Research On The Mechanical Properties Of Carbon Fiber Composites And Their Aluminum Foam Sandwich Structures

Carbon fiber reinforced resin matrix composites(CFRP)have many advantages such as light weight,good mechanical properties and long service life,and have promising applications in the sports equipment,automotive industry,aerospace and marine sectors.CFRP has received a great deal of attention from researchers.CFRP/aluminium foam sandwich structures play an important role in the military and civil industry due to their light weight,versatility and good mechanical properties.However,in these applications,CFRP can be limited by environmental factors and there is still a large upside in its mechanical properties that can affect the mechanical properties of CFRP/aluminium foam sandwich structures.Therefore,there is a need to improve the properties of CFRP and thus promote the widespread use of CFRP/aluminium foam sandwich structures.In this paper,two modification methods are used to enhance the mechanical properties of CFRP: The first is to prepare carbon nanotubes reinforced carbon fiber epoxy composites(referred to as matrix-reinforced CFRP)by adding carbon nanotubes to epoxy resin matrix,and to investigate the effect of matrix reinforcement on the mechanical properties of CFRP;The second is to use a sizing agent containing carbon nanotubes for the surface treatment of carbon fibers to prepare interface modified CFRP,and then to study the effect of the interface modification on the mechanical properties of CFRP.The CFRP/aluminium foam sandwich structure is then prepared using different CFRP as the panel and aluminium foam as the core material,to investigate the factors affecting the mechanical properties of the CFRP/aluminium foam sandwich structure and their laws,and to analyse the failure behaviour and mechanism of the sandwich structure.The main results of this paper are as follows:1.The effect of carbon nanotube fillers on the mechanical properties of CFRP was investigated.The carbon nanotube filler reinforced resin matrix improves the tensile properties of CFRP in the dry state.The carbon fibers are more closely bonded to the resin matrix in the tensile fracture in matrix-reinforced CFRP.The carbon nanotube filler reinforced resin matrix also gives the CFRP enhanced flexural properties in the dry state.2.The effect of carbon nanotube fillers on the ageing resistance of CFRP was investigated.The carbon nanotube filler reinforced resin matrix reduces the rate of reduction in the tensile properties of CFRP under different immersion ageing conditions.The tensile fracture of matrix-reinforced CFRP is lightly broken under immersion ageing conditions.The carbon nanotube filler reinforced resin matrix also reduces the rate of reduction in the flexural properties of CFRP under different immersion ageing conditions.3.The effect of interfacial modification on the mechanical properties of CFRP was investigated.A sizing agent with N-methyl-pyrrolidone(NMP),polyethersulfone(PES)and carbon nanotubes as the main components and a corresponding sizing process were developed.The sizing of carbon fibers improves the tensile properties of CFRP and the sizing of carbon fibers also enhances the flexural properties of CFRP.4.The effect of the content and size of carbon nanotubes in the sizing agent on the mechanical properties of CFRP was investigated.When the size of the carbon nanotubes in the sizing agent is constant,the tensile and flexural properties of CFRP first increase and then decrease as the carbon nanotube content increases.When the content of carbon nanotubes in the sizing agent is constant,the tensile and flexural properties of CFRP decrease as the size of the carbon nanotubes increases.5.The influence of the mechanical properties of CFRP panels on the flexural properties of CFRP/aluminium foam sandwich structures was investigated.The bending load of the CFRP/aluminium foam sandwich structure increases as the flexural strength of the CFRP panels increases.The interface-modified CFRP/aluminium foam sandwich structure has the highest bending load.