Supporting data for "Fracture toughness of automotive steel at high strain rate"

The aim of this thesis is to study and push the development of methodology surrounding fracture toughness at high strain rates. This project primarily focuses and adapts the Essential Work of Fracture (EWF) method for application at high strain rates. The EWF method is an extremely powerful tool to observe the fracture resistance of thin ductile sheets using an energy approach, calculating the work done by the fracture process and the plastic process. For safety applications, research and testing of the fracture toughness in automotive steel at high strain rate is very valuable. However, one of the main limitations of testing a materials fracture toughness at high strain rate conditions is that current common test procedures that determine material fracture toughness rely on apparatus that cannot be utilized at high speeds or methodology that can record at static or quasi-static conditions. The EWF method can obtain a value of fracture toughness that not only doesn’t require complex apparatus but also can be performed and obtained at high speeds, making the primary focus of this study, the utilization of the EWF methodology in high strain rate applications and determining its practicality and reliability. This research has attempted to find a successful and usable methodology based around the EWF in the advanced high strength steels: dual phase and TWIP steels, determining how they each respond to low and high strain rate conditions, and validation of the methodology through numerical solutions using finite element analysis. Success in this study will allow the opportunity to define more accurate fracture toughness properties, where the application of automotive steels can be chosen depending on its use cases. A material’s strain rate dependent fracture toughness could be the deciding factor whether it is safer in certain applications.Datasets include raw and processed data from experiments and simulations as well as key images for microstructures of relevant materials. Dataset also includes the FEM model files that require ABAQUS software to open. The main files types are listed as: 'ABAQUS data', which includes excel spreadsheet files of force-displacement data needed for EWF calculations outputted from the ABAQUS software (a finite element analysis software)'ABAQUS Models', which includes the entire model files that can be opened within the ABAQUS software and includes the simulation plots of force-displacement of DENT samples as well as the un-exported contour models of von Mises stress, damage states and plastic strains'EBSD', which includes a PowerPoint presentation that includes the Electron Backscatter Diffraction images of the materials' phase map, inverse pole figure and kernel average misorientation.'FEM images', which includes a PowerPoint Finite Element Method images from ABAQUS detailing specific model sections used in the thesis that come from the model files in 'ABAQUS Models'.'MTS data', which includes excel files of both raw and processed data for force and displacement of samples as well as further processing of EWF calculations.'SEM', which includes a PowerPoint presentation of Scanning Electron Microscopy images of the explored materials.

本学位论文旨在研究并推动高应变率下断裂韧性相关研究方法的发展。本项目主要聚焦于适配改造断裂本质功（Essential Work of Fracture, EWF）方法，使其可应用于高应变率场景。EWF方法是一种极具实用价值的分析工具，可通过能量法分析韧性薄板的断裂抗力，计算断裂过程与塑性变形过程所做的功。针对安全应用场景，开展汽车用钢高应变率下断裂韧性的研究与测试具有重要价值。然而，高应变率下材料断裂韧性测试存在核心局限之一：当前通用的材料断裂韧性测试流程，要么依赖无法适配高速工况的测试装置，要么仅适用于静态或准静态条件下的数据记录。EWF方法可直接获取断裂韧性数值，不仅无需复杂测试设备，还可在高速工况下完成测试并得到结果，因此本研究的核心目标为：将EWF方法应用于高应变率场景，并验证其实用性与可靠性。本研究针对先进高强度钢（双相钢与孪晶诱导塑性（TWIP）钢），探索基于EWF方法的可行测试流程，明确两类材料在低、高应变率条件下的响应特性，并通过有限元分析的数值解验证该方法的有效性。本研究若取得成功，将可实现更精准的断裂韧性性能表征，进而可根据具体使用场景合理选型汽车用钢。材料的应变率相关性断裂韧性，或将成为其在特定应用场景中安全性的决定性因素。本数据集包含实验与仿真得到的原始及处理后数据，以及相关材料微观结构的关键图像。此外，数据集还包含需使用ABAQUS软件打开的有限元模型文件。主要文件类型如下：
‘ABAQUS数据’：包含从有限元分析软件ABAQUS导出的、用于EWF计算所需的力-位移数据Excel表格文件；
‘ABAQUS模型’：包含可在ABAQUS软件中打开的完整模型文件，其中涵盖DENT试样的力-位移仿真曲线，以及未导出的冯·米塞斯应力、损伤状态与塑性应变云图模型；
‘电子背散射衍射（Electron Backscatter Diffraction, EBSD）数据’：包含一份PowerPoint演示文稿，其中展示了材料的相分布图、反极图与核平均取向差的EBSD图像；
‘有限元法（Finite Element Method, FEM）图像’：包含一份PowerPoint演示文稿，其中收录了来自‘ABAQUS模型’文件、用于本学位论文的ABAQUS特定模型截面图像；
‘MTS数据’：包含试样力与位移的原始及处理后数据Excel文件，以及EWF计算的进一步处理结果；
‘扫描电子显微镜（Scanning Electron Microscopy, SEM）图像’：包含一份PowerPoint演示文稿，其中展示了所研究材料的SEM图像。