| Abstract | A modular ice impact panel, intended for future ship / bergy bit collision tests, has been designed that incorporates new pressure-sensing technology. A single module of the panel, with sensing area of 1 m2, has been fabricated and tested in the lab by dropping heavy masses of freshwater ice on it from heights up to 1.8 m. The central component of the Impact Module is a large cast acrylic block, 1 m x 1 m x 0.5 m, housed in a strong steel frame. The Impact Module design is made possible by the strength and transparency characteristics of the acrylic. The Module utilizes two types of pressure sensors, one consisting of strain-gauged acrylic cylinders (2.5 cm diameter) that are imbedded in the face of the acrylic block at 9 locations. The other technology is an optomechanical system consisting of many thin narrow strips (13 mm x 0.9 m x 4 mm) of acrylic that cover the impacting face of the acrylic block. Elastic flattening of the slightly convex bottom surface of the strips occurs when pressed against the face of the block during impacts. A highspeed video camera, positioned behind the transparent block, records the deformation of the strips from which the corresponding pressure is determined from calibrations. The effective squareshaped unit sensing area for this technology is 13 mm x 13 mm, implying that the Impact Module has the equivalent of about 4500 symmetric-shaped pressure sensors on its surface. The acrylic block is supported on four large flat-jack load cells that measure the impact loads. The tests demonstrated that the Impact Module is very robust and the pressure-sensing technologies yield consistent results. The large capacity load sensors were also shown to be functional. |
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