（1）Make sure that you do not scope a Remote Displacement, Remote Force,or a Moment to a geometric entity that shares an edge, vertex, or node with either the specified High Boundary or Low Boundary properties of the Cyclic Region because the application could generate incorrect results.如果将远程力或力矩和循环区域的高低边界共享几何体（边缘、顶点和节点），最终会导致结果不正确。

（2）High Boundary and Low Boundary should be exactly same in shape and size, otherwise Mechanical will not be able to map nodes from Low Boundary to High Boundary to create full model from a single sector. 高低边界必须尺寸和形状必须一致，否则Mechanical不能将节点从低边界映射到高边界，进而建立单个扇区的完整模型。

（3）In similar fashion, you must define the Remote Point  for Moment loads so that its points of application lie along the cyclic axis (see warning below).   Set the Remote Point Behavior property to Deformable or Rigid. 必须为力矩加载定义远程点，使其应用点位于循环轴上； 将远程点行为属性设置为可变形或刚性。

图一 循环高低边界

图二 循环载荷（加扭矩）

图三 循环区域的变形量（动画不知道能不能播放）

（1）cyclic region and pre-meshed cyclic region循环区域和预网格循环区域的区别，具体如下：

The Pre-Meshed Cyclic Region is a symmetry option that does process the specified selections for the Low Boundary and High Boundary properties. Normally, the application uses these selections to specify the nodes to write cyclic constraint equations; however, this object instead uses the cycle angle to determine the nodes used to create cyclic symmetry.This option is used to define cyclic symmetry for cases where you cannot generate a matched mesh using the low and high boundaries. Not being able to match the mesh is often the case whenyou import mesh from an external source, such as Model Assembly, External Model, or ACP. To match your mesh, the Pre-Meshed Cyclic Region enables you to select the exact orientation of nodal coordinate systems on the sector boundaries. And the feature includes the additional property Relative Distance Tolerance that enables you to modify the automatic sector boundary detection of low and high boundary. 预网格循环区域是一个对称选项，处理低边界和高边界的指定选择。程序用指定的节点编写循环约束方程，用循环角确定用于创建循环对称的节点。预网格循环区域用于无法使用高低边界网格生成合适网格的情况。

（2）• The following support limitations and specifications must be observed: • The following boundary conditions are not supported:

– Bearing Load

– Hydrostatic Pressure

– Fluid Solid Interface (Supported for Static Acoustics but cannot be applied to the Low/High Boundary)

• The following remote boundary conditions are not supported:

– Joints

– Bearing 

（以上为Cyclic Region一些不支持的边界条件）

（3）The first illustration below depicts a Friction Support applied to the exterior faces of a symmetry model. Because this boundary condition shares topology with sector boundaries, it will not solve. 边界条件和扇形边界共享拓朴结构，所以无法求解。

（4）加载力矩边界条件都限制在轴向。因此，必须将边界条件define by属性设置为Components，只有Z轴属性可以非零并且边界条件的指定坐标系的Z轴必须和相应循环区域所使用的坐标系相匹配。

并且必须为力矩加载定义远程点，使远程点点位于循环轴上。

（5）一个小案例

案例结论：力矩和循环区域的高低边界共享几何体（边缘、顶点和节点），最终导致结果不正确。