Evaluation of Acoustic Comfort and Sound Energy Transmission in a Yacht

Abstract

After being neglected for a long time, in the last years, ships have been recognized and studied as sound emitters. The sound energy they generate impacts the outside, but it can also affect the indoor quality of life if the environments are not properly designed. In fact, acoustic comfort plays a pivotal role, particularly in recreational crafts. In the present work, room acoustics and acoustic camera measurements were performed, inside a 50 m length overall yacht, chosen as a case study in order to evaluate the acoustic comfort. The Italian classification procedure UNI 11367:2010 for buildings was applied, and results have been compared to other international comfort classes. However, all of these are based on prescription for standard buildings, and the present work highlights that they do not account for the effective ship’s acoustic issues: sound energy transfer from impacts over ceilings and sound energy leakage. While attention of shipbuilders in acoustic comfort is shown in the measured good reverberation times, the acoustic camera revealed sound energy leakages corresponding to hidden escape ways that have been poorly insulated. This compromises the standardized sound difference between contiguous compartments and also the thermal insulation, as leakage involves air passages. The present work attempts to evolve the classification procedure by also including, for the first time, the reverberation time, but future studies focused on finding correct standardized impact level noise for ship cases are needed. In fact, their values were very high and not comparable with those measured in actual buildings and for which reference values have been designed.

Review on the Prediction and Control of Structural Vibration and Noise in Buildings Caused by Rail Transit

“…Acoustic cameras combining video capture and microphone arrays can be used to obtain real-time information about the location of noise sources [21]. Kanka et al [22] measured the acoustic properties of a yacht using an acoustic camera and accurately assessed the acoustic comfort of the yacht. Barré and Ortiz [23] used deterministic signals such as sinusoidal sweeps to measure room impulse responses and combined them with beamforming to obtain objective parameters describing the sound field in three dimensions.…”

A Low-Stress Method for Determining Static and Dynamic Material Parameters for Vibration Isolation with the Use of VMQ Silicone

“…The list of measured parameters is presented in Table 1. Dynamic stiffness [N/m] Critical damping factor [1] Damping coefficient [Ns/m] Loss factor [1] Apparent Young's modulus (dynamic) [Pa] Young's modulus (dynamic) [Pa]…”

“…Poisson ratio [1] Static stiffness [N/m] Apparent Young's modulus (static) [Pa] Young's modulus (static) [Pa] Measurements were taken using cylindrical samples. Each sample differentiated by radius and height had measurements taken in four settings, i.e., 4, 8, 12, and 16 pieces.…”

“…Such nuisances are noise and vibrations in residential buildings that come from other multifamily buildings, subway, or tram crossings. Stimuli, such as noise and vibration, have a negative impact on the well-being of residents [1][2][3][4][5][6] and, in extreme cases, on their health [7][8][9][10]. First, the risks associated with exposure to these stimuli are sleep disorders [11][12][13], problems with the cardiovascular system [14,15], decreased concentration [16], and general irritability [17][18][19].…”