Ε Semester engineers

Vibration can result in ……………… defects and discomfort for the crew. Adding weight and structure and so changing the ……………………. frequency or local stiffening, are …………………. to vibration. Vibration can also be ………………. by inducing another vibration source, with contra pulses. Vibrations are usually …………………. by sound or noise as vibrations and noise often have the same source. On a ship, these sources are generally the propeller, the various diesel engines and even the waves at sea. ………………… techniques and the prevention of local resonance are used to keep the vibrations in the accommodation and at other locations within acceptable levels. Installing the diesel engines on ………………… reduces vibrations considerably. Vibration has a negative effect on many things. ……………………….. machinery gets damaged. Resonance can result in ……………………… in the structure. According to ISO-criteria, vibrations of 4-5 mm/sec are ……………………. , whereas values larger than 10 mm/sec are unacceptable.