Measurement of ground borne vibrations for foundation design and vibration isolation of a high-precision instrument

2016-11-01
ÜLGEN, DENİZ
ERTUĞRUL, ÖZGÜR LÜTFİ
Özkan, M. Yener
This study focuses on the foundation design and vibration isolation of a high-precision instrument subjected to ground-borne vibrations. The allowable vibration level for the proper operation of the sensitive equipment was 50 mu g in a frequency range of 1-300 Hz. Prior to foundation design, first, an extensive field survey including geological and geophysical tests were performed in situ to obtain the static and dynamic physical properties of the soils. Next, vibration levels at various locations in the vicinity of moving vibration sources at the site were measured by accelerometers in one third octave frequency range from 1 Hz to 1000 Hz. Background vibration levels at the site were also measured while all of the vibration sources were inactive. Based on the measurements, a special foundation system was designed to reduce the vibration levels at the base of the precision instrument to allowable vibration limits while the vibration sources were active. Consequently, measurements were performed on the actual true scale foundation structure constructed at the site to assess the vibration isolation performance of specially designed structure. The actual vibration levels on top of the inertia mass show good agreement with the predicted values.

Suggestions

Vibration isolation of inertial measurement unit
Çınarel, Dilara; Ciğeroğlu, Ender; Department of Mechanical Engineering (2012)
Sensitive devices are affected by extreme vibration excitations during operation so require isolation from high levels of vibration excitations. When these excitation characteristics of the devices are well known, the vibration isolation can be achieved accurately. However, it is possible to have expected profile information of the excitations with respect to frequency. Therefore, it is practical and useful to implement this information in the design process for vibration isolation. In this thesis, passive ...
Design and modeling elastomeric vibration isolators using finite element method
Ardıç, Halil; Özgen, Gökhan Osman; Özkan, Sami Samet; Department of Mechanical Engineering (2013)
In this thesis, a process is developed for designing elastomeric vibration isolators in order to provide vibration isolation for sensitive equipment being used in ROKETSAN A.Ş.’s products. For this purpose, first of all, similar isolators are examined in the market. After that, appropriate elastomeric materials are selected and their temperature and frequency dependent dynamic properties are experimentally obtained. Parametric finite element model of the isolator is then constituted in ANSYS APDL using the ...
Experimental characterization of a tuned vibration absorber
Aksoy, Tuğrul; Özgen, Gökhan Osman; Acar, Bülent; Gençoğlu, Caner (2016-01-01)
In this paper, experimental characterization studies conducted for a tuned vibration absorber is presented. The tuned vibration absorber has been particularly designed to reduce transverse resonant vibration response of a supported cylinder structure at its dominant two modes. Various testing configurations and techniques have been used such as transmissibility measurements, frequency response measurements, sweep sine testing, impact testing, and random testing. Different testing approaches were needed to e...
Vibration reduction of structures by using nonlinear tuned vibration absorbers
Doğan, Muhammed Emin; Ciğeroğlu, Ender; Department of Mechanical Engineering (2019)
Tuned Vibration Absorbers (TVA) are commonly used in reducing undesirable vibrations of mechanical structures. However, TVAs work in a very limited frequency range and if the excitation frequency is outside of this range, they become ineffective. In order to solve this problem, researchers started to consider nonlinear TVAs for vibration attenuation. In this study, dynamic behavior of a Linear systems coupled with a nonlinear TVA is investigated. The system is subjected to sinusoidal base excitation. Parame...
Response of acoustic imaging systems using convergent leaky waves to cylindrical flaws
Günalp, Nilgün; Atalar, Abdullah (Institute of Electrical and Electronics Engineers (IEEE), 1989-9)
A theoretical study of imaging systems utilizing focused leaky surface acoustic waves (SAWs), and their response to certain kind of defects is presented. In particular, circular cylindrical inhomogeneities with axes perpendicular to the surface are considered. The scattering of the SAW from this cylinder is formulated with some approximations. The surface wave incident on the inhomogeneity is initially found as an angular spectrum of plane waves. However, to apply the boundary conditions at the cylindrical ...
Citation Formats
D. ÜLGEN, Ö. L. ERTUĞRUL, and M. Y. Özkan, “Measurement of ground borne vibrations for foundation design and vibration isolation of a high-precision instrument,” MEASUREMENT, pp. 385–396, 2016, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/47987.