Development of a wireless measurement system for ship vibration in a sea trial

Due to the convenience of wireless measurement, wireless acceleration sensors have been widely employed to monitor the structural health of mechanical systems. Although wireless sensors for general purpose have been available in the market, a wireless measurement system still needs to be customized for the purpose of its testing condition (measurement distance and time, communication interference and blockage, frequency range, number of sensors installed, etc.). For ships, vibration measurement in a sea trial is required to evaluate the habitability of crews in the accommodation area and study the vibration characteristics of hull structures and shipboard equipment. However, there have been few attempts to utilize wireless sensors in ship vibration measurements due to concerns about a loss of measured signals caused by failures of wireless network. This article presents the wireless measurement system developed to measure ship vibration in a sea trial. System requirements are first defined, and the wireless measurement system is designed and manufactured. Comparative studies between the wireless and wired measurement systems are conducted to confirm applicability of the wireless measurement system in a sea trial. The results in a frequency domain show that both frequency and magnitude match well with each other. Finally, it is concluded that the developed wireless system is reliable as much as the conventional wired system.