The present work deals with the application of an innovative in-house developed wavelet-based methodology for the analysis of the acceleration responses of a human head complex model as a simulated diffused oedema progresses. The human head complex has been modeled as a structure consisting of three confocal prolate spheroids, whereas the three defined regions by the system of spheroids, from the outside to the inside, represent the scull, the region of cerebrospinal fluid, and the brain tissue. A Dirac-like pulse has been used to excite the human head complex model and the acceleration response of the system has been calculated and analyzed via the wavelet-based methodology. For the purpose of the present analysis, a wave propagation commercial finite element code, LS-DYNA 3D, has been used. The progressive diffused oedema was modeled via consecutive increases in brain volume accompanied by a decrease in brain density. It was shown that even a small increase in brain volume (at the level of 0.5%) can be identified by the effect it has on the vibration characteristics of the human head complex. More precisely, it was found that for some of the wavelet decomposition levels, the energy content changes monotonically as the brain volume increases, thus providing a useful index of monitoring an oncoming brain oedema before any brain damage appears due to uncontrolled intracranial hypertension. For the purpose of the present work and for the levels of brain volume increase considered in the present analysis, no pressure increase was assumed into the cranial vault and, associatively, no brain compliance variation.

The present work deals with the development and verification of a set of analytical solutions for the bearing failure of single lap composite joints, which are applied on a composite joint tested experimentally. The stress field originating from the solution is calculated and progressive failure criteria are applied, verifying their applicability as a fast way of calculating bearing failure of a joint. Additionally, the extracted stress field from the results is introduced as a load to the finite element model of the joint under evaluation, and the equivalency of this method is compared and proven against typical implicit non-linear contact analysis. The major advantage of the proposed methodology is that the highly non-linear contact problem is circumvented using the stress distribution at the hole boundary as an actual load and thus transforming the analysis to a linear one, providing considerable agreement to the exact high-cost numerical solution.

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