Investigation On Anti-bending Performance Of Automotive Thermoplastic Carbon Fiber Reinforced Metal Composite Structures

The current continuous development of the automobile industry has reduced the restrictions on people in the space area,and also brought threats to the resource environment and human lives.Consumers want to get cars that are both safe and energy efficient.Thermoplastic carbon reinforced fiber metal laminates(FMLs)and corresponding composite structures effectively combine the performance advantages of carbon fiber reinforced thermoplastic(CFRTP)composite materials with traditional metals,and have characteristics of energy saving,environmental protection and outstanding mechanical properties.This paper focus on automotive thermoplastic carbon fiber reinforced high-strength steel(HSS)composites and structures which fabricated by reasonable hot die/stamping press process design,and further combines with the laminate theory and appropriate failure criterion to in-depth study its bending mechanical properties on the basis of experiment and numerical simulation and finally draw some adaptability conclusions for designing the advanced automobile body structure.Firstly,this paper develops a process fabrication method suitable for STEEL / CFRTP laminates and corresponding composite structures.By seeking reasonable process parameters and establishing a synergistic relationship between temperature-pressure-forming qualities,it could be ensured that the fabricated STEEL / CFRTP composite structure can obtain excellent interface bonding properties and bending mechanical properties.Based on the relevant process parameters,thermoplastic carbon fiber laminates,STEEL / CFRTP laminates and corresponding composite hat beam structure were manufactured,respectively.The process of the hot moulding/stamping press combining with the thermoplastic resin system and high-strength steel was realized developed successfully.Besides,this paper conducted the basic mechanical properties experiments of aforementioned composite materials and corresponding structures.Not only the quasi-static tensile tests of CFRTP laminates,and STEEL / CFRTP laminates,but also the three-point bending tests of the STEEL / CFRTP composite hat beam structural parts were completed.The experimental results show that the thermoplastic carbon fiber material has excellent mechanical properties and good interface adhesion during bending load process.It is suitable as a metal-matrix reinforcing material to strengthen the bending mechanical properties of pure high-strength steel and enhance the lightweight effect of carbon fiber reinforced metal composite structures.Finally,this paper carried out a three-point bending numerical simulation study on the STEEL / CFRTP composite hat beam structure.Among them,a multi-layer shell unit joint modeling method is used to execute the modeling process of thermoplastic carbon fiber.Tiebreak contact is used to simulate the adhesion of interlayer resin and adhesive layer.The Chang-Chang criterion is introduced to reasonably describe its damage failure mechanism and mechanical behavior.Moreover,the anti-bending performance of STEEL / CFRTP composite hat beam structures are systematically assessed on the basis of the corresponding mechanical ability indexes such as energy absorption,specific energy absorption and peak anti-bending force.Additionally,effects of the ’structure-material-size’ factors on the bending performance of corresponding composite structures were also deeply discussed.The relevant factors include as follow: structural form,the lay angle of carbon fibers,the lay number of carbon fibers,the layer thickness of high-strength steel,and the thickness ratio between the two components,etc.The results show that: the appropriate ’structure-material-size’ design factors can improve the peak anti-bending load and energy absorption capacity of the STEEL / CFRTP composite hat beam structure.Thus,thermoplastic carbon fiber reinforced metal composite materials can be integrated adopting in the functional design of the-advanced auto-body structure,which conduces to a good lightweight reduction achievement.