Numerical and experimental studies on the rotating rotor with three active composite blades

Abstract

Numerical aNd experimeNtal studies oN the rotatiNg rotor with three active composite blades badaNia NumeryczNe i eksperymeNtalNe wirującego wirNika z trzema aktywNymi łopatami kompozytowymi [8], but the object of the research was a thin plate with PZT actuators.The aim of this paper is to determine the relation between the dynamics of a rotor blade with MFC elements in relative motion and the rotational movement of the hub. Constant angular velocity can generate undesired changes in the natural frequencies and/or eigenmodes of the active composite blades. The aim of the experimental research was to demonstrate the possibility of using the MFC actuator for reducing these changes. The experimental setupThe experimental studies were performed using a specially designed test stand which is shown in Fig. 1. This stand was built at the Department of Applied Mechanics at the Lublin University of Technology. The rotor (Fig. 1) consisted of a hub with three composite blades which were located 120 degrees relative to each other. The rotor blades were beams with a rectangular cross-section made of glassepoxy laminate.The mechanical properties of the glass-epoxy laminate were as follows:Young's modulus in fibre direction (i.e., direction 1): 46.43 GPa • and in transverse direction of the fibers (i.e., direction 2): 14.926 GPa, respectively, Poisson's ratio in plane 1-2: 0.27, • shear modulus in plane 1-2: 5.233 GPa,Each blade was composed of six layers. The lay-up configuration of the laminate was: [±45/90] S . The geometry of the rotor blades is given in Table 1. The rotor hub was driven by a DC motor. In addition, the sensors and actuators were fixed on the opposite surfaces of the beams. The strain-gauges and piezoelectric actuators were used to measure and control the dynamics of the rotor blades in their relative motion. In our case, the Macro Fiber Composite active elements were used as actuators. They were MFC elements type M-8528-P1. In this case, the piezoelectric d 33 effect occurs [15]. Each element can be powered by electric current in the range of -500 to 1500 volts.The piezoelectric properties of the MFC element depend on its dimensions. According to the literature [16], the optimal value of the d 33 parameter for MFC M-8528-P1 elements is 1.01*10 -7 m/V. The coefficient of permittivity is 8*10 -9 F/m. The mechanical properties of the MFC element were:Young's modulus in fibre direction (i.e., direction Fig. 1(b) shows the electronic equipment which was used to control the power of the electrical motor and piezoelectric transducers. Additionally, the DSP subsystem was used. The numerical model of the rotorThe numerical model of the rotor was designed by the finite elements method using the commercial system Abaqus [1]. The FE model of the rotor is shown in Fig. 2.The model consists of a base with electric drive, the hub with a drive shaft, a blade handle, three composite blades and MFC active elements [16]. The hub and the base of the rotor were built of 10-node tetrahedral, solid elements having three transl...

Influence of the piezoelectric parameters on the dynamics of an active rotor

“…It can be observed that the natural frequency of the first bending mode increases with increasing the rotational speed. This phenomenon is known as the centrifugal stiffening effect [21]. Moreover, the second stiffening effect is observed, that is generated by the active element.…”

“…Generally, the value of frequency at this moment of time is known (Ȧ 0 İ 0 t M ), and it is near to the natural frequency. Based on the procedure described in [21], the values of the first natural frequencies are estimated experimentally. The experimental results and the numerical findings for different values of the effective piezoelectric constant d 33 * and voltage signals are compared in Fig.7.…”

“…Moreover, it is observed the response of the system decreases during rotation due to the centrifugal force. In paper [21] the authors describe the experimental and numerical dynamic studies of an active rotor with three composite blades. The influences of the hub angular velocity and piezoelectric effect on the rotor dynamics are determined.…”

Calibration of bulk material model in Discrete Element Method on example of perlite D18-DN

“…Computer-Aided-Engineering programs have become important tools used by engineers in the process of designing new machines and devices in recent years. A number of engineering and scientific issues, which are too complicated to be described by analytical models or difficult to test in the laboratory, have been solved using numerical methods [1,[7][8][14][15][17][18]. In addition, relatively cheap and easy access to high computing power and rapid development of computer programs implementing specific numerical methods causes that physical phenomena are modeled with incredible accuracy in relation to reality.…”

Modal Analysis of Laminated “CAS” and “CUS” Box-Beams

“…The natural frequency and the corresponding shape modes were investigated. Mitura et al [20] considered dynamic behaviour of the rotor with three active composite blades. The influence of the hub's angular velocity and/or piezoelectric effect on the blades' dynamics in numerical and experimental studies were determined.…”