海上风力机高桩承台基础反应特性研究

STUDY ON RESPONSE OF OFFSHORE WIND TURBINE WITH HIGH-PILE CAP FOUNDATION

采用ANSYS建立由实体单元、壳单元、杆单元和管单元组成的海上风力机高桩承台混合模型。对极端工况下高桩混凝土承台进行有限元分析,得到承台混凝土和钢结构应力分布模型。通过对不同荷载组合下混凝土拉应力超限区域分布对比得到海上高桩承台基础结构在风力机荷载作用下的反应特性。结果表明:桩基础结构应力主要受波流荷载影响,塔筒过渡段结构应力主要受风力机荷载影响。高桩承台基础最易发生破坏结构为混凝土承台,在风力机荷载和波流荷载联合作用下,混凝土承台拉应力超限区主要分布在法兰盘受压区混凝土和钢管桩管壁处填芯混凝土。风力机上部结构产生的风力机荷载使高桩承台迎水面填芯混凝土处和与中心法兰盘接触处的混凝土拉应力超限;在波流荷载作用下,该超限区中高桩承台与风力机塔筒连接处和迎水面填芯混凝土处的拉应力超限区域减小。

Using ANSYS,finite element model of the elevated pile caps of bottom fixed offshore wind turbine(OWT)is established,which is composed of shell,link and pipe elements.Static analysis of substructure under ultimate load conditions(ULS)is carried,the stress of concrete caps and steel structures is obtained.By comparison of the distribution of over-limite zone of tensile stress of concrete under different ULS,the response characteristics of OWT sub-structure is validated.It can be concluded that the stress of pile foundation structure is mainly affected by wave current load,and the stress of tower transition section is mainly affected by wind turbine load.Failure of concrete caps under extreme wind turbine loads is proved,due to the overloaded maximum tensile stress of concrete structures.Under combined action of wind turbine load and wave-current load,the over-limitate zone of tensile stress of concrete platform is mainly distributed in the concrete which is in the compression zone of the flange and core concrete connected with the wall of pipe pile.The distribution of over-limite zone of tensile stress of core concrete on upstream face and at connection of high-pile cap and tower of the OWT decrease under the action of wave-current load.