Feathers can produce sound by fluttering in airflow. This flutter is hypothesized to be aeroelastic, arising from the coupling of aerodynamic forces to one or more of the feather's intrinsic structural resonance frequencies. We investigated how mode of flutter varied among a sample of hummingbird tail feathers tested in a wind tunnel. Feather vibration was measured directly at ~100 points acros...

Meshfree methods are viewed as next generation computational techniques. With evident limitations of conventional grid based methods, like FEM, in dealing with problems of fracture mechanics, large deformation, and simulation of manufacturing processes, meshfree methods have gained much attention by researchers. A number of meshfree methods have been proposed till now for analyzing complex prob...

Research into energy harvesting from ambient vibration sources has attracted great interest over the last few years, largely as a result of advances in the areas of wireless technology and low-power electronics. One of the mechanisms for converting mechanical vibration to electrical energy is the use of piezoelectric materials, typically operating as a cantilever in a bending mode, which genera...

The dynamic properties of inkjet-printed Ag thin films on flexible substrates were measured using flexural wave propagation. The Ag nanoparticle suspension was inkjet-printed on polyimide (PI), silicon wafer, and glass. The effects of flexible substrates on the dynamic properties of the films were investigated. Beam-shaped Ag-printed substrates were fabricated by pico-second laser pulse cutting...

This article deals with the free in-plane vibration analysis of a frame with four arbitrary inclined members by differential transform method. Based on four differential equations and sixteen boundary and compatibility conditions, the related structural eigenvalue problem will be analytically formulated. The frequency parameters and mode shapes of the frame will be calculated for various values...

An ab initio calculation of a secondary isotope effect on a bond length has been carried out for the first time. Single determinant molecular orbital computations indicate that the mean C-C bond length at O"K is longer in C,H6 than in C,D6 by 0.0015 A. A comparison with model calculations supports a steric interpretation in which H atoms act as if they are bulkier than 0 atoms owing to their la...

In this article, small scale effects on free vibration analysis of non-uniform nanobeams is discussed. Small scale effects are modelled after Eringen’s nonlocal elasticity theory while the non-uniformity is presented by exponentially varying width among the beams length with constant thickness. Analytical solution is achieved for free vibration with different boundary conditions. It is shown th...

This paper presents the design of a mechanical transducer for a new kind of optical-fiber accelerometer based on birefringence variation. Vibration-induced fiber deformation modifies the birefringence within the fiber and hence the state of polarization of the light. To deform the fiber a mechanical transducer has to be made. This article compares analytically different transducers using either...

This paper explores the utility of a discrete singular convolution (DSC) algorithm for beam analysis. Regularized Shannon and Dirichlet kernels are selected to illustrate the present algorithm. Three classes of benchmark beam problems, including bending, vibration and buckling, are utilized to test numerical accuracy and speed of convergence of the present approach. Numerical experiments indica...