Applied Mechanics and Materials Vols. 55-57

Abstract: Practical mechanical systems often contain several flexible components and uncertain parameters which makes it hard to predict the system behavior and performance exactly. This research presents the uncertainty analysis of flexible multibody systems with random variables. Absolute nodal coordinate formulation (ANCF), which is different from the traditional finite element method, is employed to model the flexibility here. Monte Carlo method is successfully used to simulate flexible multibody systems of index-3. The method proposed is demonstrated by an example of flexible slider-crank mechanism.

Abstract: In network manufacturing, different manufacturing resources have different functions and attributes, the evaluation method for manufacturing resources becomes ever more important and urgent to select ‘the best resource’ in product development process. This paper gives evaluation indicator for manufacturing resources; combining grey correlative analysis with hierarchical analysis method, brought forward to apply multi-hierarchy grey correlative analysis into manufacturing resources, researched deeply its principle, algorithm and evaluation execution process, and finally gave analysis sample.

Abstract: Air pollution may cause pernicious effects on human health, and is a widespread problem in the world. Air quality management systems have became an important research issue with strong implications for inhabitants’ health. Monitoring and forecasting of air quality indicators plays an important role in the management systems. Artificial intelligent techniques are successfully used in modelling of highly complex and nonlinear phenomena. In this paper, a model, which is radial basis function (RBF) neural network, is established to estimate the impact of meteorological indicators on SO₂. The proposed model achieves 9.91% in mean absolute percentage error (MAPE) compared to real observation data sequence. For air quality, it could be a promising candidate for forecasting the air quality indicators data sequence.

Abstract: The automobile braking will generate a lot of friction heat; the friction heat can reduce the brake performance and affect the safety of the automobile. This article analyzed the mechanism that heat generated by brake friction, established the mathematical model of automotive brake friction heat, and analyzed the influencing factor of braking friction heat through model parameters. Meanwhile, the finite element model of automobile brake disc is built; the brake friction heat is analyzed by the finite element thermal thermodynamics, the formation process of the friction heat, the change situation of friction heat and the deformation of brake disc are obtained. The effect of friction heat on the brake performance is analyzed; the research will provide theoretical guidance for the design of automotive brake discs.

Abstract: The porous Ultra-high Molecular Weight Polyethylene (UHMWPE) is designed to fabricate the roadside safety devices fixed on the conventional metal or concrete road highway guardrails. When the UHMWPE with pores is shocked, the material is compressed because the pores are closed and much energy is absorbed. Next, elastic deformation and plastic deformation happen further under the stress, kinetic energy is transformed into deformation energy further. The cushioning capacity of UHMWPE will be improved when the pores are induced. Then the vehicles will not be destroyed seriously when they bounce. On the other hand, it will be convenient to fix the roadside safety devices on the conventional metal or concrete road highway guardrails and the cost must be lower than changing the whole guardrails. Experimental results indicate that: UHMWPE exhibited excellent shock-absorbing capacity and it was a promising roadside safety material.

Abstract: Traction coefficients of several domestic lubricants in various operating conditions were measured on a self-made test rig. The equations for calculating the average values of limiting shear stress and shear elastic modulus of the lubricants applied in the high-speed and high-pressure bearings were advanced. The example calculations for one lubricating oil and two lubricating grease were then made. The results show that the regression precisions of the equations above are satisfied. The equations also adapt to the other lubricants in the same operating conditions.

Abstract: With the decreasing of the circumstance temperature, diesel truck should change lower freezing point diesel fuel in order to avoid paraffin deposit which makes the car fail to run normally in winter. Paraffin deposit often happens in diesel fuel filter cleaner. To avoid the paraffin deposit, in this paper, it designs a system that adapts heating method to heat diesel. It analyses its composition, working principle, technical character and experiment application. Through making experiments it proves that this equipment can improve burning purity and decreases atmosphere pollution which reduces consumption and saves fuels.

Abstract: Clustering web search results is a kind of solution which help user to find the interested topic by grouping the search results. This paper presents an improved method for clustering search results focused on Chinese web pages. The main contributions of this paper are the following: First, in this paper, a method which identifies the complete semantic information phrase by comparing the attributes of base clusters in the suffix tree document model and the overlap of their document sets is presented. Second, by analyzing the content and structure of title and snippet of Chinese web search results, one way of sentence segmentation is designed and implemented to constructing suffix tree. Third, In order to better respond to the associate degree of terms, a novel method is proposed which compute the distance in sentence-grain of terms' co-occurrences. Finally, the experiment illustrates that the new clustering method provides an efficient and effective way for user browsing and locating sought information.

Abstract: Aiming at students’ learning process, and based on the analysis of tutorship rules of students’ learning after class, a Knowledge-Based Intelligent Tutoring System is given. The system comprehensively uses agent technology, the knowledge-based automatic reasoning, resource modeling for knowledge classification, field natural language understanding, data mining, computer networks, databases and other technologies. It creates a student-oriented self-motivated learning environment in which students can learn abundant knowledge of one or many subjects, send the problems encountered in their own learning to the system server by network, and get real-time multiple tutorship information as an excellent teacher do.

Abstract: According to China's traditional teachers’ quantitative evaluation ideas and experiences about their education teaching effectiveness, learning from advanced measurement concepts and models home and abroad, to design an open, scientific quantitative evaluation system for the teachers’ teaching effectiveness. The measurement indicators, the evaluation main body of the System and its weight in the process of measurement can be for different objects to customize settings.