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标题: 求助单轴拉伸应力和应变的关系异常 [打印本页]

作者
Author: 潇潇的kk 时间: 2025-7-2 10:49
标题: 求助单轴拉伸应力和应变的关系异常
各位老师，我在做单轴拉伸应变的时候，应力和应变的关系如图。我看文献中的没有小尾巴出现，要么突然断裂要么塑性形变。我想问是我做的哪个地方不对吗？（附上我的INCAR）

作者
Author: chenfei 时间: 2025-7-4 19:48
弹性常数计算是利用有限差分法计算，你这静态计算前是否将结构优化至收敛，最好附上outcar文件，可以查看收敛情况。

作者
Author: lrl@qhu 时间: 2025-11-12 13:55
楼主您好，最近我也在学习界面模型的单轴拉伸，有几点问题想向您请教：
1.计算应力应变需要重新编译vasp固定轴吗？
2.我采用的vaspkit生成的一系列的C文件夹下面有不同应力应变的文件夹，问ai是计算单个C33的即可对应拉伸c轴。
但是计算结果全为负值，这是什么原因？
== strain_0.000/ ===
  in kB    -2.29707 -2.29707 -7.40960    0.00000    0.00000    0.00000
  external pressure =    -4.00 kB  Pullay stress =       0.00 kB

=== strain_+0.025/ ===
  in kB    -7.46276 -7.46276 -23.66026    0.00000    0.00000    0.00000
  external pressure =    -12.86 kB  Pullay stress =       0.00 kB

=== strain_+0.050/ ===
  in kB    -12.03457 -12.03457 -36.66675    0.00000    0.00000 -0.00000
  external pressure =    -20.25 kB  Pullay stress =       0.00 kB

=== strain_+0.075/ ===
  in kB    -16.45010 -16.45010 -46.55441    0.00000    0.00000 -0.00000
  external pressure =    -26.48 kB  Pullay stress =       0.00 kB

=== strain_+0.100/ ===
  in kB    -21.12315 -21.12315 -52.19550    0.00000 -0.00000    0.00000
  external pressure =    -31.48 kB  Pullay stress =       0.00 kB

=== strain_+0.125/ ===
in kB    -25.45490 -25.45490 -55.57070    0.00000    0.00000    0.00000
  external pressure =    -35.49 kB  Pullay stress =       0.00 kB

=== strain_+0.150/ ===
  in kB    -29.14567 -29.14567 -58.00326    0.00000    0.00000    0.00000
  external pressure =    -38.76 kB  Pullay stress =       0.00 kB

=== strain_+0.175/ ===
  in kB    -32.49653 -32.49653 -59.27669    0.00000    0.00000 -0.00000
  external pressure =    -41.42 kB  Pullay stress =       0.00 kB

=== strain_+0.200/ ===
  in kB    -35.04080 -35.04080 -60.77160    0.00000    0.00000 -0.00000
  external pressure =    -43.62 kB  Pullay stress =       0.00 kB

=== strain_+0.250/ ===
  in kB    -38.17822 -38.17822 -63.92614    0.00000    0.00000    0.00000
  external pressure =    -46.76 kB  Pullay stress =       0.00 kB

=== strain_+0.300/ ===
  in kB    -40.00768 -40.00768 -65.45294    0.00000    0.00000    0.00000
  external pressure =    -48.49 kB  Pullay stress =       0.00 kB

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