| Absolute Nodal Coordinate Formulation(ANCF)has been adopted extensively for multibody dynamic analysis since its proposal,because the method is suitable for decribing the large scale deformation and rotation of flexible body.It is recommonded in engineering pratice,especially for modeling areospace structure and vehicle system.The concept of ANCF could be seen as an further integration of the theory of multibody system dynamics and finite element method,and its theory basis lead to a serise of advantages for solving multibody dynamic problems,including the non-incremental dynamic equations,constant mass matrix,automaticaly taking the gyroscopic effect into consideration and zero strain for arbitary rigid body motion.Which make it an effcient way for capturing the related nonliner behavior of multibody system.ANCF has also been introduced for analysing the thermo-mechanical coupled system recently.However,the prevalent inconsistence of meshes and incompatible accuracy can hardly be avoided in the existing formulation.Besides,the detailed coulping mechanism of multidisciplinary coulped problem is still rough and inadequate.Therefore,this dessertation attempted on constructing the theory basis and expanding its application of ANCF in thermo-mechanical coupling problem.It is within the scope of study to deep in discussion of rigid body discription and rigid-flexible coupling,integrated pattern for modeling displacement field and temperature field,the implementation of coupling effects origined from the generalized energy description,as well as the complex boundary condition,multi coupling mechanism and the governing equations of thermo-mechanical coupled system.This study is aimed at establishing the rigid-flexible-thermal coupled modeling and analysing scheme based on the concept of ANCF and attempting the analysis for coupling behavior of typical objects in engineering practice by utilizing the construted strategy.For addressing the rigid-flexible coupled modeling issue of multi body system,the rigid-flexible coupled modeling scheme which based on ANCF is given,with the aid of proposed ANCF element and rigid body description.As for the needed element,the completed form of elastic force is proposed for ANCF thin plate element in this research,which makes it capable for describing the initially curved structure correctly via continuum mechanics pattern.Furthermore,the generalized viscous force has been derived based on the constitutive relationship of Kelvin-Voigt model and fractional derivative model.Integrated with the rigid body depicted by ANCF reference node or revolved cross section about rotary axis,the rigid-flexible coupled modeling could be achieved.For addressing the throny problem caused by nonmatching meshes in existing model,the method for flexible-thermal coupled modeling based on the unified description is presented under the frame of ANCF.Drawing reference from the concept of displacement formulation of ANCF,the high order interpolation pattern untilizing gradients has been proposed for describing temperature field,hence the integrated description of the two physical fields via unified hybrid mesh could be achieved.Therefore,the problem of inconsistence of meshes and incompatible accuracy could be avoided because of the unified description of temperature field and displacement field,utilizing the construted thermal integrated ANCF element.Since the existing research of coupling effects is insufficient and nonquantitative,the bidirectional coupling effects between the displacement field and temperature filed are derived quantitatively,which based on the generalized energy conservation and transformation relationship depicted by the principle of the thermodynamic laws.As for the constructed governing equations of two physical fields described in unified pattern,the corresponding solver has been provided.The presented flexible-thermal coupled modeling scheme has been verified by setting several representative numeriacl examples.As for the complex thermo-mechanical coupling behavior exposed in engineering practice,the modeling and analysis scheme for rigid-flexible-thermal coupled multi body system has been proposed,considering the multi thermo-mechanical coupling effects and thermal boundary conditions.Based on the presented method of rigid-flexible coupled modeling and flexible-thermal coupled modeling,the rigid-flexible-thermal coupled governing equations has been derived with the implementation of complex coupling effects and thermal boundary conditions.By adopting the presented solving scheme,the deployment process and feasibility of proposed rigid-flexible-thermal coupled analysis procedure is demonstrated for modeling transient behavior of multi body system,and the typical objects of vehicle system and spacecraft system are chosen as examples.Utilizing the proposed procedure of rigid-flexible-thermal coupled modeling and analysis,the dynamic modeling of tire system has been attempted,since it is a typical object which possesses several representative thermo-mechanical coupled features of energineering practice.Based on the presented completed formulation of elatic consititutive and viscosity model for ANCF thin plate element,the rigid-flexible coupled tire model is established with the aid of rigid rim depicted by ANCF reference node.The challenging tire-ground contact is implemented by the proposed direct calculation strategy for contact patch referred from geometric intersection,and the surface integral method within complex region is introduced for integrating contact pressure efficiently and accuratly.Furthermore,the detailed rigid-flexible-thermal coupled model for tire system could be achieved,taking the multi dynamical heat generation effects and complex thermal boundary into consideration.With the aid of the presented tire model,the complex coupling behavior involving multi physical field could be analysed,demonstrating the feasibility of the proposed method for rigid-flexible-thermal coupled modeling and analysis. |
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