Fracture Properties of Softwood under Mode I Loading Perpendicular to the Grain

2007 ◽  
Vol 340-341 ◽  
pp. 477-482
Author(s):  
Ming Bao Li ◽  
Jun Cao ◽  
Shi Qiang Zheng

Fracture properties of softwood under mode I loading perpendicular to the grain are studied in this paper. The stress intensity factor KIC in the R and L directions is measured by the compact tension test using small several specimens. The shape and size of plastic zone in crack tip is determined by numerical simulations based on von Hill yield criterion. The results show that anisotropic material constants do not affect the length of plastic zone along crack direction and it only operates on the plastic zone with θcr≠ 0. Strength ratios α1, α2 and toughness ratios r1, r2, influencing on the plastic zone, are discussed. Comparative analysis shows that r1 and r2 work markedly on the shape and size of plastic zone, whereas α1, α2 do less.

2017 ◽  
Vol 11 (2) ◽  
pp. 215-228 ◽  
Author(s):  
Héctor Cifuentes ◽  
Miguel Lozano ◽  
Táňa Holušová ◽  
Fernando Medina ◽  
Stanislav Seitl ◽  
...  

Author(s):  
Stanislav Seitl ◽  
Petr Miarka ◽  
Jakub Sobek

Abstract The objective of this study is to investigate the use of compact tension specimen calibration curves for evaluation data of fracture properties measurement performed on modified compact tension specimen made from cement based composites. From literature, the well-known calibration curve for compact tension specimen is compared with calibration curves for Modified compact tension specimen that are obtained from numerical calculation. The obtained results are quantified and accuracy of solution is discussed. The suggested curves could be preferably used for determining of the fracture parameters.


Holzforschung ◽  
2011 ◽  
Vol 65 (5) ◽  
Author(s):  
Hiroshi Yoshihara ◽  
Ami Usuki

Abstract The critical stress intensity factor of mode I (K Ic) obtained by compact tension (CT) tests of wood and medium-density fiberboard (MDF) was experimentally and numerically analyzed. A double cantilever beam (DCB) test was also conducted and the results were compared with those of the CT tests. Similar to the results of single-edge-notched bending (SENB) and single-edge-notched tension (SENT) tests previously conducted, the value of K Ic was obtained properly from the CT test when an additional crack length was taken into account.


2011 ◽  
Vol 399-401 ◽  
pp. 2189-2194 ◽  
Author(s):  
De Wen Zhao ◽  
Can Ming Li ◽  
Liang Yun Lan ◽  
Shun Hu Zhang

Based on GM yield criterion, the analytical solutions for shape and size of mode I crack tip plastic zone and the burst pressure for X70 pipeline steel are derived. Comparing the solutions with those based on Mises and Trasca criteria shows that under plain strain condition the area of plastic zone on GM is between Tresca and Mises solutions, and very close to Mises one. Among the areas Tresca’s is the largest and Mises is the smallest and all three zones are dumbbell shaped. However, for pipeline burst pressure based on Tresca criterion is the smallest and that on Twin shear stress criterion (TSS) is the largest, those on GM and Mises are also very close to each other and lie between Tresca and TSS results.


In the present paper, experimental investigation on the fracture of aluminum alloy AA3003 are conducted on the Compact Tension Shear CTS specimen non-welded and CTS specimen welded by FSW process under mixed mode loading by using Arcan loading device based on Richard’s principle suitable for mixed mode. All loading in mixed mode starting from pure tension (mode I) up to pure shear (mode II) can be obtained and tested by varying the loading angles from 0° to 90°. The stress intensity factor for the Compact Tension Shear (CTS) specimen are determined three normalized lengths cracks 0.3, 0.5 and 0.7.The length of notches influence on the variation of stress intensity factor KI, KII. For CTS specimen with notches with a short length, the values of KII are greater than those obtained for notches with a long length.


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