美国麻省理工大学：《结构分析与设计技术》教学资源（讲义）notes17

properties of finite dement soltions Noded point equilibrio +0 At a node, the sow of he elemeat nodal forces s in equilibriun with Hhe externed loads Follows directLy froM KU=R

② B80= 2BClE3 dv Z R E(B(g dv,Z Re e F Element eovilibriuw Exd element is in eguilibrium under its forces F cg MoTIons

(3 PVD fr elemet "e" under a rig id-boody virhood displace 88=O Since Sul is a rigid-body but otherwise arbitrary virid displace ewt field, tis'twblies the frees ene in equilibriUM 工 nterpretation of fin ncte element analsis Continuo (structure) idleelieed as aeseunbly of discrete elements connected st modes Externed forces are reduced to equivalet extemal node forces usinQ PVD

The exte nally- pplied nodd forces are equioreteod the interna eem eut noddd for rCes whic are epuivalent to the element internal stresses notability and constitutive relationship one sotisfte Equilibrium is satisfed for He whole stradone, at te nodes of the esh and boy every dewet of the wnes