Low-energy Impact Behavior And Mechanical Damage Of CFRP Laminates

Carbon fiber reinforced plastic (CFRP) is a kind of advanced material that hasbeen used widely in the aerospace and the ship industry, and so on. People raisingtheir attention on the CFRP, because its excellence performance, such as heatresistance and anti-corrosion and its high-strengh light weight. But the hiddendangers generate during its utilization, when the CFRP damaged owing to the lowenergy impact. So it is of particular importance to study the low energy impactperpormance.In This article, a laboratory study of the effect of the low energy impact onT300carbon fiber reinforced resin-based composite was carried on. The depth ofthe impact concave has been measured by micrometer. It also has a study on theevolution rule of the concave depth. The ultrasonic C-scan has been used to detectthe damage of the material. The bending test has been carried on to study theinfluence of the damage location to the bending performance. The finite elementsimulation method has been used to calculate progress of the low energy impact andbending.The results of the experiment show that, the evolution of the impact concavedepth of the CFRP can be divided into two stages: in the24hours after impact, thedepth changed quickly, the main cause is the resin restored quickly in a short timewhen it suffering a deformation; after24hours, the rate of the changes becameslow down, and tended to a constant value. The energy that the material absorbedduring the impact process released in the first24hours. The result of the ultrasonicC-scan show that the impact damage was oval, and the damage largen when theimpact energy became higher. There will be delamination around the impactdamage. The bending test after low energy impact indicated that the surface whichhave a concave on it showed a worse bending performance than the side that didn’tdamaged. The bending strength of the positive side declined20%-60%, while thenegative side declined10%-50%. When the bend load supply on the positive side,the damaged matrix and fiber were compressed, its equal to subject a compressiveload to them; while the negative side, they were stretched, and this equal to subjecta tensile load to them. Of all the after impact strength, as the predecessors havebeen studied, the CAI declined most severely. The ANSYS/LS-DYNA calculationof the low-energy impact and bending test results showed that there were15%errormargin.