Weakening of Cracktip Singularity due to Buckling of Thin Bodies under Tension
(2007) Abstract
 When thin sheets containing a crack is subjected to tensile loading in the direction perpendicular to the crack surface out of plane displacement will occur in areas surrounding the crack. By this the stress state in the vicinity of the crack tip is changed and leads to a weaker crack tip singularity than the r1/2 by linear elastic fracture mechanics. During lab testing the buckling is artificially prevented thus the conditions for transfer of predicted fracture criteria to real structures are changed. The weaker singularity is used to formulate an adopted fracture mechanical theory. Approximation is made based on the assumption that the buckled area of the paper is unable to carrying any load and that region is approximated by the region... (More)
 When thin sheets containing a crack is subjected to tensile loading in the direction perpendicular to the crack surface out of plane displacement will occur in areas surrounding the crack. By this the stress state in the vicinity of the crack tip is changed and leads to a weaker crack tip singularity than the r1/2 by linear elastic fracture mechanics. During lab testing the buckling is artificially prevented thus the conditions for transfer of predicted fracture criteria to real structures are changed. The weaker singularity is used to formulate an adopted fracture mechanical theory. Approximation is made based on the assumption that the buckled area of the paper is unable to carrying any load and that region is approximated by the region under compressive load at plane stress conditions. The result is compared with experiments performed on large paper specimens that imply that the fracture toughness does not hold a constant value for small cracks. A postbuckling analysis was performed to closely study the change of the singularity. The analysis suggests that at an applied load at 100 times the buckling load the drop of the singularity for a crack length of 20% of the sheet width is about 2%, which does not cause any major deviations from the predictions of the linear theory. However by experimental data it is predicted that the crack growth will commence at an applied load approximately 2572 times the buckling load and the drop of the singularity would be considerable larger at such load magnitudes which will result in greater impact in comparison with the linear theory (Less)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/record/925016
 author
 Chong, Li ^{LU}
 supervisor

 Per StÃ¥hle ^{LU}
 organization
 publishing date
 2007
 type
 Thesis
 publication status
 published
 subject
 keywords
 Thin foils, Fracture, Buckling
 publisher
 LTH, Lund University
 external identifiers

 other:ISRN: LUTFD2/TFHF05/1033SE
 language
 English
 LU publication?
 yes
 id
 31771eff85374ffd805afc0c96dc72f9 (old id 925016)
 date added to LUP
 20080126 16:03:58
 date last changed
 20160919 08:45:06
@misc{31771eff85374ffd805afc0c96dc72f9, abstract = {When thin sheets containing a crack is subjected to tensile loading in the direction perpendicular to the crack surface out of plane displacement will occur in areas surrounding the crack. By this the stress state in the vicinity of the crack tip is changed and leads to a weaker crack tip singularity than the r1/2 by linear elastic fracture mechanics. During lab testing the buckling is artificially prevented thus the conditions for transfer of predicted fracture criteria to real structures are changed. The weaker singularity is used to formulate an adopted fracture mechanical theory. Approximation is made based on the assumption that the buckled area of the paper is unable to carrying any load and that region is approximated by the region under compressive load at plane stress conditions. The result is compared with experiments performed on large paper specimens that imply that the fracture toughness does not hold a constant value for small cracks. A postbuckling analysis was performed to closely study the change of the singularity. The analysis suggests that at an applied load at 100 times the buckling load the drop of the singularity for a crack length of 20% of the sheet width is about 2%, which does not cause any major deviations from the predictions of the linear theory. However by experimental data it is predicted that the crack growth will commence at an applied load approximately 2572 times the buckling load and the drop of the singularity would be considerable larger at such load magnitudes which will result in greater impact in comparison with the linear theory}, author = {Chong, Li}, keyword = {Thin foils,Fracture,Buckling}, language = {eng}, note = {Licentiate Thesis}, publisher = {LTH, Lund University}, title = {Weakening of Cracktip Singularity due to Buckling of Thin Bodies under Tension}, year = {2007}, }