Our laboratory faithfully reproduces the state of the hull in a structural model on a computer based on the measured values ??of strain, acceleration, etc. generated in the hull during navigation, and infers the immediate, short-term, and long-term hull health.・We are engaged in research and development of the "Hull Structure Digital Twin" to be evaluated. In the hull structure monitoring performed on an actual ship, the pressure acting on the hull cannot be measured, and the number of strain sensors is limited mainly from the viewpoint of cost. Simulation technology is required. One of the solutions to this problem is to use the hull characteristic data obtained by direct load analysis. The direct load structure analysis program (DLSA; Direct Loads and Strength Analysis) It is the basis for twin technology development.
In order to implement the EEDI (Energy-Efficiency Design Index) regulations that came into effect in 2013 and to perform the tank tests that comply with EEDI, the 400 m towing tank in National Maritime Research Institute has acquired ISO9001 since 2013. However, in response to the growing trend in the evaluation of ship performance in actual seas in recent years, the certification organization approved the application of the tank tests in head waves in the 400m towing tank.
The tank tests in head waves is tests conducted to obtain the effect of advance speed of added resistance in short regular waves, where ship motion is small. This makes it possible to accurately estimate the amount of added resistance in short waves by complementing the theoretical calculation. NMRI is also looking to further expand ISO9001 to the other tank tests and the basins. We will continue to work to improve the quality of the tank tests on an ongoing basis.
(*note) Certification Organization: Nippon Kaiji Kyokai (ClassNK)