- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Fatigue behaviors of foreign object damaged Ti-6Al-4V alloys under laser shock peening
摘要： Two-sided and simultaneous laser shock peening (TSLSP) was used to strengthen the Ti-6Al-4V titanium alloy. The fatigue crack growth rate of the specimens was investigated by fatigue test. The results show that both direct TSLSP (TSLSP-D) and indirect TSLSP (TSLSP-I) can reduce the fatigue crack growth rate by producing high magnitude compressive residual stress. The maximum fatigue life increases by 94% (TSLSP-D) and 169% (TSLSP-I) compared with the original specimens. Moreover, the TSLSP-D results show decreased resistance to foreign object damage because of decreased plasticity while the TSLSP-I simultaneously achieves superior foreign object damage resistance and fatigue performance.
关键词： Fatigue performance,Foreign object damage,Two-sided and simultaneous laser shock peening,Titanium alloy
更新于2025-09-23 15:21:01
-
Photoplethysmography Detection of Overreaching
摘要： Introduction: Detecting the onset of functional or non-functional overreaching in endurance athletes is of prior importance to ensure reactive amendment of the scheduled training program. The objective of this study was to assess photoplethysmography (PPG) in overloaded athletes decreased in FOR and improved in AF at the end of OVL. Diastolic time was greater in AF than FOR whilst systolic slope was smaller in AF than FOR during OVL. The variances of systolic, means and variances of systolic, diastolic and dicrotic amplitudes and times as well as systolic and diastolic slopes were used to discriminate FOR and AF athletes. Results: Performance was and test whether 1) it would be affected differently in functional overreached (FOR) or non-overreached acutely fatigued (AF) athletes; 2. Specific PPG characteristics would allow timely distinction of FOR and AF. Methods: Fifteen athletes performed 2-wk baseline (BSL) training followed by 3-wk overload (+45%; OVL) and 2-wk recovery (-20%; RCV). 3000 m running time-trial was used to assess performance at the end of BSL, OVL and RCV and distinguish FOR and AF. PPG was recorded overnight using a wearable sensor, every third night. Overnight diastolic, dicrotic amplitudes, systolic, diastolic slopes and pulse areas were smaller in AF compared to FOR in the last week of OVL. Conclusion: PPG is an efficient tool for the detection of overreaching as it distinguished FOR and AF athletes during OVL (prior performance decrement). This fast-responding method would therefore allow adjusting the daily training content in order to prevent non-functional overreaching.
关键词： photoplethysmography,athlete,fatigue,performance,training overload,overreaching
更新于2025-09-11 14:15:04