Abstract:
Deployable structures play a vital role in a variety of applications such as aerospace
structures, rapid development civil engineering projects, medical devices,
reconfigurable robotics and many other engineering applications. Deployable thinwalled
booms
make
use
of
elastic
strain
energy
during
storage
and
are
capable
of
selfdeploying
to their fully deployed configuration which is an ideal candidate to
overcome the bottleneck of limited launch vehicle capacity faced in space applications.
In this research, an attempt has been made to characterise the mechanics of tape
spring booms which are the simplest form among the coilable booms. Numerical and
analytical frameworks are established to investigate the large deformation analysis of
deployable coilable tape springs during the flattening process, which is the initial
process of coiling. Geometrically non-linear finite element models implemented in
Abaqus/Standard are used to characterize the flattening mechanics of isotropic tape
springs under compressive deformation. The effects of geometric and material
properties on flattening behaviour are investigated through a numerical parametric
study. A simple analytical model is developed to predict the stresses and forces during
compression flattening, and a good correlation has been found with the numerical
study.
The tension stabilized coiling behaviour of longer tape booms is then investigated
through analytical and numerical studies. A useful analytical model is developed to
determine the required minimum tension force to prevent instabilities such as
blossoming instability and buckling instability. The influence of varying coiling radius
due to the thickness of multiple turns is taken into account in the developed analytical
framework. Also, the required minimum torque and power for tension stabilized
coiling of tape spring are developed considering energy conservation where the effect
of friction is also considered.
Coiling of isotropic tape spring booms is simulated in commercially available
finite element software Abaqus/Explicit. A good correlation has been found between
the numerical and analytical results in terms of the required torque for coiling of
longer tape-spring. Furthermore, a novel approach to predict the minimum required tension force to prevent the instabilities is proposed. A numerical parametric study is
conducted utilizing this technique in order to study the effect of the coiling ratio on the
required tension force. In terms of the bending and tension-dominated regimes, the
numerical findings exhibit good qualitative agreement with the established analytical
model. Furthermore, a linear trend is observed in the numerical results for the loss of
uniqueness region, which is helpful for the development of analytical models.
Citation:
Sutharsanan, N. (2022). Characterising mechanics of deployable coilable tape-springs [Master's theses, University of Moratuwa]. Institutional Repository University of Moratuwa. http://dl.lib.uom.lk/handle/123/21668