Comfort analysis of crane hoistman based on nonlinear biodynamics coupled with crane-rail system model

Rail defects not only cause crane structure damage but also lead to occupational disorders for the hoistman. To study the influence of rail defects on hoistman comfort, this study establishes a 7 degrees-of-freedom system dynamics model of a human body coupled with a crane-rail model on the basis of human biodynamics and Lagrange equations. Aiming at the problem of fatigue damage for human parts, this study proposes a dynamic response and analysis method for various parts of the human body on the basis of precise integration. Combined with crane optimization parameters, the vibration response of various parts of the human body is solved using the precise integration method. The calculation results are compared with the existing fatigue damage standards of various parts of the human body. Moreover, the damage situation and vibration comfort of various parts of the human body are analyzed, and the influence of seat parameters and nonlinear factors on the vibration of various parts of the human body is discussed. Results show that the comfort of various parts of the human body is poor at low speed and that the fatigue degree of various parts of the human body increases sharply with the increase of rail defects. The damping and stiffness of seats exert little influence on the force of each part of the human body. From the perspective of bearing force, no risk of injury to all parts of the human body exists. The two calculation results of the acceleration response of each part of the human body show minimal deviation under the linear and nonlinear models.