Dynamics Of Multi-body Systems With Flexible Beams And Flexible Plates Based On Floating Coordinates And Absolute Coordinates

The dynamic problems of multi-body systems with flexible beams and plates are studied in this dissertation.In the project,the subsystems of complex mechanic structures can be simplified into flexible beam components or plate components,so it is important to work out the dynamics problems of flexible beams and plates.In the flexible multi-body systems dynamics,the traditional zero order model is applied under condition of small deformation in the structure dynamics,and this model ignores the influences of the axial inertia force.When the speed of the system movement is relatively high,the results of the zero order model is divergent.Therefore,scholars pay more attention to rigid-flexible coupling problems,and a more accurate model considered the influence of inertia force which can be called the first order model is proposed.Based on the absolute node coordinate formulation,more correct models are proposed to solve the large deformation problems of the flexible beams and plates in this dissertation.The results of these study show that the proposed models can be used to deformation problems of flexible beams and plates.solve the largeIn this dissertation,the specific research works and achievements are:(1)The rigid-flexible coupled dynamic models of flexible rectangular plates,variable thickness plate and trapezoidal plate with a wide range motion are established.Here the floating coordinate method is used,and reminds the effect of axial inertia force which the traditional modeling methods ignore in the fixed-axis rotation.A rigid-flexible coupled model of flexible plate with 3d space motion is established.By comparing with the results obtained by using the software MSC.ADAMS,it is proved that the first order approximate model should be used in the high speed problems.(2)The first order model of a composite plate under large overall motion is established based on the classical laminated plate theory.And the influence of the temperature on composite material plate is also considered.The dynamic characteristics of composite material plates with high speed rotation condition are studied,and the results prove that the first order model should be used in considering the composite plate with high speed.And then the effects of the parameters(the layer angle and the layer number)and temperature of a plate on its dynamic performance are examined.The dynamic modeling and simulation of ride comfort of vehicle are studied by using the Recurdyn modeling method,and the simulations of the vehicle's running status under different road conditions are computed in this dissertation.Then the Recurdyn theaccuracy of the model and the correctness of the simulation is illustrated.(3)The dynamic models of the two-dimensional and three-dimensional beams systems with large deformation are established by using the absolute node coordinate formulation.Dynamic software is compiled,and the dynamic examples of the flexible beams with large deformations are simulated.The results are taken to compare with the results of software ADAMS and literatrues.Results show that the propose model can be well used in solving the dynamic problems of the flexible beams,and software ADAMS has limitations in solving the large deformation problems.And by the absolute node coordinates method,the frequency of rotating flexible beam are analyzed.(4)With the introduction of the absolute node coordinate formulation with damping,several kinds of movements of the two-dimensional flexible beam under the different damping coefficients are given,and the important impact of the damping in the process of expansion is analyzed.The winding rib material properties are simulated by using the absolute node coordinate formulation.(5)By using the absolute node coordinate formulation,the dynamic problems of the flexible plates with large deformation are solved and simulated.The simulation results are compared with the results of the literatrues.Results show that the proposed model can be well used in solving the dynamic problems of the flexible plates.(6)Based on the absolute node coordinate formulation,the elastic-plastic model is studied,and the failure models of the flexible beam and flexible plate,plate elastic-plastic model are simulated.The feasibility of the presented approach is verified by the examples.(7)The dynamic simulations of aviation engine are studied.The dynamic simulations of the different release and shooting locations are carried out for the inclusive of the aviation engine.In order to provide the reference for casing design and strength analysis,the target shooting experiments contain a composite plate model,a stiffened plate model,and the influence of different the parts on the casing inclusiveness.