Study on the member fracture and collapse performance of single-layer grid structures using discrete solid element method

Abstract

In this study, the discrete solid element method (DSEM) incorporating a softening model is proposed, to accurately simulate the dynamic crack propagation and the member fracture of the single-layer grid structure. Firstly, based on the fracture criteria of strain energy release rate, the bilinear softening model and the trilinear softening model are proposed to simulate the fracture in both elastic and elastic-plastic materials. Secondly, the validity of the proposed approach is assessed through a comparison with empirical results. Furthermore, the fracture of the rectangular beam, dynamic crack propagation of the circular tube and member fracture of the hexagonal spatial rigid frame are simulated and compared with other numerical methods. Finally, the DSEM with the softening model is employed to investigate the collapse performance of single-layer grid structures, and the whole process of member fracture is captured by the DSEM. A thorough analysis is conducted to evaluate the influence of material parameters, loading methods, and rise-span ratios on the bearing capacity and fracture occurrence of single-layer grid structures. The results show that the material property of steel is superior to aluminum for single-layer grid structures. Moreover, the single-layer grid structures adopting full node loading or high rise-span ratios are shown to exhibit premature member fracture and rapid structural collapse. The obtained results exhibit remarkable agreement with the experimental results and are superior to the finite particle method (FPM) and the extended finite element method (XFEM). Therefore, DSEM with the softening model possesses the potential to evolve into an effective numerical tool capable of solving complex problems such as dynamic crack propagation and structural collapse.