Inhaltszusammenfassung

Fiber-reinforced plastics can be effectively used to improve strength and stiffness especially for timber beams. There are still problems to ensure a high quality of the bond line. In the bonding region, a distinction must be drawn between the fundamentally different kinds of fracture. In addition, there is the delamination of the individual lamina with a negative effect on the overall stiffness. Lamina by lamina analyses make it possible to dimension FRP’s which experience a predominantly pl...Fiber-reinforced plastics can be effectively used to improve strength and stiffness especially for timber beams. There are still problems to ensure a high quality of the bond line. In the bonding region, a distinction must be drawn between the fundamentally different kinds of fracture. In addition, there is the delamination of the individual lamina with a negative effect on the overall stiffness. Lamina by lamina analyses make it possible to dimension FRP’s which experience a predominantly plane stress state. An appraisal of the delamination risk cannot be made on that basis. In regions subject to a three-dimensional stress state, such as in the end-anchorage zone of FRP strengthened timber structures, the laminate will also be subject to a three-dimensional stress state. Failure criteria implemented in many finite element programs do not take into account the heterogeneous nature of the lamina, treat it as a isotropic material and deliver results which probably fall on the unsafe side. In the presented study, criteria that distinguish between the different kinds of fracture have be used and implemented in the FEM program via an interface and by modifying the implemented TSAI-WU criterion. The successive failure of laminates in FRP strengthened timber structures has been treated by a layer-by-layer failure analysis. Different non-linearity’s have been considered, namely material non-linearity due to micro damage, matrix cracking and debonding. In general, there is good agreement between predictions and experimental results. Along theoretical aspects, this paper presents the results of the numerical studies compared with test results. » weiterlesen» einklappen

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Klassifikation

DFG Fachgebiet:
Bauwesen und Architektur

DDC Sachgruppe:
Ingenieurwissenschaften