Applied Mechanics and Materials Vol. 163

Abstract: Modal synthesis method is a method which can reduce structural degrees of freedom, it is applicable for analysis and calculations of Machining centers and other large-scale structure. In this paper, the dynamical performance of Five-axis boring and milling processing center was studied with component mode synthesis technology . Compared with full model FEM, component mode synthesis technology could meet the accuracy requirements and have higher computational efficiency. Modal characteristics of processing center in different positions was studied, the result showed that each frequency of processing center in different position was different while the vibration mode remained unchanged.

Abstract: When oil fields become old, the proportion of water in crude oil will get higher and higher. Using a traditional bulk separator to extract the water from crude oil has many disadvantages: e.g. high pressure loss, low separation speed, heavy equipment and sensitive to direction. Caltec Ltd. has developed Wx-12, an innovative separator for the oil and gas industry. The device has been tested on offshore platforms and has shown high performance. Currently however, the manufacturing cost of the device is too high making it unlikely to be accepted by market. This project first used QFD to transform the user requirements of Wx-12 into engineering specifications. Then DFA & DFM methods were applied to Wx-12 in order to make it compact and reduce the manufacturing cost. An alternative design for Wx-12 unit was generated according to the results from QFD, DFA and DFM. Alternative materials were also considered to support the alternative designs. Finally alternative designs and alternative materials were verified with the engineers from Caltec Ltd..

Abstract: Taking the crankshaft of the emulsion pump with high pressure and large discharge typed of BRW550/31.5 as the research object, we established the 3D solid model for integral crankshaft under Pro/E environment and made the finite element analyses of the crankshaft with two bearing and three bearing supporting structures. The stress and deformation situations of integral crankshaft under two different supporting structures were obtained and the superiority of the latter was verified. The results provide the theoretical basis for the optimization design of the crankshaft and the development of the emulsion pump with high pressure and large discharge.

Abstract: Model-based definition (MBD) promises reduced time-to-market and improved product quality. Adopting MBD concept in product development process seems to be the next reasonable step. However, some existent critical issues related to data content and presentation need to be overcome. To offer proper solutions from the standpoint of design and manufacturing integration, MBD concept was firstly introduced in order to describe its characteristics and capabilities. Then the answers to the following questions were given: what data are necessary for design and manufacturing integration, how data should be semantically organized and presented based on solid model and CATIA PPR (Product Process & Resource) tree.

Abstract: The research is presented a kind of cooling device for a vehicles brake cooling system, which comprises a thermoelectric cooling (TEC) chip and a heat exchange system. The disc-brake and drum-brake systems are discussed in the research. After inputting electric power, the TEC chip provides one cooling surface which is stick on the brake system and absorbs the heat from the brake pads or shoes. The other surface releases heat which is absorbed by a recycle water-cooling system to discharge the heat by water-cooled radiator to the surrounding. It decreased the working temperature of the brake system about 30% at most after using this cooling device and increased the braking force about 30% at least. There is a temperature control device for the device which can start the TEC chip when the temperature of the brake pads or shoes exceeded 50, which is the lowest temperature that the brake pads or shoes can maintain the most performance of the braking force. The device can efficiently keep the braking force when the driver uses the brake to reduce the vehicles speed for a long time and provide the safety for the driver.

Abstract: This paper describes the machining method of complex surface face gear used CNC machine tools and hob cutter, Based on surface characteristics and gear hob principle. A coordinate transformation process is explained in detail in the five axes CNC machining of complex parts. A CNC hob method is proposed about surface orthogonal gear. An experiment is done for validating the method.

Abstract: Compliant elements play an important role in running and hopping legged robots for improving their speed and energy efficiency. The dynamic model of the compliant legged robot was developed by taking into account the slipping, vibration and distributed compliance of the legs. The parameter variations of the system after impacts were researched for different dropping height and angles by numerical method. Meanwhile, the effectiveness of the model was verified through explicit dynamics analysis software. All these results will provide a theoretical guide for the energy efficiency analysis and mechanical design of the compliant legged robots.

Abstract: A novel method using motion skeleton and behavioral modeling in Pro/Engineer to design a motion mechanism is proposed in this paper. With this method, intuitive kinematical simulation system of a motion mechanism can be set up quickly and mechanism dimensions can be determined automatically. Deployment mechanism, as one kind of motion mechanisms, is often used to stretch out solar panels or antennas in spacecraft. This method is feasible and reliable to determine the dimensions of a six-bar-linkage deployment mechanism for stretching satellite antennas. Simulation results are obtained with kinematic simulation software Pro/Mechanism. The feasible designing solution to the six-bar-linkage deployment mechanism meets high position precision requirements accurately.

Abstract: Take serial robot with six DOF for example. On the basis of analyzing the characteristics of RBF neural network, inverse kinematics calculation of arc welding robot was achieved by RBF of six-input and single output. The forward and inverse kinematics could be seen as a nonlinear mapping between the joint space and the operation space of the robot. Take the algorithm based on RBF. Acquire RBF centers by the nearest neighbor clustering algorithm. The inverse kinematics of robot was solved. Through learning the training samples of the positive solutions to determine weight coefficient of neural network, the robots pose could be accurately solved. The example shows that the algorithm has the characteristics of simple calculation and effective solution, etc. The cumbersome derivation of traditional methods is avoided. It can be seen as kinematics trajectory tracking controller of serial mechanism system.

Abstract: A novel invariant approach is proposed for derivation of curvature relationship between conjugate surfaces of line contact. Unlike other approaches found in the literature, tensor analysis is applied to the derivation process in which rigid-body motion is represented by rotation tensor and the local geometry of surface is expressed by curvature tensor, and the final result is given in a clear and compact form. An example of helical gear is provided to illustrate the application of the proposed approach.