Applied Mechanics and Materials Vol. 482

Abstract: The applications of air cushions are briefly reviewed in airships and tethered aerostats. The stress distributions of air cushions are simulated by finite element analysis software according to its load-carrying characteristics. Three kinds of interlayer forms are proposed and simulated thereafter. A best form of interlayer has been obtained via comparing the different analyzing results. In addition, an empirical formula is proposed for the differential pressures and load at the top of the air cushions, with experiments in which two kinds of air cushions are designed and their load carrying abilities are evaluated. Some advices are then provided for the designing and using of air cushions at the end of this paper.

Abstract: A fast numerical method based on aeroelastic eigenvalue analysis is applied to study the effects of mistuning on the aeroelastic stability of turbomachinery blades in which the structural coupling is included by a simplified method and an influence coefficient method is employed to deal with the unsteady aerodynamic effects. Results show that there exists an optimal mistuning amount at which the system has the best aeroelastic stability. Structural coupling almost has no effects on aeroelastic stability of a tuned system. But the benefit of alternate frequency mistuning to aeroelastic stability is inhibited drastically when structural coupling is introduced into the bladed disk system.

Abstract: In the evolutionary structural optimization (ESO) using the rejection ratio, the criterion of the inefficient material removal cant generally be lowered during the optimization process because the rejection ratio cant be decreased. Owing to this, some sorts of structures in special load cases cannot be optimized smoothly; or the late optimization of an ordinary structure is terminated suddenly when the removal of material abruptly increases excessively. The paper puts forward the Evolutionary Structural Optimization using Material Efficiency Grades (ESO-MEG) in order to eliminate the unfavorable effects of the rejection ratio on the results of ESO. The ESO-MEG can determine inefficient material in a structural optimization according to the efficiency grades of each part of material, so it can adjust timely and flexibly the criterion of inefficient material removal. The research shows that the ESO-MEG is applicable to the optimization of different sorts of structures in varying sorts of load cases, so generalization of this method has a broad prospect.

Abstract: Wavelet theory has a key role in signal processing and image processing. In this paper, the characterization of the M-band symmetric orthogonal scaling function is obtained in higher dimensions. Then, a symmetric cardinal orthogonal scaling function is classified. The existing some results in one dimension are generalized to the case of higher dimensions.

Abstract: Removed at authors request

Abstract: A complex structure can be constructed by Boolean operations of geometric primitives such as cube, sphere, cylinder, and so on. However, Boolean operations cannot represent the structure in form of mathematical function. In this paper, we propose a new shape representation method that combines the Boolean operations with the KS function. Applications show that 2D and 3D engineering parts can be described by a single implicit KS function.

Abstract: In today's network environment, the semantic gap between machine language and human language is the most important challenge of information management. Processing of text plays an important role in information management and knowledge management. In this paper, a proposed method shows how a text is related to its background knowledge. By background knowledge, People mean the parts of domain ontology which are not expressed in the text, but are shared by the creator and potential readers. Given the text-ontology mapping, people may discover the semantic domain of a text and how the text covers the domain knowledge. The semantic relatedness between the concepts mentioned in a text, as a whole unit,and the other concepts of the domain should be measured. This measure is based on the semantic relations defined by the ontology among its concepts. The experimental results prove that proposed method presents better overall performance and is natural way to improve retrieval results of users needed.

Abstract: The non-contact ocean wave observation based on shore station could be impacted on high accuracy of surf crest 2D coordinate in wave images. Focus on previous disadvantages such as lower speed and accuracy, a novel surf crest tracking algorithm is represented with crest collapse function which could terminate the tracking process through end point adjustment. The algorithm could not only process the concerned part of the wave image automatically with higher speed, but also record 2D coordinate of every point on the concerned surf crest and the connection between every two contiguous points accurately, which are very practicable in the non-contact ocean wave observation.

Abstract: The global upsurge in research and construction of smart grid is creating new opportunities and challenges. This paper proposes a procedure and method for assessing the operation performance of the smart grid. The hierarchical analysis of factors reflects the operation situation in the overall goals. An incentive regulation model based on the optimal fuzzy algorithm and data envelopment analysis is presented.

Abstract: The CA-based Model of unidirectional pedestrian flow simulation is established. Model takes into account pedestrian forward, change lanes , side forward, backward , away from the dense crowd behavior. Simulation research and analyzed the relationship between pedestrian flow speed ,flow speed, flow , without moving the proportion of pedestrians and the pedestrian density in different pedestrian density. The results showed that: unidirectional pedestrian flow with the pedestrian density increases, there will be two thresholds K₁ and K₂. Pedestrian flow velocity will appear slight and obvious decrease after these two thresholds. Pedestrian flow traffic reaches its maximum value at K_2. The proportion of unmoving pedestrians will increase and the increased amplitude increases when it reaches at the two thresholds K₁ and K₂.