5 results about "Tangential stiffness" patented technology

This invention discloses a finite element simulation method and system for a suspension bridge tower top saddle. The method includes: collecting multiple types of parameters; iteratively solving for tangential and normal forces based on an initial tangential stiffness matrix; calculating the actual contact friction coefficient based on the coupling relationship between temperature and contact normal pressure; calculating a tangential correction coefficient based on the actual contact friction coefficient, the ratio of tangential to normal forces, and the linkage relationship between the saddle geometric parameters; dynamically adjusting the tangential stiffness matrix based on the correction coefficient, the saddle pre-offset, and the synergistic relationship between cable stress; constructing a finite element model and simulating it; and iteratively optimizing until convergence. The system corresponds to the modules described above. This invention optimizes simulation accuracy through multi-factor coupling and linkage, adapting to complex working conditions and providing reliable support for the design and construction of suspension bridges.

The present application relates to the technical field of simulation calculation, and particularly relates to a simulation calculation method of a U-shaped outer steel-concrete composite beam, which comprises the following steps: S1: establishing a double-parameter interface equivalent stiffness model of a U-shaped outer steel-concrete composite beam with post-anchoring bolts; S2: solving and response extraction; S3: calculating a slip residual error and interface energy, and judging whether the target slip characteristic is met according to a double-convergence criterion; if the convergence requirement is not met, the interface parameters are updated adaptively and the step S2 is repeated; if the convergence criterion is met, the converged interface stiffness parameters are used for the design feedback of post-anchoring bolt pre-tightening force selection, bolt spacing and joint construction. In the present application, the double-parameter interface equivalent stiffness model and the adaptive algorithm based on the slip residual error make the interface normal stiffness and the interface tangential stiffness automatically converge to the target slip characteristic, avoid manual parameter adjustment, improve the simulation stability and calculation accuracy, and realize the integration of the composite beam construction design and simulation analysis.

The application discloses a fin effect clamp jaw force-deformation theoretical modeling method based on a co-rotation model, decomposes a fin effect clamp jaw structure into a plurality of beam units, decouples local deformation and rigid body motion of each beam unit through co-rotation theoretical modeling, respectively establishes an axial deformation model and a rotational deformation model, and introduces an effective length correction coefficient to consider the influence of physical hinge connection; a tangent stiffness matrix of the beam unit is constructed and assembled into a global tangent stiffness matrix; a Newton-Raphson iteration method is used to realize force balance solving of a load increment step, and a global force-displacement relationship is constructed; and through adjustment of a global node force vector, various planar load scenarios such as single-point, multi-point and distributed load are adapted. The application breaks through the limitation of small deformation assumption, accurately represents large deformation behavior, improves the calculation efficiency by hundreds of times compared with finite elements, controls the average error within 6%, can quantize the influence of structural parameters such as connection type, beam quantity, beam inclination angle and top angle, and provides a theoretical basis for fin effect clamp jaw engineering design.

This invention provides a nonlinear finite element method for determining the critical stability section of an underground cavern. Based on rock mechanics tests in actual engineering, the rock mass strain softening parameters are determined. A secondary development of the rock mass constitutive model is performed based on these parameters. An initial nonlinear finite element model for solving the critical stability section of the underground cavern is constructed based on the secondary developed rock mass constitutive model. The nonlinear finite element model is solved to obtain the overall tangential stiffness of the model at the calculation step. Based on the overall tangential stiffness, the minimum eigenvalue of the overall tangential stiffness matrix is ​​calculated. Based on the minimum eigenvalue, the critical stability section of the underground cavern is determined. This invention directly and quantitatively reflects the essential characteristics of stiffness loss and bearing capacity reduction in the entire cavern structure system after considering complex nonlinear deformation paths, including strain softening, thereby accurately capturing the critical instability moment and potential instability sections.

The invention discloses a diagnosis method for a post-peak unloading key state point of a thin-wall structure, and particularly relates to the field of thin-wall structure performance analysis. Comprising the following steps: acquiring a displacement sequence, a load sequence, an external work sequence and an elastic strain energy sequence of a composite material with a thin-wall structure in a loading process; according to the difference value of the external work sequence and the elastic strain energy sequence, accumulated dissipated energy of each displacement point is determined; according to the accumulated dissipated energy and the displacement sequence, the dissipated energy change rate of each displacement point is determined; determining a tangent stiffness spectrum of each displacement point according to the load sequence and the displacement sequence to obtain a tangent stiffness spectrum sequence; acquiring a displacement point corresponding to the maximum load as a peak load point; determining a damage starting point in the displacement sequence according to the dissipated energy change rate; and determining an unloading inflection point in the displacement sequence according to the tangent stiffness spectrum sequence. Based on the method, the reliability of the diagnosis conclusion can be improved.