我建立了一個(gè)三維地下板柱結(jié)構(gòu)模型，梁采用梁?jiǎn)卧宀捎脷卧馏w采用實(shí)體單元，進(jìn)行抗震分析，采用動(dòng)力隱式算法，重力分析步算過(guò)去了，但是動(dòng)力分析步還沒算就出現(xiàn)了以下錯(cuò)誤提示：Global mass matrix is singular. Please specify proper material densities, concentrated masses and rotary inertias, or nonstructural mass to fix the mass matrix. As a workaround, *dynamic, singular mass=warning can be used. 請(qǐng)問(wèn)哪位大神知道是什么問(wèn)題呀?