Application Status and Research Progress of Resin Matrix Composites in Unmanned Underwater Vehicle

Unmanned underwater vehicle (UUV) is a kind of underwater unmanned vehicle. In recent years, it has been widely used in civil and military fields. With the development of the unmanned underwater vehicle to multi-function, strong concealment, high performance and other directions, different kinds of resin matrix composite materials with excellent sound absorption, corrosion resistance, high specific strength characteristics, the utilization rate of unmanned underwater vehicle gradually increased and has broad development potential. In this paper, the application status and key technologies of resin-matrix composites in the field of unmanned aerial vehicle (UUV) are studied from two aspects of function and structure, and the technical trend of resin-matrix composites in the future UUV is described, and its development prospect is forecasted.

The Effect of Different Dietary and Therapeutic Solutions on the Color Stability of Resin-Matrix Composites Used in Dentistry: An In Vitro Study

The purpose of this study was to evaluate the color stability of aesthetic restorative resin-matrix materials after their immersion in different dietary and therapeutic solutions. Thirty disc-shaped specimens (10 × 2 mm) were prepared from three different types of resin-matrix composites used in dentistry (BE, FS, AF). The color coordinates (L*a*b*, ΔL*, Δa*, Δa*, Δb* and ΔE*) were measured using a VITA Easyshade 3D-Master (VITA Zahnfabrik, Bad Säckingen, Germany) before and after the immersion of the specimens in coffee, red wine, Coca-Cola®, Eludril Care®, and distilled water solutions for 40 h. The color change (ΔE*) was calculated and analyzed by the Kolmogorov -Smirnov test and the Kruskal -Wallis multiple-comparison test. All the restorative materials showed significant color (ΔE*) changes after their exposure to red wine, followed by coffee and Coca-Cola®; however, one nanohybrid resin-matrix composite showed a high color stability in such colored test solutions. The chemical composition and content of the organic matrix played a key role in the color stability of the resin-matrix composites. Clinicians should advise their patients about the chemical interaction between dietary substances and different resin-matrix composites.

Interfacial Microstructure and Formation of Direct Laser Welded CFRP/Ti-6Al-4V Joint

Joining fiber reinforced polyether ether ketone resin matrix composite (PEEK-CFRP) with Ti-6Al-4V titanium alloy to form a composite structure is a promising manufacturing process. Huge difference of material properties is the biggies challenge to join them. Continuous laser welding process is conducted in this experiment to join the two materials. In this study, joints under different welding speeds were obtained. Mechanical properties and microstructures were observed, and the interfacial structures were tested. The results showed that fixed joint could be obtained. As the welding speed decreased, the tensile shear first increased and then decreased. The shear force reached a maximum value of 36.8 N/mm at the speed of 10 mm/s. The quality of joint could be observably affected by welding speed. The formation of bubbles, cracks, and anchor effect at the interface were the main factors affecting the mechanical property of joint. Thus, adhesion failure was the main failure form for CFRP fracture. Ti, Al and some other elements had been diffused across the interface, resulting in the formation of intermediate transition layer. The result of EDS, X-ray and XPS test indicated that CTi0.42V1.58 phase could be formed, and Ti at the interface could react with the oxygen and carbon of CFRP to form TiO2, TiO and TiC, forming a stable joint structure.

Experimental Investigation on Vibration Responses of Fiberglass Reinforced Plastic

The purpose of this study is to analyze the vibration displacement on fiberglass reinforced plastic beams with variations a number of fibers in the resin matrix. Composite beams was made of fiberglass and polyester resin matrix with a number of fiberglass: 0, 24, and 48. Composite beams was manufactured by hand lay-up method with the unidirectional fiber orientation. The composite beams used have the dimension of length: 500 mm, height: 20 mm, and width: 20 mm. During the experimental test, the beam was vibrated using an exciter motor which was placed at the end of the cantilever support then using a vibration meter, the vibration displacement data (mm) was measured by placing the vibration transducer postions : 50 mm, 250 mm, and 450 mm from the cantilever support. During the vibration test, the vibration displacement data on the vibration meter screen were recorded using a camera recorder and the data was taken 6 times at each of measurement points. The experimental and analysis results show that the value of vibration displacement (mm) decreases when the fiberglass is added to the composite beam, or in other words, the addition of fiberglass provides an increase in the ability of the beam to withstand vibrations. The maximum vibration displacement value on composites with 0 fiberglass: 0.641 mm, then the vibration displacement decreased in composites with 24 fiberglass: 0.506 mm and the lowest displacement value for the composites with 48 fiberglass: 0.395 mm. Whereas for 3 measurement points at positions 5 cm, 25 cm, and 45 cm along the beam for three kind of the composites, the maximum value of vibration displacement value was obtained at the end of beam composites or at 45 cm from cantilever support: 0.735 mm on composite beam with 0 fiberglass and minimum at position 5 cm near the cantilever support with the value of vibration displacement: 0.323 mm on composite beam with 48 fiberglass.

Comparative studies on the effect of fabric structure on mechanical properties of carbon fiber/epoxy composites

The application of carbon fiber/epoxy composites places more requirements on the selection of fabrics to meet the needs of structural components. Due to the large design space for reinforced fabric patterns, the relationship between the reinforcements and properties is essential to further understand. Four typical fabrics were manufactured in this research, named non-interlaced bidirectional fabrics, plain weave laminated fabrics, angle-interlock fabrics and bidirectional angle-interlock fabrics. The structural features of fabrics were analyzed by using representative geometric unit, and the symmetry properties were discussed based on group theory. Vacuum assistant resin transfer molding was adopted to obtain the corresponding resin matrix composite specimens. Quasi-static tensile and bending tests were conducted on these specimens. The stress-strain curves of specimens were illustrated, and the failure characterizations were also analyzed in mesoscopic scale. The results showed that the high crimp of yarns reduced the stability of composites. Both the tensile and flexural properties were affected by the curvature of yarns. The research results provided a theoretical basis for the selection of fabric structure and the application of carbon fiber/epoxy composites.