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一、序言 经典力学理论和设计思想对十九世纪以来许多灾难性的脆断事故是无法解释的。这些脆断事故有三个特点:其一,破断应力远低于屈服应力甚至设计应力,其二,断裂均起源于微小裂纹,其三,低温、厚截面构件、高变形速度条件下容易发生脆断现象。真实的材料构件由于冶金及加工因素、不同使用条件(疲劳载荷、腐蚀介质、氢的渗入、中子辐射等)均会导致类裂纹缺陷的出现,它们的存在破坏了经典力学中材料是均匀、连续、各向同性的基本假设,裂纹的存在和
I. Preface Classical mechanics theory and design ideas can not explain many of the catastrophic brittle failures since the nineteenth century. The brittle fracture has three characteristics: First, the breaking stress is far lower than the yield stress or design stress, and second, the fracture originated in the tiny cracks, the third, low temperature, thick section members, prone to brittle fracture under high deformation speed conditions phenomenon. Due to the metallurgical and processing factors of real material components, different service conditions (fatigue load, corrosive medium, hydrogen infiltration, neutron radiation, etc.) can lead to the occurrence of class defects. Their existence undermines the uniform, Continuous, isotropic basic assumptions, the existence of cracks and