Vibrations of fixed-fixed heterogeneous curved beams loaded by a central force at the crown point

This paper addresses the vibrations of heterogeneous curved beams under the assumption that the load of the beam is a dead one and is perpendicular to the centroidal axis. It is assumed that: (a) the radius of curvature is constant, and (b) Young’s modulus and the Poisson’s number depend on the cross-sectional coordinates. As for the issue of fixed-fixed beams, the objectives are the following: (1) to determine the Green’s function matrices provided that the beam is under radial load; (2) to examine how the load affects the natural frequencies given that the beam is subjected to a vertical force at the crown point; (3) to develop a numerical model which makes it possible to determine how the natural frequencies are related to the load. The computational results are presented graphically

THE OPTIMAL DESIGN OF THE TESTING SPECIMENS FOR A MORE ACCURATE EVALUATION OF THE GLUES’ MECHANICAL PROPERTIES

The main goal of the contribution consists in offering an improved method in the glues’ mechanical behaviours estimation, involving also a new type of specimen. The described method can be used successfully not only in the wood industry, but also in several other industrial applications, where the adhesives’ mechanical properties have to be determined as much as accurate possible. The authors elaborated the below-proposed method, based on their former, high-accuracy investigations by means of Holographic Interferometry, where were evaluated not only the timedependent behaviours of the glues (evaluated by means of their displacements field), but also their residual behaviours, too. The original testing bench of the authors allows a wide range of stresses, out of which, this paper describes only the longitudinal shear one. The proposed testing specimen, analysed by means of FEM method, will eliminate totally the undesired bending effect, which produces the so-called peel stress. The authors express their hope that the proposed strategy will became an useful, objective and high-efficiency modality both for testing and choosing the most adequate glue (not only for wood-industry, but also for the general industrial purpose, too)