平面機構具間隙接頭與其斷裂之研究

Abstract

本文主旨為使用向量式分析來探討平面機構中含有間隙接頭與構件斷裂行為之研究。在現今的模擬計算的準確性要求越來越高，對接頭的模擬也要求須近似於真實，若機構的接頭中存在了間隙接頭(joint clearance)，容易導致機構在運動的過程中產生磨損及衝擊等現象，造成機構的壽命降低、振動增加與輸出誤差，不過為了防止機構損壞的情況，可以在接頭中加入潤滑液體以增加機構的使用壽命。向量式分析的優點在於可處理桿件運動過程中經歷大的幾何變形的行為，如破裂、穿透、撞擊或非線性的運動情形，所以我們採用向量式分析來模擬此種工程上的問題。在計算此類問題時，本文還加入不同於以往的接觸模型，並進行探討。同時針對運動解析的優點，也會計算降低剛性後的機構含有間隙接頭時的算例，並與文獻中的結果相比較。對於構件的斷裂行為，除了計算構件受衝擊力時的內應力值與斷裂後構件的運動軌跡外，也會計算內應變，並將應力波與應變波的傳遞情形表示出來。

This study presents the analysis of the planar mechanisms with joint clearance and fragmentation behavior using the theory of vector form intrinsic finite element(VFIFE). VFIFE has the advantage of handling the process of movement associated with large deformation, such as rupture, penetration, impact or non-linear movement. Mechanisms with joint clearance may possess shorten life due to wear and impact to the mechanism that are caused by the joint clearance. Therefore, by using VFIFE associated with contact models for the joint clearance, motions of mechanisms are investigated and simulated. In addition, the fragmentation behavior for mechanisms that are subject to internal stress/strain which are caused by joint clearance are also discussed and simulated via VFIFE. It is shown that the results of the study are rational and feasible.