(1)真實(shí)性:計(jì)算簡(jiǎn)圖盡可反映結(jié)構(gòu)的實(shí)際受力情況 (2)實(shí)用性:計(jì)算簡(jiǎn)圖盡可能使力學(xué)計(jì)算簡(jiǎn)化