Implementation of the Scanning Laser Doppler Vibrometer Combined with a Light-Weight Pneumatic Artificial Muscle Actuator for the Modal Analysis of a Civil Structure

Abstract

Abstract. The identification of the modal parameters of bridges and other large civil constructions has become an important research issue. Different approaches have been proposed depending on the excitation used: ambient excitations (due to wind, traffic, . . .) or artificial excitations (e.g. impact test with heavy drop weights). In practice it turns out that not all modes are well excited by the ambient forces. Hence the application of an artificial actuator is advisable. The problem is that larger constructions often require large and heavy excitation devices, which are hard to manipulate. Another difficulty encountered in performing a modal analysis on large civil constructions is the necessity for a large number of high sensitivity sensors. Consequently a large number of cables has to be installed resulting in a large setup time.This paper is a proof-of-concept which demonstrates the possibility of using lightweight Pneumatic Artificial Muscles combined with the scanning laser Doppler vibrometer to perform a modal analysis on a civil structure. This combination allows for an important reduction in setup time and allows for sine testing as well as the application of broadband signals such as periodic chirps, true noise or multisines.

Frequency Response Function Measurements via Local Rational Modeling, Revisited

“…k ), giving a (hopefully) better estimate θ [2] . Recursive application of this procedure results in the Sanathanan and Koerner solution [19] of the local rational approximation problem [14].…”

“…From (1) and (2), it follows that the frequency resolution of the measurement equals f s /N , which is the reciprocal of the experiment duration T = N T s .…”

“…where E(k) is the DFT of N samples of the unobserved e(t). H(jω) is the noise frequency response function, T H (jω) is the noise transient term that has the same properties as T G (jω) in (2), and E(k) is white and circular complex normally distributed [see [9], Section 6. 7, pp.…”

“…M EASURING frequency response functions (FRF) is a first step towards the (physical) understanding of the dynamic behavior of real-life systems. Practical applications can be found in many disciplines of engineering and (bio-medical) sciences such as, vibration analysis of mechanical and civil engineering structures [1], [2], state-of-health monitoring of lithium-ion batteries [3], hemodialysis measurements [4], characterization of vegetable tissues [5], . .…”