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Assessment of Crack Arrest Behaviour in Modern Structural Steels

现代结构钢的止裂行为评估

基本信息

批准号：
2002942
负责人：
金额：
--
依托单位：
CRANFIELD UNIVERSITY
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2016
资助国家：
英国
起止时间：
2016 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-2002942
关键词：
Assessment Crack Arrest Behaviour Modern

项目摘要

Fracture mechanics based Fitness-For-Service (FFS) assessment of engineering structures is normally based upon the failure criterion, which is the initiation of crack extension by brittle fracture or ductile tearing at specified temperatures. The philosophy behind crack arrest is that if a crack initiates in a region of high stress or local embrittlement, it will be arrested in the surrounding material to prevent failure of the entire structure. The basic, simple idea for ensuring crack arrest is that the materials must have sufficient crack arrest toughness to ensure that fast propagating cracks, initiated in regions of low toughness and/or high stress, are arrested after they emerge from the critical zone. Obviously, during the design stage of ships, pipelines and some specific pressure vessels, analysis of crack arrest is of vital importance. The effect of temperature is another factor that needs to be taken into account in the course of the assessment of crack arrest or during design against crack arrest. The main aim of this project is to derive empirical models, which can be used to define crack arrest toughness from small test specimens (i.e. Charpy tests). It is also proposed to investigate and quantify the differences between the crack initiation and arrest toughness of two types of steels and explain the differences based on material microstructure. Finite Element modelling techniques will also be incorporated to understand crack arrest behaviour by analysing crack tip conditions in relation to a particular microstructure under specified loading condition.

基于断裂力学的工程结构的服役适应性（FFS）评估通常基于失效准则，该失效准则是在特定温度下通过脆性断裂或延性撕裂而开始裂纹扩展。裂纹止裂的原理是，如果裂纹在高应力或局部脆化区域产生，它将在周围材料中被止裂，以防止整个结构失效。确保止裂的基本、简单的想法是，材料必须具有足够的止裂韧性，以确保在低韧性和/或高应力区域中开始的快速传播的裂纹在它们从临界区出现之后被阻止。显然，在船舶、管道和某些特定压力容器的设计阶段，止裂分析是至关重要的。温度的影响是在评估止裂过程中或在设计止裂过程中需要考虑的另一个因素。该项目的主要目的是获得经验模型，可用于定义小试样（即夏比试验）的止裂韧性。还建议调查和量化两种类型的钢的裂纹萌生和止裂韧性之间的差异，并根据材料的微观结构来解释差异。有限元建模技术也将被纳入，以了解裂纹止裂行为，通过分析裂纹尖端的条件，在指定的加载条件下的一个特定的微观结构。