Experimental and numerical qualification of morphology-property-correlations using the method of essential work of fracture (EWF) by the example of polymer blends

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The J-integral, the Crack-Tip-Opening-Displacement (CTOD), the energy release rate G and the method of the Essential Work of Fracture (EWF) are different methods to evaluate the fracture mechanical behavior of ductile materials. These methods are not suitable for dimensioning in design like the quasi-static tensile test, but are able to provide more accurate information in the case of local failure behavior. It is necessary to understand the local failure mechanisms to optimize materials. Their results offer also quantitative values, but can only be used for comparisons between different modified materials based on the same polymeric matrix. By varying the material modifications and/or morphology, which have an influence on the fracture behavior, materials can be optimized. From the applicants point of view, in particular the method of Essential Work of Fracture, is more appropriate and easy to use than the other methods and can be applied to neat polymers, polymer blends as well as particle and fiber reinforced polymers. Respectively, the simulation of the mechanical properties of materials at the atomic scale is not yet able to supply dimensioning parameters for the design, as the quasi-static tensile test does, but is pretty accurate at local inspections. The applicants regard this as useful to predict the Essential Work of Fracture and to optimize polymer blends for different applications. In this planned research project, the influence of different modifications on the investigated polymer blends will be determined with the method of Essential Work of Fracture. Simultaneously, the material modifications and the test method should be adjusted for the first time to make them predictable by means of molecular dynamics simulation.