Abstract: According to embodiments of the present invention, a distributed pressure and shear stress sensor includes a flexible substrate, such as PDMS, with a waveguide formed thereon. Along the waveguide path are several Bragg gratings. Each Bragg grating has a characteristic Bragg wavelength that shifts in response to an applied load due to elongation/compression of the grating. The wavelength shifts are monitored using a single input and a single output for the waveguide to determine the amount of applied pressure on the gratings. To measure shear stress, two flexible substrates with the waveguide and Bragg gratings are placed on top of each other such that the waveguides and gratings are perpendicular to each other. To fabricate the distributive pressure and shear sensor, a unique micro-molding technique is used wherein gratings are stamped into PDMS, for example.

Abstract: A composition for vibration damping of a structure releasing vibrational energy through its surface is disclosed. The composition includes either a substantially non-homogeneous visco elastic damping layer on the surface of the structure, or a visco elastic damping layer that is either homogeneous or non-homogeneous discontinuously attached to the surface of the structure. The non-homogeneity of the damping layer is caused by substantially planar voids, substantially spherical voids, or particles. The discontinuous attachment of the damping layer and the surface of the structure is caused by a plurality of grooves, indentations, or by the presence of a non-adhesive material where the damping layer and the surface structure are not secured.

Abstract: A composition for vibration damping of a structure releasing vibrational energy through its surface is disclosed. The composition includes either a substantially non-homogeneous visco elastic damping layer on the surface of the structure, or a visco elastic damping layer that is either homogeneous or non-homogeneous discontinuously attached to the surface of the structure. The non-homogeneity of the damping layer is caused by substantially planar voids, substantially spherical voids, or particles. The discontinuous attachment of the damping layer and the surface of the structure is caused by a plurality of grooves, indentations, or by the presence of a non-adhesive material where the damping layer and the surface structure are not secured.