The antiplane shear problems of periodical rigid line inclusions between dissimilar anisotropic materials are dealt with. By using the complex variable method, the closed form solutions are obtained. The stress distri...The antiplane shear problems of periodical rigid line inclusions between dissimilar anisotropic materials are dealt with. By using the complex variable method, the closed form solutions are obtained. The stress distribution in the immediate vicinity of the rigid line is examined. The corresponding formulation between dissimilar isotropic materials and in homogeneous anisotropic medium can be derived from the special cases of those in the present paper, and the limit conditions are in agreement with the previously known results.展开更多
This paper deals with the electro-elastic coupling interaction between a piezoelectric screw dislocation which is located inside the elliptical inhomogeneity and an electrically conductive confocal rigid line under re...This paper deals with the electro-elastic coupling interaction between a piezoelectric screw dislocation which is located inside the elliptical inhomogeneity and an electrically conductive confocal rigid line under remote anti-plane shear stresses and in-plane electrical loads in piezoelectric composite material. The analytical-functions of the complex potentials, stress fields and the image force acting on the piezoelectric screw dislocation are obtained based on the principle of conformal mapping, the method of series expansion, the technical of analytic continuation and the analysis of singularity of complex potentials. The rigid line and the piezoelectric material property combinations upon the image force and the equilibrium position of the dislocation are discussed in detail by the numerical computation.展开更多
Based on the cylindrical cavity expansion theory, a plastic-damage-elastic model is proposed for the penetration problem of geo-material. In the model, the unified strength criterion (Yu, 1991) is adopted as the failu...Based on the cylindrical cavity expansion theory, a plastic-damage-elastic model is proposed for the penetration problem of geo-material. In the model, the unified strength criterion (Yu, 1991) is adopted as the failure criterion. The distributions of the radial stress and velocity are analyzed. According to the Newton's second law, a series results of the final penetration depth and the impedance load are obtained to different parameter b, when a rigid projectile normally impacts and penetrates a semi-infinite geo-material target with an impact velocity of 300-1200 m/s. By comparing with the test data available, it appears that the method can be used in analyzing the final depth and the impedance load of a rigid projectile penetrating into a semi-infinite target with different impact velocities.展开更多
The ratios of depth of penetration (DOP) of different targets under the same penetration condition was investigated according to the dimensionless formula of DOP of different targets penetrated by a non-deformable pro...The ratios of depth of penetration (DOP) of different targets under the same penetration condition was investigated according to the dimensionless formula of DOP of different targets penetrated by a non-deformable projectile.Results show that various targets may be equivalent to each other.The applicable range of the equivalence and the feasibility of targets substitution were discussed by integrating the available test data.展开更多
By using the energy criterion in [3], the impact torsional buckling for the rigid plastic cylindrical shell is studied. The linear dynamic torsional buckling equations for the rigid plastic shell is drived, and the cr...By using the energy criterion in [3], the impact torsional buckling for the rigid plastic cylindrical shell is studied. The linear dynamic torsional buckling equations for the rigid plastic shell is drived, and the critical impact velocity is given.展开更多
采用硬脂酰氯对三聚氰胺进行酰胺化改性得到十七烷基链修饰的三聚氰胺衍生物(酰胺化三聚氰胺),进而与甲醛、混合醇等进行加成、缩聚反应,制备了酰胺化密胺树脂,并将其制备成膜及硬泡材料,采用FTIR、NMR、TG、SEM及EDS对酰胺化三聚氰胺...采用硬脂酰氯对三聚氰胺进行酰胺化改性得到十七烷基链修饰的三聚氰胺衍生物(酰胺化三聚氰胺),进而与甲醛、混合醇等进行加成、缩聚反应,制备了酰胺化密胺树脂,并将其制备成膜及硬泡材料,采用FTIR、NMR、TG、SEM及EDS对酰胺化三聚氰胺、酰胺化密胺树脂以及膜层与硬泡材料进行了表征。结果表明,疏水烷基长链的引入使酰胺化三聚氰胺与水的接触角由改性前的0°升至133.5°以上;随着三聚氰胺酰胺化程度的提高,酰胺化密胺树脂的水容忍点温度逐渐降低,树脂黏度逐渐增大,不溶性颗粒逐渐增多增大。相对于常规密胺树脂制备的材料,酰胺化密胺树脂(无论是膜层材料还是硬泡材料)力学性能均未出现明显降低,样块抗压强度可达39.5 MPa,硬泡材料弯曲强度可达345.8 kPa,压缩强度可达315 k Pa,同时表现出优异的抗水和疏水效果,样块24h吸水率仅为1.1%,硬泡材料的体积吸水率降低至2.0%,膜层水接触角提高至107.5°,抗污染性能得到改善。展开更多
In this paper,the application of Abaqus-based particle finite element method(PFEM)is extended from static to dynamic large deformation.The PFEM is based on periodic mesh regeneration with Delaunay triangulation to avo...In this paper,the application of Abaqus-based particle finite element method(PFEM)is extended from static to dynamic large deformation.The PFEM is based on periodic mesh regeneration with Delaunay triangulation to avoid mesh distortion.Additional mesh smoothing and boundary node smoothing techniques are incorporated to improve the mesh quality and solution accuracy.The field variables are mapped from the old to the new mesh using the closest point projection method to minimize the mapping error.The procedures of the proposed Abaqus-based dynamic PFEM(Abaqus-DPFEM)analysis and its implementation in Abaqus are detailed.The accuracy and robustness of the proposed approach are examined via four illustrative numerical examples.The numerical results show a satisfactory agreement with published results and further confirm the applicability of the Abaqus-DPFEM to solving dynamic large-deformation problems in geotechnical engineering.展开更多
文摘The antiplane shear problems of periodical rigid line inclusions between dissimilar anisotropic materials are dealt with. By using the complex variable method, the closed form solutions are obtained. The stress distribution in the immediate vicinity of the rigid line is examined. The corresponding formulation between dissimilar isotropic materials and in homogeneous anisotropic medium can be derived from the special cases of those in the present paper, and the limit conditions are in agreement with the previously known results.
