Measurement of epoxy resin tension, compression, and shear stress-strain curves over a wide range of strain rates using small test specimens

The next generation aircraft engines are designed to be lighter and stronger than engines currently in use by using carbon fiber composites. In order to certify these engines, ballistic impact tests and computational analyses must be completed, which will simulate a blade out event in a catastrophic engine failure In order to computationally simulate the engine failure, properties of the carbon fiber and resin matrix must be known. When conducting computer simulations using a micromechanics approach, experimental tensile, compressive, and shear data are needed for constitutive modeling of the resin matrix material. The material properties of an Epon E862 epoxy resin will be investigated because it is a commercial 176 degrees C (350 degrees F) cure resin currently being used in these aircraft engines. These properties will be measured using optical measurement techniques. The epoxy specimens will be tested in tension, compression and torsional loadings under various strain rates ranging from 10(-5) to 10(-1) s(-1) and temperatures ranging from room temperature to 80 degrees C. To test the specimens at high temperatures, a specialized clear temperature chamber was used. The results show that the test procedure developed can accurately and quickly categorize the material response characteristics of an epoxy resin. In addition, the results display clear strain rate and temperature dependencies in the material response.