Analysis Of Mechanical Properties Of Laminated Plate And CRTSⅡ Type Plate Ballastless Track Structure

The slab ballastless track structure,as a typical multi-layer composite slab,is the main structural form of high-speed railroads.In the previous design calculations,the analysis is usually based on beam or thin plate theory,and shear deformation is seldom considered.Therefore,it is necessary to study the mechanical performance analysis methods of laminated slab and slab ballastless track structure by combining the force characteristics of track slab.This paper selects the most widely used CRTSⅡ type plate ballastless track structure as the research object,and takes into account the focus and shortcomings of the current research on ballastless track structure and plate structure at home and abroad,and uses different plate theories to study the bending,structural dynamic response and interlayer force analysis of laminate and track plate.The main research contents are as follows:(1)Based on the thin plate theory,the control equations of CRTSⅡ type plate ballastless track structure considering bi-directional interlaminar slip are derived,and the load and temperature field loading models which are more in line with the actual situation are summarized for the track structure subjected to the train load field and the temperature field based on the natural environment.(2)A meshless radial point interpolation method(RPIM)based on generalized layerwise(LW)theory and higher-order shear deformation theory is derived,and then the numerical stability and applicability of LWRPIM with higher-order shear deformation are verified.The self-vibration and bending of laminated slabs on elastic foundations are investigated,and the effects of elastic foundations on the vibration frequency,modal and bending properties of laminated slabs are discussed.(3)The key parameters for calculating the structural response of CRTSⅡ ballastless track are summarized,and the mechanical properties of the track structure are analyzed using the laminate theory considering bidirectional slip and the higher-order shear deformation-RPIM meshless method,respectively.The effects of slip resistance coefficient and elastic foundation coefficient on the bending deformation and bidirectional slip of the track structure,the effects of boundary conditions on the bending deformation and interlaminar stress of the track structure,and the explanations for the interlaminar damage of the track structure are analyzed.(4)Based on the classical laminate theory,first-order shear deformation theory and higher-order shear deformation theory respectively,the control equations for the dynamic response of laminate and CRTSⅡ type slab ballastless track structures under moving loads are derived.The effects of thickness to width ratio,elastic foundation,moving load speed and load eccentricity on the dynamic response of laminated slab and track slab are investigated.The variation of the difference between different laminate theories in calculating the dynamic response of laminates and track slabs is analyzed.Finally,the control equations of laminated slab based on layerwise theory are derived.