Abstract Magnetic soft materials have been extensively utilized in the development of soft robots. However, they usually fail to achieve programmable soft‐hard magnetic transformations, limiting multimodal magnetoactive deformation and locomotion. Herein, a coaxial magnetic fiber (CMF) consisting of a porous polydimethylsiloxane (p‐PDMS) sheath and a core of sodium alginate sol (SAS) mixed with neodymium‐iron‐boron (NdFeB) particles (NdFeB@SAS) is reported, fabricated using intermittent coaxial 3D printing. The CMF can reversibly transition between a hard magnetic state (coercivity H cm 6900 Oe and remanence M r 61 emu g −1 ) and a soft magnetic state ( H cm 450 Oe and M r 16 emu g −1 ) through the solvent exchange strategy, achieving a ≈15‐fold change in coercivity and a ≈4‐fold increase in remanence. Three CMF‐based samples are constructed and programmed with varying soft‐hard magnetic profiles, exhibiting multimodal magnetoactive deformation. Moreover, under a fluctuating magnetic field, a bionic butterfly robot can flap its wings over a vertical branch without falling. A magnetic brush is also constructed to paint origami objects using magnetic actuation. These demonstrations underscore that the responsiveness of the CMF to global magnetic fields can be locally tailored, allowing for the coexistence of attraction and repulsion in various regions of the CMF, providing a novel approach for developing soft robots.
Integral space concrete roof is an excellent roof structure, the application scope is wide. The characteristics of the structure and the construction methods get all through the experiment and the actual test, which shows the roof is superior to the traditional form. In order to validate the construction cost and how the social benefits, further researches is needed. Based on the traditional arch board roof for reference, it is researched of the construction cost, the directly benefit, the comprehensive character etc. And as a cold storage the basis, the social benefit is calculated. The results showed that the roof direct construction cost than traditional roof save about 20% ~ 45%, the social efficiency huge, for the popularization and application of the roof provides a strong basis.
In this paper, a new type of large span prestressed concrete integral roof was studied. The test uses full scale specimens, the roof’s span is 24 meters, the width is 2 meters, across the tallest is 3.6 meters. The different condition of roof structure properties is examined. Through experiment obtaines the deformation and the ultimate bearing capacity of the roof, the design is proved to be correct. Test results show that the roof system with one piece casting has enough bearing capacity and rigidity. Roof destruction presents brittleness nature, destroying position is in lower chord board near the end of place. This research conclusion provides a reference data for this type of roof of popularization and application.
Based on the experimental study, summarizes the disadvantages of the test roof; On the same premise of the roof to keep the overall appearance, the structural system of the roof is optimized ; The content of the optimized structural system includes the layout of the structural system, the establishment of the calculation model, the optimization of internal support system, the calculation of kinds of members, etc.; The integrity of the roof are enhanced after optimization, and more accord with the concrete shell space structure characteristics, and provided a convenient for the big water construction. Compared to the traditional roof, the optimized roof save about 30% of the costs.
Integral space concrete roof is a kind of new structure, it has the following characteristics: its integrity is very strong and the structure size is larger, its construction method is different from the general of roof structure. In order to promote its application, its construction method is researched by to adopt the technology of "high in-situ construction" and in combination with the construction a grain storehouse. In this paper, the key points of the construction is analysed and the key technology is researched, that’s including: the design of the holding bracket; the construction design of the high tension pedestal and the tension of the prestressed steel, etc. Then put forward the key points of the construction. Finally, the construction method of the roof is summarized, and the application conclusion is obtained.
In this study, we have a research on wave action on the submarine launched missile water trajectory and gesture angles during the process between launch and exit from water. Infinite water depth plane wave was used as the wave model, mathematics models of missile exceeding water under different wave conditions were established based on ideal potential flow theory. The flow field velocity potential was obtained by solving the Laplace equation, thus can obtain missile surface pressure. Considering free surface effects, simple Green’s function was introduced to solve boundary value problems. Three-dimensional Fortran program and finite software ABAQUS were combined to complete the fluid-structure interaction simulation. The rules that wave level and phases effects on submarine- launched missile were finally obtained, which shows wave affect cannot be neglected. Simulation methods and results of this study have a certain reference value for the submarine-launched missile launching.
Using the Equivalent Load Method of unbonded prestressed tendons reinforcement in cylindrical shell, and the concepts of influencing factors of pool wall boundary conditions for hydraulic or annular prestressed reinforcement, the way of unbounded prestressed tenons optimizing location is discussed. It is emphasized that the number of tenons in pool top wall is more than that of in pool bottom wall , and the optimum reinforcement ratio is only 1/3 ~ 1/4 of actual design reinforcement ratio.
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