Analysis of a Collision-Energy-Based Method for the Prediction of Ice Loading on Ships

Abstract

Ships designed for operation in Polar waters must be approved in accordance with the International Code for Ships Operating in Polar Waters (Polar Code), adopted by the International Maritime Organization (IMO). To account for ice loading on ships, the Polar Code includes references to the International Association of Classification Societies’ (IACS) Polar Class (PC) standards. For the determination of design ice loads, the PC standards rely upon a method applying the principle of the conservation of momentum and energy in collisions. The method, which is known as the Popov Method, is fundamentally analytical, but because the ship–ice interaction process is complex and not fully understood, its practical applications, including the PC standards, rely upon multiple assumptions. In this study, to help naval architects make better-informed decisions in the design of Arctic ships, and to support progress towards goal-based design, we analyse the effect of the assumptions behind the Popov Method by comparing ice load predictions, calculated by the Method with corresponding full-scale ice load measurements. Our findings indicate that assumptions concerning the modelling of the ship–ice collision scenario, the ship–ice contact geometry and the ice conditions, among others, significantly affect how well the ice load prediction agrees with the measurements.

A Combined Experimental and Numerical Approach to Predict Ship Resistance and Power Demand in Broken Ice

“…It's worth noting that, because both of its models are two dimensions, the overturning motion of the broken ice is not considered. Idrissova et al (2019) used a collision-energy-based method to predict ice loads on ships, which agrees well with full-scale measurements, but the implementation relies on the use of multiple assumed coefficients concerning the ship-ice interaction process. Using a theoretical approach Zong and Zhou (2019) considered part of fluid effects, such as the added mass of ice moving in a constant flow field, and verified the relationship between vessel speed, ice concentration, and ice resistance based on experimental results.…”

Comparison of Lightweight Structures in Bearing Impact Loads during Ice–Hull Interaction

“…The rigid body impactor must be a good substitute to the ice model. Correspondingly, the impactor dimensions is deduced, so that the mean impact pressure is equal to the largest freshwater ice crushing strength of 38 MPa observed during bore-hole tests [41], since the crushing strength represents the maximum possible ice pressure for a structure [42]. For a design vessel speed of 6 knots, the contact area corresponding to the high pressure zone (HPZ) area [43] and the length and mass of the impactor are calculated (see Table 3).…”

Special Issue on the Recent Advances in Safe Maritime Operations under Extreme Conditions

“…Idrissova et al [5] analyze the effect of the assumptions behind the Popov method by comparing ice load predictions, calculated by the method, with corresponding full-scale ice load measurements. The findings indicate that assumptions concerning the modelling of the ship-ice collision scenario, the ship-ice contact geometry, and the ice conditions, among others, significantly affect how well the ice load prediction agrees with the measurements.…”