| CSP(Concentrated solar thermal power generation)tower solar photo-thermal power station composite structure heat absorption tower is a new type of steel-reinforced concrete composite structure power generation tower.The tower is powered mainly by solar energy and used a molten salt heat storage system to extend its operation and generate electricity in the absence of solar radiation.It is essential that the research on seismic performance design of the structure may become one of the main commercial and residential power supply trends in the future for it early development.Based on NOORIII solar photo-thermal power tower heat absorption tower prototype combination structure as the research object through the heat absorption tower model shaking table test and finite element calculation model and prototype finite element calculation.The seismic performance of heat absorption tower structure and seismic design problems are analyzed,for the use of personnel to carry out the design and the compilation of the relevant specification to provide the reference value.(1)Lead-powder concrete,a kind of concrete material with high bulk density and low elastic modulus,is designed through the calculation of similarity relation.The mechanical models of lead-powder concrete and ordinary concrete are proved to be by means of the material test,and the mix ratio and stress-strain curves are given,which provide a kind of reliable material for the scale model test of the shaking table.The overall lateral stiffness of the steel truss and the copper truss was compared and calculated in ANSYSY and ABAQUS finite element software,which verified the rationality of the design and simplification of the test model.(2)The dynamic characteristics of the composite structure heat absorption tower model of solar photo-thermal power station are studied through theoretical,experimental and finite element analysis.It shows that the modes of vibration are horizontal vibration,vertical vibration and torsional vibration.The results of ANSYS,ABAQUS and SAP2000 are in good agreement with the experimental.The frequency of the model structure decreases with the increase of the excitation value of the mesa seismic wave,whereas the damping ratio increases with the degradation of the structural stiffness.(3)The 1/18 scale seismic simulation shaking table model test was carried out on the prototype structure of the heat absorption tower.It shows that top of the model structure have172 mm maximum response under action of horizontal earthquake.The acceleration response of concrete tubular structure is smaller than that of copper truss structure.The acceleration and displacement response at the center of mass of the model structure is 4.79 mm,largest one under vertical earthquake action.The maximum displacement Angle of the model structure under the action of 8-degree rare earthquake is 1/42,the maximum total displacement Angle of the tower top is 1/151,and the maximum shear force,overturning moment and maximum axial force are respectively71 k N,142 k N·m and 146 k N.(4)The experimental model of the heat absorption tower was modeled in ABAQUS finite element software and the elastic-plastic seismic response time-history analysis of the structure was carried out.The results show that the maximum response of horizontal acceleration of the tower top is 2.262 g,the maximum response of horizontal displacement of the tower top is 128 mm,the maximum response of vertical acceleration near the center of mass is 2.307 g,the maximum response of vertical displacement is 4.4mm,the maximum response of bottom shear force is 73 k N and the maximum response of axial force is 143 k N.The bottom damage of model structure is serious and the stress at the bottom of the concrete tube and the copper truss structure is extensive under the action of horizontal earthquake.Whereas,the damage of model structure’s center of mass is serious and stress of the concrete cylinder’s center is maximum and the red copper truss structure has no obvious damage.(5)The prototype seismic performance of the heat absorption tower is deduced from the test results through the similarity relation and the results are analyzed by comparing with ABAQUS.The results show that the damage analysis of the prototype structure of the heat absorption tower which has experienced 8 degree earthquakes shows that under the action of horizontal earthquake,the cumulative damage of the structure at the connection between the bottom and the base is the largest,until the concrete section is brittle fracture,and the steel reinforcement is still in the plastic development stage.Under the action of vertical earthquake,the serious damage part of the structure is 2/3 of the height of the concrete tube,the cross section appears horizontal penetrating cracking,and the steel reinforcement works well.The structure has good seismic performance.The first mode of the prototype is 3.185 s and the first order X and Y horizontal translation and the structure has no obvious torsion effect.(6)The seismic design of composite structure heat absorption tower of solar photo-thermal power station is studied.It shows that the vertical earthquake has greater influence on the tower than the horizontal earthquake under the action of8-degree earthquake.It is recommended to calculate the vertical seismic coefficient of the heat absorption tower as 0.42 in 8-degree earthquake.The vertical expansion effect of steel truss is not obvious,whereas the horizontal whipping takes opposite.The envelope value of the large coefficient under horizontal seismic action is 3.99.And the influence coefficient of vertical seismic second-order effect is 1.654.Attention should be paid to the joint design under the action of rare earthquake.TMD makes 33.0%contribution to the seismic resistance of structures. |
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