Trans RINA, Vol 152, Part B1, Intl J Small Craft Tech, 2010 Jan-Jun


the test, this energy was delivered by allowing a 500 kg steel striker to fall 6.5 m onto the hull, as shown in Figure 2. The hull was secured on heavy-load proof concrete ground by means of standard steel pillars and a fully loaded steel container. The steel striker was a block 250 x 250 x 1100 mm. The ambient temperature was 5ºC. The area chosen to be damaged was single skin laminate, situated between transverse bulkheads, as it was felt that this would favour penetrative damage resulting in a leak, rather than internal structural damage to the bulkheads. This region in question comprised 12 mm thick painted Twintex® PP-glass laminate.


In case the impact had occurred directly on a stiffener, the structural damage would have been undesirably transmitted through the structure to other areas in the hull.


Also, the stiffener or bulkhead would have


dissipated a greater amount of energy, and a larger internal repair would have been needed.


The impact velocity in the test was 11.25 m·s-1, a little over twice the envisaged speed of the craft.


Although pure PP, being just above its glass transition temperature, shows a tough-brittle transition in this region [13], this does not occur in long glass fibre-based PP composites, since


many other toughening


Figure 2: Controlled damage arrangement at BVT facilities. The hull was secured on heavy load-proof concrete ground by means of steel pillars (right) and a fully-loaded steel container (left). The steel striker was lifted and released on the hull with a truck-mounted crane.


mechanisms, involving interactions between the glass and the polymer, are present.


w = 500 kg


d = 6.5 m


3.1 3.2


3.3 3.4


B-34


©2010: The Royal Institution of Naval Architects


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