After the ship has been delivered, noise and vibration issues, such as vibrations in flywheel areas and noises in way of salon and in VIP and owners’ cabins, can sometimes occur.
In certain cases, shipowners simply need to increase their level of comfort and enjoyment, but in other cases the failure to respect contractual specification limits can endanger the yard with the concrete possibility of vessel refusal and payment of a penalty.
It is clear how helpful the troubleshooting activity could be for noise and vibration defects.
The start of the diagnosis and of the troubleshooting process consists in performing a measurement campaign and later, in the post-processing phase, in executing spectral analysis in order to detect the specific noise and vibration sources.
The fundamental next step is to create a numerical model, calibrated with on-board performed measurements, that allows to apply exciting sources in order to obtain the same noise and vibration levels gained with measurement instruments.
Once the numerical model is correctly calibrated, structural and acoustic alteration proposals are implemented until the contractual or required noise and vibration levels are reached.
Nowadays, hydrodynamic issues are always more present in the troubleshooting field, mostly due to particular and innovative hull shapes. To face this new challenge, our team of engineers processes hydrodynamic calculations (CFD) in order to identify the vibroacoustic sources and later combines the hydroacoustic calculation with the structural noise and vibration prediction calculation, providing potential engineering solutions.