Crane Load, Cranes Static/Dynamic Load Introduction
Crane in operation, to withstand a variety of loads (such as static load, dynamic load, alternating load, shock load, vibration load, etc.), the bearing parts and structural components will produce the corresponding stress and deformation, if more than a certain limit, will lose function or even destruction, thus causing danger.
1、Introduction of cranes load
Crane in the course of operations, the complexity of the load bearing is not only reflected in the diversity of load types, and with the different working conditions of the crane operation and the performance of variable characteristics. Load is the crane and its component parts of the normal working force analysis of the original basis, but also parts of the scrapping or the cause of the accident to determine the basis of analysis, load to determine the accuracy of the results of the calculations will have a direct impact on the safety of the conclusions and the correctness of the accident.
Gantry crane
2、cranes static load introduction
When the crane is at rest or stable running state, the crane is only subject to the self-weight load and lifting load static load.
(1) self-weight load PG, which includes the crane’s metal structure, mechanical equipment, electrical equipment, as well as attached to the crane on the warehouse or conveyor and its materials, such as gravity (except the gravity of the lifting load). The mode of action of the load can be considered separately, in general, the mechanical equipment and electrical equipment load is considered to be concentrated load;
(2) Lifting load PQ. This refers to the gravitational force of all lifting masses. This includes the gravity of the Z-large effective article allowed to be lifted, the pick-up device (e.g. the following pulley block, hooks, lifting beams, grabs, containers, lifting electromagnets, etc.), the suspended winding parts, and the gravity of the other prepared masses in the lift. Lifting height of less than 50 m lifting rope weight can be disregarded.
3, cranes dynamic load introduction
Dynamic load is the crane in the movement state change when the dynamic load effect. It is an important basis for strength calculation, fatigue calculation also has an impact.
Crane does not work or load static in the air. Its deadweight load and lifting load in a static state. When the crane is working. When the state of motion changes. Dynamic load effect makes the original static load value increases. The increased part is the dynamic load. Dynamic load, including the structure of the structure in variable-speed movement of self-weight and lifting load generated by the inertial load; due to the wheel through the uneven track joints or moving parts of the buffer impact generated by the impact load; inertial load and impact load to the elasticity of the metal structure and mechanism of the vibration load vibration system. Dynamic load and the direction of motion and working speed (acceleration), and structural factors (such as the distribution of system mass, system stiffness and damping, etc.), and with the use of conditions (such as the size of the external load and its change rule. There is no impact, etc.). In order to calculate the convenience, usually with power coefficient (dynamic load and static load ratio). When used, generally according to the actual situation, consult the crane design specifications and relevant manuals to choose.
