六面体元 CHEA(24-80) 五面体元 CPENTA(18-45) 四面体元 CTETRA(1230) ■约束元(无限刚硬,称为刚性元,在数学模型中不引起数值困难) 刚性杆:RROD 刚性梁:RBAR 刚性三角板: RTRPLT 刚性体:RBE1,RBE2 均方加权约束元:RBE3 内插约束元: RSPLINE One-Dimensional of DOFs R○D Pin-ended rod BAR Prismatic beam BEAM Straight beam with warping BEND Curved beam. pipe or elbow Two-Dimensional Triangular plate 15 QUAD4 Quadrilateral plate SHEAR 4-sided shear panel 8 TRIA6 Triangular plate with midside nodes QUAD8 Quadrilateral plate with midside nodes Thregeomensonal HEXA Solid with six quadrilateral faces 24-60 TETRA Solid with four triangular faces 12-30 PENTA Solid with two triangular faces and three 18-45 Zero-Di ametryn ELAS Simple spring connecting two degrees of 2 BUSH Frequency-dependent spring/damper 6■ 约束元（无限刚硬，称为刚性元，在数学模型中不引起数值困难） 刚性杆：RROD 刚性梁：RBAR 刚性三角板：RTRPLT 刚性体：RBE 1，RBE 2 均方加权约束元：RBE 3 内插约束元：RSPLINE 四面体元 CTETRA（12-30） 五面体元 CPENTA（18-45） 六面体元 CHEXA（24-80）