Yielding and crack growth testing of polymers under severe liquid media conditions
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Several techniques for testing under superimposed mechanical and environmental loading are described in terms of test devices and test arrangements implemented on conventional mechanical test equipment (universal screw-driven test machines or electro-dynamic test machines). As to the application of mechanical loads, monotonic, static and cyclic tests are covered, including standard tensile tests and fracture mechanics based experiments. The former case emphasizes the determination of liquid environments on modulus, yield and post-yield behavior using conventional dumbbell specimens of the 5A Type (ISO 527) or notched pipe ring tensile (NPR-T) specimens. The latter methods are designed to obtain fatigue life and crack growth kinetics data using cracked round bar (CRB) or compact type (CT) specimens. Selected examples of material characterization for various loading conditions in air, water and liquid hydrocarbon environments are described and discussed with respect to predict material behavior under simultaneous mechanical and environmental loads.