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.

迄今为止，材料科学与材料测试系（WWHK）开发的疲劳生活预测方法（LPV）迄今已限于LCF（低周期疲劳）和HCF（高周期疲劳）之间的过渡（高周期疲劳），以及HCF范围（大约3至3至5x10^5 cyc）。这部分导致了有关利用LPV潜力的科学问题，这就是为什么在此研究项目中进行系统研究的原因。它尚无可能将过程和方法扩展到VHCF（非常高的循环疲劳）范围的原因是，WWHK没有必要的测试基础架构，无法在合理的时间范围内实现最高10^8的周期数。通过大规模设备应用程序的批准，采购了共振测试机并进行了运行，这使得VHCF制度中的循环数字也可以在技术上合理的时间范围内实现。这里必须考虑两个因素。相关的损伤机制可以从HCF变为VHCF范围。例如，裂纹引发点转移到缺陷区域的体积，例如夹杂物和沉淀物，尤其是在高强度材料条件的情况下。在延性材料的情况下，还可以检测到损伤的发育低于持续滑动带的激活的临界阈值，这可以归因于高周期数和相关的累积过程。因此，有必要检查到目前为止使用的哪种测量技术也可以用于高周期制度。变形率对每个周期的损伤发展有重大影响。必须量化频率和损害贡献与所得疲劳寿命之间的关系，因此可用于LPV。因此，其目的是开发LPV，以在VHCF制度中使用，并在数学方法中实施对变形率和与负载相关机制的影响，并通过实验验证预测质量。在工作计划中，在Dortmund University的材料测试工程主席（WPT）主席详细的微观结构表征将支持扩展WWHK LPV的全面机械测试。钢SAE 1045（C45E，1.0503）将用作测试材料，因为已完成的研究已经可以使用测试频率5 Hz的数据库。因此，在该研究项目中，可以关注60至260 Hz的频率范围，因此可以关注共振测试系统。