Advanced Materials Research Vols. 217-218

Abstract: In order to reflect the heterogeneity of concrete at mesoscopic level and simulate the mechanics response from the mesoscopic to macroscopical in the course of load, the random aggregate model according to the Monte Carlo method and Fuller Graded Formula is carried out based on the assumption that the concrete is a multi-phases composite material composed of matrix, and the material parameters are defined based on the test. In this paper, the Numerical Manifold Method introduced not only can correctly simulate stress, deformation and failure of concrete, but can simulate propagation of multi-cracks in the concrete, and failure plane growth can be searched by stress results automatically, so it can simulate the kind high discontinuous problem very well. On this basis, NMM is adopted to simulate the tests on concrete mechanical performance. The creation, propagation and fracture process of cracks in compression of concrete are present. The computational results are in good agreement with the experimental data.

Abstract: TiO2 with 20nm in diameter have been prepared by using magnetron sputtering technique. The structure of these powers was determined by X-ray diffraction experiments. The average grain size and particle size in these powers were measured by the line profile analysis method of X-ray diffraction patterns and by scan electron microscopy, respectively. The thin films were investigated by using XRD, SEM measurements.

Abstract: Powder of Ti-46at%Al alloy was synthesized through mechanical activation (MA) and then sintered and concurrently consolidated in a short sintering time of 900 s by using spark plasma sintering (SPS) process. The XRD and SEM profiles show that the microstructures of TiAl alloys contained γ TiAl and small amount α-2 Ti3Al phase, whose amount can be controlled by the sintering temperature. The compacts retained the original fine-grained fully densified bodies by avoiding an excessively high sintering temperature. The alloys sintered at higher temperature with this process showed a coarser microstructure. So it is possible to produce dense nanostructured TiAl alloys by mechanically activated spark plasma sintering (MASPS) within a very short period of time.

Abstract: A new image feature selection method with the combination of Genetic Algorithm(GA) and Probabilistic Neural Network(PNN) is proposed and applied to potato shape feature selection and classification. The classifier selecting principle is investigated by combining with the genetic algorithm. A new feature selection method based on GA and PNN is put forward firstly. Comprehensively considering the factor of classification accuracy,selected feature number and the impact of the two factors, a new fitness function is proposed. The initial Zernike moments parameters of potatoes are optimized using improved genetic algorithm, and nineteen Zernike moments are extracted to form the shape feature. The shape detection accuracy can reach 93% and 100% respectively for the perfect and malformation potatoes. The tests indicate that the fitness function and feature selection method can be used for searching the best feature combination.

Abstract: As the most potential member in the textile composite material, stitched textile composites have already been paid a lot attention. By the simply technology form and relatively low cost, stitched composites had attracted many domestic and foreign researchers, and were gradually used in various engineering practice. This paper using 3D micro-finite element method researches the mechanical behavior and performance of stitched composites, establishing a 3D micro-finite element model for the stitched composites under the improved locking suture way. Through analysis, it shows that each material’s stress distribution characteristics under external loading and finds that the results of this paper’s finite element data results matching well with previous studies’ results, proving the feasibility of this study, so it can be used for forecasting the mechanical properties of a variety of practical stitched composites.

Abstract: Being aimed at prestressed concrete cylinder pipe itself characteristic of structure and production process, PCCP cracks were classified, the classification and kinds of the crack causes are analyzed, the control measures and repair methods of different cracks is also discussed.

Abstract: A Correlation tracking algorithm based on the function of the minimum average absolute difference is studied. It aims to search the biggest corresponding parts of the minimum average absolute difference in the next frame image using pixel gray values of part of image region as a template to match and solve the target motion parameters. The matching criterion is small computation, simple operation and can reduce the computing time, improve the algorithm running efficiency. The test to track the car running on the road using this tracking algorithm is presented. The experimental result shows that this algorithm can be very good to track the moving car and the magnitude of tracking window deviating from the moving car is very small.

Abstract: This paper is about dynamic obstacle avoidance. Delaunay Graph is used for modeling the working space, an approximate shortest path of mobile robot is determined by using floyd algorithm. Path can be found easily with genetic algorithm. Then genetic algorithm is used for obtaining the optimum path. It may meet which dynamic obstacle when robot follows optimum path. so it should avoid it. Results of simulation show that this path planning method is simple and realized easily.

Abstract: In the imaging process, the deformation of the plate caused by the structure of the drum, finally affecting the quality of the plate, we analyze and optimize the structure of the drum using the finite element method. Selecting the larger three factors affecting the plate deformation as the design variables, and taking minimizing the maximum deformation of the plate as the objective function, we establish the optimization model of the structure of the drum. We use the APDL parametrization language to create the geometric model and finite element model of the drum, and select the contact element to simulate the relationship between the plate and the surface of the drum, and use ANSYS software to optimize the optimization model. It is shown form the result that: the minimum of the maximum deformation of the drum getting from the 8th iteration is 0.0021535mm, significantly reduced compared with the initial value 0.002864mm. At this point, the internal diameter D2 of the drum is 300.04mm, the groove width L2 is 14.323mm, the external diameter of groove height D3 is 338.44mm. It indicates that that the smaller the internal diameter of the drum and the narrower the guide groove on the drum surface are, the smaller the maximum deformation of the plate is, and the guide groove height has little influence on the deformation. The results can be provided as theoretical reference for the design of CTP imaging drum, which has popularization and application value.

Abstract: After the destructive earthquake, it is urgent that the damaged houses, infrastructure and industrial projects and other related equipment and facilities are to be rehabilitated and restored. How to carry out reconstruction investment plans of various sectors became a major concern to the government. To meet the needs of rapid recovery of production and life in affected areas, the method based on BP neural network is proposed to estimate the post-earthquake rehabilitation cost of industrial, agricultural and service projects. That method considers the macro-economic characteristics of every damaged area. It can provide some guidance for the government that need to make decisions of post-earthquake recovery and reconstruction plans.