本文依Wei等人對Sn/3.9Ag/0.6Cu銲錫材料於溫度 之不同應變率之循環穩態應力-應變遲滯曲線實驗數據來定義內涵時間黏塑性理論之材料參數及應變率敏感函數 。
本文對循環損傷因子以循環最大應力的下降率來定義，並由定應變振幅 - 曲線實驗數據及Percolation理論來決定臨界循環損傷因子 。以含損傷內涵時間黏塑性理論，模擬Sn/3.9Ag/0.6Cu銲錫於定應變範圍0.8%之循環損傷之應力-應變滯遲曲線，與實驗在各損傷因子之應力振幅值皆相當接近。並利用Lee and Chen所提議之內涵損傷演化方程式，配合Zeng等人對Sn/3.8Ag/0.7Cu銲錫材料於298 下應變率 、 之 曲線，藉以推導出Sn/3.9Ag/0.6Cu銲錫材料單軸拉伸下循環損傷與非彈性應變範圍之關係式，並依此建立 關係式；在定義之 下，經由Coffin-Mason修正式計算，所得之值能有效的預測該銲錫於不同應變率下之疲勞初始壽命，進一步比較發現Frequency Modified Conffin-Manson之斜率能有效預測在定應變範圍0.8%下預測值之走勢。

In this paper, the kernel function 、material parameter 、 and the strain rate sensitive function in the Endochronic viscoplasticity were established by using Sn/3.9Ag/0.6Cu experimental cyclically steady hysteresis loops of Wei et. al., in the fixed temperature298K and strain rate( 、 、 、 ).
To define the cyclic damage factor, the reducing rate of maximum cyclic stress was used. The critical cyclic damage could be found by combining experimental vs. data and the Percolation theory. The Endochronic viscoplasticity with damage was used to simulate Sn/3.9Ag/0.6Cu cyclic stress-strain hysteresis loops with damage under strain range 0.8% provided by Wei et. al. in temperature 298K. The results were in very good agreement with stress amplitude data. Employed the evolution equation of intrinsic damage proposed by Lee and Chen and the computed cyclic stress-inelastic strain relation, according to this can established the relational equation ；modified Coffin-Manson relationship( ) was derived and used to predict the data of different strain rate fatigue initiation life very effectively，further compare slope of frequency modified Coffin-Manson and prediction data can find the slope similar the tendency of prediction data at fixed strain range=0.8%.

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