The paper presents an application of milli‐ and micro‐XCT to mesostructure characterization of CGPs and failure patterns analysis using dynamic impact simulations. In this study, XCT scanning experiments are firstly conducted on CGPs, followed by a series of image analyses with qualitative results. Then, the 3D mesomorphological parameters and internal composition of individual particles are quantitatively characterized. Finally, dynamic impact loading in y‐axis direction is modelled to investigate the 3D mesostructure and different impact velocity effects on failure patterns of individual particles. The studies show that the mesomorphological parameters present different distribution characteristics in individual CGPs. The approximate location of gangue phase is the key parameter that should be taken into account to study failure patterns as well as fracture mechanism of the heterogeneous rock materials. The XCT image‐based numerical model proved to be an effective tool that gives insights into the mesodeformation mechanisms of heterogeneous coal rock (HCR) undergoing dynamic impact failure behavior.

A thorough understanding of the impact of the 3D meso-structure on damage and failure patterns is essential for revealing the failure conditions of composite rock materials such as coal, concrete, marble, and others. This paper presents a 3D XCT dataset of coal rock with 1372 slices (each slice contains 1720 × 1771 pixels in x × y direction). The 3D XCT datasets were obtained by MicroXMT-400 using the 225/320kv Nikon Metris custom bay. The raw datasets were processed by an automatic semantic segmentation method based on the Swin Transformer (Swin-T) architecture, which aims to overcome the issue of large errors and low efficiency for traditional methods. The hybrid loss function proposed can also effectively mitigate the influence of large volume features in the training process by incorporating modulation terms into the cross entropy loss, thereby enhancing the accuracy of segmentation for small volume features. This dataset will be available to the related researchers for further finite element analysis or microstructural statistical analysis, involving complex physical and mechanical behaviors at different scales.

To improve the low viscosity and poor lubrication characteristics of high-water-based hydraulic liquid, the abrasion and leakage problems in hydraulic components need to be addressed. In a high water-based hydraulic motor with self-balanced distribution valve (HWBHM-SDV), there are two key friction pairs: the piston-crankshaft pair and piston-swivelling-cylinder (PSC) pair. To study the working performance of the PSC pair in HWBHM-SDV, we firstly designed the structural parameters. We found that, within the working speed 0–100 rpm, the leakage in the PSC pair is mainly caused by pressure-gradient flow, and the influence of the seal will not be significant when the seal length is 24 mm. Then, the friction coefficients of different matching materials were tested. It was found that the friction coefficient of 316L stainless steel with OVINO-GIC (OVINO-graphite intercalated compound) coating (316L-GIC)/PEEK reinforced with 30% carbon fibre (PEEK-30CF) is about 0.02~0.04, and the friction coefficient of 316L-GIC/316L-GIC is about 0.05–0.07. Finally, the influences of factors (clearance, temperature, pressure, and material) on leakage performance were analysed based on an orthogonal test method considering fluid-structure interaction. It was found that clearance has the most significant influence on leakage, followed by pressure and liquid temperature, and the difference between matching materials 316L-GIC/316L-GIC and 316L-GIC/PEEK-30CF is insignificant when the clearance is less than 8 μm and the working pressure is less than 10 MPa. Moreover, the difference in volume efficiency loss between theoretical analysis and calculated result considering fluid-structure interaction increases with the increase of working pressure and working speed. To ensure good working performance of a PSC pair, matching materials 316L-GIC/PEEK-30CF could be selected for pressures below 15 MPa, while 316L-GIC/316L-GIC could be used at 28 MPa.