Compact, dynamic and precise piezoelectric actuators for characterisation, cycling and environmental testing

Abstract:
In environmental testing of materials and electronic devices, vibrations and fatigue tests are of primary importance. Electrodynamic shakers and hydraulic actuators are traditionally used to perform these tests. They generally provide with high amplitude (> mm), large force (> kN) and large acceleration (> 10s Gs) at low frequency (< 1kHz). These conventional actuators are often too bulky when the test requirement are demanding in terms of dynamic operation (high frequency) for miniature devices under test (DUT) and medium mass payload (< 1 ton). The trend of many industries is to go to more and more miniaturized components and systems with high mechanical resonance frequency. In order to comply with 100% quality insurance process, those components also require fatigue and environmental tests. In order to circumvent some of the limitations of these conventional technologies, piezoelectric actuators have raised a growing interest in the environmental test labs and industry for almost 10 years. Preloaded Piezoelectric Actuators (PPA) are well known for their large force (> kN) and high resonance frequency (> kHz) in a compact volume (< cm³). In order to improve their small strain (<0.1 %), Cedrat Technologies has been developing a range of Amplified Piezoelectric Actuators APA(TM) to perform stroke up to 1 mm and force up to several kN while being very compact and suitable for dynamic applications. After reviewing the performances and limits of APA(TM) in dynamic condition, this paper will present different testing set up based on APATM, such like vibration testing, fatigue testing, fretting and material characterization as well as the capability of this piezoelectric actuators technology to operate in High Vacuum and Non Magnetic environments. The paper will present what render the piezo actuator technologies from Cedrat especially adapted for dynamic applications and will illustrate this feature by different characterisation, cycling and environmental testing applications.