Application Of Dynamic Model Validation Using RAT Moment Function In Engineering

Model validation is a process to obtain a reliable simulation model,the process includes the acquisition of reference data?verification?correlation analysis and model updating.The obtained simulation model can be further used to predict the dynamic response of the structure.There are several problems in traditional model validation:(1)The correlation analysis can not identify double modes.(2)If mode shape data is directly used in model updating,it will bring a large amount of calculation,and the updating is hard to converge.The moment function can compress mode shape data and improve the efficiency of model updating.The moment function with rotation invariance can identify double modes.The recently proposed 3-D radial axial tchebichef moment(RAT moment)is based on cylindrical coordinate system.It can only be applied to cylindrical structures instead of curved structures.This paper mainly studies the RAT moment to describe the mode shape of 3-D curved structures,and expands the application range of the RAT moment.The main research as follow:(1)An integration method is proposed.The curved structure is regarded as being composed of multiple cylindrical structures.the process of establishing mode shape image was optimized to achieve the purpose of describing mode shape of arbitrary 3D curved structure using the RAT moment.This method has wide universality.(2)The ability to denoising and the ability to identify additional mass positions of RAT moment was studied.It provides ideas to identify structural damage by RAT moment.Denoising applications of RAT moment can reduce the impact of noise during the experiment.(3)Moment functions were used to deal with axisymmetric structures,and most components in engineering were asymmetric.Local asymmetric structure will cause the separation of double modes.Take a case with asymmetrical holes as an example.Perform modal test and create a simplified model without holes,the correlation analysis and model updating were performed based on the RAT moment.The results show the frequency errors and correlation are significantly improved.(4)Take a curved asymmetric case as an example,reference model and simplified model were created,the correlation analysis and model updating were performed based on the RAT moments.The results show the frequency errors and the correlation are significantly improved.The feasibility of applying the RAT moments to the model updating of asymmetric structural with variable cross section is verified.