A Study On Energy Absorption Capability Of Carbon Hybrid Fiber Reinforced Composite Made By Filament Winding Method

Passengers have been very concerned about automotive safety since the creation of the first car,and safety issues have also plagued the industry.Statistics of Chinese National Bureau showed that vehicle number has remained a significant growth trend over the past decade.At the same time,the number of traffic accidents declined these years due to the road improvement,traffic control and transportation knowledge spread.Unfortunately it always maintained at more than 200,000.As a result,auto-industry made a lot of efforts especially on the passive safety aspect.And until now there is a variety of protective methods for safety of passengers when traffic accident happens.But experts are still on their way pursuing further development of the auto safety as well as making innovation.Meanwhile,environmental issues especially air pollution have become increasingly prominent in recent years.Air pollution problems resulted by large number vehicles on road attract increasingly global concerns.How to induce harmful gas emission without affecting car performance becomes a new development direction in this field.And new materials industry such as Fiber Reinforced Plastics(FRPs)with light weight provided auto-industry a strong support.FRPs with high strength,high modulus and light weight features,are gradually replacing alloy and wood used in the aerospace,automotive,construction,exercise equipment and other fields.Fiber reinforced composites properties and applications are determined by molding process a lot.Filament winding molding method which has the advantages of low manufacturing cost and highly repeatable product quality was chosen in this thesis.Reinforcement material is carbon,aramid and glass roves without textile,because which manufacture process is easier and cost is lower.There are two test methods for measuring the energy absorption property,which is quasi-static compression test and dynamic impact test.In compression process,composites absorb energy by delamination,cracking and fiber fracture.In order to obtain high energy absorption property of the material,progressive failure mold is expected relating to the specimen.Carbon fiber,aramid,glass fiber and epoxy were chosen as raw material and a sandwich structure with inner,intermediate and outer layer was designed.Fiber orientation of intermediate layer is near 90°,which aims to burden axial force.While fiber orientation of outer and the inner is close to 0 °,mainly playing a role in hooping intermediate layer and control crack transmission.Based on previous research,five types of circular tubes were designed.Energy absorption components in this thesis will be installed near the engine,so specimens are treated under 100 ℃ with 200 h to research the temperature affection.Specimens with 50 mm height are flat on one end while the other end is made a 45 ° taper as a trigger mechanism.Flat-end is placed on the compression test bench for compression tests.Compression test including quasi-static compression test and dynamic impact test was performed in this experiment.Shape of post-crushed specimens is fixed by resin-embedded method,and cross section observation under optical microscope is performed after cutting and polishing to help analyze the failure mechanism.Results in quasi-static compression test showed higher energy absorption values than impact test relating to the same type specimen,which indicates that tubes are speed-sensitive.Energy absorption property of carbon fiber reinforced tubes is superior to glass-fiber reinforced tubes and carbon/aramid fiber-reinforced tubes when it comes to non-temperature specimens.It is found that energy absorption ability of aramid/carbon composite tubes improved after temperature treatment.Specific energy absorption(ES)of A/C1.6’ tube(aramid/carbon/aramid :0.15mm(88°)/1.66mm(10°)/0.83mm(88°))after temperature treatment is the highest,98 k J/kg in quasi-static compression test and 82 k J/kg in the drop impact test among five types tubes.According to microscopic cross section picture analysis,Central crack of carbon/aramid fiber reinforced tubes after temperature treatment shortened and curvature of the fronds became larger as well.All tubes showed a splaying failure mode.