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Subarachnoid haemorrhage (SAH) accounts for 1 to 7% of all strokes. In France, the range of incidence of SAH varies between 3 and 8/100,000 inhabitants. Global mortality lies around 40%, including 70% during the first week. The size of more than 90% of all aneurysms is less than 10 mm. In more than 90% of the patients; SAH is sporadic and a familial screening is warranted only after SAH occurring in 2 first-degree relatives. The main risk factors of SAH are tobacco, arterial hypertension and alcohol abuse. Genetic susceptibility may exist: it could involve several genes, the expression of which would characterize pathophysiological pathways implicated in the disease. This could be identified using genomic technique of microarrays, which could explore all the genome, simply using a sample of peripheral venous blood. For example, in the future, this approach could help to identify patients who are at high risk to develop vasospasm after SAH.

This paper presents in details the fatigue life prediction models developed for lead-free assemblies in harsh environments during the 3-year European LIFE project GEAMCOS. The approach uses advanced finite element modelling as well as experimental fatigue data. It is also based on a complete material characterisation for a wide range of stress conditions. It focuses on the most critical packages of the full lead-free GEAMCOS test board and of the functional demonstrator developed for military communication.

As part of the European LIFE project GEAMCOS, this paper presents the simulation evaluation of lead-free electronic assemblies submitted to harsh environments encountered in aeronautical and military communication applications. It addresses the following questions: (1) the determination of an optimal accelerated test condition in the temperature range of -40degC/100degC for assemblies with SnAgCu alloy, (2) the evaluation of the life-time of five assemblies with SnAgCu and SnPb, (3) a sensitivity analysis on design and serigraphy parameter variations, (4) the determination of a test protocol in vibration environments. All the results give relevant life-time predictions. The CSP and PQFP components should have longer time-to- failure with SnAgCu solder joints than with SnPb joints. The contrary is expected for 1st and 2nd level interconnects of large BGA packages. In any case, the factor is found to remain less than about 2. The PCB thermal expansion coefficient has the highest impact, followed by the solder joint height. The first level interconnect reliability is not impacted by any of the parameter changes. Simulation work in GEAMCOS project shall go on in 2007-2008 with an experimental validation of the thermo- mechanical simulations. This will require to identify a new constitutive material model for SnAgCu and to calibrate the simulations with experimental test results.