Citation:
A. Skordos, P. H. Chan, J. F. V. Vincent and G. Jeronimidis; A novel strain sensor based on the campaniform sensillum of insects, Philosophical Transactions of the Royal Society of London Series A- Mathematical Physical and Engineering Sciences Vol 360 (2002) No1791 p239-253
Abstract:
The functional design of the campaniform sensillum was modelled as a hole in a
plate using twoand three-dimensional finite-element modelling. Different shapes
of opening in a fibrous composite plate amplify differently the global strains
imposed on the plate, and different configurations of reinforcement also have an
effect. In this paper, the main objective is to study the strain and
displacement fields associated with circular or elliptical openings in laminated
plates in order to investigate their potential for integrated strain sensors.
Since we are therefore primarily interested with the detection of displacement,
the detailed stress concentration levels associated with these openings are not
of primary concern. However, strain energy density levels associated with
different hole and fibre configurations have been used to assess the relative
likely strength reduction effect of the openings. To compare the relative strain
amplification effect of drilled and formed holes of the same size in loaded
plates, we have used the relative change in length of diameters (circular) or
semi-axes (elliptical) in directions parallel and normal to the load. Various
techniques which could sense this deformation were investigated, in particular,
the coupling mechanism of a campaniform sensillum of Calliphora vicina. This
mechanism was resolved into discrete components: a cap surrounded by a collar, a
joint membrane and an annulus-shaped socket septum with a spongy compliant zone.
The coupling mechanism is a mechanical linkage which transforms the stimulus
into two deformations in different directions: monoaxial transverse compression
of the dendritic tip and vertical displacement of the cap. The mechanism is
insensitive to change of the material properties of the socket septum, the
cuticular cap and the spongy cuticle. The joint membrane may serve as a gap
filler. The material properties of the collar have a substantial influence on
the coupling mechanism’s output. A 30% change of stiffness of the collar causes
45% change in the output of the coupling mechanism. The collar may be able to
tune the sensitivity of the sensillum by changing its elastic propertie