Experimental investigation of Tied Foam Core sandwich compression performance

Carbon and glass dry fibre bundles were inserted into a ROHACELL (R) 71HERO polymethacrylimide foam core under a specific inclination angle and pin pattern in order to enhance the compressive strength and stiffness of the core material. Flatwise compression tests were conducted on pin-reinforced sandwich specimens and unreinforced sandwich to investigate the effect of pin volume fraction and pin material on the compressive mechanical properties and energy absorption characteristics. X-ray computed tomography was performed on tested specimens to investigate the failure modes under compressive loads. It was concluded that the compressive strength is mainly controlled by pin failure due to bending and compression loads at pin base. Moreover, increasing the pin volume fraction improved the compressive properties of the sandwich but using glass fibre pins instead of carbon fibre pins led to a higher increase of the absorbed crushing energy. Finally, an existing analytical model to predict the compressive strength and stiffness has been tested and evaluated.