A new constitutive equation on ice materials

Abstract

The structural crashworthiness analysis involving buckling, plasticity, crushing, and fracture with the strainrate effects is required to evaluate the characteristics of structural deformations and impact energy dissipation at the event of collisions between ships or offshore platforms and icebergs. The constitutive equations of both steels and ice materials should be characterised for numerical computations as the collision impact energy is dissipated by the two colliding and deformable bodies, namely not only ships or offshore platforms but also icebergs. The primary objective of the present study is to examine ice properties and propose a constitutive equation of ice materials which shall be implemented into nonlinear finite element method computations of the structural crashworthiness associated with the collisions. Previous studies are first surveyed in terms of the influencing parameters as the many uncertainties involved make the problem highly complex. The parameters affecting the mechanical properties of ice materials are then discussed. In addition to referencing the existing test database associated with the mechanical properties of ice materials, a new test database is obtained by laboratory testing of the authors' group. Based on findings from the existing and the new test database, a new constitutive equation used for ice materials is proposed associated with quasi-static and impact responses.

Quantitative collision risk assessment of a fixed-type offshore platform with an offshore supply vessel

“…[22] provided a test database for various types of steel and aluminium. Accordingly, The strain rate ( ) significantly affects the dynamic properties of the material [24][25][26]. However, this could not be directly obtained from LS-DYNA.…”

Computational models for the structural crashworthiness analysis of a fixed-type offshore platform in collisions with an offshore supply vessel

“…Strain rate (  ) (or speed of impact loading) significantly affects the dynamic properties of the material [28,29]. It is considered to be the primary factor affecting collision mechanics and structural crashworthiness.…”

“…Fig 29. Force-deformation curves for bulb and forecastle section of bow structure to a rigid column member (L 5 ).…”

Establishing a common database of ice experiments and using machine learning to understand and predict ice behavior

“…The majority of PCCs is as expected and in line with relationships given in the literature. Higher temperature leads to lower absolute peak stress (Ince et al, 2016;Schulson, 1990), so do bigger grain size (Schulson, 1990(Schulson, , 1999 and porosity (ZhiJun et al, 2011). Higher strain rates lead to higher absolute peak stresses (Ince et al, 2016;Timco and Weeks, 2010), so do higher absolute triaxiality values (Schulson, 1999).…”