Influence of pin size on tensile and fatigue behavior of TI-CFRP hybrid structures produced by laser additive manufacturing

This paper contains mechanical investigations of metallic fabric-penetrating interfaces produced by powder-bed-based laser additive manufacturing and vacuum-assisted resin transfer moulding. Therefore, different fabric penetrations (pins) have been created which vary in length. These penetrative interfaces have been studied in quasi-static tensile (shear) tests and fatigue tests. Deformation and damage processes were determined during tensile and fatigue loading by measurement of the local strain distribution, utilizing a 3D-digital image correlation (DIC) system. Additionally, light microscopic and scanning electron microscopic (SEM) investigations were carried out in order to assess the damage mechanisms and fracture surfaces. The quasi-static tests revealed that tensile shear strength increased by 503 % compared to solely adhesive interface, due to the integration of long pins. Furthermore, different pin-size-depending failure mechanisms have been detected. The fatigue tests showed, that fabric penetration also improves the fatigue strength significantly by 246 %, whereby the damage mechanisms change in comparison to quasi-static failure