關(guān)于ansys mechanical總是出現(xiàn)接觸、邊界條件沖突?
在采用ansys對模型進(jìn)行靜力學(xué)分析時(shí),總是會(huì)出現(xiàn)未知錯(cuò)誤和兩個(gè)警告,警告分別是“一個(gè)或多個(gè)MPC接觸區(qū)域或遠(yuǎn)程邊界條件可能與施加的其他邊界條件、接觸或?qū)ΨQ區(qū)起沖突”“兩個(gè)或更多遠(yuǎn)程邊界條件共享一個(gè)公共面、邊或定點(diǎn)”。
查看求解方案信息,里面提到的內(nèi)容是“Overconstraint may occur for Lagrange multiplier or MPC based contact algorithm. The reasons for possible overconstraint are: ”然后緊跟著下一個(gè)警告:“Boundary conditions, coupling, and/or constraint equations have been applied on certain contact nodes (for example 204892). ”和“Certain contact elements (for example 934739 & 917158) overlap with other. ”。
還提到:“Multiple constraints have been applied on degree of freedom 3 of contact node 1164102. The program will remove certain internal MPCs. Please check the model carefully. ”
最后:“The dependent term of internal constraint equation 247416 created by contact pair could not be identified. It is likely that either a displacement boundary condition has been applied directly onto a constraint equation or two or more constraint equations share too many degrees of freedom. ”
查找節(jié)點(diǎn)ID號后發(fā)現(xiàn)有幾個(gè)是彈簧選擇的面上的節(jié)點(diǎn),還有幾個(gè)居然是純平面上的節(jié)點(diǎn),我將彈簧抑制后,還是有問題。警告中多次提到“過約束”,我懷疑可能是多孔共用回轉(zhuǎn)約束的問題。我想傾角一下,當(dāng)五個(gè)連桿,從左到右編號分別是1,2,3,4,5,它們一端共用一個(gè)銷軸,且滿足1和5同步運(yùn)動(dòng),2和4同步運(yùn)動(dòng)(即認(rèn)為是一個(gè)桿),這種情況下應(yīng)當(dāng)如何定義接觸?我現(xiàn)在的接觸定義是:選擇“幾何體-幾何體”中的“回轉(zhuǎn)”,將1和5的同軸心面作為“參考”,將2和4作為“移動(dòng)”,然后再插入“幾何體-幾何體”中的“回轉(zhuǎn)”,還是選擇1和5作為“參考”,然后將3作為“移動(dòng)”。這種分配方法是否有嚴(yán)重后果?理應(yīng)如何定義三桿同銷軸?

北望逸塵 


















