Dynamic dragline modeling for operation performance simulation and fatigue life prediction

In this study, the three-dimensional (3D) dynamic dragline models are developed for investigating the dynamic dragline performance and front-end structural strength. A virtual prototype of the dragline is created by the dynamic integration of the mechanical and electrical system models using Newton–Euler equations. The mechanical model is modeled as a rigid multi-body system to catch the major kinematics and dynamics behavior of the whole dragline. The electrical model is employed to represent the motors and controls. The dragline front-end is modeled as a flexible multi-body system for the structural strength evaluation using Lagrange equations and finite element analysis (FEA) method. A co-operative simulation (co-simulation) is carried out with the dragline motion, electrical motor/control and the structural flexibility models. The major motions, the machine behavior, the machine operation loads, and structural member stresses are recovered from the simulation. The results of stress-time history are used for structural fatigue life evaluation by Palmgren–Miner’s rule. The results show the boom structural members have lower fatigue lives than tri-structure structural members. The study is significant to provide a solid foundation for further study of failure life analysis of the whole dragline components.