Abstract

There were many experimental studies on measuring the water impact load. The pressure sensor has been widely used to measure the water impact pressure, but accuracy of pressure sensor has not been investigated thoroughly. The present study considers accuracy of pressure sensor for the water impact problem. For this purpose, different types of pressure sensors were attached on 2D wedge surface and water impact pressure was measured during free falling of wedge. Those pressure sensors have different types, sensing areas, and sensitivity. The peak pressure and rise time measured from the different pressure sensors were compared each other. Based on these results, the uncertainties and reliability of pressure sensor on the measurement of water impact load are discussed.

Introduction

WILS JIP-III (Wave Induced Loads on Ships Joint Industry Project- III) was carried out to investigate the hydroelastic behaviors and ship slamming phenomena on an ultra-large containership. In the WILS JIPIII, ship slamming test was conducted using a segmented model and a steel backbone. Besides, 2D wedge and various ship sections were dropped to compare the pressure and local force. Two different types of pressure sensors were attached on the ship section(piezoelectric with 9.5mm diameter, piezoresistive with 5.5mm diameter), however, slight discrepancy of the measured peak pressure was observed. Fig. 1 shows the measured pressure signals during the ship section drop test of WILS JIP-III. Piezoelectric and piezoresistive pressure sensors showed different magnitude of impact pressure. Similar tendency was also presented by Kim et al. (2015b). They tested several pressure sensors to measure sloshing impact load and showed that the sloshing impact pressure can be varied depending on the type of pressure sensor (see Fig. 2). The measured pressures of IEPE(Integrated Electronic PiezoElectric) or ICP(Integrated Circuit Piezoelectric) sensors showed a slight difference in terms of magnitude, although they have the same type.

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