均匀水流冲击下扭王字块断裂失稳过程的数值模拟研究

扭王字块是一种重要的港口防波堤护面块体,其断裂失稳过程与所受水流冲击力密切相关。文章以基于连续介质力学的离散元方法(CDEM)为基础,通过引入FVM算法及半弹簧-半棱联合接触模型,分别实现了大位移下单元变形的准确计算及单元接触的快速更新。基于改进后的CDEM方法,通过在扭王字块表面施加按流速方向逐渐增加的动态面力,对均匀水流冲击下单扭王字块的断裂过程及扭王字块群的失稳滑移过程进行了数值分析。通过分析,不同方向水流冲击下单扭王字块的主要断裂模式为沿着根部的折断,其断裂流速约为21~25m/s;不同吨位下扭王字块群的失稳模式为扭王字块单体从群体中跳出,其失稳流速约为4~11m/s。

Numerical study on failure process of accropode under the impact of uniform flow

Accropode is considered as an important breakwater armour block,and the failure process is closely related to impact force of flow.Based on Continuum-based Discrete Element Method (CDEM),and by introducing FVM algorithm and semi-spring & semi-edge combined contact model,the precise calculation of element deformation and quick update of element contact under large displacement are realized.According to modified CDEM above mentioned,and by applying gradually increased dynamic face force on accropode surface with the direction of flow,the numerical simulations are taken.The crack process of single accropode and instability process of accropodes group under impact load of uniform flow are studied.Numerical results show that,the main crack mode of single accropode is root fracture,with the crack velocity 20~24 m/s in different impact direction; and the main instability mode of accropodes group is single accropode jumping out of group,with the instability velocity 4~12 m/s in different tonnage.