Title of Document: CHARACTERIZATION OF FR-4 PRINTED CIRCUIT BOARD LAMINATES BEFORE AND AFTER EXPOSURE TO LEAD-FREE SOLDERING CONDITIONS Ravikumar Sanapala, Master of Science, 2008 Directed By: Chair Professor, Michael G. Pecht, Department of Mechanical Engineering The transition to lead-free soldering of printed circuit boards (PCBs) using solder alloys such as Sn/Ag/Cu has resulted in higher t...

Advanced carbon-fibre composite materials are increasingly used as primary structural components in aviation and aerospace industries due to their high stiffness-to-density ratio. The design of composite aerostructures is required to meet a number of safety criteria, in particular, the damage tolerance. Delaminations, which are caused by the impact of foreign objects (tool drops, runway debris,...

Two themes form the basis of this study on fibre reinforced laminated composites: namely 'thermal residual stress' and 'transverse cracking'. Thermal residual stresses are inherent to any composite structure and are internal stress within the structure that form during manufacture. Their formation arises from the difference in coefficient of thermal expansion of the fibre and the matrix. These ...

Fibre metal laminates, hybrid composite materials built up from interlaced layers of thin metals and fibre reinforced adhesives, are future-proof used in the production passenger aircraft, yachts, sailplanes, racing cars, sports equipment. The most commercially available fibre–metal laminates carbon aluminium aramid glass laminates. This review emphasises developing technologies for forming met...

Abstract Glass fiber-reinforced polymer materials have been effectively used in civil aviation aircraft, but due to low electrical conductivity, a large area of ablation damage will occur after lightning strikes, which greatly threatens the safety aircrafts. Based on this, coupled electrical-thermal finite element analysis model for glass fiber reinforced is established, and results are compare...

The present paper focuses on the development of a multiscale optimisation strategy for the optimisation of variable angle stiffness laminates. The main goal consists in proving that it is possible to design structures having complex shapes made of variable stiffness composites by taking into account, from the early stages of the design process, the constraints linked to the manufacturing process.

This paper presents an adaptive PSO algorithm whose numerical parameters can be updated following a scheduled protocol respecting some known criteria of convergence in order to enhance the chances to reach the global optimum of a hard combinatorial optimization problem, such those encountered in global optimization problems of composite laminates. Some examples concerning hard design problems a...

The efficient use of fiber reinforced polymer matrix composites in load-carrying structures requires detailed analyses to assess their mechanical performance, cost, and weight saving aspects. To accurately analyze the cyclic fatigue life of composite laminates, the influence of the physical non-linearity of the unidirectional lamina in the cyclic fatigue life analysis was examined using enhance...

We analyze the stability of laminated microstructure for martensitic crystals that undergo cubic to trigonal, orthorhombic to triclinic, and trigonal to monoclinic transformations. We show that the microstructure is unique and stable for all laminates except when the lattice parameters satisfy certain identities.

laminates by exploiting the flux concentration effect Z. Fang, S. G. Lu, F. Li, S. Datta, Q. M. Zhang, and M. El Tahchi Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, USA Materials Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, USA LPA-GBMI, Faculty of Sciences II, Department of Physics, ...