4 results about "Shell theory" patented technology

The present application relates to a kind of large section deep soft rock tunnel combined support system and construction method, the present application is combined with elastic shell theory and equivalent section method, a steel arch frame-grating combined support mode suitable for deep large section soft rock tunnel is proposed, the support rigidity of simply using steel arch frame or grid steel frame is overcome or supported, the disadvantage of lower in long-term large deformation unfavorable surrounding rock stability and deformation control, solve the problem that the stress of existing support structure is larger, the self-bearing capacity of surrounding rock cannot be fully exerted, cause material waste is serious, the safety factor of support structure is low, difficult to guarantee the stability of tunnel, and provide a simple and practical construction method for tunnel excavation and support.

The application discloses a rotating wing type variable cross-section crack blade fault characterization and dynamics analysis method, belongs to the field of rotating wing type variable cross-section crack blade fault characterization and dynamics analysis, and comprises the following steps: according to the finite element theory and the plate shell theory, based on centrifugal rigidification, rotation softening and the coriolis force effect, a motion differential equation of the wing type variable cross-section blade is established; according to the motion differential equation of the wing type variable cross-section blade, based on the crack existing in the blade, the breathing effect between crack surfaces is equivalent by adopting a spring unit, a rotating wing type variable cross-section crack blade dynamics model containing the breathing effect is established, vibration energy theory is adopted to convert the displacement response into energy response, based on the rotating crack blade crack diagnosis index with the breathing effect, the crack characteristics of the blade are obtained, and the application is more effective and accurate in analyzing the rotating crack blade fault, and can provide theoretical guidance for detection and diagnosis of the rotating crack blade.

This invention relates to a method for analyzing the turning stability of a truncated cone thin-walled structure, belonging to the field of machining technology. First, based on shell theory, a vibration differential equation considering the rotational effects of centrifugal force, Coriolis force, and initial ring tension is established. The cantilever-free boundary condition expression is substituted into the equation, and the natural frequencies and modal parameters of the rotating truncated cone thin-walled structure are obtained by solving the equation using a generalized differential quadrature method. Then, considering the vibration of the tool along the generatrix of the shell and the vibration of the workpiece perpendicular to the generatrix, a flexible workpiece-tool coupled turning dynamics model is established. This model simultaneously considers the influence of shell rotation and multi-mode vibration, achieving a more accurate prediction of the turning process of the truncated cone thin-walled structure.

The application discloses a lofted curved surface shell structure optimization design method based on mixed sensitivity. The method takes the offset amount of the initial section curve control vertex coordinates as the design variable, sorts the section curve, unifies the parameter direction, inserts nodes and the like, and generates an initial lofted curved surface through lofting. The initial lofted curved surface is refined, and a refined lofted curved surface model for structure analysis is constructed. Structural response analysis is carried out based on the equal geometry Reissner-Mindlin shell theory. The derivative of the objective function to the design variable is decomposed into the accompanying analytical sensitivity term and the finite difference sensitivity term. Under the geometric constraint, the minimum flexibility is taken as the optimization target for iteration, and the optimized section curve, the lofted curved surface and the corresponding structural response are output. The application can retain the design intention driven by the section characteristic curve, reduce the design space dimension, improve the realizability of the sensitivity analysis and the optimization efficiency, and realize the high-quality and efficient optimization design of the shell structure.