Dear all,
I would like to share with you a couple of our recent papers that I think may be of interest for the wider community:
1) Ciambella, J., Stanier, D. C., & Rahatekar, S. S. (2016). Magnetic alignment of short carbon fibres in curing composites. Composites Part B: Engineering, 1–30. http://doi.org/10.1016/j.compositesb.2016.10.038 (downloadale at: http://authors.elsevier.com/a/1TypC4rCEkOviM)
2) Stanier, D. C., Ciambella, J., & Rahatekar, S. S. (2016). Fabrication and characterisation of short fibre reinforced elastomer composites for bending and twisting magnetic actuation. Composites Part A: Applied Science and Manufacturing, 91, 168–176. http://doi.org/10.1016/j.compositesa.2016.10.001 (downloadable at: http://authors.elsevier.com/a/1Tsus,UwqXBp~n)
In the former, we have studied the process of magnetically orientating carbon fibres during the curing phase of composite materials. We were able to derive a closed form expression of the minimum magnetic field necessary to achieve the desired degree of orientation in terms of the geometrical, mechanical and magnetic properties of the system. This model represents a simple tool for the experimentalists to discriminate which material/fibre configuration can be most proficiently used to achieve a highly orientated structure.
In the latter we have applied this technique to produce a soft-actuator that responds to low magnetic fields ( <0.5 T). We have theoretically predicted and experimentally observed the presence of a mechanical instability induced by the magnetic torque acting on the fibres. To the best of our knowledge, this is the first time that elastic instabilities controlled by the magnetic torques have been observed: a thin strip of the composite placed into an electromagnet remains undeformed until a critical value of the magnetic field is reached and a sudden jump in the deformation is observed. The deformed configuration of the sample can either be pure bending, pure twisting or both according to the initial orientation of the fibres. These effects which have been demonstrated for a relatively soft matrix could be exploited for stiffer material configurations such as carbon fibres embedded into epoxy which would eventually allow larger actuation forces to be produced.
Kind regards, JC