Life Prediction of Long-Term Creep-Fatigue

长期蠕变疲劳的寿命预测

• 批准号: 61550062
• 负责人: SAKANE Masao
• 金额: $ 1.15万
• 依托单位: Ritsumeikan Universty
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1986
• 资助国家: 日本
• 起止时间: 1986 至 1987
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-61550062/
• 关键词: Creep-Fatigue; Long Term Hold-Time; Elevated Temperature; Low Cycle Fatigue; Notch Effect; FEM Analysis; Linear Summation Damage Rule; Strain Range Partitioning Method; 寿命予測; Creep-Fatigue; Long Term Hold-Time; Elevated Temperature; Low Cycle Fatigue; Notch Effect; FEM Analysis; Linear Summation Damage Rule; Strain Range Partitioning Method; 寿命予測

The objective of this project is to develop a life prediction method of long term creep-fatigue.The test material used here was a SUS 304 austenitic stainless steel and the push-pull creep-fatigue test was carried out at K. the main conclusions obtained are as follows:(1)We developed a life prediction method of long term creep-fatigue based on the static creep and the no-hold-time low cycle fatigue data. The strain controlled fatigue tests with various hold-times ranging from 5 min and 24 hr were carried out and the fatigue data were generated.The life prediction was made based on the linear summation damage rule with the critical creep/fatigue damage defined in the ASME Code Case for the short and long term creep-fatigue life.The predicted results closely agreed with the experimental creep-fatigue life with the hold-times between 5min and 24hr.(2)The life prediction method developed in the smooth specimen was extended to the notched specimen in the second year of this project.The cyclic elastic-plasticcreep FEM analysis was made for the made for the three types of the circumferential notched specimens whose elastic stress concentration factors were 2.6,4.2 and 6.0. The stress waves analyzed were the triangular stress wave with frequency of 0.1 Hz,the trapezoidal stress wave with 166-min tensile hold-time and slow-slow wave with frequency of 0.0001 Hz. The analysis was made up to 1(1/4)cycle. The creep-fatigue life was predicted based on the calculated local stress/strain at the notched root from linear summation damage rule and the strain range partitioning method. The predicted life agreed with the experimental creep-fatigue life and we concluded that the FEM method was applicable to estimating the long term hold-time and slow-slow fatigue life.

该项目的目的是开发一种长期蠕变效率的生命预测方法。这里使用的测试材料是SUS 304奥氏体不锈钢，并在K处进行了推动蠕变蠕变测试。所获得的主要结论如下：（1）我们根据长期蠕变的creep creep creep creep creep and creep creep and-not-fitection and fatection and tatic creep and tatic fateptige and tatic fatep and cateep and catep andep and-not-fitece and catep and-fitect and catep andep and catepep and catep and catepep and catepeep and进行了应变控制的疲劳测试，各种持有时间从5分钟到24小时进行并产生疲劳数据。生命预测是根据线性求和损伤规则进行的，其对ASME代码中定义的关键蠕变/疲劳损害的短期和长期蠕变效果的creep-Fatigue Life。与creep creepif的寿命之间定义的关键损害。 24小时（2）在该项目的第二年中，在光滑试样中开发的生命预测方法扩展到了缺口标本。针对三种类型的圆周凹痕标本的循环弹性弹性 - 塑性creep fem进行了分析，其弹性应力浓度为2.6,4.4.2和6.0。分析的应力波是频率为0.1 Hz的三角应力波，梯形应力波，具有166分钟的拉伸时间保持时间和慢速慢速波，频率为0.0001 Hz。分析最多可达1（1/4）周期。根据线性求和损伤规则和应变范围分配方法，基于计算出的局部应力/应变预测的蠕变效果寿命。预测的生活与实验性的蠕变寿命一致，我们得出的结论是，FEM方法适用于估计长期保持时间和缓慢的疲劳寿命。