Partitioned Strong Coupling of Discrete Elements with Large Deformation Structural Finite Elements to Model Impact on Highly Flexible Tension Structures

This article presents a staggered approach to couple the interaction of very flexible tension structures with large deformations, described with the finite element method (FEM), and objects undergoing large, complex, and arbitrary motions discretized with particle methods, in this case the discrete element method (DEM). The quantitative solution quality and convergence rate of this partitioned approach is highly time step dependent. Thus, the strong coupling approach is presented here, where the convergence is achieved in an iterative manner within each time step. This approach helps increase the time step size significantly, decreases the overall computational costs, and improves the numerical stability. Moreover, the proposed algorithm enables the application of two independent, standalone codes for simulating DEM and structural FEM as blackbox solvers. Systematic evaluations of the newly proposed iterative coupling scheme with respect to accuracy, robustness, and efficiency as well as cross comparisons between strong and weak FEM-DEM coupling approaches are performed. Additionally, the approach is validated against the rest position of an impacting object, and further examples with objects impacting highly flexible protection structures are presented. Here, the protection nets are described with nonlinear structural finite elements and the impacting objects as DEM elements. To allow the interested reader to independently reproduce the results, detailed code and algorithm descriptions are included in the appendix.

Mamoru Kawaguchi: Master of motion and lightness of structures

Mamoru Kawaguchi (1932–2019) was one of the great structural engineers of the late 20th century. He developed his career mostly in Japan and he has also superb works in China, Singapore and Spain. The spectrum of his structures is manifold: he designed shells, space frames, inflatable structures, tension structures, timber–steel hybrid systems and so on. With them, he conceived and provided the bones and muscles of sports halls, exhibition halls, museums, railway stations, towers, bridges and sculptures. Kawaguchi collaborated with some of the best architects of his time: Kenzo Tange, Arata Isozaki and Kazuyo Sejima just to cite some of the internationally most renowned. For his works, he was awarded many times in Japan, as well as internationally (the Architectural Institute of Japan award, the International Association for Shell and Spatial Structures Torroja Medal, the International Association for Bridge and Structural Engineering International Award and many others). In this article, I review Mamoru Kawaguchi’s main professional and academic achievements, and discuss his design philosophy, sources of inspiration and means to develop his ideas from my own personal experience.