We are interested in the fundamental understanding of the mechanics of smart materials and structures; including piezoelectric materials, functionally graded materials, elastomers & gels, rods, plates and shells. We also offer the design principles for relevant applications ranging from the micro-sensors & actuators to the macro-structural elements.JAPANESE
This study deals with a stress control problem in a composite disk constituting of a structural layer onto which functionally graded piezoelectric material (FGPM) layers are bonded. When a heating temperature distribution acts on the structural layer surface, the maximum thermal stress in the structural layer can be suppressed by applying appropriate voltages to electrodes arranged on each FGPM layer. In order to maximize the performance of stress control, variation in material properties of the FGPM layers is optimally designed. Obtained numerical results show that the performance of stress control is greatly improved through the optimum design of the FGPM layers.
Elastic instabilities of hard films on soft substrates emerge spontaneously from a homogeneous state during global deformation induced by growth/swelling, drying or confinement. Small compression of the system creates sinusoidal wrinkles with a broad spatial energy distribution while large compression creates sharp folds with localized energy. The wrinkle-to-fold transition has been mostly focused on two-dimensional plane-strain models under uniaxial compression. In experiments, however, the biaxial compression often lead to complex three-dimensional spatial structure due to the interplay between elasticity and geometry. The nucleation and growth of folds in biaxial compression remain elusive. Here, we explore folding dynamics of neo-Hookean bilayer systems under biaxial compression in a systematic way.