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This paper presents a Fiber Bragg Grating (FBG)-based torque sensor with high sensitivity and miniature size for MIS instruments and multi-finger hands. The proposed sensor design mainly consists of a torque-sensitive flexure structure and two diagonally arranged optical fibers embedded with FBG sensing elements. An improved hollow hexaform structure with flexible hinges has been utilized to design the torque-sensitive flexure with an excellent linear measurement range and a solid capacity to resist non-torsion loading. Two optical fibers with an FBG inscribed each adopt a two-point gluing configuration with a tightly stretched status, and they are arranged diagonally along the hyperboloid surface. This configuration can obtain improved sensitivity and resolution and avoid the drawbacks of FBG chirping and low repeatability. Finite element modeling (FEM)-enabled simulation has been implemented to perform design optimization for further sensor sensitivity improvement and performance investigation. The prototyped sensor has been calibrated and achieves a high resolution of 0.062N $\cdot $ mm within [−100, 100N $\cdot $ mm] and excellent linearity with a small linearity error of 0.68%. The crosstalk experiments on the bending moment of Mx and My and the axial force have been conducted to validate the anti-interference capacity on the basis of the small values of 0.47%, 0.31%, and 1.78%. The proposed design also supports convenient customization to achieve the adjustable measuring range and torque sensitivity, which has been validated by another sensor version with a resolution of 0.26 $\text{N}\cdot $ mm within [−500, 500N $\cdot $ mm].

A new UHMWPE-based conductive fabric was successfully prepared by radiation-induced graft polymerization and subsequent post-modification, followed by electroless deposition. The chemical structure and composition of modified UHMWPE fabrics were investigated in detail by ATR-FTIR, 29Si NMR, and XPS to confirm grafting and post-modification. After electroless deposition, the morphology, thermal stability, and crystal structure of original and modified fabrics were characterized by SEM, TG, DSC and XRD. Cu-deposited UHMWPE fabric exhibited much better thermal resistance than that of UHMWPE and Cu@UHMWPE-g-PAAc. In order to improve the oxidation resistance of copper-deposited fabric, nickel was processed on copper-coated UHMWPE fabric to protect the copper layer. An electromagnetic shielding effect test showed the nickel–copper coated UHMWPE fabric could shield 94.5% of the electromagnetic wave in the frequency range of 8–12 GHz. This work provides an approach for addressing the issue of poor thermal resistance of metal-coated polymeric materials due to the inherent low melting point of the organic support.

Herein, we report on fabrication of a highly durable smart mesh with reversible superhydrophobicity-hydrophilicity, using a two-step surface modification and hydrothermal process for on-demand oil-water separation. This wettability of transformation can be achieved under lower voltage within a few seconds than the reported literatures. Such an on-demand operation could be beneficially applied to automated and remote operation of oil-water separation situations, which would be very useful for the treatment of various effluents, including those with low levels of radioactivity. The reversible wettability not only makes our material applicable in both “oil-removing” and “water-removing” situations, with a separation efficiency of 99%, but also effectively prevents the mesh film from being contaminated with oil. The material developed in this work retained its high separation efficiency after 10 alternate-use cycles, involving oil-removing and water-removing modes, and sonication for 20 min, demonstrating its high durability. Our study provides a new pathway to improve the interface binding force between ZnO nanorod arrays and its support without affecting electrowetting performance, thus potentially making a useful contribution to the design of novel devices based on electrowetting-driven oil-water separation.

The trade-off between increased heat resistance and deterioration of mechanical properties caused by excess heat-resistant additives limits the use of silicone rubber (SR) in cutting-edge applications and extreme conditions. In this study, a novel SR composite with ultrahigh thermal oxygen stability was developed by blending SR with a small amount of cobalt-based metal-organic framework (zeolitic imidazolate framework-67, ZIF-67). The addition of only 0.125–0.5 wt% (relative to the content of SR) of ZIF-67 to SR could effectively improve its thermal-oxidative stability. Specifically, after 12 days of aging, the retentions of elongation at break of ZIF-67/SR composite reached 28.3–60.7% of the original, while the maximum decomposition temperature of ZIF-67/SR was approximately 25–30 ℃ higher than that of pristine SR. The origin of these attractive characteristics of the ZIF-67/SR composites was investigated by carrying out electron spin resonance (ESR) and X-ray absorption fine structure (XAFS) analyses.

Sulfate erosion of concrete is a kind of salt erosion which causes great harm to materials. It is also one of the important factors affecting the degradation of carbon fiber reinforced polymer (CFRP)-concrete interface. In this study, the sulfate environment was simulated by the sulfate dry-wet cycle accelerated erosion test. The bonding properties of CFRP-concrete interface under the dry and wet cycle of sulfate were studied by using 18 double-sided shear specimens. The variation trend of interface failure characteristics and interface characteristic values (interfacial shear stress peak and its corresponding slip amount) with sulfate erosion time were analyzed, and the interface bond-slip relationship curves under different erosion times were obtained. Based on the statistical regression analysis of the experimental results, the relationship between the interface ductility parameters and the interface eigenvalues as a function of sulfate erosion time was obtained. Moreover, a bond-slip degradation model of CFRP-concrete interface under the action of sulfate dry-wet cycle was proposed. The model prediction curve agreed well with the experimental curve. Compared with the experimental data, the prediction model can better reflect the trend of the interface bond-slip curve and the degradation pattern of the interface bond performance with the time of sulfate dry-wet cycles.

The bond-slip performance and constitutive model of the interface between reinforcing steel bars and brick masonry are the basis for seismic performance analysis of reinforced masonry through finite element simulation. In this study, the gradual increase of the vertical load in masonry during construction is simulated using a convenient self-developed test setup that ensures that the specimen is under constant pressure based on the actual stress state of horizontal reinforcing steel bars in reinforced brick masonry. Both the vertical compressive stress and the bond length were considered as variables and were used to form 19 groups of specimens. The bond characteristics of reinforcing steel bars were investigated using pull-out tests. The bond-slip curves of the interface between the horizontal reinforcing steel bar and brick masonry were obtained from test data; then, a five-segment bond-slip model that considered the effect of the vertical compressive stress and the bond length on the bond performance is proposed. This study analysed the variation trend of the bond parameters of each feature point influencing the bond performance in the model. The initial bond stiffness of the micro-slip segment increased with the increase in the vertical compressive stress, and the ultimate bond stress increased significantly. The calculation formulas of the bonding parameters are obtained by regression statistics taking these factors into consideration. The predictions obtained from the model show good agreement with test results.

To improve the disadvantage of the low reactivity and reduce the high curing temperature of epoxy resin cured by dicyandiamide (DICY), DICY is chemically modified with phenyl hydrazine and a new curing agent, LB-A, is developed in this research. The structure, the curing behavior, and reaction kinetics of LB-A curing epoxy resin are investigated. Results show that the DICY is modified successfully and the well-defined structure of DICY is destroyed after modification. Consequently, a new curing agent in a noncrystal form is resulted. Thereupon, the reactivity and compatibility between the epoxy resin and the curing agent are improved appreciably using LB-A instead of DICY. Meanwhile, the curing temperature and activation energy of the curing reaction decrease outstanding, whereas the rate constant increases remarkably. In addition, the compressive strength and the adhesive strength in shear by tension loading of the resulting epoxy resins have been increased using LB-A instead of DICY as the curing agent. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013