Response of corrosion protection coating systems for offshore components to high compressive loads during lifting

The paper is concerned with the damage of protective coatings and with the estimation of parameters that can characterize their performance under high compressive loads. A test device was designed that duplicated the situation when coated curved steel sections were loaded compressively with commercial hoisting belts. Fourteen multilayer coatings were tested at three different intensity levels. Inspections of the damaged areas revealed a number of damage types in the coatings, namely plastic flow, permanent deformation, crack formation, and delamination. Force-displacement curves were recorded. Two parameters from the force-displacement curves - the contact stiffness, and a typical maximum contact force - could characterize the performance of the coatings. The force-deformation curves were categorized into three types: type I (hoisting strap deformation and coating deformation), type II (hoisting strap rupture and coating deformation), and type III (hoisting strap rupture, coating cracking, and delamination). Coating systems with type III-response were particularly susceptible to compressive loads.