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CFRP is the most popular composite material due to its excellent mechanical properties. Most practical applications of CFRP in various industries require routine machining operations, such as drilling. Delamination of composites during drilling is a critical issue in high-end applications, caused by the thrust force generated throughout the drilling process. In this article, a magnetorheological elastomer (MRE)-based isolator is utilized during the drilling of CFRP to minimize the effects of thrust force. This study considers the impact of fiber orientation; thus, CFRP with unidirectional and bidirectional composites is employed for the drilling operation. An MRE-based isolator can equally reduce the thrust force in both uni-directional and bi-directional CFRP by the same percentage. An empirical model has been developed to explain the variation of thrust force concerning the last five layers of CFRP. The results demonstrate the influence of fiber orientation on magnetic-field induced thrust force. Nonetheless, a significant focus of this work is to elucidate the effect of thrust force reduction through microstructural evaluation of the drilled hole using a scanning electron microscope. Microstructural observations correlate with the analytical findings based on the empirical model. This study includes a layer-wise analysis of the effect of thrust force on drilled hole quality for both types of CFRP.
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http://dx.doi.org/10.1038/s41598-025-10568-z | 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.
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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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