Quantified evaluation of the influence of testing frequency on the fatigue behaviour of unalloyed steels for implementation in resource-efficient fatigue life prediction methods

量化评估测试频率对非合金钢疲劳行为的影响，以实现资源节约型疲劳寿命预测方法

• 批准号: 518776466
• 负责人: Professor Dr.-Ing. Peter Starke
• 金额: --
• 依托单位: Lehrstuhl für Werkstoffprüftechnik
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/518776466?language=en
• 关键词: Quantified; evaluation; influence; testing; frequency

The fatigue life prediction methods (LPV) developed at the department of Materials Science and Materials Testing (WWHK) at the University of Applied Sciences Kaiserslautern have so far been limited to the transition between LCF (Low Cycle Fatigue) and HCF (High Cycle Fatigue) as well as to the HCF range (approx. 3 to 5x10^5 cycles). This has led in part to scientific questions regarding the exploitation of the potential of LPV, which is why systematic investigations are to be carried out in this research project. The reason why it has not yet been possible to extend the procedures and methods to the VHCF (Very High Cycle Fatigue) range is that the WWHK did not have the necessary testing infrastructure to achieve cycle numbers up to 10^8 within a reasonable time frame. Through the approval of the large-scale equipment application, a resonance testing machine was procured and taken into operation, which makes it possible that cycle numbers in the VHCF regime can also be achieved in a technically justifiable time frame. Two factors must be considered here. Relevant damage mechanisms can change from the HCF to the VHCF range. For example, crack initiation points shift into the volume in the area of defects, such as inclusions and precipitates, especially in the case of high-strength material conditions. In the case of ductile materials, damage development can also be detected below the critical threshold value for the activation of persistent slip bands, which can be attributed to the high cycle numbers and the associated accumulation processes. For this reason, it is necessary to check which of the measurement techniques used so far can also be used for the high cycle regime. The deformation rate has a significant influence on the damage development per cycle. It is essential that the relationship between frequency and damage contribution and the resulting fatigue life can be quantified and thus made usable for LPV. The aim is therefore to develop LPV for the use in the VHCF regime and to implement influences regarding deformation rate and load-related mechanisms in mathematical approaches and to validate the prediction quality through experiments. Within the work program, the comprehensive mechanical tests to extend the LPV at WWHK will be supported by detailed microstructural characterization at the Chair of Materials Test Engineering (WPT) at TU Dortmund University. The steel SAE 1045 (C45E, 1.0503) is to be used as test material, since a database for the test frequency 5 Hz is already available from completed investigations. Thus, within this research project, the frequency range of 60 to 260 Hz and thus the use of the resonance test system can be focused on.

凯泽斯劳滕应用科学大学材料科学与材料测试系（WWHK）开发的疲劳寿命预测方法（LPV）迄今为止仅限于LCF（低周疲劳）和HCF（高周疲劳）之间的过渡以及 HCF 范围（大约 3 至 5x10^5 周期）。这在一定程度上引发了有关LPV潜力开发的科学问题，这就是为什么要在这个研究项目中进行系统研究的原因。之所以还无法将程序和方法扩展到 VHCF（极高循环疲劳）范围，是因为 WWHK 没有必要的测试基础设施来在合理的时间范围内实现高达 10^8 的循环次数。通过大型设备申请的批准，采购了一台共振测试机并投入运行，这使得在技术上合理的时间范围内也可以实现 VHCF 体系中的循环数。这里必须考虑两个因素。相关损伤机制可以从 HCF 范围变为 VHCF 范围。例如，裂纹萌生点转移到缺陷区域的体积中，例如夹杂物和析出物，特别是在高强度材料条件的情况下。对于延性材料，在持续滑移带激活的临界阈值以下也可以检测到损坏的发展，这可归因于高循环数和相关的累积过程。因此，有必要检查迄今为止使用的哪些测量技术也可以用于高循环状态。变形率对每个周期的损伤发展有显着影响。至关重要的是，频率和损伤贡献以及由此产生的疲劳寿命之间的关系可以被量化，从而可用于 LPV。因此，我们的目标是开发用于 VHCF 体系的 LPV，并以数学方法实现对变形率和载荷相关机制的影响，并通过实验验证预测质量。在工作计划中，多特蒙德工业大学材料测试工程 (WPT) 主席将支持详细的微观结构表征，以支持在 WWHK 进行的 LPV 综合机械测试。 SAE 1045 钢（C45E，1.0503）将用作测试材料，因为已完成的调查已提供测试频率 5 Hz 的数据库。因此，在该研究项目中，可以重点关注 60 至 260 Hz 的频率范围以及共振测试系统的使用。