Abstract. The planar 3-RRR compliant mechanism is a piezoelectric (PZT) actuator driven 3DOF parallel micro-motion device. It is widely used in micro-electromechanical systems, biotechnology engineering and aerospace. However, crack easily occurs on flexure hinge because alternate loading over a long period of time, which will compromise mechanism's accuracy. This paper presents a method for crack detection based on the pseudo rigid body model (PRBM). Particularly, the location of cracked hinge can be identified from the obtained force's variation on piezoelectric actuator of healthy and cracked configurations, while theirs elongation remaining the same. This research has good uses including fault diagnosis, facility for the real-time control and optimization of design of a compliant mechanism.

Abstract:In the present research the crack identification in rotor systems is proposed based on Holospectrum. The purpose of the research is to detect not only the crack location on a rotor shaft, but also the crack type and the angle between two cracks on a rotor shaft. 3D Holospectrum is introduced to detect crack location on the shaft, and the 2D Holospectrum to detect the crack type and angle between two cracks. The proposed technique was validated through numerical simulations on the rotor system with a two cracks.

In this paper, the vibration of power machinery on the deck which is simplified to forced vibration of four edges simply supported rectangular thin plate was studied. The theoretical model of the system is built based on the vibration properties of deck using four-pole parameters method. For analyzing optimal phase relationship among the ship power machines, the deck's kinetic energy is chosen as the objective function. To fulfil active vibration isolation,the phase difference and layout of power machinery on the deck is researched.The analysis result show that this method is simple, reliable and effective to isolate vibration.