A Laser Interferometry Method for Experimental Stress Intensity Factor Calibration

2009 ◽  
pp. 490-490-16 ◽  
Author(s):  
DE Macha ◽  
WN Sharpe ◽  
AF Grandt
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Laser Interferometry ◽  
Experimental Stress ◽  
Interferometry Method

Experimental stress intensity factors for cracks in a thin plate with stiffeners

1995 ◽  
Vol 30 (3) ◽  
pp. 235-240 ◽  
Author(s):  
A D Nurse ◽  
S Güng ◽  
E A Patterson
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Three Dimensional ◽  
Tensile Load ◽  
Stiffened Plates ◽  
Experimental Stress ◽  
Intensity Factors ◽  
Cracked Plates ◽  
Plate Geometry

The problem of cracked plates stiffened by three-dimensional stringers is investigated using transmission photoelasticity. Models were produced of the hole-in-the-plate geometry stiffened by a combination of stringers transverse and/or parallel to the applied tensile load. Cracks of different lengths emanating from one edge of the hole and approaching a stringer were examined. These cases represent geometry and loading conditions for which it would normally be very difficult to obtain results using analytical methods. The stringer-stiffened plates show a consistent reduction in the non-dimensional stress intensity factor of about 20 per cent irrespective of the arrangement of stringers.

THE USE OF XFEM FOR STRESS INTENSITY FACTOR ESTIMATION OF SURFACE CRACKS

2017 ◽  
Author(s):  
Antonio Almeida Silva ◽  
Marco Antonio dos Santos ◽  
Gabriel Coêlho
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Surface Cracks ◽  
Factor Estimation

Damage accumulation near a hole under low cycle fatigue proceeding from measurements of local deformation response

2020 ◽  
Vol 86 (10) ◽  
pp. 46-55
Author(s):  
S. I. Eleonsky ◽  
Yu. G. Matvienko ◽  
V. S. Pisarev ◽  
A. V. Chernov
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Damage Accumulation ◽  
Stress Ratio ◽  
Low Cycle Fatigue ◽  
Accumulation Process ◽  
Stress Range ◽  
Cycle Fatigue ◽  
Deformation Response

A new destructive method for quantitative determination of the damage accumulation in the vicinity of a stress concentrator has been proposed and verified. Increase of damage degree in local area with a high level of the strain gradient was achieved through preliminary low-cycle pull-push loading of plane specimens with central open holes. The above procedure is performed for three programs at the same stress range (333.3 MPa) and different stress ratio values 0.33, – 0.66 and – 1.0, and vice versa for two programs at the same stress ratio – 0.33 and different stress range 333.3 and 233.3 MPa. This process offers a set of the objects to be considered with different degree of accumulated fatigue damages. The key point of the developed approach consists in the fact that plane specimens with open holes are tested under real operation conditions without a preliminary notching of the specimen initiating the fatigue crack growth. The measured parameters necessary for a quantitative description of the damage accumulation process were obtained by removing the local volume of the material in the form of a sequence of narrow notches at a constant level of external tensile stress. External load can be considered an amplifier enhancing a useful signal responsible for revealing the material damage. The notch is intended for assessing the level of fatigue damage, just as probe holes are used to release residual stress energy in the hole drilling method. Measurements of the deformation response caused by local removing of the material are carried out by electronic speckle-pattern interferometry at different stages of low-cycle fatigue. The transition from measured in-plane displacements to the values of the stress intensity factor (SIF) and the T-stress was carried out on the basis of the relations of linear fracture mechanics. It was shown that the normalized dependences of the stress intensity factor on the durability percentage for the first notch (constructed for four programs of cyclic loading with different parameters), reflect the effect of the stress ratio and stress range of the loading cycle on the rate of damage accumulation. The data were used to obtain the explicit form of the damage accumulation function that quantitatively describes damage accumulation process. The functions were constructed for different stress ratios and stress ranges.

A new type of cracks adding to Griffith–Irwin cracks

2019 ◽  
Vol 485 (2) ◽  
pp. 162-165
Author(s):  
V. A. Babeshko ◽  
O. M. Babeshko ◽  
O. V. Evdokimova
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Tip ◽  
Stress Concentrations ◽  
New Type

The distinctions in the description of the conditions of cracking of materials are revealed. For Griffith–Irwin cracks, fracture is determined by the magnitude of the stress-intensity factor at the crack tip; in the case of the new type of cracks, fracture occurs due to an increase in the stress concentrations up to singular concentrations.

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