Sea Technology

NOV 2012

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When size, performance and robustness matter The results of failure tests of the specimens with 5- and 10-millimeter thickness bound- ed by bolted and adhesive-bonded joints. ed. The specimens came from panels of two different thicknesses: 5 and 10 millimeters, manufactured by hand- laying processes and cut from one di- rection of 0 degrees. Materials and Method The E-glass was supplied for this study by Saint-Gobain BTI UK Ltd. (Andover, England), which manufac- tures COTECH multiaxial fabric. The orthophthalic polyester resin, Dewest- er 196, came from Dewilux Paint Inc. (Izmir, Turkey). This general purpose resin is widely used in boatbuilding and readily available on the market. The panels represented the scant- lings of a hull of single-skin construc- tion. They were cured at room temper- ature and left for one month in ambient indoor conditions before testing be- gan. The panels were produced by a hand layup technique in the workshop of a boatbuilder in Izmir, who also laid the glass fibers to maintain relative uni- formity in workmanship. Hand layup is the preferred method in the boat- building industry due to its lower cost and ease of obtaining uniform thick- ness throughout the lamination. This method is sufficient to obtain medium- strength characteristics. The jointless (flat) tensile specimens of 5- and 10-millimeter thickness were marked as J05A00 and J10S00, respec- tively, with the "J" denoting "jointless," followed by numbers and characters indicating the thickness of the speci- mens, the testing environment A (air) or S (saline), and fiber orientation (00). The bolted specimens, B05A00 and B10S00, consisted of two jointed sides with a Metric5 bolt and screw nut. The area of the GFRP section in the jointed zone was equal to the area of the joint- less specimens in the same section. The adhesive-bonded specimens were manufactured from two adhesive- jointed sides and marked as Ad05A00 and Ad10S00. Prior to fatigue testing, the ultimate tensile strengths (UTS) of the speci- mens were determined. The specimens were kept at an environmental con- dition of 23° C at 50 percent relative humidity for 24 hours. The ones to be tested in seawater were kept in a 3.5 percent sodium hydroxide (NaOH) so- Inertial Measurement Unit Key features • Small size, low weight and low cost • ITAR free • Insensitive to magnetic fi elds • Solid state - high reliability • Low gyro bias instability (0.5°/h) • Low gyro noise (0.15°/√h) • ±10g acceleration input range • Low accelerometer bias instability (0.05mg) • 3 inclinometers for accurate leveling • Compensated digital output, RS422 • Customer confi gurable output for mat, sampling rate and fi lter settings • Auxiliary input Sensonor AS NOVEMBER 2012 / st 39

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