Title: Effect of Heat Damage on the Double Lap Joint Strength of Pultruded E-glass/Polyester Composites

Authors: Abdalla Alomari, Alexander B. Morgan , Donald Klostermanc, and Elias A. Toubia

DOI: 10.33599/nasampe/c.19.0645

Abstract: A comprehensive experimental investigation was conducted to study the effect of post-heat damage on fire retardant glass fiber-reinforced pultruded composites. A total of 63 double lap shear joints were tested to failure at ambient temperature conditions. The test parameters included: 1) flat plate thickness, i.e. 6.4 mm and 12.7 mm; 2) heat flux exposure prior to testing using a cone calorimeter test (10 and 20 kW/m2); and 3) load direction (0, 45 and 90°) with respect to the member’s pultrusion axis. The edge-to-hole diameter (e/d) and width-to-hole diameter (w/d) ratios were kept constant for all specimens. The test results revealed that for the post-heat damaged thin plates (6.4 mm thick), the maximum strength reduction (around 20%) occurred when the load was applied along the 0 ° fiber direction (roving direction). This was justified using post-mortem digital microscopic, SEM, and X-ray CT scan images, where a significant delamination and fiber buckling occurred at the bearing location of the bolt. In addition, for the 0° loading direction, a change in failure mode was observed for the higher heat flux (20 kW /m2), where the failure mode shifted from shear-out/bearing to shear-out/bearing and net-tension. The strength reductions of the double lap shear joints with 45 and 90° fiber orientation with respect to the load were 18% and 14 %, respectively. For both plates’ thicknesses, net-tension failure mode was the dominant mode for the 45 and 90° off-axis loaded joints. This paper also presents the temperature profiles and degradation through the thickness of the damaged pultruded GFRP plates. The knowledge and data presented shadow the market’s ongoing “standardization and certification” efforts to statistically support the development of “knock-down” factors of pultruded structural joints.

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Conference: CAMX 2019

Publication Date: 2019/09/23

SKU: TP19-0645

Pages: 20

Price: $40.00