Proceedings of the Thirty-second (2022) International Ocean and Polar Engineering Conference
Shanghai, China, June 5–10, 2022
Copyright © 2022 by the International Society of Offshore and Polar Engineers (ISOPE)
ISBN 978-1-880653-81-4; ISSN 1098-6189

www.isope.org

Experimental and numerical investigation for ultimate strength of aluminum vehicle deck under patchloading
Hui Liu, Yuyao Yang, Yao Cheng, Hanbing Xu
Marine Design & Research Institute of China
Shanghai, China

ABSTRACTclassification rules, and the level and discrete degree of plate stresses
have been discussed. Jani Romanoff (2007) studied the mechanicalproperties of I-core sandwich panel under patch loading by using
numerical and theoretical method. It is noted (Wang, 2020) that thestatic strength and mechanical properties of I-core sandwich grillage
structure under four typical position load are analyzed and studied byloading experiment. Tang (2018) discussed the stress fluctuation of thelight weight sandwich panels subjected to the patch loading, the stressstrain and the impact pressure distribution of the sandwich panels underthe different loads were obtained by explicit dynamic solution. Liu(2017) carried out an experiment to investigate the distribution
characteristics of wheel load represented by contact pressure between
the rubber wheel and stiffened plates, and revealed the high nonuniformity of the wheel load. Liu(2021) proposed a method could
effectively achieve the equivalent treatment of wheel pressure load.

The patch load is critical to the design of aluminum vehicle deck. This
paper presents an experiment to investigate the ultimate strength ofaluminum vehicle deck by using the wheel and steel-rubber block topressurize the model. The influence of the location of patch load isconsidered in the experiment. The highly non-uniformity of the patchload, the failure position under different load condition, and themaximum bearing capacity (over 700kN) under the patch load arefound in the experiment. The FEM code Msc.NASTRAN is applied tosimulate the experiment. The stress responses of the model at theelastic and the plastic stage are compared with a combination of FEM
simulation and experimental results. Good agreement is achieved. The
study in this paper is helpful for understanding of the structural
response of the aluminum vehicle deck under patch loading at theelastic and the plastic stages, and provides certain references forengineering applications.
KEY WORDS: path loading; vehicle deck; ultimate strength; numerical.

INTRODUCTION
The vehicle deck is a key component element of Ro-Ro ship structures,
which is used for the vehicles’ parking during the high-speed sailing.
The wheel load is a common load type on the vehicle deck. The wheelload has the characteristics of large local loading and uncertain loading
position, which is critical to the strength, stability and ultimate bearing
capacity of the vehicle deck. However, the wheel load is generally
approximated as a rectangular uniformly distributed load, and theultimate strength of the vehicle deck under the wheel load is notconsidered enough in the ship design, which could lead to theinsufficient use of the strength or insufficient estimation of the strength.
Therefore, exploring the ultimate strength of the vehicle deck underwheel load is significant for ship design.

In this paper, an aluminum vehicle deck model is designed and used inexperiments to study the ultimate strength. Considering the location of
the patch loads, the elastic and the plastic loading experiments arecarried out, and the wheel and steel-rubber plate is applied to exert thepatch loads. The predicted structural responses in the elastic and theplastic stages by using FEM are compared with the results from theexperiment.

STRENGTH EXPERIMENT OF VEHICLE DECK MODEL
Experimental Model
To study the strength of a ship’s aluminum vehicle deck, which has twokinds of longitudinal spans of 600mm and 400mm, a vehicle deckmodel is designed and built for the experimental program, which isillustrated in Fig.1. The material of the model is AL1561, and its elastic
modulus E is 6.9Gpa, Poisson’s ratio is 0.3, 0.2% proof stress  0.2 is

175Mpa.

In recent years, considerable amount of research has been devoted on
the deck structure under patch loading. Wang (2016) studied the plate
design under typical vehicle deck cargo loads on the basis of each3872