MAST: Modelling of advanced materials for simulation of transformative manufacturing processes

向21世纪高价值制造业的下一步过渡需要开发创新的工艺，以(I)减少周期时间和成本，以便最大限度地提高生产率和更高的利润，以及(Ii)在减少对环境影响的同时提高性能和质量。为了实现这一目标，现代制造业所需的发展和集约化需要更广泛地使用更高的温度、力、变形和加载速率。在实践中，开发和应用建模和模拟工具是应对这些挑战的唯一实际方法，特别是对于新的变革性制造工艺。传统上，轧制和锻造等工艺一直是新兴经济体的支柱，例如在印度，中国说。这些变形速率较低的过程是众所周知的。拟议的研究涉及变形速率谱另一端的过程，其特征是异常高的震级--这些过程具有创新性，具有潜在的变革性，但人们对此却知之甚少。材料去除工艺，如超声辅助加工和固态连接工艺，如线性摩擦焊接，以及新的精加工工艺，都属于这一类；这些都将在本项目中重点介绍。在这种加载制度下，人们面临着巨大的挑战。首先，由于处理速度非常快，很难或不可能出于诊断目的而中断；这一事实强调了数学建模对于分析决定最佳实践和优化最佳实践的物理因素的重要性。第二，实验验证--这是数学建模练习的重要部分--必须通过高速摄影/录像等技术进行。第三，精确的建模要求在代表过程的变形率下很好地理解材料的本构行为。对于镍基高温合金、钛合金和镁合金等新型高品位合金系统来说，情况还不是这样，因此需要进行所建议类型的新研究--例如，使用增强型分离式霍普金森压杆技术。最后，高应变率区域的温度梯度很大；这些温度梯度会导致较大的热应力，因此有可能出现开裂、破裂等情况。要准确地对这些进行建模是一个巨大的挑战，但如果要产生实际的制造模拟，就必须这样做。拟议的研究通过与工业相关的案例研究和应用，解决了使用先进材料进行变革性制造的过程模拟的具体挑战。为了有效地管理该项目，工作方案分为七个工作包，包括：(1)材料行为模型；(2)连续介质行为和加工区模型；(3)材料特性；(4)工艺特性和制造参数；(5)优化研究；(6)工业反馈分析；(7)管理和传播。

A transition to the next step in high-value manufacturing in the 21st century requires the development of innovative processes to (i) reduce cycle times and costs so that productivity and higher profitability are maximised, and (ii) enhance performance and quality whilst reducing environmental impact. To achieve this, the required development and intensification of modern manufacturing necessitates a broader use of higher temperatures, forces, deformations and loading rates. In practice, the development and application of modelling and simulation tools are the only practical way in which these challenges will be met, particularly for new transformative manufacturing processes. Traditionally, processes such as rolling and forging have been the mainstay of emerging economies, e.g. in India, China. These processes, with low deformation rates are well understood. The proposed research relates to processes at the other end of the deformation-rate spectrum characterised by exceptionally high magnitudes - which are innovative, potentially transformative and much less well understood. Material-removing processes such as ultrasonically-assisted machining and solid-state joining processes such as linear friction welding as well as novel finishing process are in this class; these will be emphasised in the present project. In this loading regime, one faces significant challenges. First, since processing is very fast it is difficult or impossible to interrupt for diagnostic purposes; this fact emphasises the importance of mathematical modelling for the analysis of the physical factors determining best practice and optimisation of it. Second, experimental validation - which is a vital part of the mathematical modelling exercise - must proceed by techniques such as high-speed photography/videography. Third, accurate modelling requires the constitutive behaviour of the material to be well understood at deformation rates representative of the process. This is not yet the case for novel, high grade alloy systems such as nickel-based superalloys, titanium and magnesium alloys, so that novel research of the type proposed - using an augmented split Hopkinson pressure bar technique, for example - is required. Finally, temperature gradients in the high strain-rate regime are significant; these cause large thermal stresses and therefore the possibility of cracking, fissuring etc. It is a significant challenge to model these accurately but this must be done if realistic manufacturing simulations are to be produced. The proposed research addresses specific challenges of process simulations for transformative manufacture with advanced materials with industrially-relevant case studies and applications. In order to manage the project effectively, the programme of work is split into seven work packages, covering modelling of (i) materials behaviour; (ii) modelling of continuum behaviour and process zone; (iii) materials characterisation; (iv) process characterisation & manufacturing parameters; (v) optimisation studies; (vi) analysis of industrial feedback and (vii) management and dissemination.