Publikation

Damage characterization in SFRP using X-ray computed tomography after application of incremental and interrupted in situ quasi static tensile loading

Outline:

G. Rao, A. Amirkhanov, D. Salaberger, J. Kastner, C. Heinzl - Damage characterization in SFRP using X-ray computed tomography after application of incremental and interrupted in situ quasi static tensile loading - Proceedings Industrial Computed Tomography (iCT2017), Leuven, Belgien, 2017

Abstract:

The use of short fibre reinforced polymers (SFRP) is increasing steadily in automotive and aerospace industries due to its mechanical properties and light weight. The mechanical and physical properties of SFRP depend on the geometrical characterestics of the reinforcing material. Under tensile stress many defects are induced in SFRP composites. X-ray computed tomography (XCT) is a non-destructive method for damage characterization of SFRP. It helps us to understand the material behaviour under different intermediate stress conditions and gauge the strength of the material. This paper aims to study the evolution of various damages in SFRP composite material. The composite consists of a polyamide matrix and 30 wt. % of short glass fibres. Sheets with two types of fibre orientation (0° and 90°) were chosen relative to the flow direction. The damages were induced after application of pre-determined tensile loads in a quasi-static method using an in situ tensile testing device.The tensile force was applied using controlled displacement inside the in situ device. Damages were analysed after every step of force application using XCT at the resolution of 4.5 µm3 voxel size. The workflow based on automatic fibre extraction followed by automated defect detection and classification was used to retrieve quantitative results of the damage evolution. The detected defects were analysed and classified into four types: 1) fibre pull-outs, 2) fibre fractures, 3) matrix fractures and 4) fibre/matrix debonding. The increase in tensile force shows changes in the number and volume of the defects. The classification of defects at every step after applying force helps to understand evolution of damage mechanisms in the stressed region.