Predictive Multiscale Modelling Protocol of Adiabatic Shear Band Initiation in Manufacturing and Aerospace Materials

制造和航空航天材料中绝热剪切带引发的预测多尺度建模协议

基本信息

批准号：
EP/W01579X/1
负责人：
Benat Gurrutxaga Lerma
金额：
$ 35.47万
依托单位：
University of Birmingham
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2022
资助国家：
英国
起止时间：
2022 至无数据
项目状态：
未结题

来源：
https://gtr.ukri.org/projects?ref=EP%2FW01579X%2F1
关键词：
Predictive Multiscale Modelling Protocol Adiabatic

项目摘要

The extremely narrow bands of localised shear deformation known as Adiabatic Shear Bands (ASBs) appear in metals and alloys subject to intense, high strain rate loading such as ballistic impacts or high rate manufacturing. Despite their reduced dimensions, the bands act as dramatic weak spots because their microstructure and morphology is radically different from the surrounding material. ASBs form suddenly and unexpectedly, and predicting them is difficult. Their sudden appearance while in-service invariably leads to the catastrophic failure of aerospace and defence systems (turbine blades, armour,...). Equally, ASBs dominate high rate manufacturing (machining, additive manufacturing, forming): efficiency calls for the sort of high rate, fast loads that tend to introduce undesired ASBs, greatly weakening the manufactured piece be- low specification. Owing to the huge volumes of manufactured pieces and to the high cost of design cycles in the defence and aerospace industries, predictive methodologies able to address ASB formation would lead to vast cost savings and efficiencies. Despite decades of research, the micro- and mesoscopic processes that cause ASB remain elusive. Whereas their growth and ultimate failure are relatively well-understood as thermomechanical instabilities, ASB initiation takes places at pico- and sub-micron scales that fall beyond current experimental measurement capabilities. Equally so, the inherently dynamic (time-dependent) loading conditions under which ASBs form have hitherto precluded the theoretical modelling of the phenomenon.Across three work packages (WP), this project addresses the inherent difficulties in modelling the initiation of ASBs by developing an ambitious, truly dynamic, multiscale modelling protocol with which to study and predict the conditions (loading, composition, microstructure) that promote the onset of ASBs in cubic and hexagonal metals. WP1 Microscale delivers a fundamental understanding of the physical source of the instability that gives rise to ASBs, by employ atomistic models (MD & lattice dynamics) with which to study sources of dislocation generation and dislocation motion under loads known to promote ASB. WP2 Mesoscale develops an entirely new formulation of thermo-elastodynamic dislocation dynamics (DD) with which to model ASB initiation and emergence at the mesoscale; this formulation addresses all current modelling limitations unable to account for the materials' inertia and thermal effects long since postulated to play a dominant role in the initiation of ASBs. WP3 Multiscale then combines WP1 and WP2 to develop a predictive multiscale model for ASB with which to study formation conditions (loading, composition, microstructure) in target metallic systems (Ti6Al4V, W, Al) of high scientific interest and industrial relevance. The resulting modelling protocol will enable the study of ASBs at the mesoscale for the first time, and produce a methodology with which to (1) predict and diagnose ASB failure in metallic systems, and (2) guide materials selection so as to select the most desirable microstructures with which to avoid or promote ASB formation. These tools will streamline the design cycle of aerospace and defence pieces subject to impacts, and optimise manufacturing operations reliant on minimising ASB formation (additive manufacturing, machining).

被称为绝热剪切带 (ASB) 的极窄局部剪切变形带出现在承受强烈、高应变率载荷（例如弹道冲击或高速制造）的金属和合金中。尽管它们的尺寸减小了，但这些带却成为了显着的弱点，因为它们的微观结构和形态与周围的材料截然不同。 ASB 的形成突然且出乎意料，因此预测它们非常困难。它们在服役期间的突然出现必然会导致航空航天和国防系统（涡轮叶片、装甲……）的灾难性故障。同样，ASB 在高速制造（机加工、增材制造、成型）中占主导地位：效率要求高速率、快速负载，而这往往会引入不需要的 ASB，从而极大地削弱制造出的低于规格的零件。由于国防和航空航天工业中的制造件数量巨大以及设计周期成本高昂，能够解决 ASB 形成问题的预测方法将带来巨大的成本节约和效率。尽管经过数十年的研究，导致 ASB 的微观和介观过程仍然难以捉摸。虽然它们的生长和最终失效相对容易理解为热机械不稳定性，但 ASB 的引发发生在皮微米和亚微米尺度，超出了当前的实验测量能力。同样，迄今为止，ASB 形成的固有动态（时间相关）加载条件已经排除了对该现象的理论建模。在三个工作包 (WP) 中，该项目通过开发一个模型解决了对 ASB 启动进行建模的固有困难。雄心勃勃、真正动态的多尺度建模协议，用于研究和预测促进立方和六方金属中 ASB 发生的条件（负载、成分、微观结构）。 WP1 Microscale 通过采用原子模型（MD 和晶格动力学）来研究位错产生的来源和已知会促进 ASB 的载荷下的位错运动，从而对引起 ASB 的不稳定性的物理来源有基本的了解。 WP2 Mesoscale 开发了一种全新的热弹动力学位错动力学 (DD) 公式，用于模拟中尺度 ASB 的起始和出现；该公式解决了当前所有无法解释材料惯性和热效应的建模局限性，长期以来一直被假定在 ASB 的引发中发挥主导作用。然后，WP3 Multiscale 将 WP1 和 WP2 结合起来，开发 ASB 的预测多尺度模型，用于研究具有高度科学意义和工业相关性的目标金属系统（Ti6Al4V、W、Al）的形成条件（负载、成分、微观结构）。由此产生的建模协议将首次实现中尺度 ASB 的研究，并产生一种方法，用于 (1) 预测和诊断金属系统中的 ASB 失效，(2) 指导材料选择，以选择最适合的材料。避免或促进 ASB 形成的理想微观结构。这些工具将简化受冲击的航空航天和国防部件的设计周期，并优化依赖于最大限度地减少 ASB 形成（增材制造、机械加工）的制造操作。