TY - JOUR A1 - Chavez, Jhohan A1 - Böhm, Valter A1 - Becker, Tatiana I. A1 - Gast, Simon A1 - Zeidis, Igor A1 - Zimmermann, Klaus T1 - Actuators based on a controlled particle-matrix interaction in magnetic hybrid materials for applications in locomotion and manipulation systems JF - Physical Sciences Reviews N2 - The paper deals with the investigation of magneto-sensitive elastomers (MSE) and their application in technical actuator systems. MSE consist of an elastic matrix containing suspended magnetically soft and/or hard particles. Additionally, they can also contain silicone oil, graphite particles, thermoplastic components, etc., in various concentrations in order to tune specific properties such as viscosity, conductivity and thermoelasticity, respectively. The focuses of investigations are the beneficial properties of MSE in prototypes for locomotion and manipulation purposes that possess an integrated sensor function. The research follows the principle of a model-based design, i.e. the working steps are ideation, mathematical modelling, material characterization as well as building first functional models (prototypes). The developed apedal (without legs) and non-wheeled locomotion systems use the interplay between material deformations and the mechanical motion in connection with the issues of control and stability. Non-linear friction phenomena lead to a monotonous forward motion of the systems. The aim of this study is the design of such mechanical structures, which reduce the control costs. The investigations deal with the movement and control of ‘intelligent’ mechanisms, for which the magnetically field-controlled particle-matrix interactions provide an appropriate approach. The presented grippers enclose partially gripped objects, which is an advantage for handling sensitive objects. Form-fit grippers with adaptable contour at the contact area enable a uniform pressure distribution on the surface of gripped objects. Furthermore, with the possibility of active shape adaptation, objects with significantly differing geometries can be gripped. To realise the desired active shape adaptation, the effect of field-induced plasticity of MSE is used. The first developed prototypes mainly confirm the functional principles as such without direct application. For this, besides the ability of locomotion and manipulation itself, further technological possibilities have to be added to the systems. The first steps are therefore being taken towards integrated MSE based adaptive sensor systems. KW - apedal locomotion systems KW - field-controlled particle-matrix interaction KW - field-induced plasticity KW - form-fit gripper KW - integrated sensor-actuator systems KW - magneto-sensitive elastomer Y1 - 2020 U6 - https://doi.org/10.1515/psr-2019-0087 VL - 7 IS - 11 SP - 1263 EP - 1290 PB - de Gruyter ER - TY - JOUR A1 - Becker, Tatiana I. A1 - Raikher, Yuriy L. A1 - Stolbov, Oleg V. A1 - Böhm, Valter A1 - Zimmermann, Klaus T1 - Magnetoactive elastomers for magnetically tunable vibrating sensor systems JF - Physical Sciences Reviews N2 - Magnetoactive elastomers (MAEs) are a special type of smart materials consisting of an elastic matrix with embedded microsized particles that are made of ferromagnetic materials with high or low coercivity. Due to their composition, such elastomers possess unique magnetic field-dependent material properties. The present paper compiles the results of investigations on MAEs towards an approach of their potential application as vibrating sensor elements with adaptable sensitivity. Starting with the model-based and experimental studies of the free vibrational behavior displayed by cantilevers made of MAEs, it is shown that the first bending eigenfrequency of the cantilevers depends strongly on the strength of an applied uniform magnetic field. The investigations of the forced vibration response of MAE beams subjected to in-plane kinematic excitation confirm the possibility of active magnetic control of the amplitude-frequency characteristics. With change of the uniform field strength, the MAE beam reveals different steady-state responses for the same excitation, and the resonance may occur at various ranges of the excitation frequency. Nonlinear dependencies of the amplification ratio on the excitation frequency are obtained for different magnitudes of the applied field. Furthermore, it is shown that the steady-state vibrations of MAE beams can be detected based on the magnetic field distortion. The field difference, which is measured simultaneously on the sides of a vibrating MAE beam, provides a signal with the same frequency as the excitation and an amplitude proportional to the amplitude of resulting vibrations. The presented prototype of the MAE-based vibrating unit with the field-controlled “configuration” can be implemented for realization of acceleration sensor systems with adaptable sensitivity. The ongoing research on MAEs is oriented to the use of other geometrical forms along with beams, e.g. two-dimensional structures such as membranes. KW - adaptable sensor unit KW - amplification ratio KW - bending vibration KW - eigenfrequency KW - Magnetic field control KW - magnetoactive elastomer Y1 - 2020 U6 - https://doi.org/10.1515/psr-2019-0125 SN - 2365-659X VL - 7 IS - 10 SP - 1 EP - 28 PB - de Gruyter ER - TY - JOUR A1 - Prem, Nina A1 - Sindersberger, Dirk A1 - Striegl, Birgit A1 - Böhm, Valter A1 - Monkman, Gareth J. T1 - Shape memory effects using magnetoactive Boron-organo-silicon oxide polymers JF - Macromolecular Chemistry and Physics N2 - Thermomechanical shape memory materials have certain disadvantages when it comes to 3D volumetric reproduction intended for rapid prototyping or robotic prehension. The need to constantly supply energy to counteract elastic retraction forces in order to maintain the required geometry, together with the inability to achieve conformal stability at elevated temperatures, limits the application of thermal shape memory polymers. Form removal also presents problems as most viscoelastic materials do not ensure demolding stability. This work demonstrates how magnetoactive boron−organo−silicon oxide polymers under the influence of an applied magnetic field can be used to achieve energy free sustainable volumetric shape memory effects over extended periods. The rheopectic properties of boron−organo−silicon oxide materials sustain form removal without mold distortion. Y1 - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:898-opus4-23205 N1 - Corresponding Author: Gareth J. Monkman VL - 221 IS - 15 SP - 1 EP - 8 PB - Wiley ER -