The compression experiment was conducted by using Gleeble3500 thermal-mechanical simulator, and the mechanical property of LD10 aluminum alloy in high temperature was analyzed. The hot rolling experiment was taken in ...
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The compression experiment was conducted by using Gleeble3500 thermal-mechanical simulator, and the mechanical property of LD10 aluminum alloy in high temperature was analyzed. The hot rolling experiment was taken in D51-160 hot ring rolling mill to identify that the initial rolling temperature of LD10 aluminum alloy ring was 470°C. The numerical simulation of hot rolling process of LD10 aluminum alloy conical ring with inner steps was taken based on the experimental data. The mechanism of rolling deformation defects of conical ring with inner steps was analyzed and the pre-rolled ring was designed. In order to validate the simulation results, the hot rolling experiment was also performed. The results showed that, numerical simulation and hot rolling experiment had a good agreement and the design scheme of pre-rolled ring was reasonable.
A three pattern development mode based on Client/Server, Browser/Server and Browser/ArcIMS is proposed, and its architecture is formed by analyzing the geology survey and construction information of Yangtze River emba...
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A three pattern development mode based on Client/Server, Browser/Server and Browser/ArcIMS is proposed, and its architecture is formed by analyzing the geology survey and construction information of Yangtze River embankment projects. The background database is optimized and reorganized. A multilevel recurrent algorithm of super-entity based on tree data structure is presented and a way of dynamic dropdown listbox with infinite layers is put forward. The object oriented technology and related development tools are introduced, software of embankment information service system of Yangtze River is developed, which integrates DBMS and GIS.
A new algorithm based on cross-correlation vector Toeplitz reconstruction, called CVT method, is proposed in this paper. The CVT method can estimate coherent signal source effectively. The CVT utilizes the internal re...
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A new algorithm based on cross-correlation vector Toeplitz reconstruction, called CVT method, is proposed in this paper. The CVT method can estimate coherent signal source effectively. The CVT utilizes the internal relation of array receiving data to realize signal sources de-coherent. Compared with the classical spatial smoothing algorithms the proposed algorithm has higher estimation precision under the condition of the same phase. The reason is that the CVT method can realize de-coherent completely, but the spatial smoothing algorithms realize rank reconstruction only. The produce of rank reconstruction introduces cross- correlation noise into modified signal covariance matrix. But the CVT method can transform the signal covariance matrix of coherent source into diagonal matrix. Therefore, the CVT algorithm has some advantages of low computational load, better robustness and higher estimation precision than spatial smoothing algorithm. The theoretical analysis and simulation results show that the proposed method is effective.
作者：
卫军周锡武朱玉罗昕Civil Engineering Department
Huazhong University of Science and Technology Wuhan430074 China Civil Engineering Department
Huazhong University of Science and Technology Wuhan430074 ChinaChina Communications Second Highway Survey Design and Research Institute Wuhan430052 China
The theoretical results of axial force distribution models differ greatly from tests because of the complication of the rock type material. A three-parameter combined-power model is proposed by curves fitting the test...
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The theoretical results of axial force distribution models differ greatly from tests because of the complication of the rock type material. A three-parameter combined-power model is proposed by curves fitting the test data recorded from the pull tests on anchoring bars used in different engineering projects. Based on the comparison of the mechanical characteristics of shaft anchors and prestressed tendons, a two-parameter combined-power function model for prestressed tendons is proposed. The bounded length derived from the model and the suggested values of the parameters are also proposed. Compared with the Gaussian model, the three-parameter combined-power model is more precise and simple in expression. Results also suggest that the bounded length calculated from the average stress method is not safe enough.
An algorithm for computing the minimum distance between two convex polyhedra is presented. The algorithm is applied to polyhedral objects which can be represented as convex hulls of its value of vertices in three-dime...
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An algorithm for computing the minimum distance between two convex polyhedra is presented. The algorithm is applied to polyhedral objects which can be represented as convex hulls of its value of vertices in three-dimensional space. Nonlinear programming techniques are then employed to computer the minimum distance between two convex polyhedra, and according to the minimum distance, it can be concluded whether or not the objects will collide. The algorithm of collision detecting presented in this paper improves the efficiency of collision detecting by simulation experiences.
The performance of explorer in the deep underwater is evaluated traditionally according to accumulating data and statistical analysis by the goal tracked characteristic experiments in the outfield. A non-feedback simu...
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The performance of explorer in the deep underwater is evaluated traditionally according to accumulating data and statistical analysis by the goal tracked characteristic experiments in the outfield. A non-feedback simulation method was proposed for getting the abroad goal noise model by simulating a target power pedigree chart, generating the signal in real time by digital to analog conversion with a large capacity FIFO storage, and injecting electronic signal against an acoustic fuze in the loop simulation by attenuation with power supply. The effect is better. It could be an accessorial important manner in judging the performance of products.
Due to complicated rock structure and environment, a prototype test for a tunnel-type anchorage is infeasible. Based on the rock mass parameters from tests, a three-dimensional （3D） elastoplastic analysis was perfor...
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Due to complicated rock structure and environment, a prototype test for a tunnel-type anchorage is infeasible. Based on the rock mass parameters from tests, a three-dimensional （3D） elastoplastic analysis was performed to simulate the influence of the construction procedure of Siduhe bridge with tunnel-type anchorage （TTA） in Hubei Province, China. The surrounding rock and concrete anchorage body were simulated by 8 nodes 3D brick elements. The geostatic state of the complex geometric structure was established with initial data. The in-situ concrete casting of the anchorage body and excavation of the rock mass were simulated by tetrahedral shell elements. The results show that the surrounding rock is in an elastic state under the designed cable force. The numerical overloading analysis indicates that the capacity of the surrounding anchorage is 7 times that of the designed cable force. The failure pattern shows that two anchorage bodies would be pulled out in the end. The maximum shear stress appears 10 m before the back anchorage face. The maximum range influenced by the TTA under ultimate loads is about 16 m.
An improved genetic algorithm (IGA) is proposed to identify the structural damage under noised vibration data in this paper. It has two functions. One is model updating by direct comparison of changes between initial ...
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ISBN:
(纸本)9788781606000
An improved genetic algorithm (IGA) is proposed to identify the structural damage under noised vibration data in this paper. It has two functions. One is model updating by direct comparison of changes between initial analytical data and undamaged experimental data, the other damage identification by direct comparison of the changes between updated analytical data and damaged experimental data. A conventional cantilever beam model is adopted to evaluate the efficiency and robustness of the proposed technique when a single and multiple damage cases are set up for the beam respectively.
With the coming competition and deregulation from marketplace, electric utilities are beginning to pay much more attention on maintenance because it makes great sense in reducing operative costs and improving competit...
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A three-parameter combined-power model was proposed by curve fitting of the test data recording from the pull-out tests on shaft anchor used in different geotechnical engineering. The representation of the parameters ...
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A three-parameter combined-power model was proposed by curve fitting of the test data recording from the pull-out tests on shaft anchor used in different geotechnical engineering. The representation of the parameters was also discussed. The two-parameter combine-power function model for prestress tendon was derived. The method to determine the bounded length from the degenerate model and the suggested value of its parameter G were also proposed. It was pointed out that the bounding length calculated from the average stress method was not safe enough.
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