Research On Train-track Mechanical Characteristics Analysis Test Platform Based On Similitude Theory

China’s high-speed railway is developing towards a running speed of more than400km/h.In order to ensure the safety,stability and comfort of high-speed train,the test of train and track is essential.On-site test has huge difficulties in time and economic cost.A train-track mechanical characteristic analysis test platform based on similarity theory is built.And the use of model test instead of prototype test can avoid the problem of on-site test.In this thesis,based on rigid-flexible coupling method,a train-track rigidflexible coupling model is established,which is used as prototype model to establish complete similarity model.The correction method for the distortion similarity model is proposed.The corrected distortion similarity model can accurately correspond to the prototype results in both static characteristic and dynamic response.And the applicability of the materials of scaled rail is studied when different mechanical indexes are the target physical quantities.The research provides theoretical basis and technical support for the construction of train-track test platform.The specific research contents in the thesis are as follows:(1)Based on the multi-body dynamics and finite element theory,the train multibody model is established in SIMPACK,which is considered as rigid body.In ABAQUS,the CRTSII slab ballastless track finite element model is established.Using the Flextrack module,the track finite element model is imported into SIMPACK as flexible bodies,and the train-track rigid-flexible coupling model is established.The accuracy of rigid-flexible coupling model is verified by using the high-speed railway ballastless track spectrum superimposed with the Sato spectrum as the excitation.(2)Taking geometric size,acceleration and density as the basic physical quantities,the dimensional analysis method is used to deduce the similarity coefficients of other physical quantities according to the similarity coefficients of the basic physical quantities,and then the complete similarity model with all parameters satisfying the similarity theory is established.The static characteristic analysis is carried out for the complete similarity model under the action of vehicle load,temperature load and uneven settlement.The static results after conversion are highly consistent with the prototype results.The dynamic response analysis of the complete similarity model at different speeds,different fastener stiffnesses and different support stiffnesses is carried out.The dynamic results after conversion are also close to the prototype results,and the maximum error don’t exceed 8%.It shows that the complete similarity model can accurately invert the prototype results under the action of static and dynamic loads,and it is accurate and reliable when the complete similarity model is used.(3)Aiming at the elastic modulus and density distortion of rail scale parts,the prediction factor correction method is proposed to correct the distortion similarity model.A series of static and dynamic tests are carried out by numerical simulation.In the case of single-factor distortion,the functional relationship between prediction factor and distortion factor with goodness of fit above 0.99 was fitted.In the case of multifactor distortion,considering that the elastic modulus and density of the rail are distorted at the same time,the response surface equations of the prediction factor and the distortion factor are determined.The correction of the distortion similarity model can be achieved by using the relationship between the predictor and the distortion factor.(4)For the material selection of rail scale component,four common metal materials are identified: cast iron,brass,aluminum bronze and aluminum alloy.Using the prediction factor correction method,the static characteristics and dynamic responses of the distortion similarity model of different metal materials are calculated.The corrected mechanical indexes are compared with the prototype results.The applicability of the four metal materials to different mechanical indexes was studied.