Advanced Materials Research Vol. 819

Abstract: Cable percussive drill is an important drilling machine in the construction of large diameter pile foundation, and complicated dynamic system. However, the design of cable percussive drill is mainly relied on empirical methods or simplified formulas, the dynamic characteristics of coupling system has not been fully understood. Based on the special conditions, the two degrees of freedom dynamic system coupling with buffering mechanism and bit is analyzed, and the vibration differential equation is built. Finally, the modal frequency of system is obtained by numerical method, and the correlation between the modal frequency of system and the structure parameters is built. The result develops the design theory of cable percussive drill and provides valuable preferences for the optimal design.

Abstract: Cutter Engagement Region (CER) is the part of tool that contacts with stock, where a series of energy exchange and material transportation take place. A full understanding of its shape and area is indispensible for cutting force calibration, chatter analysis, and tool wear prevention. It can provide a criterion for efficient tool-path planning as well. In literature, however, there is no available modeling of CER. We hereby propose a modeling method for ball-end tool with design surface represented in triangular mesh. First, design surface is offset to form a stock surface. Next, compute the intersection between every triangular facet and the tool. Then, connect all the intersecting arcs to form the boundary of CER. Finally, compute the area of CER. Experimental validation for the proposed method is still needed.

Abstract: The paper applied Finite Element Method (FEM) to study performance of escalator structure. A case study is given to demonstrate the method of the FEM. To validate the results of FEM, some experiments were conducted. The results show that all the test samples meet the requirements of the truss, and the experimental results verify the numerical calculation results.

Abstract: With the highest product performance, quality and reliability requirements, oil casing is the most demanding service conditions in the oil and gas fields. However, when solving with thin-walled seamless steel pipes by the existing straightening theory, the cross section distortion phenomenon shall not be considered, and when the proportion of diameter to wall thickness increases, an ideal straightening effect can't be obtained. With the elastic-plastic bending straightening theory, this paper analyzes straightening process of thin-walled seamless steel pipes, studies the relationship of the flattening rate, deflection and straightening force in thin-walled pipes straightening, deduces the best reduction calculation method in the practical six roller skew rolling straightening machine, and in the meantime, results of several steel pipes flattening rate are compared.

Abstract: In this paper, elastic hydrodynamic lubrication theory was introduced into bearing dynamic stiffness calculation process to take into account the impact of the oil film on the rolling stiffness. Dynamic characteristics of NC boring machine spindle system dedicated to the manufacturing of bearing retainer were studied based on finite element analysis software. The rationality of the structural design of spindle was verified in the paper. The research provided a theoretical basis for the improvement of machine performance and dynamic design of NC boring machine spindle.

Abstract: Great efforts have been made to improve the accuracy of NC machine tools, within which thermal error compensation is one of the most efficient ways. A new thermal error compensation instrument which is based on thermal modal analysis for NC machine tools is introduced in this paper. OMRONsCJ2M-CPU11 is used as microcontroller, and SAILING TECHNOLOGYs STA-A08 temperature measuring modules as temperature transmitter. Through hardware and software design, high precision and stability can be achieved. By measuring several key points temperature and making use of a thermal error compensation theory, real-time thermal error compensation can be output to the machine tool, thus thermal error can be reduced.

Abstract: Heavy general transport vehicles are recommended as lashing points during rescue operations of winch. Taking SX2190 heavy transport vehicles frame as the experimental object, this paper introduces contents and methods of the test, and gets evaluation result of the rear frame through finite element simulation and experimental validation of the real frame-towing hook system for winch lashing car.

Abstract: the aero-blades are often easy to be damaged because of the severe working conditions, and the invading of out objects. Repairing is preferred to replacing with a new one due to the very high expense. The mathematical model of cross section curve is very important to the process of repairing the blade and to the analysis for the working performance of repaired blade. The method of remodeling the curve of cross section is studied including scanning the broken blade, denoising the data points, analyzing the points of cross section and dividing them into four assembles, and fitting them with adaptive mathematical equations. Lastly, the future research plans are given.

Abstract: For thousands of years, people have been in nature to make use of our natural materials, among them some are harder than iron and steel, some are superior than the best optical device, what let human more amazing is that the natures reasonable application of these materials. Through the study and research of nature, humans create the biomimetic material to meet the demand of industrial design; they were widely used in the field of industrial design according to the different characteristics. Application of these new materials opened up a brand-new road for the development of industrial design.

Abstract: The curved surface simple expression which met a given tolerance and fairing can be obtained under the conduction that the surface tolerance and fairing had been predetermined by the fitting optimization of the scattered points of the origin curved surface. The genetic factor and evaluation function are designed for the optimized expression of surface is acquired. The validity of the solution is verified by comparing the computed error between fitting optimization surface and the original surface through the numerical simulation.