The goal of the present work is to extend an existing integrative simulation chain used for the lifetime assessment of short glass fibre reinforced polymers. This includes the material characterisation, the deviation of a data set and the development of models and methods, each of which can be integrated into the simulation chain. For material characterisation, a comprehensive methodical characterisation of the fatigue behaviour of a short fibre reinforced polyphthalamid is undertaken, and the applicability of the existing models is validated and supplemented based on the test results. Consideration of these, hitherto littlie studied, influences expands on the understanding of the examined material, in particular relating to the behaviour in cases of variable amplitude, multiaxial and strain controlled loading. Models and methods are derived from the results obtained and implemented in computer-based lifetime assessment. Based on the test results, an extensive data set for FEMFAT is derived and used to develop a method and test matrix for the determination of the systematic derivations of optimised data-sets. To reduce the number of specimen types and to enhance the future comparability of the data a new specimen is developed based on experience. In addition to enhancing the description of the material’s behaviour using models, the simulation chain is extended to consideration of swell-induced stresses and process-related weld lines. A meshing guideline for structure meshing is developed for process simulation and FE-analysis to reduce the inaccuracies caused by the size and shape of the elements. As a result of this process, a better understanding of cyclic material behaviour is obtained and the developed models and methods lead to better predictions of the lifetimes of short fibre reinforced polymers.