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Numerical Study on Phase Transformation Induced Material Fracture

Description: 

The physical mechanisms triggering intermediate-depth earthquakes remain a puzzle for the scientific community. However, many studies discussed phase transformation as the primary mechanism behind generating these earthquakes. The objective of this study is to develop a numerical model for simulation of phase transformation-induced failure in geo-materials. The materials of interest include different minerals found in the mantle transition zone such as olivine. To study the phase transformation behavior under the loading condition mimicking earth’s crust, a thermo-mechanical finite element modeling approach has been taken. A multiscale model, based on Mahnken et al., 2015, has been developed to capture the evolution of phase transformation. The results from the model capture the signature behavior reported in the literature and validate the experimental phase diagram for olivine to spinel transformation. To study the microstructural failure induced by phase transformation, extended finite element method has been used with the above model. The results show an early and higher amount of crack propagation with phase transformation and a higher volume fraction of transformed mineral near the crack. A multigrain model with micro defects has been constructed to study the fracture evolution under confining pressure, and temperature conditions and has been validated with the load-displacement data from the laboratory experiments (Wang, Y et al., 2017).The model will be further upscaled to simulate the fault generation at the macroscale to investigate the role of phase transformation in the formation of large-scale faults.

REFERENCES
Mahnken, R., Schneidt, A., Antretter, T., Ehlenbröker, U. and Wolff, M., 2015. Multi-scale modeling of bainitic phase transformation in multi-variant polycrystalline low alloy steels. International Journal of Solids and Structures, 54, pp.156-171.
Wang, Y., Zhu, L., Shi, F., Schubnel, A., Hilairet, N., Yu, T., Rivers, M., Gasc, J., Addad, A., Deldicque, D. and Li, Z., 2017. A laboratory nanoseismological study on deep-focus earthquake micromechanics. Science advances, 3(7), p.e1601896.

Session: Structure and Properties of Subducting Slabs and Deep Earthquakes

Type: Oral

Date: 4/19/2023

Presentation Time: 02:15 PM (local time)

Presenting Author: S Sindhusuta

Student Presenter: Yes

Invited Presentation: 

Authors