Design and manufacturing optimization of epoxy-based adhesive specimens for multiaxial tests

authored by: Michael Wentingmann, Nikolas Manousides, Alexandros Antoniou, Claudio Balzani
Abstract: Specimen design and manufacturing quality are decisive factors in the experimental determination of material properties, because they can only be reliably determined if all undesired influences have been minimized or are precisely known. The manufacture of specimens from highly viscous, two-component and fiber-reinforced structural adhesives presents a challenge from this point of view. Therefore, a design and manufacturing optimization procedure for fiber-reinforced structural adhesives and multiaxial testing was developed. It incorporated a finite element parametric study to minimize stress concentrations in the specimen geometry. Vacuum speed mixing was combined with 3D printed mold inserts to enable the manufacture of homogeneous specimens with negligible porosity. The method was demonstrated by means of a structural adhesive used to manufacture wind turbine rotor blades, while the manufacturing quality was verified with high-resolution X-ray microscopy (μCT scanning), enabling detailed detection of pores and geometrical imperfections. The results of uniaxial and biaxial static tests show maximized strength and stiffness properties, while the scatter was minimized in comparison to that stated in international literature. A comparison of the mechanical properties and associated manufacturing techniques is given. The comparison includes a porosity analysis of a specimen from an industrial dosing machine used for rotor blade manufacture.
Organisation(s): Institute of Wind Energy Systems
External Organisation(s): Fraunhofer Institute for Wind Energy Systems (IWES)
Type: Article
Journal: Materials and design
Volume: 212
Pages: 1-14
No. of pages: 14
ISSN: 0264-1275
Publication date: 15.12.2021
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: General Materials Science, Mechanics of Materials, Mechanical Engineering
Research Area (based on ÖFOS 2012): Endurance strength, Computational engineering, Renewable energy, Endurance strength, Computational engineering, Strength of materials
Sustainable Development Goals: SDG 7 - Affordable and Clean Energy
Electronic version(s): https://doi.org/10.1016/j.matdes.2021.110213 (Access: Open)