The crack propagation rates of T6 peak aging and T7951 secondary aging 7055 aluminium alloys were tested under stress ratios (R) of 0.6, 0.05 and ?1, respectively. The microstructures and fracture surfaces were analyz...The crack propagation rates of T6 peak aging and T7951 secondary aging 7055 aluminium alloys were tested under stress ratios (R) of 0.6, 0.05 and ?1, respectively. The microstructures and fracture surfaces were analyzed by TEM and SEM. The results reveal that the crack propagation rate is affected by the stress ratio and microstructure such as the distribution, dimension and volume fraction of matrix precipitates, grain boundary precipitates and precipitate free zone. For both heat-treated specimens, crack propagation rate increases with the improvement of R when it is a positive value while crack propagation rate at R=?1 is much similar to that at R=0.06. The crack growth rates exhibit no obvious difference in lower stress intensity factor range (ΔK), while the difference starts to be obvious when ΔK exceeds certain value. The fracture analysis testifies a better fracture toughness for 7055-T7951 with a smaller striation space in Paris region.展开更多
This paper presents the characteristics of the crack growth at the interface of rubber-rubber and rubber-steel bimaterials undertensile deformation using the non-linear finite element method. By using the commercial f...This paper presents the characteristics of the crack growth at the interface of rubber-rubber and rubber-steel bimaterials undertensile deformation using the non-linear finite element method. By using the commercial finite element software ABAQUS,the J integral calculations are carried out for the initial interface crack in the interfaces in-between two Neo-Hookean materials,two Mooney-Rivlin materials, Neo-Hookean and Mooney-Rivlin rubbers, Neo-Hookean and Polynomial, Mooney-Rivlin andPolynomial, and the Mooney-Rivlin and steel bi-materials. The computational results of the maximum J integral directionaround the crack tip illustrate the possible direction of crack growth initiation. Furthermore, it is found that the crack bends tothe softer rubber material at a certain angle with the initial crack direction if the crack depth is relatively small. For the crackwith a larger depth, the crack propagates to grow along the interface in-between the bimaterials.展开更多
基金Project(51405309)supported by the National Natural Science Foundation of ChinaProject(2013024012)supported by the Natural Science Foundation of Liaoning Province,China
文摘The crack propagation rates of T6 peak aging and T7951 secondary aging 7055 aluminium alloys were tested under stress ratios (R) of 0.6, 0.05 and ?1, respectively. The microstructures and fracture surfaces were analyzed by TEM and SEM. The results reveal that the crack propagation rate is affected by the stress ratio and microstructure such as the distribution, dimension and volume fraction of matrix precipitates, grain boundary precipitates and precipitate free zone. For both heat-treated specimens, crack propagation rate increases with the improvement of R when it is a positive value while crack propagation rate at R=?1 is much similar to that at R=0.06. The crack growth rates exhibit no obvious difference in lower stress intensity factor range (ΔK), while the difference starts to be obvious when ΔK exceeds certain value. The fracture analysis testifies a better fracture toughness for 7055-T7951 with a smaller striation space in Paris region.
基金supported by the Hong Kong Polytechnic University (Grant No. G-YH32)
文摘This paper presents the characteristics of the crack growth at the interface of rubber-rubber and rubber-steel bimaterials undertensile deformation using the non-linear finite element method. By using the commercial finite element software ABAQUS,the J integral calculations are carried out for the initial interface crack in the interfaces in-between two Neo-Hookean materials,two Mooney-Rivlin materials, Neo-Hookean and Mooney-Rivlin rubbers, Neo-Hookean and Polynomial, Mooney-Rivlin andPolynomial, and the Mooney-Rivlin and steel bi-materials. The computational results of the maximum J integral directionaround the crack tip illustrate the possible direction of crack growth initiation. Furthermore, it is found that the crack bends tothe softer rubber material at a certain angle with the initial crack direction if the crack depth is relatively small. For the crackwith a larger depth, the crack propagates to grow along the interface in-between the bimaterials.
