Advanced Materials Research Vols. 368-373

Abstract: This paper concludes and analyses the main contents of sustainable urban space researches, including various viewpoints and spatial conceptions. Key issues and trends of sustainable urban space planning are analyzed from the aspects of space, material, society and culture. This study will further clarify the characteristic development elements involved in urban planning guidelines, promote planning of an ecological and socially sustainable new urban, and enhance the completive edges of the urban in global urban hierarchies.

Abstract: To improve the accuracy of parameter identification and to reduce the test cost in the high-rise structure health monitoring systems , the paper proposes an optimal placement method combines genetic algorithms with improved information matrix criterion (GA-IIM). With traditional improved effective independent method (EFI-DPR), it is easily trapped into bureau of optimum solution, and the proposed method can resolve this problem. The solutions were coded by a two-dimensional integer array, each line stored a feasible solution and compulsory mutation was adopted to avoid the solution reappeared in the same position. To improve the convergence speed, each generation of optimal group was kept to the next one to participate in the competition. With the improved information matrix criterion embedded in the genetic algorithms, the placement design was produced. This technique was used to optimize the sensor placement of a nineteenth layer frame structure. Comparing the optimized sensor placement of the proposed method with that of improved effective independent method by the modal assurance criterion and the mean square error, the proposed method performs better.

Abstract: As one of meshfree methods, reproducing kernel particle method (RKPM) is usually associated with semi-Lagrangian formulation for large deformation problem to avoid the failure of one-to-one mapping from current configuration to reference configuration. However, numerical crack may happen for large deformation problem working with semi-Lagrangian formulation, if we keep the support size of reproducing kernel shape function as constant. This paper proposed an algorithm to adjust the support size at every step and some numerical results are presented to demonstrate the improvement by the proposed algorithm. Meanwhile, this algorithm is very easy to implement for coding, which does not add much computational cost.

Abstract: Over decades phased array antenna technique attracts much more attention in Lamb wave based structural damage detection. Lamb wave generated by the piezoelectric wafers omnidirectionally could be steered at a specific direction during its propagation. Thus, the wave beam steering and focusing has been established, the location of structural damage is done with pulse-echo method by wave propagation. However, the detection accuracy will decrease as side bands energy leakage during wave propagation, so, signals to be generated have to be modified by window tone burst in order to concentrate energy in main bands and minimize the effect of dispersion side bands. In this paper, signals modified by Hanning-windowed tone burst was used to decrease the effect of side bands energy leakage, the results improved the detection accuracy better than signals without window tone burst and show good agreement with theoretical results. Meanwhile, A numerical simulation of aluminium plate demonstrates that phased array antenna technique is feasible in structural damage detection.

Abstract: Bistable stochastic resonance is described by visual explanation. Engineering application feasibility of stochastic resonance is investigated, and the example of engineering application also given. Its application expectations are prospected.

Abstract: Because the ambient excitation is difficult to test, it is necessary to study the damage detection method only with structure responses. In this paper, two node structure responses under white noise are used to calculate the virtual impulse response function, the amplitude of the virtual impulse response function is decomposed by wavelet packet to calculate the node energy. The wavelet packet node energy change pre and post damage is used as the damage characteristic vector, and the pattern classification function of BP neural network is employed to determine the structure damage location. The numerical simulation and model experiment results of the offshore platform show the effectives of the method, whereas which is easy to be influenced by the noises.

Abstract: This paper presents an analytical study on a minimum patch thickness necessary to fully recover structural performance of corrosion-damaged pipe piles under axial compressive loads using welding repair. Load transfer mechanism, the repaired stiffness and strength of pipe piles are examined. An accurate calculation of load share ratio of patch plates considering weld stiffness is derived, and the results are compared with experimental results and finite element analysis results. The minimum thickness of patch plates to fully recover the stiffness and the design strength of the corrosion-damaged piles to their intact state considering the existing loads is proposed.

Abstract: As the "Urban and Rural Planning Law " had been promulgated in 2008, the paper studied the context of socio-economic development and the actual situation of urban and rural development in Guangdong Province, drawing on the experience of the British planning system, proposing the framework of urban and rural planning system as "Provincial Spatial Plan" and "Local Development Plan", which including urban system planning, master plan, detailed plan, village plan four types. The new framework will streamline the planning system, reduce the levels of planning and clear the relationship between different types of planning, contributing to regional coordination in urban and rural areas.

Abstract: Cultural heritage serves as memory of history, authentic historical memory is certainly integral. The system of urban cultural heritage is a sequential combination of urban cultural heritages, and this is a new idea of heritage selection. this paper is to discuss the method of system construction of urban cultural heritage in Xi'an.

Abstract: In Mainland China, especially in Northwest China, the central county cities are the basic units that directly and closely connect all other rural areas. Therefore, the education facilities, which serves to improve residents’ quality of life in these cities, serve not only local residents but also people living in other towns and within the counties administration boundary. This paper takes Chengcheng in Shaanxi province as an example and starts with analyzing existing problems in education facility planning and implementation in central county cities. Based on the investigation of status quo of education facilities for primary and secondary schools and comparing with present index system of education facilities planning, this paper tends to explore a methods suitable for education facilities planning and also a feasible strategy for its implementation.