Akihiro Ota, Hideaki Nozato, Wataru Kokuyama, Sakae Chiba, Masao Shimizu, Hiroyuki Kudo, Kenji Maki, Ryuuichi Tada, Chihiro Mochizuki, Shouji Iso
PROFICIENCY TEST AMONG CENTRIFUGE CALIBRATION LABORATORIES

A proficiency test was carried out to check proficiency of centrifuge calibration among four participants in Japan; KYOWA, TTDC, JARI and NICS, as a pilot laboratory of AIST. AIST provides reference value to the test by using primary shock calibration system. As a result, the proficiency for all participants was evaluated by using z-scores. The z value for respective participants is estimated to be below 2. This means all participants have enough proficiency for centrifuge calibration.

Martin Iwanczik, Franck Larsonnier, Philipp Begoff, Michael Mende
PRIMARY CALIBRATION OF GEOPHYSICAL AND SEISMIC VELOCITY SENSORS

This paper describes first measurement results determined with a new primary calibration system according to ISO 16063-11 that can handle very heavy devices under test (DUT) with a weight up to 50 kg allowing a precise vertical excitation of the DUT. This required the development of a new vibration exciter that can compensate the high payload and covers the broad frequency range from 0.05 Hz to 400 Hz without exceeding the cross motion and THD limits defined in the ISO standard.

Torben R. Licht, Sven Erik Salboel, Jacob H. Winther
CALIBRATION OF VIBRATION REFERENCE TRANSDUCERS WITH PRIMARY AND SECONDARY METHODS. PROPOSALS FOR HANDLING THE DEPENDANCE OF HIGH FREQUENCY RESPONSE ON MOUNTING PARAMETERS

Dissemination of vibration sensitivity values to the broader vibration community has been dominated over several decades by the calibrations performed at NMIs using primary vibration calibration by laser interferometry using the methods described in the ISO 5347-1 (latest edition1993) replaced by 16063-11 in 1999.
In most cases this method is applied to reference transducers, either single-ended or meant for back-to-back calibration.
In recent years there has been a push towards very low uncertainties and frequencies above 5 kHz. About 5 years ago it became evident that although the calibration at the NMIs with similar equipment could be reproduced with high confidence it is questionable if these results and uncertainties can be disseminated with sufficient confidence to the users of the reference transducers.
It has been demonstrated that the results depend on the actual mounting conditions described by the mechanical impedance of the structure which calls for recommendations for increased uncertainties and/or correction factors and methods for use of the results.
Calibration of reference transducers have in some countries been performed by using transfer standards to calibrate back-to back references for the users and naturally the results obtained and the stated uncertainties are questionable in the light of the newest discoveries.
Examples and some proposed solutions to these challenges including uncertainty calculations will be presented.

Chenguang Cai, Yuntai Jiang, Biao Tang
DEFINITION AND MEASUREMENT OF TRANSVERSE MOTION RATIO OF SHAKERS

Four different measurement methods of transverse motion ratio of shakers are used in ISO standards and practice. The theoretical analysis and experiment results reveal that the four different measurement methods lead to different results, and the maximum measurement error of the transverse motion ratio between the different measurement methods should be up to 41.4%. Based on the theoretical analysis and experiments, a unified transverse motion ratio measurement method is proposed.

Claire Bartoli
RESULTS OF A EUROPEAN COMPARISON IN LOW FREQUENCY DOMAIN

A comparison in the area of vibration including 10 countries was conducted for the first time within the framework of the Euramet community in the low frequency domain DC - 200 Hz with a mandatory range of 1 - 80 Hz. The aim of this work is to compare primary interferometric measurements of complex voltage sensitivity for a standard accelerometer following standard ISO 16063-11. This comparison is registered in the BIPM database.