基于直流电压降法的三点弯曲试样疲劳裂纹扩展速率测量方法  

Measurement on Fatigue Crack Growth Rate of Three-Point Bending Specimens Based on Direct Current Potential Drop Method

作　　者：胡梦[1] 陈凯[1] 张乐福[1] 

机构地区：[1]上海交通大学核科学与工程学院,上海200240

出　　处：《上海交通大学学报》2015年第12期1778-1784,1791,共8页Journal of Shanghai Jiaotong University

基　　金：国家重点基础研究发展规划(973)项目(2014CB046701)资助

摘　　要：通过有限元分析得到了三点弯曲试样的裂纹长度与电压降及裂纹尖端应力强度因子的关系式,开发了可以在应力强度因子恒定、可控升高和降低的条件下进行疲劳试验的软件,通过编写测试程序的方式连续进行不同载荷、载荷比、频率条件下的疲劳试验,在线测量裂纹扩展速率,且根据裂纹长度扩展情况自动改变测试条件.通过对2种镍铝青铜合金材料疲劳裂纹扩展速率测量,对该方法进行了验证,得到了裂纹扩展速率与应力强度因子关系曲线,并利用Priddle公式和ParisErdogan公式拟合得到了裂纹扩展应力强度因子门槛值等疲劳特征参数.The relationships between crack length and potential drop,and stress intensity factor（K）were obtained by finite element analysis.The software for fatigue tests was developed,which could realize constant Kcontrol.Fatigue tests controlled by this software could in-situ monitor crack growth rates at different Kvalues,stress ratios（R）and frequencies,and the loading condition can be automatically changed during crack growths.Two kinds of nickel aluminum bronze（NAB）were used for fatigue crack growth rate（FCGR）test,and the relation between fatigue crack growth rate and stress intensity factor amplitudeΔK was obtained,which verified this testing method.The results were analyzed by the Priddle model and Paris-Erdogan equation,from which the threshold of stress intensity factor amplitude（ΔKth）were obtained.

关 键 词：直流电压降 疲劳裂纹扩展速率 三点弯曲试样 

分 类 号：TL341[核科学技术—核技术及应用]