The line-spring model of surface cracks is applied to the fully plastic analysis of corner cracks at a hole in a plate. The generalized fully plastic constitutive relations and the fully plastic J-integral, as well as...The line-spring model of surface cracks is applied to the fully plastic analysis of corner cracks at a hole in a plate. The generalized fully plastic constitutive relations and the fully plastic J-integral, as well as its coefficients in polynomial expressions are given. The model obtained is incorporated into a finite element program. The corner cracks at a hole in a plate subjected pure tensions are calculated by the present model. The fully plastic J-integral is then estimated. The results obtained show that the line-spring model is effective for the analysis of corner cracks. The influence of the crack depth and the hardening exponent on the fully plastic J-integral is also discussed.展开更多
A new method based on a modified line-spring model is developed for evaluating the natural frequencies of vibration of a cracked beam.This model in conjunction with the Euler-Bernoulli beam theory,modal analysis and l...A new method based on a modified line-spring model is developed for evaluating the natural frequencies of vibration of a cracked beam.This model in conjunction with the Euler-Bernoulli beam theory,modal analysis and linear elastic fracture mechanics is applied to obtain an approximate characteristic equation of a cracked hinged-hinged beam.By solving this equation the natural frequencies are determined for different crack lengths in different positions.The results show good agreement with the solutions through finite element analysis.The present method may be extended to analyze other cracked complicated structures with various boundary conditions.展开更多
The authors have developed a new line-spring boundary element method in the present paper, which combines the advantage of the line-spring model with that of the boundary element method. This method reduces the three-...The authors have developed a new line-spring boundary element method in the present paper, which combines the advantage of the line-spring model with that of the boundary element method. This method reduces the three-dimension problem of the surface cracks into a quasi-one-dimension problem and can be used to analyze the surface cracked plate under various loading conditions. In this paper theoretical analyses and numerical verifications are carried out. The calculated results are reported, which indicate that the present method is efficient and can be used to analyze the surface crack problem on a personal computer.展开更多
In this paper a method based on a line-spring model was proposed to analyze approximately vibration responses of cracked beams. The method is conjunction with the Euler-Bernoulli beam theory, modal analysis and fractu...In this paper a method based on a line-spring model was proposed to analyze approximately vibration responses of cracked beams. The method is conjunction with the Euler-Bernoulli beam theory, modal analysis and fracture mechanics principle was applied to derive a characteristic equation for the cracked beam vibration. As application examples, natural frequency responses for a cracked hinged-hinged beam and a cracked cantilever beam were examined. It was shown that the present solutions obtained are quite in agreement with the solutions or experimental results in available references.展开更多
The highlight line model is a powerful tool in assessing the quality of a surface. It increases the flexibility of an interactive design environment. In this paper, a method to generate a highlight line model on an ar...The highlight line model is a powerful tool in assessing the quality of a surface. It increases the flexibility of an interactive design environment. In this paper, a method to generate a highlight line model on an arbitrary triangular mesh is presented. Based on the highlight line model, a technique to remove local shape irregularities of a triangular mesh is then presented. The shape modification is done by solving a minimization problem and performing an iterative procedure. The new technique improves not only the shape quality of the mesh surface, but also the shape of the highlight line model. It provides an intuitive and yet suitable method for locally optimizing the shape of a triangular mesh.展开更多
基金The project is supported by Provincial Natural Science Foundation of Sichuan.
文摘The line-spring model of surface cracks is applied to the fully plastic analysis of corner cracks at a hole in a plate. The generalized fully plastic constitutive relations and the fully plastic J-integral, as well as its coefficients in polynomial expressions are given. The model obtained is incorporated into a finite element program. The corner cracks at a hole in a plate subjected pure tensions are calculated by the present model. The fully plastic J-integral is then estimated. The results obtained show that the line-spring model is effective for the analysis of corner cracks. The influence of the crack depth and the hardening exponent on the fully plastic J-integral is also discussed.
文摘A new method based on a modified line-spring model is developed for evaluating the natural frequencies of vibration of a cracked beam.This model in conjunction with the Euler-Bernoulli beam theory,modal analysis and linear elastic fracture mechanics is applied to obtain an approximate characteristic equation of a cracked hinged-hinged beam.By solving this equation the natural frequencies are determined for different crack lengths in different positions.The results show good agreement with the solutions through finite element analysis.The present method may be extended to analyze other cracked complicated structures with various boundary conditions.
文摘The authors have developed a new line-spring boundary element method in the present paper, which combines the advantage of the line-spring model with that of the boundary element method. This method reduces the three-dimension problem of the surface cracks into a quasi-one-dimension problem and can be used to analyze the surface cracked plate under various loading conditions. In this paper theoretical analyses and numerical verifications are carried out. The calculated results are reported, which indicate that the present method is efficient and can be used to analyze the surface crack problem on a personal computer.
文摘In this paper a method based on a line-spring model was proposed to analyze approximately vibration responses of cracked beams. The method is conjunction with the Euler-Bernoulli beam theory, modal analysis and fracture mechanics principle was applied to derive a characteristic equation for the cracked beam vibration. As application examples, natural frequency responses for a cracked hinged-hinged beam and a cracked cantilever beam were examined. It was shown that the present solutions obtained are quite in agreement with the solutions or experimental results in available references.
基金Supported by National Science Foundation of China (Grant Nos. 60533070, 60625202)National Basic Research Program of China (Grant No. 2004CB719400)+3 种基金National High-Tech Research & Development Program of China (Grant No. 2007AA040401)Fok Ying Tung Education Foundation (Grant No. 111070)National Science Foundation of USA (Grant Nos. DMI-0422126, DMS-0310645)Kentucky Science & Technology Corporation (Grant No. COMM-Fund-712)
文摘The highlight line model is a powerful tool in assessing the quality of a surface. It increases the flexibility of an interactive design environment. In this paper, a method to generate a highlight line model on an arbitrary triangular mesh is presented. Based on the highlight line model, a technique to remove local shape irregularities of a triangular mesh is then presented. The shape modification is done by solving a minimization problem and performing an iterative procedure. The new technique improves not only the shape quality of the mesh surface, but also the shape of the highlight line model. It provides an intuitive and yet suitable method for locally optimizing the shape of a triangular mesh.
