@conference{
author = "Ilić, Nemanja and Momčilović, Nikola",
year = "2023",
abstract = "In service, ships are likely to be subjected to various types of loads which are foreseen in the
design phase. In addition, ships can experience rare events and consequently, extreme or oncein-
a-lifetime loads (Paik, 2018). The cause of these loads can be attributed to failed attempts
to evade storms, ship overloading, incidents of grounding and collisions. Such scenarios might
produce a hull girder bending moment reaching the hull’s collapse, i.e., hull girder ultimate
capacity (UC). Thus, the main idea behind the ultimate strength assessments of ships is to
predict the structural capacity of the hull girder until its collapse. Rules and regulations for
sea-going ships have acknowledged the issue (IACS, 2022).
Nevertheless, for inland vessels (or even river-sea ships), no fully developed technical
standards and studies involving state-of-the-art methods for UC assessments exist in practice.
Moreover, studies using sophisticated progressive collapse analysis (PCA) are rare, see one
in (Ilić & Momčilović, 2023). Compared to sea-going ships, inland vessels have a larger length
to height ratio and low hull modulus, and thus, they are prone to longitudinal strength issues.
Coupled with the prolonged service life of inland vessels, UC can be vastly affected. This can
significantly reduce UC and decrease the margin between the elastic and the ultimate strength
response.
Therefore, in order to benchmark the phenomena, the effects of corrosion-induced degradation
on UC of a typical inland waterway vessel are explored by using incremental-iterative
progressive collapse analysis (PCA), a procedure thoroughly defined in (IACS, 2022). The
selected inland vessel is a typical Danube mild steel made barge with the following
dimensions: Loa = 72.9 m, B = 11.40 m, H = 3.7 m, T = 3.55 m. The cross-section of the
vessel is divided into segments according to (IACS, 2022), see Figure 1. The vessel is already
assessed for UC (Ilić & Momčilović, 2023), but just for intact condition.
Firstly, UC is determined using as-built scantlings (new ship). Secondly, ageing effects are
considered by modelling scenarios which include both pitting and uniform corrosion (ageing
ship). Pitting corrosion is defined by pitting intensity degree (DOP) and corrosion intensity
degree (DOC) which define the actual total loss of the volume of the element (ΔV), using the
approach given by (Piscopo & Scamardella, 2021). On the other hand, uniform corrosion is
defined by corrosion wastage (thickness reduction). Namely, uniform corrosion is considered
by 10% of corrosion wastage applied to all structural elements, which is a corrosion level
often found in such structures. In addition, pitting corrosion incidence is presumed in several
locations (segments: 4*, 7*, 8*, and 9*.) and throughout three cases in which ΔV has occurred
(Figure 1): 4%, 10%, and 20%. Pit affected segments were chosen due to their service life. Although corrosion models were not severe, the vessel’s UC is significantly reduced (up to
20%) when various real-service degradation scenarios were considered. Thus, the corrosion
effect significantly influences the UC of the vessel and should not be neglected in the design
phase for the estimations of the strength of ageing ships.",
publisher = "ZONGULDAK BÜLENT ECEVİT UNIVERSITY MARITIME FACULTY",
journal = "I. INTERNATIONAL MARITIME AND LOGISTICS CONGRESS (DELOK’23) 22-23 SEPTEMBER",
title = "Hull Girder’s Ultimate Capacity of the Inland Vessel Under Corrosion Effect",
volume = "1",
url = "https://hdl.handle.net/21.15107/rcub_machinery_7624"
}
