DEVELOPING THE NEXT GENERATION OF HYDROGEN ASSISTED FRACTURE MODELS

该项目旨在开发新一代多物理和多尺度模型，可以预测氢脆材料的断裂，实现虚拟测试，防止灾难性故障。氢气无处不在，具有显著的性质和应用。它的同位素将在未来半个世纪为人类提供核聚变燃料，利用氢作为能源载体是解决我们能源危机的最有前途的解决方案之一。与这些机会背道而驰的是，一百多年来，氢一直被认为会导致金属结构的灾难性故障。这种现象不仅危及氢作为即将到来的能源载体的作用，而且继续限制现代钢铁在当前能源基础设施中的使用。在氢的存在下，金属材料的抗断裂性大大降低(最高可降低90%！)材料的氢损伤敏感性随材料强度的增大而增大。因此，氢辅助开裂在高强度钢中尤为严重，由于缺乏了解，它们已停止在能源、国防、运输和建筑部门使用，牺牲了数十年的冶金进步。在现代高性能合金中，即使在良好的环境中(例如，由于湿度)也会观察到氢脆，其影响无处不在：从Leadenall大楼的螺栓断裂到离岸结构的坍塌。由于目前的工程方法主要是经验的和高度保守的，因此迫切需要：(1)了解这种氢诱导降解的机制；以及(2)开发能够在与工程实践相关的尺度上再现微结构依赖的机械响应的基于机制的模型。该项目的成功将带来新一代氢脆模型，能够在与工程应用相关的尺度上定量地预测氢助开裂的发生。该项目的主要目标如下：(1)开发一个多物理计算框架，能够处理工程实践固有的大范围问题，同时解决问题的微观结构性质。(2)通过进行批判性实验，获得对潜在物理机制的基本见解。(3)发展新的基于机制的本构模型，通过明确考虑潜在的物理机制来减少经验主义。(4)在基于机理的框架下预测裂纹门槛值和亚临界裂纹扩展速率，并通过先进材料试验验证预测。EPSRC研究领域：结构工程、制造技术、材料工程-金属和合金、能源应用材料

The project aims at developing a new generation of multi-physics and multi-scale models that can predict material fracture due to hydrogen embrittlement, enabling Virtual Testing and preventing catastrophic failures. Hydrogen is ubiquitous and has remarkable properties and applications. Its isotopes will provide the nuclear fusion fuel for humanity in the next half century and the use of hydrogen as energy carrier is one of the most promising solutions to our energy crisis. In defiance of these opportunities, hydrogen has been known for over a hundred of years to cause catastrophic failures in metallic structures. This phenomenon not only jeopardizes the role of hydrogen as a forthcoming energy carrier but also continues to restrict the use of modern steels in current energy infrastructure. The fracture resistance of metallic materials is drastically reduced in the presence of hydrogen (by up to 90%!) and the susceptibility to hydrogen damage increases with material strength. Thus, hydrogen assisted cracking is particularly severe in high-strength steels and the lack of understanding has halted their use in the energy, defence, transport and construction sectors, sacrificing decades of metallurgical progress. In modern high-performance alloys, hydrogen embrittlement is observed even in benign environments (e.g., due to humidity) and its impact is ubiquitous: from bolt cracking at the Leadenhall building to off-shore structural collapse. With current engineering approaches being mainly empirical and highly conservative, there is a strong need to: (1) understand the mechanisms of such hydrogen-induced degradation; and to (2) develop mechanistic-based models able to reproduce the microstructure-dependent mechanical response at scales relevant to engineering practice. The successful project will lead to a new generation of hydrogen embrittlement models, able to quantitatively predict the occurrence of hydrogen assisted cracking at a scale relevant to engineering applications. The main objectives of the project are the following: (1) Developing a multi-physics computational framework capable of dealing with the large scales inherent to engineering practice while resolving the microstructural nature of the problem. (2) Acquiring fundamental insight into the underlying physical mechanisms by performing critical experiments. (3) Developing new mechanism-based constitutive models that reduce empiricism by explicitly considering the underlying physical mechanisms. (4) Predicting cracking thresholds and subcritical crack growth rates in a mechanism-based framework, and validating predictions through advanced materials testing.EPSRC research areas:Structural engineering, Manufacturing technologies, Materials engineering - metals and alloys, Materials for energy applications