Dynamic Fracture Toughness of Composite Materials
The Dynamic fracture toughness KId, is determined for unidirectional carbon-epoxy and glass-epoxy composite materials, by means of an experimental–numerical method. An instrumented Hopkinson bar is used to make the tests with pre-cracked specimens loaded on a three point bending configuration. Specimen receives a sudden impact load that generates the opening of the crack faces. Dynamic pulses registered on the incident and transmitted bars are used to determine the load history applied on the specimen. A strain gage is placed on the specimen to register the wave propagation and therefore to determine the onset of the crack growth. This load history is then used in a numerical analysis done by the ABAQUS software to determine the Dynamic Stress Intensity Factor time evolution. Knowing the time to fracture it is possible to estimate the Dynamic Fracture Toughness KId. For the composite material specimens, the tests were made for different impact velocities.
KeywordsDynamic Fracture Dynamic Stress Intensity Factor Bend Specimen Dynamic Fracture Toughness Projectile Velocity
This research was supported by the Texas A&M University-CONACYT Collaborative Research Grant Program.
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