A Basic Study for Influence of Temperature on Impact Damge of CFRP Laminates

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In the present study, they influence of temperature on impact damege in carbon fiber reinforced plastic (CFRP) Iaminates was investigated experrimentally. In this three years, we aimed following items for the investigation :(1) Ovservations and evaluation of damage of the CFRP laminates subjected to impact load from forein object under several temperature conditions.(2) Measureing of the caracteristic of the thermo-viscoelastic behavior of CFRP.(3) Evaluation of the anisotropic elastic behavior of CFRP using ultrasonic microscope(4) Estimation of fracture toughness (Mode I,Mode II) under under several temperature conditions.(5) Analysis of the damage propagation of CFRP subjected to transveres load.The conclusion of these subjects are summarize as follows :(1) Dynamic impact test was carried out using air-compression gun with steel ball (phi=5mm), Delamination areas in the specimens were measured using ans ultrasonic microscope. The results revealed the total delamination areas to be p … More ropotional to the temperature, and the delamination area decreased with increasing temperature.(2) Dynamic elastic modulous E (t) was estimated with range of the tempareture from -150ﾟC to 250ﾟC.We confirmed that the elastic modulous of CFRP.(3) Amplitude-and-phase-measuring Acoustic Microscope was applied to evaluation of the elastic moduli, like Young's modulous and density, of the anisotropic body. It was confirmed that the line-forcus-lens in valid to measure the anisotropic elastic moduli.(4) In order to evaluate the arising and propagation of the delamination, Mode I and Mode II fracture toughness are measured by CNF test and ENF test under -100ﾟC-200ﾟC temp.range. It is confirmed that the fracture toughness depends on the tempereture and the caracteristic of the visco-elasticity of the specimen.(5) Finete element analysis was carried out to evaluate of CFRP fracture pattern subjected to transverse load. The mixed mode fracture pattern of the CFRP laminates consist of transverse crack and delaminations can be simulated with FEM with well conditions. Less