Environmental effects on the mechanical properties of E-glass and S-glass fiber epoxy composite ring specimens used in aircraft fuel pipes

An experimental investigation was performed in predicting the consequences of the exposure to seawater and moisture absorption on the mechanical properties of two different GFRE pipe rings made of E-glass and S-glass fiber and utilized in aircraft fuel pipe line system. Filament winded tubular composite pipe rings were immersed in seawater for two, four and six months, respectively and their moisture absorption was noted. The outcomes exhibit a remarkable decrease in fatigue life for saturated GFRE sample rings. In contrast, a water absorption up to 40% of the maximum content exhibited no impact. The tests revealed debonding and cracks in the fiber and matrix interphase in the case of samples immersed in seawater on a long-term basis, although the applied mechanical load was zero.

Design and Fabrication of a Stacked Three-Phase Piezoelectric Composites Ring Array Underwater Ultrasound Transducer

A stacked three-phase piezoelectric composites ring array underwater ultrasound transducer was developed in this paper. The circular structure of three-phase piezoelectric composite with a large open angle was improved based on the 1-3 piezoelectric composites. The structure size of the transducer’s sensitive component was designed by using ANSYS simulation software, and the single-ring samples of three-phase piezoelectric composites with different thicknesses were fabricated. Based on the bandwidth broadening theory of multimode coupled vibration, the piezoelectric composite ring-shaped sensitive component was fabricated by the piezoelectric composite curved-surface-forming process. According to the design structure of the transducer, the stacked three-phase piezoelectric composites ring array underwater ultrasound transducer was processed. The experimental results show that the maximum transmission voltage response is 154 dB, the open angle of the horizontal beam reaches 360°, and the bandwidth of −3 dB is 86 kHz. The developed transducers achieved a high frequency, broadband, and large open angle to radiate sound waves.

Puckering and wrinkling in a growing composite ring

Pattern formation driven by differential strain in constrained elastic systems is a common motif in many technological and biological systems. Here we introduce a biologically motivated case of elastic patterning that allows us to explore the conditions for the existence of local puckering and global wrinkling patterns: a soft growing composite ring adhered elastically to a constraining rigid ring. We explore how differential growth of the soft ring and the elastic resistance to shear and stretching deformations induced by soft adherence lead to a range of phenomena that include uniform aperture-like modes, localized puckers that are Nambu–Goldstone-like modes and global wrinkles in the system. Our analysis combines computer simulations of a discrete rod model with a nonlinear stability analysis of the differential equations in the continuum limit. We provide phase diagrams and scaling relations that reveal the nature and extent of the deformation patterns. Overall, our study reveals how geometry and mechanics conspire to yield a rich phenomenology that could serve as a guide to the design of programmable localized elastic deformations while being relevant for the mechanical basis of biological morphogenesis.

Reducing Rotor Temperature Rise in Concentrated Winding Motor by Using Magnetic Powder Mixed Resin Ring

The demand for high-speed servomotors is increasing, and minimal losses in both high-speed and high-torque regions are required. Copper loss reduction in permanent magnet motors can be achieved by configuring concentrated winding, but there are more spatial harmonics compared with distributed winding. At high-speed rotation, the eddy current loss of the rotor increases, and efficiency tends to decrease. Therefore, we propose a motor in which a composite ring made from resin material mixed with magnetic powder is mounted on the stator to suppress spatial harmonics. This paper describes three characteristic motor types, namely, open-slot motors, composite-ring motors, and closed-slot motors. Spatial harmonics are reduced significantly in composite-ring motors, and rotor eddy current loss is reduced by more than 50% compared with open-slot motors. Thermal analysis suggests that the saturation temperature rise value is reduced by more than 30 K. The use of a composite ring is effective in reducing magnet eddy current loss during high-speed rotation. Conversely, the torque characteristics in the closed-slot motor are greatly reduced as well as the efficiency. Magnetic circuits and simulations show that on electrical steel sheets with high relative permeability, the ring significantly reduces the torque flux passing through the stator, thus reducing the torque constant. To achieve reduced eddy current loss during high-speed rotation while ensuring torque characteristics with the composite ring, it is necessary to set the relative permeability and thickness of the composite ring according to motor specifications.

Studies on changes in the temperature field and recrystallization properties of glass fiber reinforced polypropylene composite strip winding process

The glass fiber reinforced polypropylene (GF/PP) composite ring specimens were fabricated based on the composites prepreg tape winding process. The heated winding process was simulated by ANSYS software to obtain the temperature distribution of the wound layer of the specimen. At the same time, the temperature of the wound layer was collected and stored using a temperature-controlled recorder. The temperature fields between the wound layers were found to be different significantly, and the temperature measured through experiments was generally below the simulation results, where it is especially noticeable in the fusion zone. After the recrystallization of GF/PP specimen, the maximum shear strength that the specimen can withstand was improved. The response surface method was used to test and analyze the influence of recrystallization on the mechanical properties of the specimen, Obtain optimized process parameters, heating temperature of 91 °C, pressure of the press roller is 106 N, heating time of 13 min, the highest sample obtained is 28.67Mpa. The experimental results show that the influence of recrystallization parameters on the mechanical properties of the composite specimens (from large to small) are: heating temperature, heating time, and the roller pressure.