On the modelling aspect of low-velocity impact composite laminates / M.S. Meon...[et al.]

Composites suffer a degradation of structural stiffness due to various types of impact loading resulting in damage which is difficult to observe from the surface of the structure. The paper deals with the finite element model (FEM) to study the possible modelling procedures in low-velocity impact (LVI) and failure mechanism of carbon fiber reinforced polymer (CFRP) composite laminate of CCF300/epoxy and its structural responses. In finite element calculation, a proposed three-dimensional progressive damage model is used to determine the intralaminar damage, whereas the cohesive contact formulation is employed to analyse the interlaminar damage. The failure model performances are validated and verified based on different boundary conditions while maintaining the impact energy. Through simulation, the variation in boundary conditions significantly changes the structural responses and energy absorption of the laminates. It is hoped this study will be a great tool in determining the different composite impact scenarios

Do good institutions enhance the effect of technological spillovers on productivity? Comparative evidence from developed and transition economies

This paper argues that institutional quality has both direct and indirect (moderating) effects on productivity of countries. These hypotheses are tested using a battery of institutional proxies (governance, economic freedom, intellectual property rights and ease of doing business) and two channels for technological spillovers (trade and FDI) in a panel of developed and transition economies. The results confirm that good institutions have positive and comparable direct effects on productivity across the board. However, they moderate differently the relationship between foreign technological spillovers and productivity. Thus, governance, IPR and economic freedom exhibit negative moderation in the case of transition economies, while easiness of doing business moderates positively this relationship for both groups of countries. Further, the moderation effects are larger for transition economies and for trade-related spillovers. Overall, these results suggest a trade-off for transition countries between pursuing institutional upgrades and enjoying greater gains from technological spillovers. (C) 2014 Elsevier Inc. All rights reserved