Analysis of Mechanical Properties and Environmental Effect on Composite Sandwich Structure by Varying the Face Sheet Thickness

Abstract

In this study, composite sandwich panels were fabricated by vacuum-assisted hand lay-up method. Carbon fiber is used as face sheet material, and Nomex™ PN1 honeycomb is used as core material. Three panels were fabricated of different configurations; thickness of core took 8 mm remains the same in all three panels, but total thickness of face sheet took 0.4 mm, 0.8 mm and 1.2 mm for different panels. After fabrication, the specimens were prepared as per ASTM standards available for different tests and carried out various tests like compression test, three-point bending test, water absorption test, acid attack resistance test and soil degradation test on all panels and then analyzed the effect of varying face sheet thicknesses. The results showed that when specimen thicknesses were 8.4 mm, 8.8 mm and 9.2 mm, then compression strengths were 16.43 N/mm2, 103.86 N/mm2 and 571.65 N/mm2, respectively and deflections were 2 mm(approx), 2.5 mm(approx) and 3 mm(approx), respectively; so increasing the face sheet thickness of structure increases the compression strength and deflection. For acid attack resistance test, when specimen thicknesses were 8.4 mm, 8.8 mm and 9.2 mm, then changes in weight were +50.20%, +27.08% and +20.92%, respectively so that effect of acid was less when the face sheet thickness increases. When specimen thicknesses were 8.4 mm, 8.8 mm and 9.2 mm, then changes in their weight for water absorption test were +8.98%, +6.08% and +9.92%, respectively, and changes in their weight for soil degradation test were +3.41%, +0.55% and +0.79%, respectively, so water absorption and soil degradation tests showed that increasing the face sheet thickness was better, but it should not be over thick.