The complex deformation usually involves wide strain-rate change. However, few efforts have been devoted to investigate the effect of strain rate history on the tensile behavior of α + β titanium alloy. In present paper, tensile tests of Ti-6.6Al-3.3Mo-1.8Zr-0.29Si alloy were carried out under both constant and variable strain-rate conditions within the region from 10⁻³~500 s⁻¹. A single stress pulse experimental technique was utilized to conduct the recovery tests. The strain-rate history effect was examined. It is found that the flow stress is independent on the strain rate history, though the alloy exhibits obvious positive strain rate sensitivity. The Taylor-Quinney coefficient of the plastic work converted to heat is proved as 0.9 at high strain rates. The cavitation fracture mechanism is revealed by microstructural observation over the full range explored. In basis of the experimental results and other pulished literatures, empirical Khan-Huang-Liang constitutive model was suitably modified to account for the strain-rate dependent behavior. Good agreement is achieved between the modeling prediction results and experimental data.

Experimental research and numerical simulations of the structural response to shock waves with pulse durations of hundreds of milliseconds, or even seconds, are extremely challenging. This paper takes typical single-layer and sandwich cylindrical shells as the research objects. The response rules of cylindrical shells under long-duration blast loadings were studied. The results show that when the pulse duration is greater than or equal to 4~5 times the first-order period of the structure, the maximum response of the structure tends to be consistent, that is, the maximum response of the cylindrical shells with different vibration shapes shows a saturation effect as the pulse duration increases. This study established the relationship between the saturation loading time and the inherent characteristics of the structure. It was found that the saturation effect was applicable under the following conditions, including different load waveforms, elastic–plastic deformation of the structure, and the loading object being a sandwich shell. This will help transform the long-duration explosion wave problem into a finite pulse-duration shock wave problem that can be realized by both experiments and numerical simulations.

Uniaxial tensile flow properties of a duplex Ti-6.6Al-3.3Mo-1.8Zr-0.29Si alloy in a temperature range from 213 K to 573 K are investigated through crystal plasticity modelling. Experimental results indicate that the initial yield stress of the alloy decreases as the temperature increases, while its work-hardening behavior displays temperature insensitivity. Considering such properties of the alloy, the dependence of the initial critical resolved shear stress (CRSS) on temperature is taken into account in the polycrystal plasticity modelling. Good coincidence is obtained between modelling and the experimental results. The determined values of CRSS for slip systems are comparable to the published data. The proposed polycrystalline model provides an alternative method for better understanding the microstructure–property relationship of α + β titanium alloys at different temperatures in the future.

The duration of an explosion shock wave is a critical parameter in actual explosion scenarios. Insufficient attention has been paid to its influence on surface loading and the consequent damage effects. To investigate how blast wave duration impacts shell pressure loading, we conducted a numerical analysis of fine flow structures and pressure-loading distributions during blast wave interactions with cylindrical shells using high-order large-eddy simulation. The research findings demonstrate that the interaction of explosive waves with cylindrical shells leads to reflected shock waves, expansion waves, decelerating shock waves, and Mach stems. The inherent structural differences within this wave system led to a correlation between the angle and height of the surface load exerted on the shell. The increase in duration enhances the reflected shock wave and results in the more complex and variable wake vortex and shock wave structures on the shell leeward, which enhances the pressure-loading oscillation on the shell leeward. The research also revealed that when the duration surpasses a specific critical threshold, various forms of stationary shock waves will be generated. The structure of the flow field and the surface loads will remain steady-state as the duration continues to extend.

The characterization of near-field blast loads in arbitrary orientation is critical for accurately evaluating damage effects. However, conventional equivalent spherical-blast correlations frequently overlook the flow-field anisotropy induced by the finite geometry and end-initiation mode of cylindrical charges. In this study, numerical simulations were conducted to investigate the shock-wave evolution generated by an end-initiated cylindrical charge using a multiphase Eulerian approach. The research findings demonstrate that the blast field undergoes a multistage evolution involving near-source high-pressure formation, wavefront coalescence, multistage shock interactions, and quasi-spherical attenuation. This wave structure produces pronounced directional nonuniformity in the near-field blast loads. When the scaled distance surpasses a certain critical threshold, the directionality of the pressure load decreases significantly. As the aspect ratio increases, the near-field disparity between axial and lateral loads becomes more pronounced, whereas the critical scaled distance shows an overall decreasing trend with local fluctuations. A semiempirical model grounded in Fourier expansion has been developed to delineate the coupled influences of aspect ratio, scaled distance, and azimuthal angle on peak overpressure and specific impulse. Good consistency with the simulation results was obtained. These results provide a basis for the rapid characterization of directional blast loads and damage assessment for end-initiated cylindrical charges.

Fast calculations are widely required in the traditional applications and the emerging digital twin fields. For those considerations, a novel physics-based fast algorithm, namely generalized rotation-superposition method, is proposed for fast calculating linear elastic responses of generalized rotationally axisymmetric structures under arbitrary mechanical loads. This improved method breaks through the limitations of the previous basic rotation-superposition method in rotational similarity of load and structural axisymmetry, and greatly expands its application scope. In this paper, firstly, the basic theory of the rotation-superposition algorithm is introduced; secondly, the theoretical model of the generalized rotation-superposition method is established; thirdly, the effectiveness and accuracy are verified by using finite element simulations; finally, through a complex case study, the applicability of the generalized rotation-superposition method for complex engineering problems and its advantages in efficiently obtaining massive amounts of data are further illustrated.