Anisotropic yielding in AM Ti-6Al-4V: Experimental methods, models, and case study justifications

AM Ti-6Al-4V 中的各向异性屈服：实验方法、模型和案例研究理由

• 批准号: 2592733
• 金额: --
• 依托单位: University of Nottingham
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2592733
• 关键词: Anisotropic; yielding; AM; Ti; 6Al

The advantages of additive manufacturing (AM) over traditional subtractive methods are well known. Exciting opportunities will be enabled by AM. Efficient structures with complex external and internal features are made possible in AM, allowing for broader design envelopes and optimised systems. Paramount to the adoption of both AM materials and the advanced designs that they promote is an understanding of how materials deform and fail in complex loading configurations. At present, the experimental studies that underpin predictive models are (often) limited to uniaxial conditions. Multiaxial behaviours can be inferred from these observations. However, the results are susceptible to large levels of uncertainty. This, in turn, limits the degree to which anisotropy can be represented in the predictive models.Unacceptable levels of uncertainty in predictive material models limit confidence in novel designs enabled in AM, thereby undermining the potential impacts of AM. What is required is both an intelligent testing methodology that explores anisotropy in AM materials and a general modelling approach that allows accurate predictions to be made at the design stage.The project proposed here will develop these approaches using new testing capabilities at UNOTT. Generic multiaxial test coupons will be established. These will be built in Ti-6Al- 4V (as a demonstration material) through collaborations with Renishaw and tested using novel yield locus probing techniques (enabled by the new multiaxial test frame at UNOTT). Hill's anisotropic yield criterion (or a modification of it) will then be used to develop generic plasticity models for the Ti-6Al-4V material. Results will be verified through additional testing along non-standard loading axes. Finally, the value of the work will be quantifiably demonstrated through a design case study of an AM bracket. Conventional (with large but justifiable safety factors resulting from modelling uncertainty) and advanced (developed in the project) material models will be used to analyse an AM bracket component to determine safe working loads. The value will be demonstrated through a greater structural capacity in the case of advanced deformation representations.

增材制造（AM）相对于传统减材制造方法的优势是众所周知的。AM将带来令人兴奋的机会。具有复杂外部和内部特征的高效结构在AM中成为可能，允许更广泛的设计范围和优化系统。对于AM材料和它们所促进的先进设计的采用来说，最重要的是了解材料在复杂载荷配置下如何变形和失效。目前，支持预测模型的实验研究（通常）仅限于单轴条件。多轴行为可以从这些观察推断。然而，结果容易受到很大程度的不确定性的影响。这反过来又限制了各向异性在预测模型中的表现程度。预测材料模型中不可接受的不确定性水平限制了AM中启用的新颖设计的置信度，从而破坏了AM的潜在影响。所需要的是探索增材制造材料各向异性的智能测试方法和能够在设计阶段作出准确预测的一般建模方法，这里提议的项目将利用联合国技术转让办事处的新测试能力开发这些方法。将建立通用多轴试样。这些将通过与雷尼绍的合作，用Ti-6Al- 4V（作为演示材料）制造，并使用新型屈服轨迹探测技术（由联合国技术转让办事处的新多轴测试框架实现）进行测试。然后将使用Hill各向异性屈服准则（或其修改）开发Ti-6Al-4V材料的通用塑性模型。将通过沿非标准加载轴的附加测试沿着验证结果。最后，通过一个AM支架的设计案例研究，量化地展示了工作的价值。将使用传统（由于建模不确定性而具有较大但合理的安全系数）和先进（在项目中开发）材料模型来分析AM支架组件，以确定安全工作载荷。在高级变形表示的情况下，该值将通过更大的结构能力来证明。