Dynamic magneto-mechanical properties of magneto-sensitive elastomers determined using a new experimental test involving forced longitudinal vibration

Wei Gao,Xingzhe Wang

doi:10.1063/1.5113821

Abstract

A new experimental method involving forced longitudinal vibration is presented for experimentally determining the dynamic magnetomechanical properties of a magnetosensitive elastomer in a magnetic field. A cylindrical sample is attached to a vibration platform and placed in a longitudinal magnetic field generated by a solenoid electromagnet, and a resonant technique is used to obtain the dynamic magnetomechanical properties of the tested sample. The results indicate that the resonant frequency (i) increases with the intensity of the applied magnetic field and the content of the magnetic-particle filler in the matrix but (ii) decreases with the sample length. The dynamic properties of the storage and loss moduli depend significantly on the excitation frequency and the magnetic-particle content. The testing process shows that it is simple and easy to evaluate the dynamic properties using forced longitudinal vibration, with the additional advantage of it being a nondestructive technique. This method could be extended to characterize the coupled magnetomechanical behavior of magnetosensitive functional elastomers such as Terfenol-D/epoxy composites.

Highlights

Combining the elasticity of polymers and the magnetic properties of ferromagnetic particles in a single composite material has recently promoted the emergence and development of a new type of smart material that can respond to an external magnetic field by switching its physical properties rapidly
The results indicate that the resonant frequency (i) increases with the intensity of the applied magnetic field and the content of the magnetic-particle filler in the matrix but (ii) decreases with the sample length
To ensure that the established experimental apparatus was not influenced by the external magnetic field applied during the testing process, as a reference sample that was insensitive to the magnetic field, a polycarbonate rod with a diameter of 5 mm and a length of 50 mm was glued to the vibration platform with YH-840 glue and tested in the range of 0–2 kHz

Summary

INTRODUCTION

Combining the elasticity of polymers and the magnetic properties of ferromagnetic particles in a single composite material has recently promoted the emergence and development of a new type of smart material that can respond to an external magnetic field by switching its physical properties rapidly. The technique of forced longitudinal vibration introduced by Norris and Young has been widely used to measure dynamically the Young’s modulus of viscoelastic materials This involves exciting a bar-shaped sample harmonically at one end and measuring the ratio of the end amplitudes, and the response of the sample at resonance can be used to obtain the complex modulus. A new experimental test with the simple method was conducted to determine the complex Young’s modulus of MSEs in different magnetic-field environments. This test could be extended to measure the magnetomechanical coupling performance of other magnetosensitive functional materials.

Sample preparation

Experimental apparatus

Measurement procedure

RESULTS AND DISCUSSION

CONCLUSIONS