Strong Coupling Algorithm And Analysis Of A Inner Flow Field-curved Boundary Cylindrical Shell-rigid Body System

Curved boundary cylindrical shell-rigid body system has been widely applied in many fields such as aerospace engineering, national defense, mechanical engineering and electric power industry, due to its light weight, high strength and the property of expanding with large deformation but small strain. Previous research on this system focused on investigating the independent components of the system, or studying the whole system by adopting simplified computational model(e.g., by ignoring the corrugated shell). In this thesis, a strong coupling algorithm is presented to study the ineraction of the curved boundary cylindrical shell-rigid body system and the internal flow field, the kinematics of the rigid bodies and the expansion properties of the corrugated shell.The thesis first integrate the theory of nonlinear deformation of shells, two-phases theory of inner flow field and the kinematic analysis of the rigid bodies outside the curved boundary cylindrical shell, build a complete theory for this inner flow field-corrugated shell-rigid body system, and then implement strong coupling algorithm between curved boundary cylindrical shell and inner flow field by Newton-Raphson iterative method, which is stable and has the merit of coverging independently of the solving sequence of subsystems.Based on the above theory and solving algorithm for the system, the thesis further consider the possibility of replacing the complex two-phase flow theory with poor universality by fluid theory. The results show that the difference caused by this replacement can be ignored when the particle concentration in the flow filed is low; therefore, the flow theory can be adopted to save computational costs with negligible loss of accuracy. In addition, an equivalent method of using circular boundary to replace the complex boundary condition of flow domain has been investigated by studying the equivalent parameter in that method.The strong coupling algorithm presented for the inner flow field-curved boundary cylindrical shell-rigid body system, which has a good accuracy and reliable convergence, can provide a solid foundation for future investigations on the dynamic characteristics of the system.