Stress field analysis in a stony meteorite under thermal fatigue and mechanical loadings

Bowen Liang, Jefferson Cuadra, Kavan Hazeli, Soheil Soghrati

In Press, Accepted Manuscript, Available online 20 July 2019



• 3D finite element (FE) analysis of the micromechanical behavior of an asteroidal rock.
• Creating realistic 3D microstructures based on micro-computed tomography images.
• Performing in-situ imaging during experiments to study crack growth in the rock.
• Analyzing predicted stress fields to quantify damage initiation mechanisms in the rock.
• Comparing the behavior of the rock under mechanical loading versus thermal cycling.”

“A micromechanical approach relying on 3D image-based finite element (FE) models, together with experimental testing, is employed to investigate the stress distribution in an L6 ordinary chondrite’s microstructure subjected to thermal and mechanical loadings. An in-situ X-ray micro-computed tomography (micro-CT) setup capable of applying thermal and mechanical loads shed light on crack initiation mechanisms in chondrite samples. Micro-CT images were further used to reconstruct realistic microstructural models of the samples, which were transformed into FE models using an automated non-iterative mesh generation algorithm. FE approximation of stress fields showed that under mechanical loads, the stress often concentrates in matrix-particle interfacial regions with higher curvatures. This could result in the nucleation and eventually propagation of cracks in such regions. However, when the thermal cycling takes place, the stress concentrates more uniformly along with particle interfaces, resulting in their debonding from the surrounding matrix. Both observations were verified by experimental data obtained from in-situ micro-CT imaging.”