Study On Low-velocity Impact And Bending Property Of Foam Sandwich Structure Composites

Stitched foam sandwich composites as a new type of composite material,which improves the Interlayer properties of the material by introducing reinforcing stitches along the thickness of the foam sandwich panel square,significantly improves the impact resistance and bending performance of the foam sandwich composite structure.Gradually,it is highly concerned by the academia of composite materials.Stitched foam sandwich composites have advantages such as high strength,stiffness,light weight,fatigue resistance,and high temperature resistance.In recent decades,they have been used in aviation,aerospace,energy,transportation,construction,machinery,biomedical Science,sports,etc.The department is increasingly used extensively.In order to study better performance of composite materials to improve the performance of materials,hybrid fiber composite materials use fiber hybrid methods to enhance the performance of composite materials,achieve complementary functions,and reduce the cost of materials.Due to the diversity of the hybrid forms,the space for structural optimization based on the composite structure is broadened.Therefore,it is of great significance to study the mechanical properties of hybrid fiber foam sandwich composites.In this paper,the low-velocity impact properties and three-point bending properties of the composite foamed-sandwich foam composites are studied.The main research work is as follows:Firstly,the foam sandwich composite board was fabricated by VARTM filling and forming process.The low-speed impact test of 10 J and 20 J energy was performed on the stitched and unstitched carbon fiber foam sandwich composite board respectively by the drop weight impact tester.Ultrasonic water scanning imaging system was used to inspect the impacted composite plate,and the internal damage of the sandwich composite plate was obtained.Then,the impact properties of the carbon fiber and glass fiber interlayer hybrid reinforced suture foam sandwich composites were studied.A 10 J impact test was performed on a carbon fiber,glass/carbon inter-layer hybrid fiber,and glass fiber foam sandwich composite panel using a drop weight impact tester.microscopic photographing and ultrasonic immersion scans of the impacted composite panel were then performed.The damage test was conducted.The results after the impact and the test results were comprehensively analyzed to obtain the internal and external damages of the composite sandwich panel.Finally,the three-point bending performance of the stitched and unstitched carbon fiber foam sandwich composites was discussed.The spliced foam sandwich panel with reinforced ribs was prepared without changing the properties of the rib material.The three-point bending test was performed on the foam sandwich composite panel using a universal testing machine.Due to the introduction of stiffeners,the bending strength and stiffness of the foam sandwich composite board can be effectively improved,and the bending performance of the sandwich structure is effectively improved.In addition,the influence of the number of reinforcement ribs and the placement of ribs on the three-point bending of suture sandwiched carbon fiber composites was discussed.