DETERMINATION OF EPOXY RESIN ’ S MECHANICAL PROPERTIES BY EXPERIMENTAL-COMPUTATIONAL PROCEDURES IN TENSION Assist . Prof . VLDILV
The use of epoxy resins in metal structures for adhesive reasons is getting wider. Epoxy resins possess enhanced mechanical, chemical and physical properties, i.e. increased shear and compression strength, resistance in solvents, as well as at high temperatures. Tensile tests were carried out with standard aluminium tension specimens glued with epoxy resins. The thickness of the glue and the acting crosssection area were variable. The specimens were cemented under constant temperature and humidity conditions. The experimental results were simulated with the aid of FEM-based procedures, while the stress–strain curves of the epoxy resins, as obtained by nanoindentations and corresponding FEM-supported algorithm, were taken into account. The obtained results allow the determination of the epoxy resins’ strength versus its thickness and the occupying cross-section area.
Actual indenter tip geometries, material elastoplastic deformation laws and universal hardness
The precise knowledge of materials mechanical properties is always a core issue in every technical application. Through a developed finite elements method (FEM) continuous simulation of the nanoindentation, the applied force course versus the penetration depth is adequately simulated during the loading and unloading phases of this test, and the corresponding material stress ‐ strain curves, as well as the universal hardness, are stepwise defined. Furthermore, the actual tip geometries of various indenters are approached and through equivalent magnitudes described. The results show that the defined material elastoplastic deformation characteristics are independent of the indenter type, as Vickers or Berkovich, since the existing indenter tip form deviations from their ideal geometry are considered. Furthermore, using the developed FEM-based nanoindentation simulation, the influence of the indenter tip geometry on the defined constitutive laws and the universal hardness is sufficiently elucidated. Various materials stress ‐ strain curves and universal hardness courses versus the indentation depth, determined by means of the developed procedure, are presented.
What is an archival education?1
This article introduces the approach to Master's level archival education adopted at the University of Manitoba. It is intended as a contribution to the recently renewed discussion of graduate archival education in the UK and Ireland. The author maintains that recent major developments in the accessibility, uses, and very conception of archives powerfully underscore the distinctiveness of archival work. These developments foster continued collaboration between archivists and those in related professions such as records management, but, more importantly, reinforce their longstanding distinctiveness. The article discusses why and how the University of Manitoba has responded to the increasingly complex challenges facing archivists and archival educators in this evolving setting with an archival, conceptual, historical, and research-oriented curriculum.