Identification of Complex Shear Modulus of MR Layer Placed in Three-Layer Beam – Part 2: Algorithm

Abstract

The paper presents the procedure of identification of a complex shear modulus which describes properties of MR fluid in the pre-yield regime as a function of magnetic field. Data necessary for identification were collected basing on measurements of free vibrations of a three-layered cantilever beam at a special laboratory stand. Magnetic field exerting on MR fluid placed in the beam was generated by electromagnet. In the next step, complex modes of beam vibrations for various places of applying the magnetic field and its strength were calculated.

Comparison of semi-active damping strategies for magnetorheological sandwich beams

“…2 like Romaszko, Snamina, and Paku la. 26 Using the bisection method, the values of the storage and loss moduli at each magnetic field strength are estimated to minimize the error between the experimental measured modal parameters and the modal parameters calculated from the eigenvalue like in Eq. 3.…”

“…24 Romaszko and Snamina then developed a method of calculating the relevant dynamic material properties of an MR fluid by first developing a finite element model of the beam 25 and then (with Paku la joining the previous authors) developing an optimization scheme using the eigenvalue problem that matches experimentally measured modal parameters for a given complex shear modulus. 26 Romaszko and Sapiński then investigated the relationship between the MR fluid dynamic properties to the location of the electromagnet along the beam's length. 27 With respect to damping strategies, Sapiński and Snamina explore the concept of switched stiffness, 28 while Romaszko employs that damping method to an MR sandwich beam, though his results suggest that damping is slower than for a constant magnetic field.…”

Effect of particle sedimentation on the dynamic properties of magnetorheological sandwich beams

“…28 Romaszko and Snamina developed a finite element model for the popular MR sandwich beam model, 29 while Paku ljoined the former two authors to solve the material properties of an MR fluid within an MR-sandwich beam using the beam's experimentally determined modal parameters. 30 Romaszko and Sapiński investigated how the position of an electromagnet along the beam's length (assuming the magnet does not span the beam's entire length) contributed to a change in an MR sandwich beam's modal parameters. 31 Sapiński and Snamina studied the merit of implementing a stiffness-switching damping method for MR sandwich beams 20 normally seen in piezeolectric materials, while Romaszko attempted to applies this stiffness-switching damping method on an MR sandwich beam and compared the damping results to those from a constant magnetic field.…”