**6. Conclusions**

The Griffith crack problem and the interaction between screw dislocation and semiinfinite crack in cubic quasicrystal piezoelectric materials were studied. With the help of complex function theory, the analytical expression of stress intensity factor was obtained. Numerical examples showed that for the Griffith crack problem, the magnitude of the linear force and the distance from the crack tip have obvious effects on stress intensity factor, while for the interaction between screw dislocation and semi-infinite crack problem, the coupling elastic constant of the phonon and phason fields has a significant effect on the stress intensity factor.

**Author Contributions:** Project administration, Writing—review & editing, J.P.; Conceptualization, Methodology, L.L. All authors have read and agreed to the published version of the manuscript.

**Funding:** This study was supported by the National Natural Science Foundation of China (Nos. 11962026, 12002175, 12162027 and 62161045), the Natural Science Foundation of Inner Mongolia (Nos. 2020MS01018, 2021MS01013) and the Fundamental Research Funds for Inner Mongolia Normal University (Nos. 2022JBYJ020, 2022JBZD010).

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** Not applicable.

**Conflicts of Interest:** The authors declare that they have no conflict of interest with this work. We declare that we do not have any commercial or associative interest that represents a conflict of interest in connection with the work submitted.
