An I-integral method for crack-tip intensity factor variation due to domain switching in ferroelectric single-crystals
An I-integral method for crack-tip intensity factor variation due to domain switching in ferroelectric single-crystals
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铁电单晶中由于磁畴切换引起的裂纹尖端强度因子变化的 I 积分方法
DOI：
10.1016/j.jmps.2016.04.031
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发表时间：
2016-09
影响因子：
5.3
通讯作者：
Kitamura Takayuki
中科院分区：
文献类型：
--
作者：
Yu Hongjun;Wang Jie;Shimada Takahiro;Wu Huaping;Wu Linzhi;Kuna Meinhard;Kitamura Takayuki
本文建立了求解铁电单晶裂纹尖端强度因子的I积分方法。将I积分与相场模型相结合，成功地研究了在机电载荷作用下铁电体中的磁畴转变引起的裂纹尖端强度因子的变化，这与以往基于小尺度转变的方法相比显示出了一些优点。首先，用含时的Ginzburg-Landau方程预测裂纹尖端周围的转换区的形状，该方程不需要预先设定的基于能量的转换准则。其次，通过在实际状态上叠加一个辅助状态，I积分可以直接求解裂纹尖端强度因子，并将不同模式的裂纹尖端强度因子解耦。第三，I积分是面积无关的，也就是说，I积分不受积分面积大小、极化分布或磁区壁的影响。这使得I积分适用于大规模的域切换。为此，我们计算了PbTiO_3铁电单晶中非渗透裂纹在电、机械和联合载荷作用下的电弹性场强度因子。由I积分得到的强度因子与用外推技术得到的强度因子符合得很好。从数值结果中可以得出以下结论，即铁电材料在大范围开关下的断裂行为。在位移控制的机械载荷作用下，应力强度因子(SIF)单调下降，这意味着发生了裂纹尖端的屏蔽或有效的开关诱导增韧。在外加电场的情况下，所有情况下的电位移强度因子(EDIF)都会增加，即形成的磁畴图案增加了电裂纹尖端的载荷。用裂纹尖端J积分表示的能量释放率在所有的例子中都是由域转换而减小的，这突出了转换诱导增韧效应。相反，在应力控制载荷作用下，应力强度因子由于大范围的切换而演化到一个高于非切换初始值的稳定值，即在这种情况下促进了断裂。
In the present study, an I-integral method is established for solving the crack-tip intensity factors of ferroelectric single-crystals. The I-integral combined with the phase field model is successfully used to investigate crack-tip intensity factor variations due to domain switching in ferroelectricity subjected to electromechanical loadings, which exhibits several advantages over previous methods based on small-scale switching. First, the shape of the switching zone around a crack tip is predicted by the time-dependent Ginzburg–Landau equation, which does not require preset energy-based switching criterion. Second, the I-integral can directly solve the crack-tip intensity factors and decouple the crack-tip intensity factors of different modes based on superimposing an auxiliary state onto an actual state. Third, the I-integral is area-independent, namely, the I-integral is not affected by the integral area size, the polarization distributions, or domain walls. This makes the I-integral applicable to large-scale domain switching. To this end, the electro-elastic field intensity factors of an impermeable crack in PbTiO3ferroelectric single crystals are evaluated under electrical, mechanical, and combined loading. The intensity factors obtained by the I-integral agree well with those obtained by the extrapolation technique. From numerical results, the following conclusions can be drawn with respect to fracture behavior of ferroelectrics under large-scale switching. Under displacement controlled mechanical loading, the stress intensity factors (SIFs) decrease monotonically due to the domain switching process, which means a crack tip shielding or effective switching-induced toughening occurs. If an external electric field is applied, the electric displacement intensity factor (EDIF) increases in all cases, i.e., the formed domain patterns enhance the electric crack tip loading. The energy release rate, expressed by the crack-tipJ-integral, is reduced by the domain switching in all examples, which underlines the switching-induced-toughening effect. In contrast, under stress controlled load, the SIF evolves due to large-scale switching to a stable value, which is higher than the non-switching initial value, i.e., fracture is promoted in this case.
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机械载荷下极化 BaTiO3 单晶的畴切换与裂纹扩展之间的相互作用
影响因子：
9.4
作者：
通讯作者：
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影响因子：
9.4
作者：
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通讯作者：
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影响因子：
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DOI：
10.1093/acprof:oso/9780198507789.001.0001
发表时间：
1977-10
期刊：
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影响因子：
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作者：
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通讯作者：
M. Lines;A. Glass;G. Burns
影响因子：
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