scholarly journals Subcritical crack growth parameters in glass as a function of environmental conditions

2020 ◽  
Author(s):  
Christopher Brokmann ◽  
Stefan Kolling ◽  
Jens Schneider
Keyword(s):  
Crack Growth ◽  
Environmental Conditions ◽  
Subcritical Crack Growth ◽  
Growth Parameters ◽  
Crack Depth ◽  
Indentation Test ◽  
Soda Lime ◽  
Initial Crack ◽  
Chemical Compositions ◽  
Critical Crack

Abstract In the present work, subcritical crack growth in soda–lime silicate glass is investigated under different environmental conditions. Crack growth parameters as a function of temperature and humidity were determined by dynamic fatigue tests, which has been verified by using the in-situ method of filming crack growth during experiments. The specimens were pre-damaged for constant initial crack lengths in all specimens using the Vickers indentation test. The determined parameters were compared with those from literature in order to discuss existing deviations of sub-critical crack growth parameters in literature. These deviations may be caused by environmental conditions and different chemical compositions of the glass. Arrest lines were used to determine the ratio of crack width to crack depth in Vickers indented specimens. For the initial crack depth, images of fracture surfaces were taken using an scanning electron microscope. Furthermore, the influence of humidity and temperature on the failure stress of unindented specimens with a constant initial crack length was simulated.

Subcritical Crack Growth Parameters for Glass under Different Environmental Conditions

ce/papers ◽  
2021 ◽  
Vol 4 (6) ◽  
pp. 97-105
Author(s):  
Christopher Brokmann ◽  
Stefan Kolling ◽  
Jens Schneider
Keyword(s):  
Crack Growth ◽  
Environmental Conditions ◽  
Subcritical Crack Growth ◽  
Growth Parameters

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.

Numerical Analysis of the Crack Growth in a High Loaded Bolt Connection

2007 ◽  
Vol 348-349 ◽  
pp. 625-628
Author(s):  
Marko Knez ◽  
Srečko Glodež ◽  
Janez Kramberger
Keyword(s):  
Crack Growth ◽  
Crack Size ◽  
Initial Crack ◽  
Structural Elements ◽  
Element Analysis ◽  
Critical Crack ◽  
Critical Crack Length ◽  
Final Failure ◽  
Heavy Loads ◽  
Bolt Connection

The present paper deals with the research on the crack growth in a bolt connection of a lug for crane counter weight bars. Counter weight bars are structural elements that are subjected to very heavy loads and therefore special attention must be paid. The main purpose of this research is to determine the number of the load cycles required for a crack to propagate from initial to critical crack length, when the final failure can be expected to occur. All required material parameters and the experimental results were determined in our previous research. The influence of the initial crack size upon the remaining life of the lug is researched numerically by means of finite element analysis and analytically by use of the corrected analytical model.

Understanding the Directional Dependence of Intergranular Corrosion in Aluminium Alloys

2010 ◽  
Vol 654-656 ◽  
pp. 946-949 ◽  
Author(s):  
Steven P. Knight ◽  
Graham Clark ◽  
A.J. Davenport ◽  
Anthony R. Trueman
Keyword(s):  
Crack Growth ◽  
Environmental Conditions ◽  
Aluminium Alloys ◽  
Intergranular Corrosion ◽  
Atmospheric Corrosion ◽  
Alloy Composition ◽  
Extrusion Direction ◽  
Inhomogeneous Distribution ◽  
Critical Crack ◽  
Composition Product

Intergranular corrosion can lead to significant problems such as sub-critical crack growth or loss in section strength, potentially leading to failure, as well as a substantially increased maintenance burden. This type of corrosion is found in most types of aluminium alloys, but is a particularly significant problem in aerospace aluminium alloys. The form of intergranular corrosion can vary widely, and may depend on alloy composition, product form, environmental conditions and the presence or otherwise of local or global stresses. One notable example is the occurrence of intergranular corrosion due to atmospheric corrosion, in which salts and deposits deliquesce on the surface forming discrete corrosion cells. Intergranular corrosion of aluminium alloys is usually most rapid in the rolling or extrusion direction of wrought alloy. The reasons for this are not fully understood, and may include texture effects that produce highly susceptible grain boundaries, the inhomogeneous distribution of noble constituent particles, and stresses acting at a microscale. This paper will review and discuss the evidence for and against for the different effects mentioned.

scholarly journals Effect of pH variation on the subcritical crack growth parameters of glassy matrix ceramics

2019 ◽  
Vol 16 (6) ◽  
pp. 2449-2456 ◽  
Author(s):  
Renata M. Melo ◽  
Cristiane Pereira ◽  
Nathália C. Ramos ◽  
Fernanda A. Feitosa ◽  
Amanda M.O. Dal Piva ◽  
...  
Keyword(s):  
Crack Growth ◽  
Subcritical Crack Growth ◽  
Growth Parameters ◽  
Glassy Matrix ◽  
Effect Of Ph ◽  
Ph Variation
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