Flexural and Dynamic Characteristics of FRP Composite Sandwich Beam

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IJERTV9IS060702
Flexural and Dynamic Characteristics of FRP Composite Sandwich Beam

Shah Alam , Guoqiang Li

This study presents the flexural and impact testing results of composite sandwich beams. The sandwich beams are constructed from balsa wood in the core and high strength steel wire and E-glass fiber reinforced polymer composite in the facings. The testing of these beams is performed using a monotonic static three-point loading to failure in accordance with ASTM standard C393-00. Local strain distribution in the mid- span of the beams is obtained using strain gauges. Mid-span deflections of the beams are real-time measured using linear variable displacement transducer (LVDT). From the experimental results, flexural properties of the beams are calculated, including bending stiffness, bending strength, shear strength etc. The experimental results have shown that the beams have all failed in the compression zone local buckling of the top face and shear of the core. The bottom skin does not exhibit any type of premature failure or distress. No bond failure of the composite in the tension zone is observed in any of the tested beams. After the bending tests, the overhanging portion of the sandwich beams are machined into various scaled-down specimens for tension testing, low velocity impact testing, and residual bending strength testing. Uniaxial tensile tests per ASTM D3039 are conducted on the laminated facing to determine its tensile modulus of elasticity along the longitudinal direction. Low velocity impact tests using the DynaTup impact machine are conducted on the machined beam specimens per ASTM D2444 with varying hammer weights. After impact testing, the residual load carrying capacity of the sandwich beam specimens are determined using a four-point bending test. In this test, the ASTM C393 test method is followed. Mid-span deflections of the beams were again real-time measured using the LVDT.