Determination of dynamic loads in the crane suspension when lifting a load from a rigid base

Abstract

Loading and unloading works are an integral part of the construction process. Cranes of various types were mostly use to perform these works. To ensure trouble-free operation and increase the reliability of cranes, when calculating structures and components of their working equipment, it is important to take into account dynamic loads, which are several times higher than static loads. Elements of dynamic loads in the crane suspension are its elastic components (flexible traction bodies) - ropes. The process of lifting a load from a rigid base and picking it up is considered, which divided into three stages: the first is the selection of clearances and the tension of the ropes; the second is the pre-opening stage of lifting the load; the third is the post-detachment stage of lifting the load. For each stage, the initial conditions accepted, the differential equations of the movement of loads compiled, their solution given taking into account many factors, and expressions derived for determining the forces in the load suspension. At the first stage, the duration of the gap selection (tension of the ropes) is determined, at the second stage, the speed of separation of the load from the base is determined, at the third stage, the maximum force in the elastic element determined. The method of determining the forces in the suspension of the load, the duration of the selection of clearances (tension of the ropes), the speed of separation of the load from the base, and the maximum force in the elastic element presented in the work allows you to significantly simplify the solution of complex equations, to determine simple expressions and to determine them with sufficient accuracy for practical calculations values.

Keywords

• crane
• mechanism
• load
• moment
• effort