This study aimed to develop a method to construct tensegrity structures from elementary cells, defined as structures consisting of only one bar connected with a few strings. Comparison of various elementary cells leads to the further selection of the so-called 'Zshaped' cell, which contains one bar and three interconnected strings, as the elementary module to assemble the Z-based spatial tensegrity structures. The graph theory is utilized to analyse the topology of strings required to construct this type of tensegrity structures. It is shown that 'a string net can be used to construct a Z-based tensegrity structure if and only if its topology is a simple and bridgeless cubic graph'. Once the topology of strings has been determined, one can easily design the associated tensegrity structure by adding a deterministic number of bars. Two schemes are suggested for this design strategy. One is to enumerate all possible topologies of Z-based tensegrity for a specified number of bars or cells, and the other is to determine the tensegrity structure from a vertex-truncated polyhedron. The method developed in this paper allows us to construct various types of novel tensegrity structures.

A phase field method is developed to investigate the morphological evolution of a vesicle in an electric field, taking into account coupled mechanical and electric effects such as bending, osmotic pressure, surface tension, flexoelectricity, and dielectricity of the membrane. The energy of the system is formulated in terms of a continuous phase field variable and the electric potential. The governing equations of the phase field and the electric field are solved using the Galerkin weighted residual approach. The validation and robustness of the algorithm are verified by direct comparisons of the obtained numerical solutions with relevant experimental results. The morphological evolution of an axisymmetric vesicle under an electric field is studied in detail. The results demonstrate that the present method can simulate complex morphological evolutions of vesicles under coupled mechanical–electrical fields.

We here demonstrate that surface charges on a spherical soft particle may induce its morphology instabillity. It is found that various patterns can be obtained by varying the surface charge density. The critical condition for the occurrence of surface instability and the wavelength of the induced surface patterns are derived analytically and, thereby, the morphological phase diagram of soft particles can be provided easily. Besides the electric stress, surface tension also plays a significant role in the surface evolution process. In addition, the morphological evolution behavior of a soft particle is demonstrated to exhibit distinct dependence on its size. (C) 2009 American Institute of Physics. [DOI: 10.1063/1.3177189]

Journal of the Mechanics and Physics of Solids, 2008, Vol. 56, No. 9, pp. 2844–2862.

Composites Part B: Engineering, 2008, Vol. 39, No. 6, pp. 933-961.