Papers by Keyword: Crack Length

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Authors: Xiao Peng Zhang, Yan Qiang Chen, Huai Nian Xing, Li Qiang Jin, Da Li
Abstract: In fatigue crack growth experiment and fracture toughness test, the crack length measurement is very important. Here, this paper proposes a new method for measuring crack length, namely in the case of a known load, according to the strain on the front end face of the three point bending specimen would be to get crack length.
Authors: Yong Sang Cho, Yeon Shik Ahn, Sang Ki Park, Jae Hoon Kim
Authors: Qi Zi Huang Peng, Wen Wei Huang, Ying Lu
Abstract: The safety of concrete structure can be evaluated by manual survey through the visible crack shown on structural surface, but the manual survey is costly and time-consuming. To improve this, a novel image-based crack length measurement is proposed. The method starts with getting time varying crack images by proposed inspection system. Then retrieve crack skeleton from crack images by pre-processing, and construct crack skeleton of tree structure. After getting crack trunk by pruning small edges from crack skeleton, the length of crack is figure out. This method can measure crack length automatically, which will make contribution to enhance the stability, durability and safety of concrete structure. The validity and accuracy of the proposed method was tested by an experiment using images of a real concrete surface.
Authors: Cheol Woong Kim, Dong Joon Oh, Kee Joo Kim, Ki Weon Kang
Abstract: The diverse studies on Al/GFRP laminates with the circular holes, therefore, have been carried out recently. The recent studies just focused on the behavior of the fatigue crack propagation and the delamination when the shape and the size of the notches were changed. Therefore, this study evaluated the location effect of the defects in the vicinity of the circular notch of the high strength monolithic aluminum and Al/GFRP laminates on the initiation life (Ni) of the fatigue cracks, the relationship between the crack length (a) and the fatigue life (N). In addition, the fatigue crack behavior of Al/GFRP laminates was studied when the fatigue loading and the interlaminar delamination took place at the same time during crack propagation. In conclusions, (1) for the monolithic aluminum, 10% of the failure life at θ2=30° was more increased than that at θ3=60°. (2) The crack length and the fatigue life behavior of Al/GFRP laminates according to the location of the artificial defect were different from those of the monolithic aluminum. Namely, the fatigue life of θ1=0° and θ2=30° were remarkably shorter than those of θ3=60° and θ4=90°.
Authors: Ion Dumitru, Anghel Cernescu
Abstract: The purpose of this study was making evident the overload effect in a spectre with constant amplitude cycles. The crack growth simulation was made on cracked specimen and was studied for four loading cases. Fatigue crack growth rate was calculated applying NASGRO equation and the crack growth retardation analyzed.
Authors: Zhi Li, Min You, Mei Rong Zhao, Gang Yan Li
Abstract: The finite element method was used to study the stress distribution of strip joints under different elastic modulus and crack length. The results show that with the elastic modulus increases, the crack tip of the peak stress also increases, which provide maximum load continue to expand on the joint crack is SY stress, while little impact to the continued crack expansion on joints is SXY stress. I-type crack perpendicular the surface Crack under the stress of characteristics; With the initial crack length increases, I-stress intensity factor present weak tendency to increase, II-stress intensity factor is still almost zero, so that even after a longer crack length, strip adhesive joints under load the fracture is still mainly based on I-type crack, which is also consistent with the strip load characteristics: external stress perpendicular to crack surface. Another I-type stress intensity factor slight increasing trend.
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