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To obtain the filling material with good compression mechanical properties, two kinds of orthogonal trapezoidal honeycomb aluminum with different structures were manufactured（90°orthogonal trapezoidal honeycomb aluminum and 45° orthogonal trapezoidal honeycomb aluminum）, the mechanical properties of the material under quasi-static axial loading was analyzed. Two kinds of orthogonal trapezoidal honeycomb aluminum were filled with polyurethane foam, and the effect of polyurethane filling on the orthogonal trapezoidal honeycomb aluminum was analyzed. The results show that compared with 45° orthogonal trapezoidal aluminum honeycomb, the performance of 90° orthogonal trapezoidal honeycomb aluminum is better, and the peak stress, plateau stress and unit volume absorption energy of the two kinds of orthogonal trapezoidal honeycomb aluminum are improved after polyurethane filling. However, the energy absorption efficiency is not significantly improved after being filled with polyurethane, and the strain corresponding to the maximum energy absorption efficiency decreases.

Aiming at the problem that the upper limb rehabilitation robot has secondary damage caused by inertial impact,a new mechanism of a rope traction upper limb rehabilitation robot is designed by using the hybrid mechanism. To ensure the safety and stability of the rehabilitation robot,the static strength analysis and modal analysis of the structure of the upper limb rehabilitative robot is carried out by using ANSYS Workbench.Moreover,the multi-objective genetic algorithm is applied to the lightweight optimization design of the support frame. The result shows that the total mass of support frame after optimization is comparatively 48% less than before. At the same time,the inherent characteristic of the whole frame is obtained,which is prepared for the later control strategy.

The crystal orientation effect on the mechanical properties and micro-deformation behavior of single-crystal iron (SC Fe) were revealed by molecular dynamics (MD) simulations. The results show that the surviving defects in the SC Fe models are [110] < [100] < [111], and only the vacancy and interstitial atomic clusters are formed in the [111] SC Fe model. Irradiation leads to the increase of elastic modulus owing to the annihilation of irradiation point defects. However, the non-annihilable irradiation clusters reduced the strength. The decrease of yield strain and yield strength of the [111] SC Fe model is significantly higher than those of [110] and [100] SC Fe models, exhibiting worse radiation damage resistance. This is due to the number and types of operation of slip systems in the [110] and [100] SC Fe after irradiation, which is caused by its poor inhibition of [111] crystal orientation on clusters under irradiation, being much lower than those in the [111] SC Fe. The yield strength of SC Fe increases with the increase of the number and length of 1/2 111 and 100 dislocations, while the plasticity decreases with the increase of the falling gradient of dislocations after yield. The purpose is to provide theoretical guidance for the microstructure design and regulation of radiation-damage-resistant iron-based materials. [ABSTRACT FROM AUTHOR]

The variable stiffness of robot joints plays an important role in improving the robot's compliance, safety, and energy efficiency. In this paper, a novel type of variable stiffness joint based on a rack and pinion structure (VSJ-RP) is proposed. The structure and the variable stiffness principle of the joint are described in detail. The theoretical stiffness calculation and the dynamic model of the joint are established, and the correctness of the model is validated by simulation. The compliance, safety, energy storage, and release characteristics of the joint are validated by position, bearing capacity, hitting ball, and safety detection experiments, respectively. These experimental results show that the joint stiffness can be adjusted from 14.74 Nm/rad to 726.58 Nm/rad, and the overshoot of the position response is about 5.56–0.5%. The larger the stiffness of the joint, the faster the adjustment response, the smaller the fluctuation, and the more stable the operation are. The maximum output torque of the joint is about 20 Nm, and the torque difference between the minimum and the maximum stiffness of the joint is about 10%. The energy conversion efficiency of the joint is 17.56%~89.86%, and the deformation angle range is 2.66°~4.37°. These phenomena reflect the safety, energy storage, and release capacity of the joint. An effective exploration is performed regarding the miniaturization, safety, and energy utilization of robot variable stiffness joints. [ABSTRACT FROM AUTHOR]

Bi-directional corrugated honeycomb aluminum has two-way energy absorption performance intended to be used as impact limiter filling material for nuclear spent fuel transport casks. It is made of aluminum plate, corrugated plate and adhesive. The bonding parameters determine the bonding effect of Bi-directional corrugated honeycomb aluminum thus affect the energy absorption performance. This paper verifies the bonding parameters from three aspects (type of adhesive, surface roughness, and thickness of the adhesive layer). The results show that when an acrylic adhesive is used to perform the compression test, no matter which bonding parameters are used, all samples debond. When an epoxy resin is used, except for the sample with an adhesive layer thickness of 0.2 mm and the surface was polished with the grit number of 320 sandpaper, samples with other parameters showed debonding to varying degrees. In addition, the bonding parameters have a great influence on the energy absorption performance of the specimen. The deformation and the energy absorption was also discussed. [ABSTRACT FROM AUTHOR]

In this paper, a porous material–bi-directional corrugated honeycomb aluminum (Bi-DCHA) was manufactured, and quasi-static compression experiments were performed in axial (Y/Z-direction) and radial (X-direction) directions. It was concluded that the mechanical properties in the Y/Z directions were better than those in X-direction. Further, to verify the effect of expanded polypropylene (EPP) on the properties of Bi-DCHA, three different density EPP were used to fill them, and the property of Y/Z-direction was performed. As a result, compared with Bi-DCHA unfilled with EPP, the performance of Bi-DCHA filled with EPP improved, and is better than the sum of EPP and Bi-DCHA unfilled with EPP. Observing the stress-strain curves of the four groups of samples, we can find that the initial peak stress (σP) of the Bi-DCHA filled with EPP is lower than Bi-DCHA; the stress in the plateau zone (σpl) increases with the increase of the EPP density. Observing the deformation process of the specimen, it was found that after filling the EPP, the deformation process of the specimen changed from global buckling/tilt mode to local compact plastic deformation mode. The energy absorption effect of Bi-DCHA filled with EPP is stronger than that of unfilled specimen. [ABSTRACT FROM AUTHOR]

Rational design of active and earth‐abundant catalysts toward oxygen evolution reaction (OER) is of particular significance for archiving highly efficient water electrolysis. Herein, a series of perovskite oxide quantum dots with abundant oxygen vacancies adhered on oxidized carbon nanotubes (LaNiXFe1‐XO3‐δ‐QDs/CNTs) were fabricated by simple sol‐gel and pyrolysis methods. The results indicate that the optimized LaNi0.3Fe0.7O2.759‐QDs/CNTs sample with adjust crystal structure, proper ratio of Ni to Fe, and desirable oxygen vacancy concentration shows a low overpotential (0.34 V at 10 mA/cm2), a low Tafel slope (74 mV dec−1), and excellent stability when it was evaluated as OER electrocatalyst. This work will shed light on the development of precious‐metal‐free catalysts with promoted catalytic performance [ABSTRACT FROM AUTHOR]