Research On Model Updating And Thermal Modal Uncertainty Of Typical Structure Of Hypersonic Vehicle

Finite element analysis has occupied an important position in the field of engineering with high analysis speed,short design cycle and low cost,and its accuracy requirement also develops rapidly with the development of science and technology.To improve the accuracy of the finite element model,it has to deal with structural or system uncertainty.In order to improve the modeling accuracy of the typical structure of hypersonic vehicle in thermal environment,this paper focuses on the topic of thermal modal uncertainty of two typical structures of hypersonic vehicle,using the finite element model updating method and the interval analysis method to study the methods for increasing accuracy of finite element model and uncertainty transfer law in heat environment.The finite element model updating method,which is widely used in engineering field because of its effectiveness and practicability,is a popular research topic.Ignoring the uncertainties in the experiment and assumed the test result is accurate,the model updating method is used as a method to deal with the uncertainty.It corrects the finite element model with the test result,so that the finite element model is improved.This paper summarizes the general process of the modal-based parametric updating method.From this process,we can see that the initial finite element model is very important for the model updating.Therefore,the composite laminated plate model and composite sandwich plate model are established by different methods and updated according to the general process summarized before.As a mainstream uncertainty analysis method,interval analysis method has the characteristics of low data dependency.In another word,when data were insufficient,interval analysis still have good performance.It has been several decades from the interval analysis method is established and used to study the uncertainties of the natural frequencies.However,the research focuses on the method for solving the standard interval eigenvalue problem and the generalized interval eigenvalue problem.There is little work studing uncertainties of natural frequency,and no work studying uncertainties of thermal modal analysis.Using the parameter vertex solution theorem,the Chen Suhuan method and the Modares method to study the transfer law of uncertainties of the composite laminated plate and composite sandwich plate under the thermal environment,the uncertain transfer law in the thermal environment is obtained.In view of traditional interval analysis methods based on simple structure such as bar structure and so on,this paper proposes an improved method to improve the computational efficiency of the Modares method aimed at plate structure.The improved method can also directly determine natural frequency uncertainties by the parameters uncertainty.By combining the interval method with the model updating method,a method is proposed to determine the boundary of the parameters by the test result and the finite element model,which gives a reference for choosing updating parameters boundaries.The work of this paper mainly studies the uncertainties in the thermal environment,and hopes to make some contribution to the accurate modeling work in the thermal environment.