Applied Mechanics and Materials Vols. 300-301

Abstract: Improper tool orientation planning often causes four typical types of inappropriate four-axis tool paths. They are included: 1. Severe changes of tool orientations occur, 2. Reversions of tool orientations exist, 3. Discontinuous tool paths occur, 4. Gouging. After explore the common methods of the present four-axis machining and their restrictions, the research proposes a hybrid tool orientation planning (HTOP) method to improve the above shortcomings and to get smoother rotary tool paths. An example is done in the last to verify its feasibility.

Abstract: A rubber isolator which is used to connect two plates is designed. Based on the Mooney-Rivlin model, the static characteristics of the rubber are studied experimetally to obtain the model's parameters.According to operational requirements,the basic parameters and the basic dimensions are designed ,and then an optimization algorithm is adopted for the detailing of the rubber isolator, in which the dimensions of the isolator,the preload,the distance between the two plates and the maximum stress are considered as the design variables, and the stiffness is considered as the objective function.In the condition of satisfying the vibration-isolation effect, the numerical calculation is made by the nonlinear finite element method, and the rubber isolator is designed successfully.

Abstract: The progressing cavity pump (PCP) always works in the waxy oil well. Therefore the research on the influence of various liquid paraffin contents in crude oil on the friction and wear behaviors of the progressing cavity pump`s stator is very important for choosing the best stator rubber and developing the service life of PCP. Wear behavior of nitrile butadiene rubber (NBR) and fluororubber (FKM) was investigated at room temperature using a reciprocating friction and wear testing machine under the various paraffin contents in crude oil (0%、10%、30%、50%、100%). The wear morphology of blend was analyzed through the stereomicroscope and the wear behavior of two blends was also discussed and compared. The results show that the wear resistance of FKM is better than that of NBR under the same paraffin content in crude oil; With the increase of the paraffin content, the wear and coefficient of friction also increase. When the paraffin content in crude oil is less than 30%, the wear loss of NBR and FKM are basically the same; When the paraffin content in crude oil is more than 30%, the wear loss of NBR is far more than that of FKM.

Abstract: First analyzes the perceptual beauty of molecule motion rhythm sensation,infinite reach sensation and stability sensation in accordance with Brownian Motion,diffusion and Maxwell speed distribution law.Through the calculation of area about Maxwell speed distribution curve corresponds to the rate range, can find the Maxwell speed distribution law in the quasi-golden section, rational aesthetic and philosophy meaning in gas molecule motion are oneness beauty and symmetry beauty,but simple is the nature of the beauty of molecule motion.

Abstract: The wind speed forecast is the basis of the wind power forecast. The wind speed has the characteristics of random non-smooth so obviously that its precise forecast is extremely difficult. Therefore, a forecasting method based on the theory of chaotic phase-space reconstruction and SVM was put forward in this paper and a forecasting model of Chaotic Support Vector Machine was built. In order to improve the precision and generalization ability, the key parameters in the phase space reconstruction and the key parameters of SVM were carried out joint optimization by using particle swarm algorithm in the paper. Then the optimal parameters were brought into the forecasting model to forecast short-term wind speed. The above method was applied to wind speed forecast of a wind farm in Inner Mongolia, China. In the experiments of computer simulation, the absolute percentage error of forecasting results was only 12.51%, which showed this method was effective for short-term wind speed forecast.

Abstract: Data sets of high–dimensional spaces are problematic when it comes to classification, compression, and visualization. The main issue is to find a reduced dimensionality representation that corresponds to the intrinsic dimensionality of the original data. In this paper we try to investigate a practical Bayesian method for feature extracting problem, in particular we will apply Gaussian Process Latent Variable Model (GPLVM) to a real world data set. Feature extraction experiments were performed on a cancer treatments’ components data set using GPLVM, then we used PCA on the same data set for comparison of the results.

Abstract: Reach envelope is one of the design tools to ensure industrial workspace accommodates users. As for fighter pilots, their reach capability must be considered during the design of cockpit. Normally fighter seat back rest angle is between 13°and 30°, and due to the fact that postural change affects the reach capability of the pilot, the reach envelope can be different under different seat backrest angle, which is normally ill considered and thus limits the cockpit design. This research employed a reach envelope transformation model based on the anthropometric measurement approach to transform experiment based reach envelope at 0° of back rest angle to that at other seat back rest angles. 12 male subjects’ Reach data under 4 different seat angles and other anthropometric data were collected using motion capture system with a sample rate of 120Hz. A simplified model of human body was introduced and modified using the captured data from 4 subjects, with which other subject’s reach points at 0° seat backrest angle were transformed to reach points at other seat backrest angles. Comparison between the transformed envelope and measured reach envelope indicated that the average of difference, SD of difference was -5.5 and 42.76(mm) respectively.

Abstract: Reliability of load-carrying structures has been assessed by various calculation procedures based on probability theory and mathematic statistics, which have been becoming more and more popular. The calculation procedures are well-suited for the design of elements in load-carrying structures with the required level of reliability if at least some input parameters are random and contribute to a qualitatively higher level of the reliability assessment and, in turn, higher safety of those who use the buildings and facilities. This paper discusses application of the original and new probabilistic methods – the Direct Optimized Probabilistic Calculation (“DOProC”), which uses a purely numerical approach without any simulation techniques. This provides more accurate solutions to probabilistic tasks, and, in some cases, to considerably faster completion of computations.

Abstract: Landing gear is the critical component for aircrafts’ flight safety. According to the statistics, the accidents caused by the structure of landing gears and other structures relating to landing gears probably account for more than two thirds of the structural accidents. Fatigue failure is a key failure mode when the landing gears under the condition of alternating loads. Therefore it is very meaningful to develop the research on the fatigue life of the landing gears. The traditional fatigue analysis based on the test methods has many disadvantages, such as high cost and long test cycle. So a numerical simulation method was used to analyze the structural fatigue. Then the stress distribution and the fatigue life of the landing gear connecting parts under specific working conditions were studied. It turned out that the local fatigue performance of the component needed to be improved. The results have a certain value in engineering application and theoretical research, especially in improving the design level and working reliability of the aircraft landing gear.

Abstract: This article introduces the function, the method of selection and related criterion of standard internal crusher gauge, and systematically analyzes three factors that affect the measuring uncertainty of standard internal crusher gauge, including: inconsistency of pressure’s true value from pressure source, the uncertainty imported by standard copper-cylinder and the random fluctuations of the individual character of pressure measuring gauge. According to usage characteristics and selection methods of the standard internal crusher gauge, discusses computing methods of components of the measuring uncertainty and establishes evaluation model for measuring uncertainty of standard internal crusher gauge. The model can quantitatively calculate through experimental data of selection, which lay a theoretical foundation for the control of the pressure measuring uncertainty of standard internal crusher gauge.