13th International Conference on Fracture June 16–21, 2013, Beijing, China -9- 10 100 1000 0 50 100 150 200 250 Age [hours] G f [N/m] Contec DTUI DTUII 10 100 1000 0 50 100 150 200 250 Age [hours] Gf [N/m] Contec-F DTUIF DTUIIF Figure 8. Development in fracture energy. Fig. 9 shows the development in characteristic length. The general trend in the development of the characteristic length despite the scatter was observed to decrease with maturity. The same results were also found in literature, e.g. [4]. 10 100 1000 0 100 200 300 400 500 600 700 800 900 Age [hours] L ch [mm] Contec DTUI DTUII 10 100 1000 0 200 400 600 800 1000 1200 1400 1600 1800 Age [hours] L ch [mm] Contec-F DTUIF DTUIIF Figure 9. Development in characteristic length. 5. Conclusion This paper presents knowledge of the inverse analysis of the WST. The fracture behaviour of three fiber reinforced and regular HPC were investigated. The wedge splitting test setup with 48 cubical specimens was used experimentally and the cracked non-linear hinge model based on the fictitious crack model was applied for the interpretation of the results. The stress-crack opening relationships were extracted by using inverse analysis algorithm for various multi-linear softening curves. The fracture mechanics parameters such as crack opening displacement (COD), fracture energy and characteristic length were experimentally determined. Experiments were performed at 1, 3, 7 and 28 days. Fracture energy, Gf, was found to increasing with age, while the characteristic length, Lch, was found to decrease. The conclusions that can be drawn from this study are that: - The wedge splitting test is suitable test method for assessment of fracture properties of regular and glass-polypropylane fiber reinforced HPC. - The test method is easy to handle and the execution is relatively fast. - Using the inverse analysis, the both elastic and fracture properties may be interpreted from the test results as a bi-linear or multi-linear stress-crack opening relationship. - The refinement of the softening curves reflects in improved accuracy of the WST simulation in comparison with bi-linear softening curves with acceptable increase of computational time.
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