"Effects of Defects" in Multiaxialgelegen unter mehraxialer Belastung
Zusammenfassung der Projektergebnisse
A wide data base on the fatigue of composites under both, uniaxial and multiaxial loading has been established, taking into account a set of defects, as e.g. voids, impacts and fibre waviness. A deep understanding of the phenomena and mechanisms occurring in these cases has been achieved. Modelling tools were developed for fatigue degradation and describing the influence of single voids on composites properties. The comparison of coupon tests with multiaxial tests on stringer stiffened panels (demonstrator test) showed, that the behaviour of internal damages as voids or impacts can already well be studied on the coupon level, however, a final verification on its influence on the level of panels is evident, as here further influencing factors from the specific panel geometry and design (stiffeners) have to be considered. Pressure modulated lockin-interferometry successfully allowed to detected damage in GFRP tubes. Sensitivity of the air-coupled guided waves method has to be increased to detect fatigue damage in CFRP, because the measurable effects appear to be smaller than in GFRP. The effects of higher guided wave modes need to be better understood to exploit them for damage characterization. For the NDT investigation of damage and its development on the panel level adapted systems have to be developed which take the panel geometry into account. They have to be further extended to also examine areas close to the fixation in the multiaxial test rig.
Projektbezogene Publikationen (Auswahl)
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Modeling of the strain rate dependent material behavior of 3D-textile composites with production and operational defects, Advanced Materials Research 403-408 (2012) 651-655
Hufenbach, W., Gude, M., Protz, R.
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(2011). Air-coupled guided waves combined with thermography for monitoring fatigue in biaxially loaded composite tubes. Composites Science and Technology 71 (2011) 600–608
Rheinfurth, M., Schmidt, F., Döring, D., Solodov, I., Busse, G., & Horst, P.
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Compressive failure of UD-CFRP containing void defects: In situ SEM microanalysis. Composites Science and Technology 71 (2011) 1242-1249
Hapke J., Gehrig, F., Huber N., Schulte K., Lilleodden E.T.
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Effects of local fibre waviness on damage mechanisms and fatigue behaviour of biaxially loaded tube specimens, Composite Science and Technology 72 (2012) 1075-1082
Schmidt, F., Rheinfurth, M., Horst, P., Busse, G.
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Lamb waves for non-contact fatigue state evaluation of composites under various mechanical loading conditions, Composites A 43 (2012) 1203–1211
M. Rheinfurth, N. Kosmann, D. Sauer, G. Busse, K. Schulte
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Monitoring of multiaxial fatigue damage evolution in impacted composite tubes using nondestructive evaluation. Composites Part A 43 (2012) 537–546
Schmidt, F., Rheinfurth, M., Protz, R., Horst, P., Busse, G., Gude, M., Hufenbach, W
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Multiaxial fatigue behaviour of GFRP with evenly distributed or accumulated voids monitored by various NDT methodologies, Int. J. of Fatigue 47 (2012) 207-216
Schmidt, F., Rheinfurth, M., Horst, P., Busse, G.
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Ultrasonic birefringence as a measure of mechanically induced fatigue damage in laminated composites. Int. J. of Fatigue 48 (2013) 80 ‐ 89
Rheinfurth, M., Fey, P., Allinger, S., Busse, G.
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Evaluation of a critical impact energy in GFRP under fatigue loading, Composites Science and Technology 102 (2014) 28-34
N. Kosmann, B. T. Riecken, H. Schmutzler, J. B. Knoll, K. Schulte, B. Fiedler
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A quantitative comparison of the capabilities of in situ computed tomography and conventional computed tomography for damage analysis of composites, Composites Science and Technology 110 (2015) 62–68
Böhm, R., Stiller, J., Behnisch, T., Zscheyge, M., Protz, R., Gude, M., Hufenbach, W.
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Determining the effect of voids in GFRP on the damage behaviour under compression loading using acoustic emission, Composites B, 70 (2015) 184-1888
N. Kosmann, J.M. Karsten, M. Schuett, K. Schulte, B. Fiedler
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Voids and their effects on the strain rate dependent and fatigue damage behaviour of non-crimp fabric composites, Composites B 83 (2015) 346-351
Protz, R., Kosmann, N., Gude, M., Hufenbach, W., Schulte, K. Fiedler, B.
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Hierarchical analysis of the degradation of FRP under the presence of void imperfections. Phil. Trans. R. Soc. A374 (2016) 2015079
Liebig W., Schulte K., Bodo Fiedler W.
