(1. 核工業(yè)理化工程研究院 四所，天津 300180；
2. 國防科技工業(yè)核材料技術創(chuàng)新中心，天津 300180)
摘 要: 計算半橢圓裂紋的Ⅰ型應力強度因子(KI)是研究含缺陷部件損傷容限、評估剩余壽命的關鍵技術。針對機械設備類盤型件應力分布復雜、有限元建模繁瑣耗時等問題，建立一種計算高速旋轉條件下復雜結構盤狀部件表面半橢圓裂紋KI的權函數(shù)方法。在一定的適用條件下，將盤型件局部小裂紋簡化為平板表面裂紋。在半橢圓形狀參數(shù)0.2≤α≤2、0.05≤β≤0.6的范圍內，通過平板表面裂紋模型，擬合得到表面半橢圓裂紋權函數(shù)參數(shù)M的多元線性表達式，其中擬合值與有限元計算值的殘差平方和均值為0.00975。結合某機械設備盤型件的設計特點，研究該權函數(shù)法在不等厚及中部突起型圓盤表面徑向、切向裂紋問題的適用性。經驗證，權函數(shù)解與有限元結果的相對誤差為-4.45%~2.80%。
關鍵字: 應力強度因子；半橢圓裂紋；權函數(shù)；盤型件；旋轉載荷
（1. Institute of Physical and Chemical Engineering of Nuclear industry, Tianjin 300180, China;
2. Innovation Center of Nuclear Materials for National Defense Industry, Tianjin 300180, China）
Abstract:The assessment of mode Ⅰ stress intensity factors (KI) is a crucial step to calculate the damage tolerance and evaluate the residual life of structures with defects. Solving the problem of time consuming in finite element modeling, general weight function is developed to calculate KI of surface cracks on the rotating disk-shaped part with complex structure. A cracked finite plate model based on some hypothesis was presented to describe the fracture performance for small semi-elliptical cracks on surface of disk-shaped part. Within the range of α from 0.2 to 2, β from 0.05 to 0.6, correction coefficients of surface semi-elliptical cracks on finite plate of aluminium alloy were fitted by multiple linear regression, which was applied to calculate the weight function of cracked disk-shaped part. The average squared residual of FEM and analytical solutions is 0.00975. Based on calculated stress distribution of certain parts, weight function method was used to obtain KI factors of surface semi-elliptical cracks on rotating disks with non-uniform thickness and central bulge, whose feature is similar with that in special purpose equipment. The comparison between the results obtained from proposed weight function method and numerical solutions by FEM is presented, the relative error is from -4.45% to 2.80%.
Key words: stress intensity factor; semi-elliptical crack; weight function; disk-shaped part; centrifugal load
