Overhead cranes are a critical tool in many steel mills and other production sites. The goal is to have them in a good shape. Sometimes however, cracks appear. This is not good, as it affects structural integrity, and the crane shouldn’t be used till the issue is resolved and the integrity restored.
Many cracks result from repetitive loading: fatigue. Sometimes the design was not perfect (resulting in stress concentrations), sometimes the usage of the crane was not correct (non-vertical loading, modifications over the years…), connections came loose, welds were not done fully up to spec, or an overload occurred, resulting in a structural change.
Unfortunately, a number of cases in the recent past have learned us that this sort of issues can have even fatal consequences.
An other use case involving structural integrity is related to so-called lifetime extension. This occurs when the plant investigates the option to use a crane longer than it original design life, or when performing an upgrade, or increasing the lifting capacity.
In all these cases it can be relevant to monitor the actual fatigue behavior. This can be connected to a system to monitor deformations at specific locations or parts.
This type of solution is part of Zensor’s modular solution for overhead crane (EOT Crane) monitoring, also applicable to portal cranes and other lifting devices. Measuring strains and deformations and combining it with operational data such as position of the crane, speed, lifted weight and motor currents allows one to get a full overview of the behavior and evolution of the crane’s health. Excessive load cases are identified, the general evolution (ageing) is monitored, and suggestions for improvement are generated.