There are drought and harsh natural environment in northwest China, and the surface weathering causes most earthen sites here disappearing gradually. The paper uses glutinous rice slurries and SH as injecting paste materials to reinforce the weak weathering layers on the top of earthen sites in site. After this reinforcement, the mechanical strength and durability are measured via a mini-penetrometer, an infrared imaging device and an acoustic-waves-monitor, adding to a simulation rain test. In addition, some supplementary tests have been done indoor to make remolded samples in order to compare with the experiment results of uniaxial resist compression, wave velocity, disintegration and field tests. The experiment results show that the SH reinforcement effects on strength and resistance to water-erosions of earthen sites' surface are better than those reinforced by glutinous rice slurries. When the grouting aperture reaches 25mm, the maximum infiltration radius can be obtained. After using concentration of 2% of SH to reinforce, the strength is improved by 2.6 times, and the ability to resist disintegration is improved by 1.63 times. So the concentration of 2% of SH is the optimum to be the anti-weathering material.
Frame of solar sweeper is complexly welded structure with thin steel plate. The finite element method is applied of the frame strength analysis in two working conditions, full-load static and braking state. HyperMesh software is used for analysis of integral and welded frame model. CWELD is created to simulate the welding connection. The numerical results show that maximum stress of integral frame is 60.24MPa, and maximum stress of welded frame is 70.7MPa under full-load static state. The maximum stress different is 14.8% of two working conditions. The frame of solar sweeper satisfy strength requirement under the two working conditions, when the welding connection is considered. And the frame can be optimized by using these results.
Abstract Understanding the impact of space weathering on the mechanical properties of materials can provide strong implications for the exploration of the space including the building of a permanent base on airless planets. By examining the structure of solar flare tracks, which exist prevalently in lunar soils returned by Chang’e-5 mission, we revealed that the solar flare tracks are nanosized tubular defects where the silicon and oxygen atoms are delocalized. They are created by implantations of particles with atomic number larger than vanadium. The solar flare tracks first function as dislocation sources and act as strong hindrance for dislocation motions subsequently, resulting in dislocation multiplication and strain hardening. These changes make the mechanical properties of lunar soil significantly distinct from its counterpart residing on the Earth.
This paper presents an experimental method to investigate the effect of nanomagnetic particle on mechanics performance of magneto-rheological (MR) fluid, including the normal force and shear torque. Under different currents, the mechanics performance of a series of MR fluids with different quantities of nanomagnetic particles (0%, 4%, 7%, 12%, and 16% respectively) are measured by the plate-on-plate shearing test rig. The experimental results indicate that, with an increasing quality percentage of nanomagnetic particles, in a small range of currents (0–1.5 A), the mechanics performances are increasing, but their increment is no longer obvious when the current is above 1.5 A.
Abstract Aiming at investigating the working of magneto‐rheological fluid absorber, a test system used for detecting the damping characteristics of the magneto‐rheological fluid absorber was designed. The test system included sensors, data acquisition card, and so on. The vibration signals were detected by the sensors, put into LabVIEW data acquisition system, and then collected through the processing of closed‐loop Proportion Integration Differentiation control algorithm. Considering that the feedback current could be output to the magneto‐rheological fluid absorber by the data acquisition card, thus the damping force could be changed. The test results showed that the amplitude of the structure vibration response was obviously reduced through the closed‐loop Proportion Integration Differentiation control algorithm, and the control damping characteristics of the magneto‐rheological fluid absorber was improved.
A hydraulic cylinder model is established using Pro/E software. Nonlinear finite-element analysis of hydraulic cylinder various parts, enduring the axial loads and the radial loads were carried on by ANSYS software. By finite element analysis the stress distribution and the deformation of the hydraulic rod, piston, guiding bushing and the cylinder body were given. Based on this, the optimization design to the hydraulic cylinder tube is carries on, and it ensures the safety of the hydraulic cylinder enduring the axial loads and the radial loads, through increases the cylinder bottom to the internal cavity wall transition region radius of curvature.
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