Design and Fabrication of a Fully Elastic Ship Model

Abstract Ship structures are subjected to various deteriorating mechanisms throughout their service life. Continuous awareness of the vessel’s structural health is a critical aspect of the overall situational awareness. Model tests are often used to validate software which predicts the vessels’ hydrodynamic loading and dynamic structural response. Generally, two different methods can be used to model the flexibility of the ship. The most common method is to sub-divide the hull into a number of rigid segments that are interconnected by a flexible backbone beam. The elasticity of the model is represented by the elastic beam to which rigid segments are connected. However, the segmented model limits the measurements to prescribed locations between segments. The other method is to fabricate the model using a continuous elastic material. In this paper, a new method for fabricating a fully elastic model is introduced as part of a structural health monitoring system. Since the model is built from continuous materials with known elastic properties, it can be instrumented to measure strain at a larger number of locations. A suitable material for construction of the elastic model has been identified. Material tests are conducted to better understand the static and dynamic behavior of the elastic material. The material shows linear stress-strain relationship and stable mechanical properties within the loading range. Due to the low elastic modulus of the material, the strain gauge stiffening effect is obvious and has been taken into account in the calibration process. Using the elastic material, a fully elastic model of the S175 midship section is designed. As a first step trial, the middle part of the model representing a three-cargo hold is manufactured. Static bending tests are conducted to examine the elastic characteristics of the fabricated model. Wave experiments are carried out. The results from these experiments are compared to numerical simulations.