第4章 ANSYS 求解技术.docVIP

第4章ANSYS 的求解技术 4.1 第一类边界条件的处理 以2D恒定磁场矢量位计算为例，在某边界上的矢量磁位值已知。如在电磁铁磁场分析中，求解区的外边界上可认为AZ =0 即在L1，L2，L3和L4上所有节点的AZ =0。可用下述指令施加边界条件： LSEL,S,,,1,4,1,1 !选择L1,L2,L3,L4 D,ALL,AZ,0 !对边界节点赋值AZ=0 NSLL, Type, NKEY Selects those nodes associated with the selected lines. Type Label identifying the type of node select: S ?—? Select a new set (default). R ?—? Reselect a set from the current set. A ?—? Additionally select a set and extend the current set. U ?—? Unselect a set from the current set. NKEY Specifies whether only interior line nodes are to be selected: 0 ?—? Select only nodes interior to selected lines. 1 ?—? Select all nodes (interior to line and at keypoints) associated with the selected lines 对于永磁电机磁场分析，可假定定子铁心外圆上的AZ=0，其指令为 CSYS,1 ！选择圆柱坐标系统 NSEL,S,LOC,X,0.0849,0.0851 !根据半径选取定子铁心外表面上的节点 D,ALL,AZ,0 ！对边界节点赋值AZ=0 4.2 对称边界条件的处理 对于电磁铁的磁场分析，为了减少计算工作量，根据磁场相对于Y 轴对称关系，求解区可只选一半。 对于4极永磁电机的磁场分析，根据对称关系，可以取电机的二分之一进行计算。 施加对称边界条件的指令： DSYM, Lab, Normal, KCN Specifies symmetry or antisymmetry DOF constraints on nodes. Lab SYMM ?—? Generate symmetry constraints as described below (default). ASYM ?—? Generate antisymmetry constraints as described below. Normal Surface orientation label to determine the constraint set (surface is assumed to be perpendicular to this coordinate direction in coordinate system KCN): X ?—? Surface is normal to coordinate X direction (default). Interpreted as R direction for non-Cartesian coordinate systems. Y ?—? Surface is normal to coordinate Y direction. ?θ direction for non-Cartesian coordinate systems. Z ?—? Surface is normal to coordinate Z direction. ?Φ direction for spherical or toroidal coordinate systems. KCN Reference number of global or local coordinate system used to define surface orientation. Notes Specifies symmetry or antisymmetry degree of freedom constrain