A full-field approach for the elastic characterization of anisotropic materials

Elastic characterization of CVD diamond by static and dynamic measurements

“…The load is applied by laying one or two steel spheres along the knives and is measured with a resolution of 10 −3 N by a beam transducer (connected to a strain-gage amplifier) which supports the base and the specimen. More details about the loading device can be found in 18 where the whole procedure was previously tested on a carbon steel specimen whose elastic properties found in literature are well known. For completeness and clarity the results obtained for the steel are reported in Table 1.…”

“…An alternative way consists in adopting an integral approach [16][17][18] : in this case the stress components are evaluated by averaging the punctual quantities over a sufficiently wide area of the specimen (at worst the whole specimen). By this approach in some loading configurations it is possible to obtain an analytical expression of the average stress components, which is suitable for heterogeneous materials, such as composite materials, or for those materials whose mechanical behavior is influenced by the grain size; on the other hand the determination of the average strain components involves the use of more complex experimental techniques than the standard techniques based on strain-gages.…”

“…The corresponding average strain states are measured by a speckle interferometer sensitive to the out-of-plane displacements. By the procedure described in detail by the authors in 18 an analytical expression of the displacements is obtained for each stress state; then, by applying the definition of strain for a thin plate, 19 the strain components are calculated as:…”

Exact and efficient interpolation using finite elements shape functions

“…These applications include mesh-interaction [4,22], geological topography [10], visualization [16,20], calibration of boundary conditions [17] and material identification [5,7,9,11,12,14,15]. In general, a finite elements solver provides information only at nodal or integration points.…”

“…Available data points may not always coincide with mesh points, and before a comparison can be performed, it is necessary to map one field of points onto the other. Three types of mapping techniques can be employed for this purpose: node placement, where FE nodes and experimental points are forced to coincide [7,14], approximation and interpolation 1 [8,13,12]. Since the accuracy of the FE models is a function of node position, node placement techniques introduce an undesired coupling between the position of data points and the accuracy of the finite elements model.…”