Dynamic analysis of the simultaneous starting of the boom and load lifting mechanisms hoisting for the jib and the cargo of the jib crane with a hydraulic drive

Combining the work of individual mechanisms is carried out to improve the productivity of jib cranes. In particular, the task of joint starting of hoisting mechanisms of jib and cargo is considered in this article. Dynamic loads on crane structural elements, drives, and cargo on a flexible suspension increase with such movement of mechanisms. Increased loads lead to a decrease in the reliability of the crane and an increase in energy costs. When researching the dynamics of the joint starting of hoisting mechanisms of jib and cargo, the jibs system is represented by a mechanical system with four degrees of freedom, which takes into account the main movement of the mechanisms and the oscillatory movement of links with elastic and dissipative properties, as well as the cargo on a flexible suspension in the plane of departure change. A mathematical model of the joint movement of hoisting mechanisms of the jib and cargo was built for such a dynamic model of the boom system of the crane. The obtained model is a system of nonlinear differential equations of the second order, the solution of which was carried out by a numerical method in the form of a computer program. The dynamic of the joint starting of the hoisting mechanisms of the jib and cargo in the jib crane with specific numerical parameters were calculated and studied based on the developed program. The performed calculation made it possible to conduct a dynamic analysis of the joint starting of the hoisting mechanisms. High-frequency oscillations of links with elastic and dissipative properties in the drive of the hoisting mechanism were found as a result of the analysis. Also, low-frequency vibrations of the load on the flexible suspension were found. In the process of starting the mechanisms, high-frequency oscillations are attenuated during the transition process, and low-frequency oscillations of the load are sufficiently long and are attenuated during a significant period. It is recommended to optimize the starting and braking modes to improve the dynamic properties of the hoisting mechanisms of the jib and cargo during their joint movement.