Four different types of three-body model composed of rock and coal with different strength and stiffness were established in order to study the failure characteristics of compound model such as roof-coal-floor. Throug...Four different types of three-body model composed of rock and coal with different strength and stiffness were established in order to study the failure characteristics of compound model such as roof-coal-floor. Through stress analysis of the element with variable strength and stiffness extracted from the strong-weak interface, the tri-axial compressive strength of the weak body and strong body near the interface as well as the areas away from the contact surface was found. Then, on the basis of three-dimensional fast Lagrangian method of continua and strain softening constitutive model composed of Coulomb-Mohr shear failure with tensile cut-off, stress and strain relationship of the four three-body combined models were analyzed under different confining pressures by numerical simulation. Finally, the different features of local shear zones and plastic failure areas of the four different models and their development trend with increasing confining pressure were discussed. The results show that additional stresses are derived due to the lateral deformation constraints near the strong-weak interface area, which results in the strength increasing in weak body and strength decreasing in strong body. The weakly consolidated soft rock and coal cementation exhibit significant strain softening behavior and bear compound tension-shear failure under uni-axial compression. With the increase of confining pressure, the tensile failure disappears from the model, and the failure type of composed model changes to local shear failure with different number of shearing bands and plastic failure zones. This work shows important guiding significance for the mechanism study of seismic, rock burst, and coal bump.展开更多
Objective To study the effect of liver resection for spontaneous rupture of primary hepatocellulal carcinoma (PHCC). Methods The clinical data of 12 patients with ruptured PHCC treated by liver resection in Xiangya ...Objective To study the effect of liver resection for spontaneous rupture of primary hepatocellulal carcinoma (PHCC). Methods The clinical data of 12 patients with ruptured PHCC treated by liver resection in Xiangya Hospital since 1970 were analyzed retrospectively. Results There were 10 males and 2 females with mean age of 42 (ranged 22–65) years in this series. Of the 12 patients, 11 underwent emergent hepatectomy and one 2-stage hepatectomy, including left segmental liver resection in 6 patients, left median lobectomy in 1, left hemihepatectomy in 1, partial right hepatectomy in 2, and tumor resection in 2. There was no operative death in 11 patients with liver function in grade A of Child-Paugh classification, but 1 patient with grade B liver function died of liver failure after operation. The operative mortality was 8.3%. In 11 survived patients, the postoperative median survival time was 16.5 months. The 1?, 3?, 5-year survival rate was 72.7%, 18.2%, 9.1% respectively; among them one patient has been alive free of the tumor for 25 years and 9 months. Conclusion Liver resection is the best treatment for ruptured PHCC when possible, which can result in long survival time. Key words liver resection - spontaneous ruptare - primary hepatocellular carcinoma展开更多
This paper deals with the progressive failure analysis of composite laminates. Triangular elements which include the transverse shear effects are us.d for the stress analysis. A new method for the calculation of the s...This paper deals with the progressive failure analysis of composite laminates. Triangular elements which include the transverse shear effects are us.d for the stress analysis. A new method for the calculation of the shear correction factors is presented. Several failure criteria are used to check the first ply failure and distinguish the laminate failure modes into fiber breakage or buckling, matrix cracking and delamination. After the failure is detected, the stiffness of the failed ply is modified according to the failure modes. The ultimate strength of the laminate is obtained by an iterative way. Several examples are given in the paper for stress analysis and progressive failure analysis of composite laminates.展开更多
基金Project(51174128)supported by the National Natural Science Foundation of ChinaProject(20123718110007)supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘Four different types of three-body model composed of rock and coal with different strength and stiffness were established in order to study the failure characteristics of compound model such as roof-coal-floor. Through stress analysis of the element with variable strength and stiffness extracted from the strong-weak interface, the tri-axial compressive strength of the weak body and strong body near the interface as well as the areas away from the contact surface was found. Then, on the basis of three-dimensional fast Lagrangian method of continua and strain softening constitutive model composed of Coulomb-Mohr shear failure with tensile cut-off, stress and strain relationship of the four three-body combined models were analyzed under different confining pressures by numerical simulation. Finally, the different features of local shear zones and plastic failure areas of the four different models and their development trend with increasing confining pressure were discussed. The results show that additional stresses are derived due to the lateral deformation constraints near the strong-weak interface area, which results in the strength increasing in weak body and strength decreasing in strong body. The weakly consolidated soft rock and coal cementation exhibit significant strain softening behavior and bear compound tension-shear failure under uni-axial compression. With the increase of confining pressure, the tensile failure disappears from the model, and the failure type of composed model changes to local shear failure with different number of shearing bands and plastic failure zones. This work shows important guiding significance for the mechanism study of seismic, rock burst, and coal bump.
文摘Objective To study the effect of liver resection for spontaneous rupture of primary hepatocellulal carcinoma (PHCC). Methods The clinical data of 12 patients with ruptured PHCC treated by liver resection in Xiangya Hospital since 1970 were analyzed retrospectively. Results There were 10 males and 2 females with mean age of 42 (ranged 22–65) years in this series. Of the 12 patients, 11 underwent emergent hepatectomy and one 2-stage hepatectomy, including left segmental liver resection in 6 patients, left median lobectomy in 1, left hemihepatectomy in 1, partial right hepatectomy in 2, and tumor resection in 2. There was no operative death in 11 patients with liver function in grade A of Child-Paugh classification, but 1 patient with grade B liver function died of liver failure after operation. The operative mortality was 8.3%. In 11 survived patients, the postoperative median survival time was 16.5 months. The 1?, 3?, 5-year survival rate was 72.7%, 18.2%, 9.1% respectively; among them one patient has been alive free of the tumor for 25 years and 9 months. Conclusion Liver resection is the best treatment for ruptured PHCC when possible, which can result in long survival time. Key words liver resection - spontaneous ruptare - primary hepatocellular carcinoma
文摘This paper deals with the progressive failure analysis of composite laminates. Triangular elements which include the transverse shear effects are us.d for the stress analysis. A new method for the calculation of the shear correction factors is presented. Several failure criteria are used to check the first ply failure and distinguish the laminate failure modes into fiber breakage or buckling, matrix cracking and delamination. After the failure is detected, the stiffness of the failed ply is modified according to the failure modes. The ultimate strength of the laminate is obtained by an iterative way. Several examples are given in the paper for stress analysis and progressive failure analysis of composite laminates.
