Objective. To investigate the difference between the measurement of vibration sensation without and with socks. Material and Methods. Fifty healthy volunteers (H group) and 19 patients with diabetic polyneuropathy (PNP group) were included. The sites of measurement were the great toe (GT) and medial malleolus (MM). A standard 128 Hz tuning fork was used in the measurements. Results. Mean durati...

We report on the use of a high-speed wavelength division multiplexing (WDM) technique for multiplexing Fiber Bragg Grating (FBG) sensors applied to structural Vibration Control for the measurement of strain, permitting many sensing devices along a single optical fiber at different locations collecting samples at 5000 Hz with microstrain resolution. In this demonstration, a cantilevered flexible...

The critical issue of vibration test on hull structures with large size is the numerous amounts of sensors. Too many sensors lead to excessive consumption whereas notable error would come from reducing the number of sensors. An approach is proposed to reconstruct the complete structural vibration via much fewer sensors. This iterative progress eliminates the sensor location that contributes the...

Using a simultaneous phase sensor, the proposed instrument performs highly repeatable measurements over an extended range in the presence of vibration common to a laboratory setting. Measurement of a 4.5 μm step standard in the presence of vibration amplitudes of 40 nm produces a repeatability of 1.5 nm RMS with vertical scanning data acquired at 400 nm intervals. The outlined method demonstrat...

This paper presents an investigation into development of feed-forward and feedback control strategies for active vibration suppression and attitude control of flexible spacecrafts. The feed-forward loop consists of a computed-torque scheme and a command shaping technique based on component synthesis vibration suppression (CSVS) method which was developed based on linear systems theory. For rela...

Structural analysis demands the localized vibration study of metallic, ceramic and composite structures. This paper reports the design and development of a vibration sensor to measure the instantaneous amplitude and frequency of vibrations of structures over very small-localized surface area. Optical fiber based displacement sensor is extended as a vibration sensor, based on the consideration t...

Vibrothermography is a nondestructive technique for finding defects through vibration-induced heating imaged with an infrared camera. To model the crack heating process in Vibrothermography, it is essential first to understand the vibration that causes heat generation. We describe a method for calculating internal motions from surface vibrometry measurements. A reciprocity integral and Gauss’s ...

Structural mechanical vibration is commonly measured through punctual sensors, i.e. sensors that measure the structural behavior at only one point. Examples of such sensors are accelerometers, LVDTs, non-scanning laser vibrometers, and proximity probes. This project aims at developing an acquisition system able to measure the dynamic behavior of a structure as a whole (many points) using only o...

Precision vibration measurements depend on accurate and repeatable calibration methods. Standardization of calibration test equipment and measurement techniques ensures more accurate and repeatable measurements. The use of the back-to-back accelerometer as a laboratory standard has become widespread. However, this use has been somewhat limited because of inadequate calibration methods. Recent d...

Experimental data collected over the years, for defining limits of vibration exposure to human beings, have resulted in a set of vibration criteria specified in ISO Standard 2631. In this article, instrumentation requirements for evaluation of the responses of humans to vibration according to these criteria are described, as well as some of the pitfalls to be avoided during these measurements. ...