填空題結(jié)構(gòu)力學(xué):位移法計(jì)算超靜定結(jié)構(gòu),基本未知量為( );其特點(diǎn)是通過( )約束將超靜定結(jié)構(gòu)計(jì)算轉(zhuǎn)化成基本或獨(dú)立單跨梁的計(jì)算.(有限元求位移) ...