Сrack Branching in Catastrophic Fractures of Metal Structures and Environmental Damages

In this article, fracturing in large-scale metal structures such as main gas pipelines, fuel and oil tanks operated in arctic were investigated. it is shown that catastrophic accidents involved in large thin-walled metal structures in large diameter pipelines, tanks and pressure vessels. the fractures occurred not only due to stretch propagation of brittle or viscous fractures, but also followed branching that leads to fragmented fractures with simultaneous movement of many cracks. the character of the fracture depends on the level of the fracture strength. at high levels cracks propagated at a high speed by a mechanism of separation; as a result of crack branching fragment damage occurred. at low level, cracks propagate at a low speed by a cutting mechanism; that does not cause extensive fracturing. the cracks may cause structural and environmental damages.