Combined strain rate, mesh size and calibration test influence on structural failure: Miniature ship grounding test

Abstract

This paper investigates the influence of the strain rate and element size on the fracture of steel plates presented in marine structures undergoing grounding when modeled by the finite element method. Three different experimental tests (tensile, tearing and perforation tests), performed at different velocities, are used in the study. These tests are conceived to cover diverse rupture modes related mainly to crack initiation and propagation. Plastic strain-and stress state-based failure criteria were calibrated from these experiments. Sensitivity to strain rate and mesh size were also evaluated. A ship grounding event was reproduced experimentally in 1:100 reduced scale. This experiment was FE modeled to evaluate the performance of the aforementioned failure criteria. The results verified the significant influence of the strain rate and stress state on the failure strain. In addition, it is shown that the sole use of tensile tests is not enough to properly characterize the material failure observed in the structural collapse mode of the miniature ship bottom structure. This collapse is shown to be a combination of stretching and tearing of structural members.

Impact Response of a Double-Bottom Structure with High and Penetrated Girders and Floors

“…In such simulations, most numerical definitions have become standardised except the definition of material nonlinearities. The key material definitions are involved in plastic strain hardening, strain rate sensitivity, and dynamic 3 of 17 fracture strain [3,[17][18][19][20][21]. The material strain hardening is captured accurately by the true stress-strain curve, which is often described by a power-law relationship.…”

Experimental and numerical investigation of the damage characteristics of a ship side plate laterally punched by a scaled raked bow indenter

“…In addition, the experimental data was used to validate novel numerical simulation techniques by Kõrgesaar and Romanoff (2013) and Woelke et al (2015). Furthermore, Calle et al (2019) and Zhang et al (2019a) designed tension test specimens that can be conducted on the universal tension testing machine to calibrate the critical failure strain to simulate out-of-plane crack propagation responses. The failure models of the side shell shown in Fig.…”

An analytical method to assess the structural responses of ship side structures by raked bow under oblique collision scenarios

“…Calle et al 16 carried out scaled experiments to validate the finite element analysis and discussed the effects of different numerical and experimental factors on impact tests of marine structures. Miniature ship grounding tests were conducted by Calle et al 17 to investigate the influence of the element size and strain rate on the fracture of steel plate when analysis by finite element method. Experimental investigations need a large amount of capital for real ship tests or large-scale model tests.…”