scholarly journals Determination of Stress Intensity Factors under Shock Loading Using a Diffraction-Based Technique

2021 ◽  
Vol 11 (10) ◽  
pp. 4574
Author(s):  
Matúš Turis ◽  
Oľga Ivánková ◽  
Peter Burik ◽  
Milan Držík
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Shock Loading ◽  
Electric Signal ◽  
Unknown Boundary ◽  
Intensity Factors ◽  
Linear Character ◽  
Light Passing ◽  
Mode Stress ◽  
Unknown Boundary Conditions

An experimental optical method has been developed for the measurement of opening and sliding notch face movements. The light passing through a thin slit is monitored by a photodiode detector. Two parts of the slit are fixed independently on the notch faces of the simulated crack. Dynamic variations of the notch face movements are recorded as an electric signal by an ‘oscilloscope. The sensitivity of such displacement measurement is comparable with the wavelength of light. Dynamic mixed-mode stress intensity factors under shock loading were evaluated from the data obtained and subsequently compared with a numerical simulation by ANSYS software. As it was approved, the technique has shown sufficient sensitivity, good linearity, and measurement reliability. Due to its non-destructive nature and overall robustness, the arrangement is applicable even for structural component condition determination taking into consideration potentially unknown boundary conditions and the non-linear character of mechanical parameters.

Experimental Determination of KI for Short Internal Cracks

2001 ◽  
Vol 68 (6) ◽  
pp. 937-943 ◽  
Author(s):  
K. Bearden ◽  
J. W. Dally ◽  
R. J. Sanford
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Edge Crack ◽  
Series Solution ◽  
Experimental Studies ◽  
Experimental Methods ◽  
Internal Crack ◽  
Intensity Factors ◽  
Mode Stress

Since the pioneering discussion by Irwin, a significant effort has been devoted to determining stress intensity factors (K) using experimental methods. Techniques have been developed to determine stress intensity factors from photoelastic, strain gage, caustics, and moire´ data. All of these methods apply to a relatively long single-ended-edge crack. To date, the determination of K for internal cracks that are double-ended by experimental methods has not been addressed. This paper describes a photoelastic study of tension panels with both central and eccentric internal cracks. The data recorded in the experiments was analyzed using a new series solution for the opening-mode stress intensity factor for an internal crack. The data was also analyzed using the edge-crack series solution, which is currently employed in experimental studies. Results indicated that the experimental methods usually provided results accurate to within three to five percent if the series solution for the internal crack was employed in an overdeterministic numerical analysis of the data. Comparison of experimental results using the new series for the internal crack and the series for an edge crack showed the superiority of the new series.

Mixed Mode Interface Cracks in a Bi-Material Half Plane and a Bi-Material Strip

1999 ◽  
Author(s):  
Haiying Huang ◽  
George A. Kadomateas ◽  
Valeria La Saponara
Keyword(s):  
Stress Intensity ◽  
Free Boundary ◽  
Half Plane ◽  
Stress Intensity Factors ◽  
Mixed Mode ◽  
Infinite Strip ◽  
Infinite Plane ◽  
Intensity Factors ◽  
Interface Cracks ◽  
Mode Stress

Abstract This paper presents a method for determining the dislocation solution in a bi-material half plane and a bi-material infinite strip, which is subsequently used to obtain the mixed-mode stress intensity factors for a corresponding bi-material interface crack. First, the dislocation solution in a bi-material infinite plane is summarized. An array of surface dislocations is then distributed along the free boundary of the half plane and the infinite strip. The dislocation densities of the aforementioned surface dislocations are determined by satisfying the traction-free boundary conditions. After the dislocation solution in the finite domain is achieved, the mixed-mode stress intensity factors for interface cracks are calculated based on the continuous dislocation technique. Results are compared with analytical solution for homogeneous anisotropic media.

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