Magnetic response of aligned nickel coated carbon fibres in a pdms matrix

We study the behaviour of magnetically responsive fibres embedded in an elastomer and oriented under a magnetic field to produce an anisotropic material. PDMS reinforced with nickel-coated carbon fibres, orientated under the influence of a magnetic field, are produced with different primary reinforcing angles. The resulting elastomer material is responsive to the application of a magnetic field, showing potential for magnetic actuation. Further to this, the material has mechanical properties that are controlled by the strength and direction of the magnetic field during the cure of the material. The result is that the reinforcing fibres can be tailored in both its mechanical and magnetic responses, in a complimentary manner. The large strain macroscopic behaviour of the composite is shown to be closely described by a transversely isotropic constitutive equation up to around 30%; above this strain, the model struggles to capture the non-linear behaviour of the material although it does describe the rotation of the fibres at strain and in particular gives an insight into both the short strain stiffness and large strain dependence of the reinforcement orientation. In addition, it is also possible to actuate the material under a magnetic field. Deflection and twisting behaviour is possible by consideration of both the strength of the magnetic field, and the direction of the magnetic field with respect to the orientation of the fibres.