Influence of Anisotropic Properties Upon Stress Intensity Factors under Biaxial Stress

2008 ◽  
Vol 385-387 ◽  
pp. 193-196
Author(s):  
Akira Shimamoto ◽  
Hiroshi Ohkawara ◽  
Jeong Hwan Nam
Keyword(s):  
Stress Intensity ◽  
Mechanical Behavior ◽  
Stress Intensity Factors ◽  
Extrusion Direction ◽  
Biaxial Stress ◽  
Intensity Factors ◽  
Anisotropic Properties ◽  
Biaxial Load ◽  
Crack Tips ◽  
Crack Angle

In this study, stress intensity factors were investigated and determined by photoelastic and caustics methods to clarify the mechanical behavior of crack tips under various biaxiality ratios. Polycarbonate (PC) plates with isotropic and anisotropic properties were used as specimens. The results confirmed that regardless of biaxiality ratio or the material’s property only ‘KI’ was generated in cases of a crack angle θ = 0º. It was also confirmed that only KI was generated in the isotropic PC plate with crack angle θ = 45º under a biaxial load (1:1). When the biaxiality ratio is more than 1:1 with a crack angle θ = 45º, both KI and KII are simultaneously generated in the isotropic specimen. Furthermore, KI, and KII values are influenced most by the extrusion direction in the anisotropic specimens as the biaxiality load ratios increase.

Influences of Isotropic and Anisotropic Material Properties on Stress Intensity Factors of the Crack Tip under Biaxial Stress

2005 ◽  
Vol 297-300 ◽  
pp. 1598-1603
Author(s):  
Taku Shimomura ◽  
Akira Shimamoto ◽  
T. Nemoto ◽  
Satoru Yoneyama
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Biaxial Loading ◽  
Extrusion Direction ◽  
Crack Tip ◽  
Local Deformation ◽  
Biaxial Stress ◽  
Intensity Factors ◽  
Caustics Method ◽  
Stress States

In order to clarify the effect of anisotropy on local deformation and the stress intensity factors in the vicinity of the crack tip under complicated stress states, biaxial loading tests were carried out on isotropic (Photoelastic sheet: PSM-1, Measurements Group, Inc) and anisotropic (LEXAN 9030, General Electric Company) polycarbonate materials. The biaxial dynamic loading device, which was developed by the authors, was fully utilized in the experiments. We carried out the experiments using isotropic and anisotropic specimens with a pre-processed 0°, 15°, 30°, 45°, 60°, 75° or 90° crack angle. We applied the equal biaxial stress, that is, the loads for both the Y- and X-axis as 0N : 0N-3920N : 3920N (1 : 1). We determined the stress intensity factors of specimens using both photoelasticity and caustics method. The results of the experiments were compared. As a result, when the materials with anisotropic property are used as machine or structural members, it is important to consider the extrusion direction of the material in their design.

Acousto-elastic measurement of stress and stress intensity factors around crack tips

Ultrasonics ◽  
1983 ◽  
Vol 21 (2) ◽  
pp. 57-64 ◽  
Author(s):  
A.V. Clark ◽  
R.B. Mignogna ◽  
R.J. Sanford
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Intensity Factors ◽  
Crack Tips

Elastodynamic Stress-Intensity Factors for a Crack Near a Free Surface

1981 ◽  
Vol 48 (3) ◽  
pp. 539-542 ◽  
Author(s):  
J. D. Achenbach ◽  
R. J. Brind
Keyword(s):  
Stress Intensity ◽  
Half Space ◽  
Stress Intensity Factors ◽  
Elastic Half Space ◽  
Mode I ◽  
Dimensionless Frequency ◽  
Subsurface Crack ◽  
Intensity Factors ◽  
Time Harmonic ◽  
Crack Tips

Elastodynamic Mode I and Mode II stress-intensity factors are presented for a subsurface crack in an elastic half space. The plane of the crack is normal to the surface of the half space. The half space is subjected to normal and tangential time-harmonic surface tractions. Numerical results show the variation of KI and KII at both crack tips, with the dimensionless frequency and the ratio a/b, where a and b are the distances to the surface from the near and the far crack tips, respectively. The results are compared with corresponding results for a crack in an unbounded solid.

Complex Stress Intensity Factors in Bent Plates With Cracks

1982 ◽  
Vol 49 (1) ◽  
pp. 87-96 ◽  
Author(s):  
P. S. Theocaris
Keyword(s):  
Stress Intensity ◽  
Stress Intensity Factors ◽  
Complex Stress ◽  
Intensity Factors ◽  
Simple Method ◽  
Cracked Plates ◽  
Crack Tips ◽  
Asymmetric Bending ◽  
Bent Plates

The experimental method of caustics was applied to the study of asymmetric bending of isotropic cracked plates and to the determination of the complex stress intensity factors (S.I.F’s) at the crack tips. It was shown that the method of reflected caustics is convenient for detecting and evaluating both KI and KII stress intensity factors. Based on the singular approximation of the elastic solution around the crack tip, the theory of formation of the caustics was developed and related to the evaluation of both components of stress intensity factors. It was also shown that the generalized method of caustics, known as the method of pseudocaustics, is a potential and simple method for determining S.I.F’s in cracked plates submitted to bending. Experimental evidence with specimens made either of optically inert materials, such as plexiglass, or of any opaque material like steel, and elastically loaded, has corroborated the theoretical results.

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