Applied Mechanics and Materials Vols. 71-78

Abstract: Aggregate is one of the most important and strength determining ingredients of concrete as it serves as reinforcement and occupies three quarter of the total volume of concrete. Moreover, for good compact concrete, aggregate with minimum void is always desirable. This paper represents a study on obtaining the effective dense gradation by combining naturally available aggregate in Bangladesh. In this purpose a program has been developed based on analytical approach to find out the desired mix proportion of different aggregate samples to reach the target of getting an compact, economic and environment friendly concrete. Finally after preparing the concrete in the laboratory with different mix design ratio and combined gradation of prepared single sized aggregate is found to have 20% more strength than that of the concrete made with the same design mix and combination of aggregate gradation presently available in the industry.

Abstract: Concept design is the heart and soul of structural design. Combining with applications of PKPM series computer construction structural CAD system software, the paper described that software has some applicability, limitations, and approximate in practical construction applications. The structural design personnel should start from structural concept and par more attention to value of calculation parameters, computing model processing and calculation results determination, so as to ensure safety, economy and rationality of structural design.

Abstract: Digital image correlation method is an important optical technique for surface displacement and strain measurement. An approach based on Particle Swarm Optimization algorithm for sub-pixel correlation search is described in this paper. The new Algorithm does not involve reasonable guess of displacement and deformation gradient and the calculation of second-order derivatives of the digital images. Benefiting from the abilities of global optimum and parallelism searching, and compared with genetic algorithm, the new approach can complete the sub-pixel correlation search with high accuracy and less computational consumption. Computer-simulated images are then used to verify this method. The experimental results show that the new approach is a practicable sub-pixel searching method.

Abstract: Non-destructive testing and safety monitoring of structure has been a hot and difficult engineering research problems, and an effective extraction of damage characteristic factor is a critical and theoretical research on structural damage detection and monitoring technology. The basic theory of modal strain energy and the steps to damage diagnosis are discussed in the paper.A a radial gate with different damaged locations and damaged degree is studied,and the results show that modal strain energy can be used as structural damage location sensitive factor,and that the indicator can be a very good identification of the location and extent of structural damage,and that the results of damage diagnosis are clear and reliable.

Abstract: Damage diagnosis and safety monitoring of large hydraulic structures are becoming one of the hot and difficult research subjects in the present structural engineering circle. Based on the wavelet theory, the measured data of a dam is operated by wavelet transform separating in different frequency bands and signal de-noising,and then the effective information of structure settlement can be obtained from the measured data with noise.This paper introduces an effective method to eliminate the error for the survey data.

Abstract: Elastic cushion layer between the steel spiral case and surrounding concrete is often used as a structural type in large-scale hydropower plant in China. In view of the uncertainty of the optimal elastic coefficient of friction and the transfer mechanism of internal water pressure to the surrounding concrete, Spiral case with cushion layer of large-scale hydropower plant is simulated with ANSYS nonlinear finite element program, considering the slip contact characteristics between steel spiral case and the surrounding concrete, the more reasonable coefficient of friction between the steel spiral case and concrete is studied. This provides reliable theoretical analysis for the design of large-scale hydropower plants.

Abstract: Based on the coordinate transformation, the paper analyzes and constructs the mathematical model for electromagnetic torque online measuring system with three-phase induction motor. Additionally, the author proposes the improved scheme for model limitations. The system can meet the random and fast requirements on the occurrence and measurement of the three-phase induction motor torque and has high practical engineering value.

Abstract: The problem of output feedback for the unstable discrete-time linear systems with input amplitude constraints is studied. Based on the precise description of controllable region, the typical implementation method of observer-based output feedback will decrease the system’s controllable region, a new approach is proposed in this paper, which make the system’s controllable domain as big as possible. Finally, two illustrative examples and simulation results are given to demonstrate the effectiveness of the proposed method.

Abstract: According that town plan is mainly drawn with software AutoCAD, this article realizes to automatically select a shortest transport route on urban road and dynamically display traffic flow based on VC++ and ObjectARX and lays a foundation for future development taking traffic limit, traffic conditions and other complex conditions into account.

Abstract: A good deal of high water content sludge which is produced in engineering construction, with high water content, low strength, high compressibility, low permeability, high sensitivity and other undesirable engineering properties, and often contaminated. How to deal with and make rational use of high water content sludge becomes the hot topic discussed by engineering and academia. The material used in this study is sludge with high water content from the Metro construction sites in Hangzhou. In this paper, our main research is the influences of the different contents of cement, lime, gypsum, fly-ash on the curing strength character of silt. The product structure was analyzed by XRD.