The effect of the extension of the instrumentation on the measured ice-induced load on a ship hull

Abstract

Due to the complexity of the ice-structure interaction, the knowledge about the ice-induced loads on a ship hull has been gained from full-scale measurements. As the instrumentation of the hull for the measurements is expensive, the extension is concerned at the planning phase. However, a narrow instrumentation can cause an error in the measurements, as the response of the adjacent frames with respect to the observed frame is not known. Thus, this paper studies the differences between loads measured from one or several frames on board S.A. Agulhas II. The difference results from the ability of the structure to transport loading internally. The results show that when the loads affect only an individual frame, the instrumentations give similar results. However, the difference increases with the load length and the loading that is determined can be 15% higher for one frame instrumentation for a structure similar to the aft shoulder of S.A. Agulhas II. Furthermore, the difference in the mean value and standard deviation of the measurement time histories can be up to 10%. The study presents a new efficient method to obtain a rough estimate of the possible difference in the measured results between extensive and narrow instrumentation.