Experimental and Numerical Study on Mode I-II Crack Propagation for Small Size Specimens of Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 908-912
Author(s):  
Wei Dong ◽  
Hua Nan He ◽  
Zhi Min Wu
Keyword(s):  
Crack Propagation ◽  
Numerical Study ◽  
Initial Crack ◽  
Mode I ◽  
Propagation Process ◽  
Crack Propagation Process ◽  
Series Of Experiments ◽  
The Difference ◽  
The One ◽  
Good Agreement

The crack criterion is important to determine the crack propagation for mode I-II fracture in concrete. The paper aims to obtain the initial crack criterion of four-point shearing beams experimentally, which can be applied in the numerical simulation for crack propagation process. A series of experiments of four-point shearing notched beams of concrete with five different heights of 80mm, 100mm, 120mm, 140mm and 160mm respectively were carried out to measure the initial loading Pini. The different combinations of KiniI and KiniII corresponding to Pini were obtained according to different positions of pre-cracks in the specimens, and the initial crack criterion was fitted using the combinations of KiniI and KiniII. With the assumption that the crack will extend when the difference between the stress intensity factor at the crack tip caused by the load P and the one caused by the cohesive force attained the above KiniI- KiniII curve, the criterion was applied to simulate the crack propagation process in the paper. It was found that the numerical analysis showed a good agreement with the experimental results and that the size effect is not remarkable for the KiniI-KiniII curves of different heights specimens in the test.

Numerical Simulation on Mixed Mode I-II Crack Propagation Process in Concrete

2008 ◽  
Vol 385-387 ◽  
pp. 233-236 ◽  
Author(s):  
Qing Xu ◽  
Wei Dong ◽  
Zhi Min Wu
Keyword(s):  
Crack Propagation ◽  
Mixed Mode ◽  
Uniaxial Tensile ◽  
Mode I ◽  
Displacement Curve ◽  
Uniaxial Tensile Strength ◽  
Unstable Failure ◽  
Crack Propagation Process ◽  
The Difference ◽  
The One

A crack propagation criteria is proposed for mixed mode I-II fracture in concrete based on the initial cracking KⅠ-KⅡ curve obtained from experiment. Once the difference between the stress intensity factor at the crack tip caused by the external load and the one caused by the cohesive force attains the above KI-KII curve, the crack begins to propagate. Based on this criteria, the finite element method was used to simulate the mixed mode I-II crack initiation, stable propagation and unstable failure in concrete. For the four-point shear concrete specimens, the crack propagation trajectory and P-CMSD (Crack Mouth Sliding Displacement) curve were obtained. Upon the comparison with the experimental results, the calculated results show good agreement. It is concluded that, if the elastic modulus E, the uniaxial tensile strength ft and the initial cracking KI-KII curve of concrete are measured from experiment, the complete process of mixed mode I-II crack propagation can be simulated using the proposed criterion.

Effect of leakage and blockage on the acoustic behavior of particle filters

2019 ◽  
Vol 67 (6) ◽  
pp. 483-492
Author(s):  
Seonghyeon Baek ◽  
Iljae Lee
Keyword(s):  
Transfer Matrix ◽  
Particle Filters ◽  
Acoustic Analysis ◽  
Transmission Loss ◽  
One Dimensional ◽  
Filter System ◽  
The Difference ◽  
The One ◽  
Analytical Approaches ◽  
Good Agreement

The effects of leakage and blockage on the acoustic performance of particle filters have been examined by using one-dimensional acoustic analysis and experimental methods. First, the transfer matrix of a filter system connected to inlet and outlet pipes with conical sections is measured using a two-load method. Then, the transfer matrix of a particle filter only is extracted from the experiments by applying inverse matrices of the conical sections. In the analytical approaches, the one-dimensional acoustic model for the leakage between the filter and the housing is developed. The predicted transmission loss shows a good agreement with the experimental results. Compared to the baseline, the leakage between the filter and housing increases transmission loss at a certain frequency and its harmonics. In addition, the transmission loss for the system with a partially blocked filter is measured. The blockage of the filter also increases the transmission loss at higher frequencies. For the simplicity of experiments to identify the leakage and blockage, the reflection coefficients at the inlet of the filter system have been measured using two different downstream conditions: open pipe and highly absorptive terminations. The experiments show that with highly absorptive terminations, it is easier to see the difference between the baseline and the defects.

Numerical Study on Progressive Failure of the Marble Plate Based on the Thin-Layer Tri-Node Jointed Element

2011 ◽  
Vol 255-260 ◽  
pp. 1867-1872
Author(s):  
Jing Hua Qi ◽  
Zhen Nan Zhang ◽  
Xiu Run Ge
Keyword(s):  
Crack Propagation ◽  
Thin Layer ◽  
Numerical Study ◽  
Progressive Failure ◽  
Triangular Element ◽  
Compressive Loads ◽  
Joint Element ◽  
The Common ◽  
Edge Cracks ◽  
Good Agreement

In order to model the mechanical behavior of joints efficiently, a thin-layer tri-node joint element is constructed. The stiffness matrix of the element is derived in the paper. For it shares the common nodes with the original tri-node triangle element, the tri-node joint element can be applied to model the crack propagation without remeshing or mesh adjustment. Another advantage is that the cracked body is meshed without consideration of its geometry integrity and existence of the joints or pre-existed crack in the procedure of mesh generation, and then the triangular element intersected by the crack or joint is automatically transformed into the tri-node joint element to represent pre-existed cracks. These make the numerical simulation of crack propagation highly convenient and efficient. After CZM is chosen to model the crack tip, the mixed- energy simple criterion is used to determine whether the element is intersected by the extended crack or not, the extended crack is located in the model. By modeling the marble plates with two edge cracks subjected to the uniaxial compressive loads, it is shown that the numerical results are in good agreement with the experimental results, which suggests that the present method is valid and feasible in modeling rock crack propagation.

The Comparison of Self-Compacting Rock-Filled Concrete with Large-Size Natural and Recycled Aggregate

2014 ◽  
Vol 513-517 ◽  
pp. 20-23
Author(s):  
Hai Chao Wang ◽  
Xue Hua Wang ◽  
Xue Hui An
Keyword(s):  
Fracture Toughness ◽  
Crack Propagation ◽  
Fracture Energy ◽  
Fracture Mechanism ◽  
Recycled Aggregate ◽  
Propagation Process ◽  
Fracture Characteristics ◽  
Three Point Bending ◽  
Large Size ◽  
Crack Propagation Process

The different fracture characteristics of self-compacting rock-filled concrete with large-size natural and recycled aggregate are analyzed by three-point bending experiment. According to the analysis of the crack propagation process, the fracture mechanism differences of self-compacting rock-filled concrete with large-size natural and recycled aggregate are discussed. The further analysis of the differences of fracture toughness, fracture energy, and are gain

1928 Evaluation of Thermal Fatigue Micro-crack Propagation Process in Flip Chip Interconnects by Synchrotron Radiation X-ray Micro-tomography

2007 ◽  
Vol 2007.7 (0) ◽  
pp. 221-222
Author(s):  
Hiroyuki Tsuritani ◽  
Toshihiko Sayama ◽  
Yoshiyuki Okamoto ◽  
Takeshi Takayanagi ◽  
Kentaro Uesugi ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Crack Propagation ◽  
Thermal Fatigue ◽  
Flip Chip ◽  
Propagation Process ◽  
X Ray ◽  
Crack Propagation Process ◽  
Micro Tomography
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