Mechanical properties of buckled pipe materials

扣管材料的力学性能

• 批准号: 470108-2014
• 负责人: Poole, WarrenJ
• 金额: $ 3.35万
• 依托单位: University of British Columbia
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=598508
• 关键词: Mechanical; properties; buckled; pipe; materials

The in-service mechanical buckling of pipelines is an important technological problem. The pipeline can experience complex loading paths after construction due to seismic events, soil shifting due to melting of permafrost or even the movement of heavy equipment over the buried pipeline. Thus, it is necessary to have models to predict the material behaviour of the pipe in service, such as the yield stress and the initial working hardening behaviour. Here, there are several important metallurgical phenomena which are relevant. First, it is qualitatively known that when the direction of the loading changes, this can affect the yield stress (classically known as the Bauschinger effect). In this case, the relevant scenario would be that the direction of deformation during forming the pipe can be orthogonal to bending strains that the pipe experiences in-service. Second, it is also known that the after plastic deformation and a static period at ambient temperatures, a "yield point" can be produced due to segregation of carbon atoms to crystal dislocations. However, there is a lack of knowledge on the basic mechanisms and the ability to predict this behaviour is limited to qualitative values.

管道在役机械屈曲是一个重要的技术问题。由于地震事件、永久冻土融化导致的土壤移动，甚至重型设备在埋地管道上移动，管道在施工后会经历复杂的加载路径。因此，有必要建立模型来预测管道在使用中的材料行为，例如屈服应力和初始加工硬化行为。这里，有几个重要的冶金现象是相关的。首先，我们定性地知道，当加载方向改变时，这可能会影响屈服应力（经典地称为鲍辛格效应）。在这种情况下，相关的情况是，管道成形过程中的变形方向可以与管道在使用中经历的弯曲应变正交。其次，我们也知道，在环境温度下，经过塑性变形和一段静态时间后，由于碳原子的偏析导致晶体位错，可以产生一个“屈服点”。然而，缺乏关于基本机制的知识，预测这种行为的能力仅限于定性值。