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Real service requirements of the assembly performance and joining properties of design components are critical for composite usage in the aerospace industry. This experimental study offers a novel and comprehensive analysis of dry drilling optimization for glass-reinforced, high-performance epoxy matrix composites used in aerospace structures, focusing on thrust force and delamination. The study presents a first-time investigation into the combined effects of spindle speed (1000, 2250, 4000 and 5750 rpm), feed rate (0.2, 0.4, 0.6 and 0.8 mm/rev) and tool diameter (3 and 5 mm) using a custom-designed drill tool specifically developed for this application, filling a gap in the current literature. By employing the Taguchi design of experiments, the study identified that medium spindle speeds (2250-4000 rpm), lower feed rates (0.2 mm/rev) and smaller tool diameters (3 mm) provided optimal conditions for minimizing thrust force and delamination. These results present actionable insights into improving the structural integrity and performance of drilled aerospace-grade composite components, offering innovative advancements in both the aerospace and defense industries.
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http://dx.doi.org/10.3390/polym16213011 | DOI Listing |
J Mech Behav Biomed Mater
September 2025
Department of Biomechanical Engineering, Faculty of Engineering Technology, University of Twente, Enschede, 7522 NB, the Kingdom of the Netherlands. Electronic address:
In orthopaedic surgical procedures, bone cutting is often performed with an oscillating saw. Achieving an optimal cut requires high accuracy, low temperature, minimal surgeon effort, and time efficiency, all of which may be influenced by the forces applied on the sawing device, and the microstructure of the cut bone. The relation between bovine bone microstructure and sawing forces has been studied.
View Article and Find Full Text PDFInt Symp Med Robot
May 2025
Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, USA.
Vertebral compression fractures are estimated to affect over 200 million people globally. Percutaneous vertebroplasty is a widely accepted minimally invasive treatment, but it has limitations including prolonged radiation exposure for providers and a steep learning curve. To address these challenges, we present two cannula-mounted robot designs for semi-autonomous, high-precision cannula insertion.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2025
Guangdong Provincial Key Laboratory of New Energy Materials Service Safety, Shenzhen Key Laboratory of New Information Display and Storage Materials, College of Materials Science and Engineering, Shenzhen University, Shenzhen, 518060, China.
Halogenation emerges as a key strategy to enhance the performance of organic solar cells (OSCs) by tuning molecular packing, energy levels, and charge dynamics. Here, we report three new benzo[a]phenazine-core small-molecule acceptors, namely NA5, NA6, and NA7, and systematically evaluate their photovoltaic properties in o-xylene-processed binary and ternary OSCs. Halogenation significantly strengthens intermolecular interactions, improves charge carrier mobility, and facilitates exciton dissociation, leading to a remarkable increase in binary device efficiencies from ∼2% (NA5) to over 17% (NA6, NA7).
View Article and Find Full Text PDFSci Rep
August 2025
College of Energy and Power Engineering, University of Shanghai for Science and Technology, Shanghai, 200093, China.
An array of micro-ramp vortex generators (MRVGs) is deployed on the bottom of the ship's hull just before the inlet, aiming to mitigate flow separation on the ramp wall at low inlet velocity ratios (IVR). Four parameters, including height, wedge angle, side length, and spanwise spacing, were analyzed using the numerical methods. Through parametric screening, the optimal height ranges from 20 to 40% of the hull boundary layer thickness upstream of the inlet, while wedge angle and length have negligible effects.
View Article and Find Full Text PDFPolymers (Basel)
August 2025
Department of Airframe and Powerplant Maintenance, Faculty of Aeronautics and Astronautics, Kocaeli University, Kocaeli 41001, Türkiye.
Drilling-induced damage in fiber-reinforced polymer composite materials was measured excavating four laminates, basalt (B), glass (G) and their two sandwich type hybrids (BGB, GBG), with 6 mm twist drills at 1520 revolutions per minute and 0.10 mm rev under dry running with an uncoated high-speed steel (HSS-R), grind-coated high-speed steel (HSS-G) or physical vapor deposition-coated (high-speed steel coated with Titanium Nitride (TiN) and Titanium Aluminum Nitride (TiAlN)) drill bits. The hybrid sheets were deliberately incorporated to clarify how alternating basalt-glass architectures redistribute interlaminar stresses during drilling, while the hard, low-friction TiN and TiAlN ceramic coatings enhance cutting performance by forming a heat-resistant tribological barrier that lowers tool-workpiece adhesion, reduces interface temperature, and thereby suppresses thrust-induced delamination.
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