Based on Donnell's shallow shell equation, a new method is given in this paper to analyze theoretical solutions of stress concentrations about cylindrical shells with large openings. With the method of complex var...Based on Donnell's shallow shell equation, a new method is given in this paper to analyze theoretical solutions of stress concentrations about cylindrical shells with large openings. With the method of complex variable function, a series' of conformal mapping functions are obtained from different cutouts' boundary curves in the developed plane of a cylindrical shell to the unit circle. And, the general expressions for the equations of a cylindrical shell, including the solutions of stress concentrations meeting the boundary conditions of the large openings' edges, are given in the mapping plane. Furthermore, by applying the orthogonal function expansion technique, the problem can be summarized into the solution of infinite algebraic equation series. Finally, numerical results are obtained for stress concentration factors at the cutout's edge with various opening's ratios and different loading conditions. This new method, at the same time, gives a possibility to the research of cylindrical shells with large non-circular openings or with nozzles.展开更多
Discarding any assumption about displacement models and stress distribution andintroducing δ-function into the present study, we established the state equation for thecontinuous orthotropic open cylindrical shells. A...Discarding any assumption about displacement models and stress distribution andintroducing δ-function into the present study, we established the state equation for thecontinuous orthotropic open cylindrical shells. An thentical exocl solution is presentedfor the statics of thin. moderately thick and thick laminated continuous openrylindrical shells. Numerical results are obtained and compared with those calculatedusing SAP5.展开更多
Stress concentrations about thin cylindrical shells with small openings are reconsidered front a nerv angle. There is a sort of special internal relation between theoretical solutions about cylindrical shells,vith lar...Stress concentrations about thin cylindrical shells with small openings are reconsidered front a nerv angle. There is a sort of special internal relation between theoretical solutions about cylindrical shells,vith large openings and one,with small openings. Using this relation, the extent of applying the theory about small openings to engineering practice is estimated again, thus an idea of how to use this theory and a nerv appraisal of the application of theoretical solutions about cylindrical shells with small openings to engineering practice are given.展开更多
Projective-iterative version of finite element method has developed for numerical simulation of the stress-strain state of nonhomogeneous shell-type structures (shells with openings). Plastic deformation of the materi...Projective-iterative version of finite element method has developed for numerical simulation of the stress-strain state of nonhomogeneous shell-type structures (shells with openings). Plastic deformation of the material is taken into account when using the method of elastic solutions that reduce the solution of elastoplastic problems to solution of elastic problems. Developed PIV’s significant savings of computer calculation has been compared with the calculation on a fine mesh of traditional FEM. Designed scheme allows analysis of the mutual influence of openings. Analysis of the transformation zone of plastic deformation is developed. For definiteness, the cylindrical shell structures with several rectangular openings are considered.展开更多
钛合金制深海载人潜水器耐压球壳属中厚度壳结构,上面设有人孔、观察窗等多个开孔,加工建造过程中又会产生初始缺陷,因此,这类结构的极限强度乃是设计者所必须关注的问题。本文利用AN SY S软件对上述有开孔耐压球壳的极限强度进行非线...钛合金制深海载人潜水器耐压球壳属中厚度壳结构,上面设有人孔、观察窗等多个开孔,加工建造过程中又会产生初始缺陷,因此,这类结构的极限强度乃是设计者所必须关注的问题。本文利用AN SY S软件对上述有开孔耐压球壳的极限强度进行非线性有限元分析,计算了局部缺陷范围及幅值的变化对壳体极限强度的影响。计算结果表明,有围壁加强的开孔耐压球壳与无开孔耐压球壳的极限强度相差不大。展开更多
文摘Based on Donnell's shallow shell equation, a new method is given in this paper to analyze theoretical solutions of stress concentrations about cylindrical shells with large openings. With the method of complex variable function, a series' of conformal mapping functions are obtained from different cutouts' boundary curves in the developed plane of a cylindrical shell to the unit circle. And, the general expressions for the equations of a cylindrical shell, including the solutions of stress concentrations meeting the boundary conditions of the large openings' edges, are given in the mapping plane. Furthermore, by applying the orthogonal function expansion technique, the problem can be summarized into the solution of infinite algebraic equation series. Finally, numerical results are obtained for stress concentration factors at the cutout's edge with various opening's ratios and different loading conditions. This new method, at the same time, gives a possibility to the research of cylindrical shells with large non-circular openings or with nozzles.
文摘Discarding any assumption about displacement models and stress distribution andintroducing δ-function into the present study, we established the state equation for thecontinuous orthotropic open cylindrical shells. An thentical exocl solution is presentedfor the statics of thin. moderately thick and thick laminated continuous openrylindrical shells. Numerical results are obtained and compared with those calculatedusing SAP5.
文摘Stress concentrations about thin cylindrical shells with small openings are reconsidered front a nerv angle. There is a sort of special internal relation between theoretical solutions about cylindrical shells,vith large openings and one,with small openings. Using this relation, the extent of applying the theory about small openings to engineering practice is estimated again, thus an idea of how to use this theory and a nerv appraisal of the application of theoretical solutions about cylindrical shells with small openings to engineering practice are given.
文摘Projective-iterative version of finite element method has developed for numerical simulation of the stress-strain state of nonhomogeneous shell-type structures (shells with openings). Plastic deformation of the material is taken into account when using the method of elastic solutions that reduce the solution of elastoplastic problems to solution of elastic problems. Developed PIV’s significant savings of computer calculation has been compared with the calculation on a fine mesh of traditional FEM. Designed scheme allows analysis of the mutual influence of openings. Analysis of the transformation zone of plastic deformation is developed. For definiteness, the cylindrical shell structures with several rectangular openings are considered.
文摘钛合金制深海载人潜水器耐压球壳属中厚度壳结构,上面设有人孔、观察窗等多个开孔,加工建造过程中又会产生初始缺陷,因此,这类结构的极限强度乃是设计者所必须关注的问题。本文利用AN SY S软件对上述有开孔耐压球壳的极限强度进行非线性有限元分析,计算了局部缺陷范围及幅值的变化对壳体极限强度的影响。计算结果表明,有围壁加强的开孔耐压球壳与无开孔耐压球壳的极限强度相差不大。
