MARSTRUCT benchmark study on nonlinear FE simulation of an experiment of an indenter impact with a ship side-shell structure

This paper presents a benchmark study on collision simulations that was initiated by the MARSTRUCT Virtual Institute. The objective was to compare assumptions, finite element models, modelling techniques and experiences between established researchers within the field. Fifteen research groups world-wide participated in the study. An experiment involving a rigid indenter penetrating a ship-like side structure was used as the case study. A description of how the experiment was performed, the geometry model of it, and material properties were distributed to the participants prior to their simulations. The paper presents the results obtained from the fifteen FE simulations and the experiment. It presents a comparison of, among other factors, the reaction force versus the indenter displacement, internal energy absorbed by the structure versus the indenter displacement, and analyses of the participants' ability to predict failure modes and events that were observed in the experiment. The outcome of the study is a discussion and recommendations regarding mesh size, failure criteria and damage models, interpretation of material data and how they are used in a constitutive material model, and finally, uncertainties in general

Data for: The effect of low stress triaxialities and load paths on ductile fracture simulations of large shell structures

This contains all input files needed to run MK-analysis presented in the paper. This example applies for alfa=0.5 and fii=90 degrees, see paper for details. For different stress states or principal stress direction respective values in the *.for file need to be changed. MASTER.inp - Abaqus input file that is runned.Equation.inp - Called by MASTER.inp. Contains linear constraint equations that constrain each boundary node based on the nodal displacement on the opposite edge and phantom node displacement.NODES.inp - Called by MASTER.inp. Gives the nodal coordinates of the unit cell model. vdisp-NODES-imp.for - Example user defined loading file called by Abaqus along with MASTER.inp

MK analysis example setup using periodic boundary conditions

Supplementary data for Marine Structures article "The effect of low stress triaxialities and load paths on ductile fracture simulations of large shell structures"

Data for: The effect of low stress triaxialities and load paths on ductile fracture simulations of large shell structures

This contains all input files needed to run MK-analysis presented in the paper. This example applies for alfa=0.5 and fii=90 degrees, see paper for details. For different stress states or principal stress direction respective values in the *.for file need to be changed. MASTER.inp - Abaqus input file that is runned.Equation.inp - Called by MASTER.inp. Contains linear constraint equations that constrain each boundary node based on the nodal displacement on the opposite edge and phantom node displacement.NODES.inp - Called by MASTER.inp. Gives the nodal coordinates of the unit cell model. vdisp-NODES-imp.for - Example user defined loading file called by Abaqus along with MASTER.inp.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Performance prediction of a hard-chine planing hull by employing different cfd models

This paper presents CFD (Computational Fluid Dynamics) simulations of the performance of a planing hull in a calm-water condition, aiming to evaluate similarities and differences between results of different CFDmodels. The key differences between thesemodels are the ways they use to compute the turbulent flow and simulate themotion of the vessel. The planingmotion of a vessel on water leads to a strong turbulent fluid flowmotion, and themovement of the vessel fromits initial position can be relatively significant, which makes the simulation of the problem challenging. Two different frameworks including k-" and DES (Detached Eddy Simulation) methods are employed to model the turbulence behavior of the fluid motion of the air–water flow around the boat. Vertical motions of the rigid solid body in the fluid domain, which eventually converge to steady linear and angular displacements, are numerically modeled by using two approaches, including morphing and overset techniques. All simulations are performed with a similar mesh structure which allows us to evaluate the differences between results of the applied mesh motions in terms of computation of turbulent air–water flow around the vessel. Through quantitative comparisons, themorphing technique has been seen to result in smaller errors in the prediction of the running trim angle at high speeds. Numerical observations suggest that a DES model can modify the accuracy of the morphing mesh simulations in the prediction of the trim angle, especially at high-speeds. The DES model has been seen to increase the accuracy of the model in the computation of the resistance of the vessel in a high-speed operation, as well. This better level of accuracy in the prediction of resistance is a result of the calculation of the turbulent eddies emerging in the water flow in the downstream zone, which are not captured when a k-" framework is employed. The morphing approach itself can also increase the accuracy of the resistance prediction. The oversetmethod, however, overpredicts the resistance force. This overprediction is caused by the larger vorticity, computed in the direction of the waves, generated under the bow of the vessel. Furthermore, the overset technique is observed to result in larger hydrodynamic pressure on the stagnation line, which is linked to the greater trimangle, predicted by this approach. The DESmodel is seen to result in extra-damping of the second and third crests of transomwaves as it calculates the stronger eddies in the wake of the boat. Overall, a combination of themorphing and DESmodels is recommended to be used for CFDmodeling of a planing hull at high-speeds. This combined CFD model might be relatively slower in terms of computational time, but it provides a greater level of accuracy in the performance prediction, and can predict the energy damping, developed in the surrounding water. Finally, the results of the present paper demonstrate that a better level of accuracy in the performance prediction of the vessel might also be achieved when an oversetmeshmotion is used. This can be attained in future bymodifying themesh structure in such away that vorticity is not overpredicted and the generated eddies, emerging when a DESmodel is employed, are captured properly.QC 20220314</p