Quasi-static indentation and sound-absorbing properties of 3D printed sandwich core panels

Abstract

The use of 3D printing to produce acoustic panels with good mechanical and acoustic properties was investigated in this paper. Various fiber layups of the fiberglass face sheet and core designs were fabricated and tested for their indentation resistance and acoustic absorption performance. It was found that the bidirectional face sheet layup exhibited the best indentation energy absorption recording 4.2 J, which is 37% more than the 45-degree layout and 66% more than the quasi-isotropic layup. The specific energy absorption of the hybrid honeycomb core is the best among the three core designs recording 404 J/kg, which is 56% higher than the corrugated triangle with horizontal beam core (359 J/kg) and 20% higher than double ellipse core (335 J/kg). Computed-Tomography (CT) scan was used to study the fracture behavior of the sandwich structures. It was found that the bidirectional layup exhibited a different failure mode as compared to the 45-degree and quasi-isotropic layup. In terms of the acoustic properties, the face sheets with various layup patterns have a low acoustic absorption coefficient with minimal differences from each other at low frequencies (500 Hz–3000 Hz) and have higher absorption coefficients with greater differences from each other at frequencies between 3000 Hz–6500 Hz. The absorption curve was significantly affected by the design of the core. The orientation of the core also comes into play if the core is asymmetrical. The hybrid honeycomb sandwich structure was the optimal structure among the three designs for balanced indentation resistance and acoustic insulation.

Printing of Zirconia Parts via Fused Filament Fabrication

“…In 2021, the fabrication of zirconia parts applying MEX methods with an ethylene vinyl acetate containing binder was published [30,31]. A new field of 3D-printing application was opened quite recently, namely the fabrication of lightweight structures considering different materials and printing strategies described, e.g., in [32,33].…”

3D Printing of Robotic Soft Grippers: Toward Smart Actuation and Sensing

“…[ 124 ] A huge benefit of the technique is that a broad spectrum of thermoplastics can be used through this process, ranging from standard thermoplastics such as polylactic acid (PLA) [ 125,126 ] and Nylon [ 127 ] to aerospace‐grade Ultem thermoplastics, [ 128 ] elastomers such as thermoplastic polyurethane (TPU) and composite materials. [ 129–131 ] Figure 15a depicts the illustration of the FFF technique.…”

Non‐Planar Multiprocess Additive Manufacturing of Multifunctional Composites

“…Other authors also report the use of FFF for the fabrication of sandwich panel structures that feature a sound absorption functionality. [ 25–27 ]…”

“…Other authors also report the use of FFF for the fabrication of sandwich panel structures that feature a sound absorption functionality. [25][26][27] In the aerospace industry, aircraft engines operate in one of the most demanding environments, where thermal expansion, misalignment, or rotation-induced stresses can cause rotating parts to rub against their casing. [28,29] To minimize the clearance between rotor blade tips and casing, sacrificial abradable coatings are applied on the casing inner surface.…”