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1.疲劳寿命估算方法概述 目前,工程中广泛采用的疲劳裂纹形成寿命估算方法主要有两种——名义应力法和局部应力-应变法。名义应力法利用所计算元件的名义应力历程和相应材料的光滑和缺口小试件的S-N曲线,通过线性累积损伤理论(Palmgren-Miner假设)计算疲劳损伤。名义应力法不考虑应力集中区进入塑性后的真实应力、应变状态,也不考考高、低峰值载荷对疲劳寿命
1. Overview of fatigue life estimation method At present, there are mainly two methods for fatigue life prediction of fatigue cracks widely used in engineering - the nominal stress method and the local stress-strain method. The nominal stress method calculates the fatigue damage by the linear cumulative damage theory (Palmgren-Miner assumption) using the calculated nominal stress history of the element and the S-N curve of the small and smooth specimens of the corresponding material. Nominal stress method does not consider the stress concentration zone into the plastic after the true stress and strain state, nor test the high and low peak load fatigue life