The effect of three different aging methods (immersion in hot water, freeze-thaw cycles and wet-dry cycles) on the mechanical properties of GRC were studied and compared.Test results showed that immersion in hot water may be an unreliable method for modified GRC formulations, with it being in probability a very harmful procedure.A new aging method, mixing freeze-thaw cycles and wet-dry cycles, seems to be the most accurate simulation of weather conditions that produce a noticeable change in GRC mechanical properties. Future work should be carried out to find a correlation between real weather and the proposed aging method.

This paper summarizes the utilization of analytical and numerical computation as valuable tools for lightweight armour design optimisation. Several analytical models for ballistic impact simulation onto composites and ceramic faced targets have been developed at our department. This paper shows a few examples of the utilization of those models as well as numerical computations using commercial hydrocodes.

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This article presents a relatively simple analytical model aimed at simulating high-speed penetration into composite materials targets. The model is based on a set of basic hypotheses common to other previous analytical models developed in our department and elsewhere. However, this new model is of a more refined nature acquisition that allows for reliable results without requiring the use of parametric data needed in previous models. For the first time, the model provides a qualitative explanation of the sudden drop of energy absorbed by the target with impact velocities slightly higher than the ballistic limit. A qualitative explanation, experimentally observed, of the shape of woven fabric laminates after impact is also noted. The model predictions of both ballistic limit and residual velocity after perforation reasonably agree with experimental results, in spite of the use of static data of the target material. Thus, this model may serve as a useful tool for a primary stage of composite armour design, permitting a large number of parameters to be screened before using higher cost numerical and experimental approaches.

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