Authors: Wei Wei Zhang, Zhi Hua Wang, Hong Wei Ma

Abstract: The objective of this study is to show the potential of the crack detection method based on Wavelet Packet Transform (WPT), which is depending on the response at a single point on a beam subject to moving load. In this paper, an ANSYS model of a cracked beam is established. The moving load is transient analyzed by shifting the point of the concentrated force. The response at mid-span of the beam is calculated and wavelet packet transformed. The crack on the beam can be found by the abnormal signal in WPT branches. The size is also estimated by a defined damage index (Dindex) which relates to the energy of the abnormal signal. Finally, the effects of both crack location and wavelet selection on Dindex are discussed in detail.

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Abstract: This paper mainly studies the deflection under short-term loading of recycled course aggregate reinforced concrete beam is calculated by using of the formula of short-dated rigidity in code for design of concrete structures. According to testing the flexural performance of 6 recycled course aggregate beams with the same section size, different replacement ratio of recycled coarse aggregate of 0%, 50%, 70%, 100% respectively and different percentage reinforcement of 0.68%, 0.89%, 1.13% respectively, analyzes relation between deflection and replacement ratio of recycled coarse aggregate, deflection and percentage reinforcement, compare measured value and calculated value using of current codes and make statistical analysis this data . By regressing and analyzing the experimental data from literature, supplied short-dated rigidity modified formula of recycled course aggregate beam. The calculation results are in good agreement with the experimental data. The formula of short-dated rigidity can accurately calculate deflection under short-term loading of recycled course aggregate reinforced concrete beam, and can be referenced in engineering practice and correlative regulations.

1443

Authors: Jing Yan, Ya Wu Zeng, Rui Gao

Abstract: For the research of beam’s deformation, material mechanics uses equation of small deflection curve which neglects 1^{st}^{ }order derivative of deflection and regards bending moment M is merely a function of abscissa x, and then gets the approximate solution of vertical displacement. However in some case, small deflection curve isn’t efficacious, so two methods come up in this paper to solve the accurate differential equation of beam’s deformation. This paper takes a slightness beam from temperature controlling device as an example and shows detailed process of mathematical modeling and solving. For iteration, firstly governing equations are founded, then an initial value is put into it to work out a new value, next see the new value as a new initial value and calculate again, by doing the operation repeatedly steady-state solution will be got in the end. For functional analysis, deflection equation is assumed as a kind of function containing some undetermined coefficients, then make it satisfy all the boundary conditions, and establish residual fonctionelle, by partial derivative operation to make the fonctionelle minimum, undetermined coefficients are estimated and deflection curve is got. At the end, impacts of gravity and axial deformation are discussed.

6144

Authors: Yu Liu, Shen Liu, Wen Ji Xiong, Hong Ming Zeng

Abstract: Establishing the system model of free beam vibration gyro under the influence of the Support structure, deriving and analyzing its vibration performance, comparison between model simulation through ANSYS software and relative theoretical calculation indicates that the relative error is less than 0.25%. Researches on the relations among system sensitivity, bandwidth, shock resistance and anti-interference ability of its model and sizes of Support structure contribute to principles of system optimization design and a set of design parameters: free beam (50mm×4.1mm×4.12mm), cylindrical Support structure(radius0.25mm×2.46mm), the performance of model is as: system driving frequency (8589.8HZ), bandwidth (39.4HZ), shock resistance (411.02g) and anti-interference frequency (above2381.3HZ).

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