基于耗散能密度的疲劳裂纹扩展规律研究

On the Fatigue Crack Propagation Based on Dissipated Energy Density

在疲劳裂纹扩展过程中,裂纹尖端的能量耗散决定了裂纹扩展能力。研究基于耗散能密度的裂纹扩展规律更有物理意义。耗散能密度是材料疲劳性能的一种表征参数,实验测得了镍基高温合金GH4169材料室温和450℃高温的耗散能密度与控制应力幅值的关系曲线。参照Paris公式的形式提出了基于耗散能密度的裂纹扩展方程,并通过疲劳裂纹扩展试验测量了GH4169材料在室温和450℃高温下的裂纹扩展速率与耗散能密度的关系。试验结果的总体趋势与所提出的扩展方程一致。

In the fatigue crack propagation process, the dissipated energy on crack tip determines the capability of fatigue crack propagation. Dissipated energy density is a characteristic parameter describing material fatigue performance. The fatigue crack propagation study will have more significance based on dissipated energy density. The curve between dissipated energy density of Nibased alloy GH4169 and controlling stress amplitude was experimentally measured at room temperature and 450℃ respectively. According to the form of Paris equation, fatigue crack propagation equation was established based on dissipated energy density. Experiments were carried out to verify the relation between fatigue crack propagation rate and dissipated energy density for GH4169 at room temperature and 450℃ respectively. The trend of experimental results agrees with proposed equation in a whole.