裂纹深度和韧带尺寸对K_c的影响

根据实际构件的特点，主要研究了两种弹体金属材料的非比例试件面内尺寸（α，Ｗ－α）对Ｋ＿（１ｃ）的影响及有效性评价。通过不同试件形状及尺寸的对比试验，初步认为在满足Ｂ≥２．５（Ｋ＿（１ｃ）／σ＿（０．２））￣２的条件下，裂纹深度、韧带尺寸的最低要求是：５８ＳｉＭｎ钢α≥１．７（Ｋ＿（ＩＣ）／σ＿（０．２））￣２、（Ｗ－α）≥２．０（Ｋ＿（１ｃ）／σ＿（０．２））￣２５０ＳｉＭｎＶＢ钢α≥１．６（文中讨论了材料强度级别（σ＿Ｓ／Ｅ）对试件几何尺寸限制要求的影响。

EFFECTS OF CRACK DEPTH AND TOUGHNESS BAND SINE ON K_(IC)

Accordjng to the characteristic of real component,the effects of inner surface size of non-proportional specimen on K_(IC) as well as the Validity evaluation for two kinds of projectile matallic materials are studied The comparing test of different spec imen shape and size showed that,under the condition of B≥2. 5,the lowest requirement of crack depth, toughess band size is α≥.7(for 50SiMn steel and α≥1.6 for 50SiMnVB steel.In the meanwhil,the limitation of material strength level on specimen geometry size is also discussed.