The parts and metal structures of the Crane shall be calculated as follows: fatigue, wear or heat calculation; Strength calculation; strength check. In accordance with these three types of calculations, the crane's computing load has the following three combinations:
1. (Durability), life calculation load --the first class load. The load is used to calculate the durability, wear, or heat of a component or metal structure. According to the equivalent load of normal operation, it not only calculates the load size, but also considers their working time.
The fatigue calculation should be carried out when the stress change cycle is sufficient for the parts and metal structure of the body subjected to variable load. When the stress change cycle is less, then no fatigue calculation is required. The metal structure components and parts of the cranes with working level of A6, A7, A8 should be checked for fatigue.
2. Strength calculation load--the second class load. This class of load is used to calculate the strength of the parts or metal structure, the stability of the compression and bending parts, structural stiffness, the global stability of the crane and wheel pressure. The strength is calculated according to the maximum working load. When determining the strength calculation load, the most unfavorable load combination and that are impossible to occur should be selected.
3. The calculation of load --the class three load. This class is used for calculation of some devices (such as clip rail), luffing mechanism, some parts of the bearing rotating device and the stability and strength of the metal structures and components, as well as the overall stability of the crane. The strength is calculated according to the maximum load and special load in non-working state (installation load, transport load and impact load, etc.) for strength calculation.
In the case of crane accident, the accident caused by the damage of the metal structure and the parts of the mechanism should be checked. The check should according to the actual load of actual condition.