制备了β晶型无规共聚聚丙烯(PPR)管材专用树脂,并研究了5种不同β成核剂对β晶型PPR性能的影响。结果表明:β晶型PPR的性能与β成核剂的种类和加入量相关。当β成核剂E的质量分数为0.20%时,β晶型PPR的β晶含量达80%以上,简支梁缺口冲...制备了β晶型无规共聚聚丙烯(PPR)管材专用树脂,并研究了5种不同β成核剂对β晶型PPR性能的影响。结果表明:β晶型PPR的性能与β成核剂的种类和加入量相关。当β成核剂E的质量分数为0.20%时,β晶型PPR的β晶含量达80%以上,简支梁缺口冲击强度达100 k J/m2。β成核剂C对β晶型PPR负荷变形温度影响最大,能使其升至76℃左右。分别加入β成核剂A,B,C,D,则β晶型PPR断裂伸长率均增加20%。综合考虑,加入β成核剂E能满足β晶型PPR对抗冲击性能和耐热性能的要求。展开更多
According to the concept of virtual bending force,a rational explanation for SHOHET's model was presented. Considering the deformation characters of the work rolls in four-high mill,the deformation model of the wo...According to the concept of virtual bending force,a rational explanation for SHOHET's model was presented. Considering the deformation characters of the work rolls in four-high mill,the deformation model of the work roll was regarded as a cantilever beam and new influence coefficients were deduced.The effect of the bending force was taken into account independently. Therefore,the contribution to work roll deflection caused by rolling load,rolling pressure between rolls and bending force can be got from the new formulas.To validate the accuracy of the formulas,the results obtained from the new formulas were compared with those from SHOHET's formulas.It is found that they highly coincide,which illustrates that the formulas are reliable.展开更多
This paper presents a simple solution of the dynamic buckling of stiffened plates under in-plane impact loading. Based on large deflection theory, a discretely stiffened plate model has been used. The tangential stres...This paper presents a simple solution of the dynamic buckling of stiffened plates under in-plane impact loading. Based on large deflection theory, a discretely stiffened plate model has been used. The tangential stresses of stiffeners and in-plane displacement are neglected. Appling the Hamilton's principle, the motion equations of stiffened plates are obtained. The deflection of the plate is taken as Fourier series, and using Galerkin method the discrete equations can be deduced, which can be solved easily by Runge-Kutta method. The dynamic buckling loads of the stiffened plates are obtained form Budiansky-Roth criterion.展开更多
In this paper,the problem of axially symmetric deformation is examined for a composite cylindrical tube under equal axial loads acting on its two ends,where the tube is composed of two different incompressible neo-Hoo...In this paper,the problem of axially symmetric deformation is examined for a composite cylindrical tube under equal axial loads acting on its two ends,where the tube is composed of two different incompressible neo-Hookean materials.Significantly,the implicit analytical solutions describing the deformation of the tube are proposed.Numerical simulations are given to further illustrate the qualitative properties of the solutions and some meaningful conclusions are obtained.In the tension case,with the increasing axial loads or with the decreasing ratio of shear moduli of the outer and the inner materials,it is proved that the tube will shrink more along the radial direction and will extend more along the axial direction.Under either tension or compression,the deformation along the axial direction is obvious near the two ends of the tube,while in the rest,the change is relatively small.Similarly,for a large domain of the middle part,the axial elongation is almost constant;however,the variation is very fast near the two ends.In addition,the absolute value of the axial displacement increases gradually from the central cross-section of the tube and achieves the maximum at the two endpoints.展开更多
文摘制备了β晶型无规共聚聚丙烯(PPR)管材专用树脂,并研究了5种不同β成核剂对β晶型PPR性能的影响。结果表明:β晶型PPR的性能与β成核剂的种类和加入量相关。当β成核剂E的质量分数为0.20%时,β晶型PPR的β晶含量达80%以上,简支梁缺口冲击强度达100 k J/m2。β成核剂C对β晶型PPR负荷变形温度影响最大,能使其升至76℃左右。分别加入β成核剂A,B,C,D,则β晶型PPR断裂伸长率均增加20%。综合考虑,加入β成核剂E能满足β晶型PPR对抗冲击性能和耐热性能的要求。
基金Project(20050216007) supported by the Specialized Research Fund for the Doctoral Program of Higher Education of China
文摘According to the concept of virtual bending force,a rational explanation for SHOHET's model was presented. Considering the deformation characters of the work rolls in four-high mill,the deformation model of the work roll was regarded as a cantilever beam and new influence coefficients were deduced.The effect of the bending force was taken into account independently. Therefore,the contribution to work roll deflection caused by rolling load,rolling pressure between rolls and bending force can be got from the new formulas.To validate the accuracy of the formulas,the results obtained from the new formulas were compared with those from SHOHET's formulas.It is found that they highly coincide,which illustrates that the formulas are reliable.
文摘This paper presents a simple solution of the dynamic buckling of stiffened plates under in-plane impact loading. Based on large deflection theory, a discretely stiffened plate model has been used. The tangential stresses of stiffeners and in-plane displacement are neglected. Appling the Hamilton's principle, the motion equations of stiffened plates are obtained. The deflection of the plate is taken as Fourier series, and using Galerkin method the discrete equations can be deduced, which can be solved easily by Runge-Kutta method. The dynamic buckling loads of the stiffened plates are obtained form Budiansky-Roth criterion.
基金supported by the National Natural Science Foundation of China(Grant Nos.10872045 and 11232003)the Program for New Century Excellent Talents in University(Grant No.NCET-09-0096)+1 种基金the Fundamental Research Funds for the Central Universities(Grant No.DC120101121)the Program for Liaoning Excellent Talents in University(Grant No.LR2012044)
文摘In this paper,the problem of axially symmetric deformation is examined for a composite cylindrical tube under equal axial loads acting on its two ends,where the tube is composed of two different incompressible neo-Hookean materials.Significantly,the implicit analytical solutions describing the deformation of the tube are proposed.Numerical simulations are given to further illustrate the qualitative properties of the solutions and some meaningful conclusions are obtained.In the tension case,with the increasing axial loads or with the decreasing ratio of shear moduli of the outer and the inner materials,it is proved that the tube will shrink more along the radial direction and will extend more along the axial direction.Under either tension or compression,the deformation along the axial direction is obvious near the two ends of the tube,while in the rest,the change is relatively small.Similarly,for a large domain of the middle part,the axial elongation is almost constant;however,the variation is very fast near the two ends.In addition,the absolute value of the axial displacement increases gradually from the central cross-section of the tube and achieves the maximum at the two endpoints.