基金supported by the Science Fund of State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body (60870005)the National Natural Science Foundation of China (10872065)
文摘This paper deals with the electro-elastic coupling interaction between a piezoelectric screw dislocation which is located inside the elliptical inhomogeneity and an electrically conductive confocal rigid line under remote anti-plane shear stresses and in-plane electrical loads in piezoelectric composite material. The analytical-functions of the complex potentials, stress fields and the image force acting on the piezoelectric screw dislocation are obtained based on the principle of conformal mapping, the method of series expansion, the technical of analytic continuation and the analysis of singularity of complex potentials. The rigid line and the piezoelectric material property combinations upon the image force and the equilibrium position of the dislocation are discussed in detail by the numerical computation.
文摘Based on the cylindrical cavity expansion theory, a plastic-damage-elastic model is proposed for the penetration problem of geo-material. In the model, the unified strength criterion (Yu, 1991) is adopted as the failure criterion. The distributions of the radial stress and velocity are analyzed. According to the Newton's second law, a series results of the final penetration depth and the impedance load are obtained to different parameter b, when a rigid projectile normally impacts and penetrates a semi-infinite geo-material target with an impact velocity of 300-1200 m/s. By comparing with the test data available, it appears that the method can be used in analyzing the final depth and the impedance load of a rigid projectile penetrating into a semi-infinite target with different impact velocities.
文摘The ratios of depth of penetration (DOP) of different targets under the same penetration condition was investigated according to the dimensionless formula of DOP of different targets penetrated by a non-deformable projectile.Results show that various targets may be equivalent to each other.The applicable range of the equivalence and the feasibility of targets substitution were discussed by integrating the available test data.
基金Project supported by the National Natural Science Foundation of China
文摘By using the energy criterion in [3], the impact torsional buckling for the rigid plastic cylindrical shell is studied. The linear dynamic torsional buckling equations for the rigid plastic shell is drived, and the critical impact velocity is given.
文摘采用硬脂酰氯对三聚氰胺进行酰胺化改性得到十七烷基链修饰的三聚氰胺衍生物(酰胺化三聚氰胺),进而与甲醛、混合醇等进行加成、缩聚反应,制备了酰胺化密胺树脂,并将其制备成膜及硬泡材料,采用FTIR、NMR、TG、SEM及EDS对酰胺化三聚氰胺、酰胺化密胺树脂以及膜层与硬泡材料进行了表征。结果表明,疏水烷基长链的引入使酰胺化三聚氰胺与水的接触角由改性前的0°升至133.5°以上;随着三聚氰胺酰胺化程度的提高,酰胺化密胺树脂的水容忍点温度逐渐降低,树脂黏度逐渐增大,不溶性颗粒逐渐增多增大。相对于常规密胺树脂制备的材料,酰胺化密胺树脂(无论是膜层材料还是硬泡材料)力学性能均未出现明显降低,样块抗压强度可达39.5 MPa,硬泡材料弯曲强度可达345.8 kPa,压缩强度可达315 k Pa,同时表现出优异的抗水和疏水效果,样块24h吸水率仅为1.1%,硬泡材料的体积吸水率降低至2.0%,膜层水接触角提高至107.5°,抗污染性能得到改善。
基金the National Natural Science Foundation of China(Grant No.41807223)the Fundamental Research Funds for the Central Universities(Grant No.B210202096)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDA 23090202).
文摘In this paper,the application of Abaqus-based particle finite element method(PFEM)is extended from static to dynamic large deformation.The PFEM is based on periodic mesh regeneration with Delaunay triangulation to avoid mesh distortion.Additional mesh smoothing and boundary node smoothing techniques are incorporated to improve the mesh quality and solution accuracy.The field variables are mapped from the old to the new mesh using the closest point projection method to minimize the mapping error.The procedures of the proposed Abaqus-based dynamic PFEM(Abaqus-DPFEM)analysis and its implementation in Abaqus are detailed.The accuracy and robustness of the proposed approach are examined via four illustrative numerical examples.The numerical results show a satisfactory agreement with published results and further confirm the applicability of the Abaqus-DPFEM to solving dynamic large-deformation problems in geotechnical engineering.
