Project Field A: Materials

The project field A comprises material based research work for the components textile fabrics and matrices as well as the description of constitutive laws in the material meso-plaine.

The composite material "Textile Reinforced Concrete" requires the development, technological and constructive realisation as well as the manufacturing of textile reinforcements with load-adapted adjustment of the linear placed filament yarns. Due to the gained consolidated findings of the subproject A1 the requirement of improved utilisation of the single filament strength in the yarn, the fabric and in the composite material is obvious. A great influence to the efficiency of the reinforcement is not only caused by the alignment of the textile fabric beyond the manufacturing process up to the insertion into the composite material but also the improvement of the adhesion between single filaments and yarn to the matrix material. The corresponding basic research requires a interactive, close collaboration with subproject A5. The intermediate results are directly introduced into the work of the subproject A1.

The results from the collaboration of subproject A1 and C3 done during the first research state of the collaborative research centre 528 show an excellent effect of the reinforcement of timber components through the establishment of a timber-textile-plastic composite material. In subproject A4 near net shape manufactured three-dimensional performs are developed by using the flat knitting technology which leads to an cost effective production on the one hand and to improved composite properties on the other hand. According to the project aim first of all the technological and constructive analysis of the selected flat knitting technique regarding the principle possibilities of manufacturing a predetermined near net shape reinforcement fabrics has been investigated. The determined mechanical properties of yarns and out of this manufactured fabrics as well as a correlative amount of test specimens of test versions enter in the theoretical and experimental basic research work in subproject C1.

The subproject A2 comprises the basic investigations of matrix optimisation for textile structures with the aim of adhesion improvement, corresponding probably to high LOP- and MOR values. First cognitions of predominantly investigations show that for the adhesion in the linear area of material deformation an "interlocking" of the outer filament layers of the yarn with the crystallites of the matrix system is necessary. Therefore the matrix composition will be investigated and optimised to chemical-mineralogical and grain-size distribution criteria for the control of the reaction process and to resulting texture structures. For the optimised matrices material equations are deduced and with those of textile yarns and fabrics as basis for the development of a mechanical model introduced in subproject A3.

The use of approximations by mixture rules for modelling the composite material like used e. g. for composite plastics is not sufficient. The reinforcement with multi-axial orientation of the filament yarns, the low distance between single layers and the low total reinforcement content requires rather the continuum mechanic approach.

As access to the complicated sterical tension and deformation states the three-dimensional FE-discretisation is chosen. Due to the stepwise and partly iterative research process in the corresponding subprojects A1 and A2 the development of the constitutive laws and first low benchmark tests is limited to mono-axial static performance of fibre reinforced material. The modelling of introduced dynamic and cyclic loads and the development of a suitable diagnostic methods in the subproject A2 will be a main focus in the following research states of the collaborative research centre.