Abstract:
The present invention provides a semi-active vibration absorption and energy dissipation control system for restraining vortex-induced vibration of bridges. It has the advantages and characteristics that: (1) springs are horizontally placed at the bottom of a beam, and lengths are not limited, so that the frequency requirement of a low-frequency target can be satisfied; (2) different target frequencies can be realized through different combinations of a plurality of springs connected in series and in parallel, so that multi-order vortex-induced vibration control needs are satisfied; (3) the springs made of fiber reinforced nylon materials are adopted, and are notched, so that a frequency implementation range can be greatly widened; (4) the material and the form of a mass body are not limited, and a water bag can be used, which has low cost and is convenient for disassembly, assembly and mass adjustment.
Abstract:
The present invention provides a method for moving and transferring nanowires using tapered hair of diameter in micron range. The nanowires have a diameter of 60-150 nm. The tapered hair has a diameter of 1-100 μm, a tip curvature radius of 0.8-3 μm and a length of 4-10 mm. A plastic film on a copper grid used for a TEM is removed, the copper grid is reserved, and holes have a diameter of 50-100 μm. The copper grid after ultrasonic cleaning gains the nanowires from the acetone liquid with ultrasonic dispersed nanowires. The copper grid with distributed nanowires and the tapered hair are respectively placed on mobile platforms of two different optical microscopes. Millimeter movement and micron movement of the tapered hair are realized, thereby realizing movement and transfer operation for the nanowires. The tip of the tapered hair is dipped in a small drop of conductive silver epoxy, and the conductive silver epoxy is respectively dropped on both ends of the nanowires; and the radius of the dropped conductive silver epoxy is 4-8 μm. The present invention realizes a method for moving and transferring nanowires using tapered hair through the mobile platforms of the two optical microscopes.
Abstract:
A method for determining a reduction factor of a bearing capacity of an axial load cylindrical shell structure relates to stability checking of main bearing strength thin-walled members of aerospace and architectural structures. Different from experiment experience-based conventional defect sensitivity evaluating method represented by NASA SP-8007, a depression defect is introduced in a manner of applying a radial disturbance load. First, an influence rule of a depression defect amplitude of a single point to an axial load bearing capacity is analyzed by using numerical values, so as to determine a load amplitude range; then, defect sensitivity analysis is performed on depression defects of multiple points; then, experiment design sampling is performed by using load amplitude values and load position distribution as design variables; and finally, based on optimizing technologies such as an enumeration method, a genetic algorithm and a surrogate model, the most disadvantageous disturbance load of the multiple points that limits the defect amplitude is searched for, and a reduction factor of the bearing capacity of the axial load cylindrical shell structure is determined, so as to establish a more physical method for evaluating the defect sensitivity and the bearing performance of the axial load cylindrical shell structure.
Abstract:
A vibration isolation/damping satellite mount of a chopped carbon fiber reinforced thermoplastic composite material mainly includes two parts, and the two parts are connected through bolts. Considering the limitation of the molding process, the mount configuration is further optimized, and the mount structure is prepared by using the injection molding process. Furthermore, the vibration isolation/damping satellite mount of the chopped carbon fiber reinforced thermoplastic composite material prepared in the present invention can be used for large loads and complex working conditions, and the connectivity, overall strength stability, vibration isolation performance and service life of the mount all meet the design requirements. The present invention provides an efficient optimization design and manufacturing method for engineering manufacturing of thermoplastic composite materials, and vibration isolation/damping satellite mount manufactured by the method is low in cost, high in practicability and easy to produce on a large scale.
Abstract:
A method for establishing a geometrical imperfection database of aerospace thin-walled structures is disclosed. The method comprises the following steps: 1) design the shell quality inspection card that is suitable and convenient to measure the geometrical imperfections for field workers. Obtain the parameters and geometrical imperfections of shells by filling data of measurement points in the shell quality inspection card; 2) perform characteristics combing, mathematical description and component analysis for the geometrical imperfections obtained in the first step; 3) collect and analyze the geometrical imperfection information of multiple aerospace thin-walled shells and establish the geometrical imperfection database based on the first step and second step. The method will effectively serve the development of aerospace equipment, shorten the design cycle and provide guidance and specifications for the design of the thin-walled components carrying main load.
Abstract:
The present application provides a thin-walled shell model updating method and system. The method includes converting an influence of fine feature structures in a space shell structure on stiffness and mass equivalently onto a skin and a stiffener, so as to simulate the influence of the fine feature structures on a bearing capacity of a whole structure.
Abstract:
An intelligent layout design method of curvilinearly stiffened structure based on image feature learning. Firstly, the design variables of the curvilinearly stiffened structure are determined based on the path function. The autoencoder network is built to complete the learning of the structural characteristics of the image, and the transfer learning of the model is further carried out. The convolution neural network is built to complete the learning of the image set with mechanical response labels. Finally, the evolutionary algorithm is used to optimize the layout of the curvilinearly stiffened structure based on the model. The invention solves the problem that the traditional optimization method is difficult to deal with the optimization design with many and variable design variables, and is expected to become one of the most potential technical means involved in the layout design of components in the engineering field.