Evaluation of the shear properties of long and short fiber composites using state-of-the art characterization techniques

As the use of short fiber and textile thermoplastic composites is expanding in many industrial fields, particularly the automotive, it is necessary for each manufacturer in every sector to assess the mechanical characteristics and behavior of these materials in various loading and environmental conditions. Among the most difficult mechanical tests are those for calculating the shear properties and behavior of these materials. As a result, a variety of standards have been developed throughout the years. Among these, the most promising one may be considered the V-notched rail shear test as it incorporates the unique features of two different mechanical tests, i.e. the Iosipescu and rail shear test. In the present work, this state-of-the-art mechanical test, originally designed for unidirectional composites, was implemented in different material architectures and its apparatus was modified and used for mainly two purposes; the investigation of the effect of the infusion direction on the mechanical properties of short and the warp-weft direction of the woven textile thermoplastic composites, as well as producing reliable data regarding the mechanical characteristics and the behavior of these materials for simulating the manufacturing process. The testing device was developed in a way to produce robust and accurate results, ensuring the alignment of its components as well as the stress uniformity in the section gauge. The results revealed a dependency of the infusion direction of the short fiber thermoplastics and the textile direction of the woven composites. To this end, this mechanical testing technique may be considered as a benchmark on the material characterization in shear deformation.