侧槽的拘束作用及对断裂韧性参量的影响

本文研究了侧槽对预制疲劳裂纹Ｃｈａｒｐｙ尺寸试样的拘束效应以及其对断裂韧性参量的影响。当侧槽深度大于临界值时，峰值载荷韧性Ｊｍ值与起裂韧性Ｊ１值基本相等。侧槽对试样的加厚作用可用试样的附加厚度表示，对于同样的侧槽深度，不同材料具有不等的附加厚度，试样取得最大附加厚度的侧槽深度为３３％。文中提出用拘束系数定量地估计侧槽对裂纹尖端的塑性拘束作用，能较好地解解放本试验结果。

Constraint of Side-groove and Its Influenceon Fracture Toughness Parameterin Charpy-size Specimens

This paper has studied the effect of side-groove constraint on pre-cracked Charpy-size specimen,and the influence of side-groove on fracture toughness parameters. The results indicate that when the-groove depth approach a critical value, the maximum load toughness J_m values are nearly coincidentwith the initiation toughness J_i values. Thickening action of side-groove may be expressed by calculat-ing the extra thickness of specimen. For different materials the additional thickness due to side-grooveis distinct. When the depth of side-grooves is 33% of specimen thickness the specimen obtains themaximum additional thickness. The side-groove constraint coefficient(C) presented by this paper canquantitatively evaluate the level of plastic constraint at crack tip, and explain the experimentul resultswell.