Applied Mechanics and Materials Vol. 461

Abstract: The overall heat dissipation coefficients of the sandwich panels with bio-inspired lightweight composite cores were analyzed by using the effective medium model, Then the effective heat dissipation objective function of the panel was constructed. The author took advantage of the Latin hypercube sampling method to sample the experimental data and then to calculate it. On this basis, the static and dynamic mechanical objective functions of the panel were obtained by using the response surface method. Finally, the overall objective function was constructed and solved to achieve the target of multi-functional optimization.

Abstract: Hole shapes and their locations in lotus roots were studied and presented in this paper. The finite element method was used to study the effect of several factors on the structural integrity of a lotus root-like component. The factors considered in this paper include hole shape, number, size and location. The analysis of different structures was carried out using ANSYS software and assuming a porosity of 20% for each case. Stress values, effects of each factor and interactions between factors are discussed in the paper. The results from the analysis showed that engineering component design can be inspired by the lotus root which has several holes of different shape and size.

Abstract: Based on the microstructure of the beetles elytras cross-section, a bio-inspired metallic structure was designed. The mechanical property and the thermal property of the structure were analyzed with finite element method, and the compressive force-displacement curve and temperature distribution the structure were obtained, respectively. At the same time, the bio-inspired metallic structure sample was made with the material of the stainless steel sheet, and the quasi-static experiment and the thermal experiment of the structure were carried out. Comparing the experimental results with the FEM analysis, the results proved both the accuracy and reliability of FEM. Key words:beetle elytra;microstructure;bio-inspired structure; finite element analysis

Abstract: Cavitation noise is the major source of noise in fluid power transmission system. Noise value is the most important index to measure the quality of equipments. So reducing noise is the primary goal. Honeycomb called a natural miracle has unique structure and good acoustic performance. A kind of noise reduction device was presented in this paper based on micropore structure of honeycomb and micro-perforated panel theory. The design idea and design scheme of the device had been discussed. Then simulation of the device had been done in order to optimize the design ,the number and position of cavitation had been assured and the open porosity was selected as a judgment index. The results of simulation indicated the device added to fluid system could reduce cavitation noise effectively. The device was made and added to the water circuits in experiment field. Eliminating interference of environmental noise,the noise of water circuits system used the device was decreased by 3dB or so compared with system without the device.

Abstract: In order to develop the lightweight composite materials, we developed an integrated manufacturing method. The first trial production of the integrated honeycomb plate was fairly rough. This paper focuses on the trial manufacture of bionic honeycomb plates and discusses their mechanical properties. The conclusions were :1) An edge-sealing bionic integrated honeycomb plate has been provided; 2) some specific cases of improving the integrated manufacturing technology have been studied; and 3) the failure strength in the integrated honeycomb plate is significantly higher than that of the honeycomb plate with the adhesive layer.

Abstract: Mole rat, a typical soil-burrowing animal, has high working efficiency during digging procedure, its claws are good biomimetic prototypes, and the geometrical structure of its claws and its movement type during digging can provide certain foundation for improving the design of the tillage implement. In this paper, based on the reverse engineering, the original data points of the claw was collected by a 3D laser scanner, then the accurate surface of the claw was created by using special software of reverse engineering on the premise of point-curve-surface method. The reconstructed CAD model was established in Pro/E software, and the model of interaction between the claws of mole rat and soil was obtained. The finite element method (FEM) was utilized to simulate the interaction of the claw against soil. The simulated results showed that the movement type of claw of mole rate during digging could get lower cutting resistance and bigger impact to soil.

Abstract: Deployable structures, as an important kind of structure, have been widely used in a variety of satellite antennas and space reflectors. The research of deployable structures usually faces a series of theoretical and technical challenges because the size and mass are not only the limitations of deployable structure but also the key issues in the design process. Nevertheless, the appearance of bionic provides a new concept to develop the deployable structures. Inspired by the eclosion and development of butterfly wings, a bionic inflatable deployment structure has been presented in this paper. The whole system of emulate model is established and has a simulation analyzed with the help of dynamic analysis software. This simulation is aimed at emulating the deploying process, and calculating the stress distribution of the structure. Then some relative curve fitting is conducted on the deploying trajectory. A prototype has been fabricated and tested to be able to deploy smoothly and steadily.

Abstract: A bio-robot treats the living animal itself as the robot-moving carrier, which possesses good mobility and adaptability even in complicated non-structured environments. As one of the flyable bio-robots, pigeon-robots have been studied for several years. However, how to arrange the equipments on board effectively to minimize the impact to pigeons natural flight has not been considered. In this study, we estimated the bearing capacity of a pigeon during takeoff by increasing the weight gradually. Different loading modes have also been compared to find a rational way to reduce the influence of the loading to flyability. These results are expected to be helpful to the design of pigeon-robots.

Abstract: This report reviews biomimetic studies performed in China on the beetle forewing, noting that Chinese scholars studying bionics have substantially advanced various branches of biomimetic research in beetles. The report also proposes the development of branches of bionic research and establishes the foundation for corresponding experiments and theories. Then, using the A. dichotoma forewing as a an example, the cross-sectional shape, orientation of the laminated fiber layers, structure of the trabeculae, and respective mechanical properties of the forewing, as well as their biological significance, are reviewed. 1) The forewing has a lightweight border frame structure and an optimal design of variable cross-sections suitable for different positions, which achieves the specific second moment of inertia required for flight. 2) Due to the non-equiangular, laminated structure of the forewing, there are two types of tensile fracture morphologies: fiber breakage and residual bridging. This study demonstrates the anisotropy and the effectiveness of the forewings tensile strength by analyzing the orientation direction of the fibers. 3) The trabecular structure can be used to efficiently improve the peel resistance of the laminated composites. Based on the above points, possible directions for future work are also indicated in this paper.

Abstract: Grasshopper [Chondracris rosea rosea (De Geer)] possesses sharp and serrated incisors that have an advantageous capacity for cutting crops including leaves and stalks. To quantitatively analyze the geometrical structures of the incisors cutting edge, MATLAB digital image processing and edge detection technology were used to obtain incisors outer margin 2-dimensional point cloud from incisors stereomicroscope photograph. Then, the least squares fitting method was used to fit the curves mathematical model and the outer margin curves of incisors which were segmented into five curves. The serrated outline of incisor was fitted and expressed by nine-order polynomial function. Furthermore, the second derivative and curvature of the outer edge curves were calculated. Finally, the geometrical characteristics of grasshopper incisors outer edge curves were analyzed and discussed. In conclusion, the special shaped incisor of grasshopper is a potential prototype that can be exploited to develop new cutting element to cut lignocellulosic biomass more efficiently. These results would be helpful for designing cutting elements on crop harvesting, biomass size reduction and other cutting machinery.