Advanced Materials Research Vols. 163-167

Abstract: In order to obtain structural optimization design of rear banjo axle housing, a seven degree of freedom dynamic model of vehicle was presented. Based on the model, vehicle vibrating equations were presented. Random phase method was used to generate C grade road surface irregularity of time history that applied to vibrating equations to acquire dynamic load imposed on the banjo axle housing. A detailed CAD model of the housing was developed by using of UG software. The finite element model of the housing was built, and the stress and strain of the housing were obtained by using of ANSYS Workbench software. The mathematical model of optimal design was constructed and analyzed based on the result of finite element method. The optimization result shows that the weight of banjo axle housing can be reduced under satisficing the stress and strain condition that excited by dynamic load.

Abstract: Based on integral property of unit glazing curtain wall (UGCW), considering the co-effect of glass and grids, set up the calculating method of cooperation of glass and grids; through the numerical simulation analysis with this method, we can conclude that take the glass’s rigidity into consideration is both reasonable and economical.

Abstract: The aim of this work is to analyse the mechanical response of the masonry specimens under long-term action by means of cyclic tests. To this end laboratory tests were carried out at the Non-Destructive Testing Laboratory of the Politecnico di Torino. The Acoustic Emission technique was employed to assess the damage evolution, and the mechanical properties decay in order to evaluate the extent and the evolution of micro and macro-cracking due to cyclic action until structural collapse in masonry blocks and mortar layers by means of a novel Acoustic Emission analysis technique.

Abstract: Due to the relevance of item damages on a building, a power transmission mechanism that can reflect the damage relevance is introduced into the dangerous houses hierarchical fuzzy evaluation model (JGJ125-99). The proposed item description model uses a force-delivery tree to describe the relevant relationship among items. A new risk rating formula and a method to calculate the model parameters are addressed. The practical result by applying the approach to Ezhou city primary school in Hubei province shows that the item description model can reduce error judgments in appraising dangerous buildings.

Abstract: A practical method, based on the Akaike Information Criterion (AIC), is used to detect automatically the first P-wave arrival times during Acoustic Emissions (AE) monitoring. This method is used to increase the accuracy of detection procedure and to reject the data errors automatically. Two parameters, the quantification of the degree of certainty and the apparent velocity between observation sensors, were proposed to check the validity of AE events and to neglect errors. Both the original AIC-picker and improved AIC-picker algorithms are applied to AE signal processing. It can be shown that the improved AIC-picker is a reliable tool for automatic onset detection of AE signals.

Abstract: To make the active and semi-active vibration control system in civil engineering get rid of external power supply, a new piezoelectric friction damper with self-power and sensing is designed in this paper and a semi-active control system based on this damper is presented. This system includes three key parts: a piezoelectric friction damper, a power generator based on the piezoelectric stack electro-mechanical energy conversion and a control circuit. It makes full use of the direct and converse piezoelectric effect. At the same time, it also overcomes the deficiency that the frictional force as damping can not be accurately desired in semi-active vibration control system. On the basis of it, the control equation of PFD is formulated. Numerical simulations for seismic protection of story isolation equipped with this system excited by a historical earthquake are conducted by MATLAB. Skyhook control is used to command a piezoelectric friction damper in the semi-active control. It is noticed that only one accelerometer is needed to monitor the response to realize the skyhook control, which greatly simplifies the classical semi-active vibration control system.

Abstract: In this paper, a new rough-probabilistic neural network (RSPNN) model, whereby rough set data and a probabilistic neural network (PNN) are integrated, is proposed. This model is used for structural damage detection, particularly for cases where the measurement data has many uncertainties. To verify the proposed method, an example is presented to identify both single and multi-damage case patterns. The effects of measurement noise and attribute reduction on the damage detection results are also discussed. The results show that the proposed model not only has good damage detection capability and noise tolerance, but also reduces data storage memory requirements.

Abstract: A 3×3 coupler based Mach-Zehnder Interferometer is used for delamination patch detection in FRP composite. Mechanical tests are performed and the sensing arm of the interferometer is embedded along the neutral plane of the laminate. A quasi-impulse loading is applied and the total elongation of the embedded optical fiber is measured as a function of load position. When a delamination is present, the shift of neutral axis position can be clearly reflected in the fiber integral strain versus load position plot. Experimental results demonstrate the feasibility of detecting both the size and location of delamination patch with the proposed technique.

Abstract: The gear structure is equivalent to disposed as a circinal plate, and also, the root crack of gear are simulated by setting the radial direction crack. Because of the appearing of crack, it will divide the whole circinal plate into some areas, and set different polynomials of vibrational flexibility in every area, then using District Technology and Rayleigh-Ritz method, the dynamical characteristic of circinal plate with radial direction crack is analyzed, the influence of the size of crack on dynamical characteristic(natural frequency, modal shape etc.)of circinal plate are deep studied. On this basis, making use of Finite element method, the first some order mode of the acoustic character of cracked plate are investigated using discrete Rayleigh integral, and the distribution of sound pressure on the r=0.5m sphere surface is obtained. At the same time, the influence of the different depth of crack on acoustic characteristic of gear disc are discussed, and the rule of influence of crack on radiated acoustic field is given out. This result shows that the influence of crack on radiated acoustic field of circinal plate with the increase crack depth is increscent; moreover, with the increase in crack distance from the fixed end, the crack of plate increases the effect of the sound field. So, these provide a theoretic foundation for gear fault diagnosis using the dynamic and acoustic method in engineering.

Abstract: Based on the grey system theory, and combined with the construction features of cable-stayed bridges and construction control method, the paper takes the cable-stayed bridge under construction as the interferential grey technology system with physical prototype and analyzes the random process as grey process in line with grey system theory. The grey model is established by the initialize heights of main girder and cables’ tension as two control inputs of system during the construction of the cable-stayed bridge. Through the feedback information and rectifying the grey model, the initialize heights of main girder and the cable force of next construction stage are predicted in order to control the bridge configuration and cable tension successfully.