SLOSHING AND DYNAMIC INTERACTION BETWEEN LIQUID AND FLOATING ROOF IN A STORAGE TANK UNDER SEISMIC EXCITATION

给出了均匀各向同性浮顶和单层浮顶圆柱形储液罐在地震激励下的晃动问题的解析解。在线性位势理论的框架下，准确地考虑了液体与浮顶的动力相互作用，并提出了一种基于有限元和解析解的计算方法，用于处理由变厚度直板组成的浮顶。为了验证理论方法的有效性，用小比例尺水池模型进行了实船试验。本文的研究结论如下：1)单层屋面对降低波浪高程的影响很小，屋面位移与自由面高程相差不大。双层屋盖和加肋屋盖以刚体模式…运动为主更多。内部区域的位移显著减小，而沿油罐壁面的位移与自由面标高相比变化不大。2)内甲板下单层屋盖的动水压力相对较小，而沿浮箱底部的动水压力则相对较高。在与外浮桥的连接处，内甲板产生较大的弯曲应力，与钢材的屈服应力相当。钢材的屈服应力在双层屋面和加肋屋面上的动水压力比单层屋面的内甲板上的动水压力大，但弯曲应力仍远低于钢材的屈服应力。3)屋顶位移的解析解与振动台试验测得的结果吻合较好。单层屋面内板发生非线性双谐共振振动。4)为防止浮顶在2003年东京大地震中遭受的破坏，建议将单层屋盖改为双层屋面或加筋屋面。较少

ANALYTICAL SOLUTIONS HAVE BEEN PRESENTED FOR THE SLOSHING IN A CYLINDRICAL LIQUID STORAGE TANK WITH A UNIFORM ISOTROPIC FLOATING ROOF AND A SINGLE-DECK TYPE FLOATING ROOF UNDER SEISMIC EXCITATION. DYNAMIC INTERACTION BETWEEN THE LIQUID AND THE FLOATING ROOF HAS BEEN TAKEN INTO ACCOUNT EXACTLY WITHIN THE FRAMEWORK OF LINEAR POTENTIAL THEORY A COMPUTATIONAL METHOD BASEN ON COUPLED FINITE ELEMEMT AND ANALYTICAL SOLUTIONS HAS ALSO BEEN PROPOSED TO DEAL WITH AFLOATING ROOF COMPOSED OF AN ORTHCYIROPIC PLATE OF VARIABLE THICKNESS. IN ORDER TO CONFIRM THE VALIDITY OF THE THEORETICAL APPROACH, SHAING TABLE TESTS HAVE BEEN PERFORMED USING A SMALL-SCALE TANK MODEL THE CONCLUSIONS ARISING FROM THE PRESENT STUDY CAN BE SUMMARIZED AS FOLLOWS : 1) THE EFFECT OF THE SINGLE-DECK TYPE ROOF ON REDUCING THE WAVE ELEVATION IS SO SMALL THAT THE ROOF DISPLACEMENT IS NOT SO DIFFERENT FROM THE FREE SURFACE ELEVATION. THE DOUBLE-DECK TYPE ROOF AND THE RIB-STIFFENED ROOF MOVE PREDOMINANTLY IN THE RIGID-BODY MODE … More . THE DISPLACEMENT IN AN INNER REGION IS REDUCED CONSIDERABLY, WHILE THE DISPLACEMENT ALONG THE TANK WAIL IS NOT SO CHANGED FROM THE FREE SURFACE ELEVATION. 2) THE HYDRODYNAMIC PRESSURE ON THE SINGLE-DECK TYPE ROOF IS RELATIVELY LOW UNDER THE INNER DECK, WHILE IT BECOMES RELATIVELY HIGH ALONG THE PONTOON BOTTOM LARGE BENDING STRESSES ARISE IN THE INNER DECK ALONG THE CONNECTION WITH THE OUTER PONTOON, WHICH IS COMPARATIVE IN MAGNITUDE ID THE YIELDING STRESS OF THE STEEL THE HYDRODYNAMIC PRESSURE ON THE DOUBLE-DECK-TYPE ROOF AND THE RIB-STIFFENED ROOF BECOMES HIGHER THAN THAT ON THE INNER DECK OF THE SINGLE-DECK TYPE ROOF, BUT THE BENDING STRESSES REMAIN WELL BELOW THE YIELDING STRESS OF THE STEEL 3) THE ANALYTICAL SOLUTIONS FOR THE ROOF DISPLACEMENT COINCIDE WELL WITH THOSE MEASURED BY THE SHAKING TABLE TESTS, WHILE NON-LINEAR BI-HARMONIC RESONANCE OSCILLATION IS OBSERVED TO OCCUR IN THE INNER DECK OF THE SINGLE-DECK TYPE ROOF. 4) IN ORDER TO PREVENT THE DAMAGES OF THE FLOATING ROOF AS EXPERIENCED DURING THE 2003 TOKACHIOKI EARTHQUAKE, IT IS RECOMMENDED TO REPRACE THE SINGLE-DECK TYPE ROOF BY THE DOBLE-DECK TYPE ROOF OR THE RIB-STIFFENED ROOF. Less