES) was studied under static and cyclic loading at 23°C and in either dry or humid conditions using the double cleavage drilled compression (DCDC) test. Crack growth rates under cyclic loading were significantly greater than under static loading, indicating that stress corrosion effects are negligible and that crack tip plasticity controls cyclic fatigue crack growth at silane (3-APES) bonded epoxy/glass interfaces. After aging at 94°C in water, these silane bonded epoxy/glass interfaces exhibited somewhat greater resistance to cyclic fatigue crack growth than the unaged samples; however, after aging at 98°C in water cyclic fatigue crack growth became cohesive and fractal in nature. Mechanisms for fatigue crack growth at silane (3-APES) bonded epoxy/glass interfaces are discussed.

Stress-Corrosion Cracking at Ceramic-Metal Interfaces

1993 ◽  
Vol 314 ◽  
Author(s):  
J. C. Card ◽  
R. M. Cannon ◽  
R. H. Dauskardt ◽  
R. O. Ritchie
Keyword(s):  
Stress Corrosion ◽  
Water Content ◽  
Stress Corrosion Crack ◽  
Crack Growth ◽  
Stress Corrosion Cracking ◽  
Liquid Water ◽  
Fracture Resistance ◽  
Subcritical Crack Growth ◽  
Corrosion Cracking ◽  
Metal Interfaces

AbstractIt is known that the fracture resistance of glass-copper interfaces depends strongly on the water content in ambient gaseous environments. In the present study, subcritical crack growth stimulated by water and other environmental species is investigated for such interfaces. Tests were conducted in various liquids, namely water, N-methylformamide, and n-butanol. All were found to accelerate fracture with the greatest effects from liquid water. Results are considered in the context of current models for stress-corrosion crack growth.

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