Die kontinuumsmechanische Untersuchung der Lastübertragungsmechanismen zwischen den Rovings im textilbewehrten Feinbeton trägt wesentlich zum Gesamtverständnis des mechanischen Verhaltens des Verbundmaterials bei. Neben der Erfassung der gegenseitigen Beeinflussung sich kreuzender Rovings erfordert insbesondere die mechanische Modellierung und numerische Simulation von Bewehrungsstößen und Endverankerungen die Kenntnis dieser Übertragungsmechanismen. Die numerischen Simulationen sollen u. a. zeigen, welche Endverankerungslängen und welche Übergreifungslängen an Bewehrungsstößen erforderlich sind und wie die Querbewehrung die Rissbildung beeinflusst. / This paper concerns with the investigation of stress transfer mechanisms between yarns and concrete matrix and their influence on the overall behavior of textile reinforced concrete (TRC). This investigation considers textile reinforcement splices and textile reinforcement development lengths and carried out by means of Finite-Element simulations and fracture mechanic approaches. A first modeling procedure is made towards analyzing and investigating the damage mechanisms in TRC specimen under tension loading which are mainly characterized by matrix cracking and yarn pullout. This modeling approach allows for considering the yarn crack bridging which is a main characteristic behavior of TRC. In the same manner, 3D Finite-Element models are conducted for calculating the required reinforcement development lengths and the reinforcement overlapping lengths. The conducted approach takes into account different damage mechanisms observed in the corresponding experimental investigations which are also used for calibrating the modeling procedures. Moreover, the presented approach covers a wide range of required textile reinforcement overlapping lengths and development lengths and provides the corresponding ultimate loads.

Die kontinuumsmechanische Untersuchung der Lastübertragungsmechanismen zwischen den Rovings im textilbewehrten Feinbeton trägt wesentlich zum Gesamtverständnis des mechanischen Verhaltens des Verbundmaterials bei. Neben der Erfassung der gegenseitigen Beeinflussung sich kreuzender Rovings erfordert insbesondere die mechanische Modellierung und numerische Simulation von Bewehrungsstößen und Endverankerungen die Kenntnis dieser Übertragungsmechanismen. Die numerischen Simulationen sollen u. a. zeigen, welche Endverankerungslängen und welche Übergreifungslängen an Bewehrungsstößen erforderlich sind und wie die Querbewehrung die Rissbildung beeinflusst. / This paper concerns with the investigation of stress transfer mechanisms between yarns and concrete matrix and their influence on the overall behavior of textile reinforced concrete (TRC). This investigation considers textile reinforcement splices and textile reinforcement development lengths and carried out by means of Finite-Element simulations and fracture mechanic approaches. A first modeling procedure is made towards analyzing and investigating the damage mechanisms in TRC specimen under tension loading which are mainly characterized by matrix cracking and yarn pullout. This modeling approach allows for considering the yarn crack bridging which is a main characteristic behavior of TRC. In the same manner, 3D Finite-Element models are conducted for calculating the required reinforcement development lengths and the reinforcement overlapping lengths. The conducted approach takes into account different damage mechanisms observed in the corresponding experimental investigations which are also used for calibrating the modeling procedures. Moreover, the presented approach covers a wide range of required textile reinforcement overlapping lengths and development lengths and provides the corresponding ultimate loads.

It was found that a significant improvement of mechanical properties of CFRPs can be achieved by the adjustment of the matrix properties such as toughness and CF/matrix adhesion via the chemical modification, as well as the physical modification by a small amount of cheap and environment-friendly nano fibers. Based on investigation of fracture mechanisms at macro/micro scale, the effects of matrix properties and nano fiber on the mechanical properties of CFRP have been discussed. Subsequently, the relationship has been characterized by a numerical model to show how to modulate the parameters of the matrix properties to achieve excellent fatigue properties of CFRP. / 博士(工学) / Doctor of Philosophy in Engineering / 同志社大学 / Doshisha University