MEASUREMENT AND EVALUATION OF ENVIRONMENTAL VIBRATIONS

PART 1. PROBLEMS CONCERNING MEASUREMENTS

Abstract

A vibration level meter has recently been used for evaluation of environmental vibrations, which has a frequency weighting circuit corresponding to human vibration sensation and an indication part with two dynamic characteristics of "slow" and "fast". Values measured with this meter is shown as dBVL. There are still problems in evaluation of non-stationary or impulsive vibrations by this meter.
Using this vibration level meter, difference between values observed by fast and slow characteristics was examined on 13 sample environmental vibrations with station-ary, non-stationary and impulsive wave forms. On the same vibrations, equal sensa-tion was observed on 10 subjects by comparing one of them with sinusoidal vibration at standard frequency individually.
It was endorsed from these physical and subjective experiments that VL value at 50% on ogive determined by statistical analysis was reasonable for evaluation of the non-stationary vibration, and peak VL value was better for evaluation of the im-pulsive vibration. Besides, it was recognized that slow characteristic was suitable for vibration measurement from the standpoint of reliability of measured value.