Novel nickle foil micro-bend tests and the need for a relook at length scale parameter’s numerical value
Bhakti N. Patel, Srinivasan M. Sivakumar
Abstract
The current study provides a discussion on two aspects of size-effects which is known to be a characteristic behavior of micro-scaled structures. First it provides the experimentalists with a novel micro-bend technique wherein the micro-cantilever is loaded at different points along its length. This eases the experimental process by reducing the efforts of the experimentalists in sample preparation (as the same sample can be used for obtaining results corresponding to different L/H ratio). Also, precision cutting and mounting of the samples to obtain the micro-cantilever of desirous overhang length is not required. Further, the above described technique is used to test nickle micro-cantilevers of three thicknesses (15, 25, 50 μm) and different L/H (=200, 300, 400) ratios. They are elastically bent to undergo small deflections. Apart from reporting the obvious size-effects for smaller thicknesses and fitting the experiments with a model for determining the length scale parameter, size-effects for beams with different thicknesses and varying L/H ratios are presented. Secondly, a discussion on the widely fluctuating nature of numerical values that the length scale parameter assumes is presented. And it is postulated that the numerical value of length scale parameter is a function of material, model and geometry of beam cross-section.