3 results
Now showing1 - 3 of 3
- Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Influence of pin size on tensile and fatigue behavior of TI-CFRP hybrid structures produced by laser additive manufacturingThis 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.Publicationtype: Conference Paper105 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: without files , Performance of various designs of hybrid loop-loaded CFRP-titanium strapsLoop-loaded straps are capable of transmitting high tensile loads using lightweight materials like CFRP. Additionally, these loops have the benefit to implement metallic components to reduce wear between the CFRP and the connecting part. This paper investigates loop-loaded CFRP straps which integrate titanium parts into a Resin Transfer Molding process. On the textile side, preforms are manufactured by winding and by Tailored Fiber Placement. On the metal side, parts had been manufactured by Laser Additive Melting. Two metallic parts made of Ti-6Al-4V have been manufactured. The first metallic part is a hull which is placed at the one end of the CFRP strap to connect the strap to the testing machine. On the other end of the strap a titanium insert element was integrated to simulate a flange connection. Furthermore, different designs for this insert have been chosen, varying in radius and the quantity of the loops. The influence on the tensile strength depending on the design of the inserts has been tested using a tensile testing machine. The strap specimens with different cores had been manufactured and examined using a tensile test. From these test results an insight into the influences of the flange design on the mechanical tensile properties as well as failure mechanisms of the hybrid strap were determined evaluated. Hereby, it could be shown that cascaded cores provide and increased tensile strength of 5 % compared to a standard loop strap. Furthermore, different core radii have an influence regarding the tensile strength of nearly 20 % of hybrid loop-loaded straps. Finally, a crossed loop was tested with only 25 % fiber rovings like the other specimens but with a 50 % higher UTS compared to the highest UTS of a cascaded specimen.Publicationtype: Conference Paper79 - Some of the metrics are blocked by yourconsent settings
Item type:Publication, Access status: with files , Effects of defects in laser additive manufactured Ti-6Al-4V on fatigue propertiesLaser Additive Manufacturing (LAM) enables economical production of complex lightweight structures as well as patient individual implants. Due to these possibilities the additive manufacturing technology gains increasing importance in the aircraft and the medical industry. Yet these industries obtain high quality standards and demand predictability of material properties for static and dynamic load cases. However, especially fatigue and crack propagation properties are not sufficiently determined. Therefore this paper presents an analysis and simulation of crack propagation behavior considering Laser Additive Manufacturing specific defects, such as porosity and surface roughness. For the mechanical characterization of laser additive manufactured titanium alloy Ti-6Al-4V, crack propagation rates are experimentally determined and used for an analytical modeling and simulation of fatigue. Using experimental results from HCF tests and simulated data, the fatigue and crack resistance performance is analyzed considering material specific defects and surface roughness. The accumulated results enable the reliable prediction of the defects influence on fatigue life of laser additive manufactured titanium components.Publicationtype: Journal ArticleScopus© Citations 402 249 367