Applied Mechanics and Materials Vol. 159

Abstract: STEP-NC is used to transfer machining data between STEP-NC compliant Computer Aided Design (CAD), Computer Aided Manufacturing (CAM) and Computer Numerical Controller (CNC). It overcomes G&M code weakness which has thousand lines of codes but none of them define the machining process. In order to create a complete chain of STEP-NC system to be a new way of producing product in manufacturing environment, a new CNC machine and CAM software that are compliant to STEP-NC has to be developed. Internationally the research and development of STEP-NC has gain many achievement until now, but there is still no commercial STEP-NC system that are fully working in producing variety of features. This research focusing on the software development, named as GEN-M. The software that has been successfully developed are capable to generate code for drilling referring to selected case study from Annex F (Example 1) in ISO 14649 Part 11.

Abstract: This paper presents an approach to evaluate the structural fatigue life of port cranes. Based on a testing of 40t/45m container crane in a port of China, the stress time-history collection, data processing, the determination of S-N curve and the distribution of the load amplitude is analyzed in detail. Finally, the modified linear cumulative damage law is employed to evaluate the remaining safety service life of the container crane. The result of this study can be a reference for the anti-fatigue structural design of cranes, and it also provides a guideline for ports’ management and maintenance departments to make maintenance plans for port cranes.

Abstract: The paper discusses the structural stability of 4-dof manipulator, which is suitable for welding spot of three-dimensional space concentrated distribution and approximate single-axis distribution in car body. By using the UG/CAE module, static analysis is applied to the main structure of the manipulator, and the results show that the whole structure meets the design requirement of stiffness and strength.

Abstract: 4Cr9Si2 Martensitic heat-resistant steel is inlet valve and the exhaust tappet materials. This paper is based on the constitutive relationship of 4Cr9Si2 Martensitic heat-resistant steel obtained by isothermal compression; a finite element model of Cross Wedge Rolling was build up for 4Cr9Si2 Martensitic heat-resistant steel. In the model the heat conduction between billet and the die, the convection of heat transfer, and the thermal conversion of plastic work and friction work were taken in account, the value of damage was obtained in the rolling and central porosity was analysis. Then verify the correctness of the FEM and feasibility of simulation results by the experiment

Abstract: In this paper, a sort of modeling and meshing method based on the characteristic size of antennas is put forward, which can be used to numerically compute the wind loads. Based on the Reynolds-averaged N-S equations and Renormalization Group k-ε turbulence model (RNG k-ε), the wind loads on antenna are computed in considering of some modeling parameters, such as the sizes of computational domain, grid size. Through the comparison between the results obtained by numerical computation and the ideal value derived by wind tunnel tests, the method of modeling and meshing the computational domain has proved to be effective, and the fitted curves of the drag coefficients show that the computational results for wind loads on antennas will be more accurate if the large sizes of the computational domain and little sizes of the grid are adopted.

Abstract: In this paper, a KIC gradient composite plate was designed and prepared by changing material prescriptions to make the KIC gradient change along the thickness direction. The expression of fracture toughness at any point within the gradient composites was derived, and the crack propagation behavior was examined by drop-weight impact test. The test results show that under impacting, the macro-crack propagates rapidly in the layer with lower KIC value because of the structure of this gradient composite material, but the high crack propagation resistance in the thickness direction of the plate observed.

Abstract: It is of significance to research high-removal efficiency and low-cost CMP process for the 65 nm and below node. Chemical mechanical polishing (CMP) can realize the planarization of the wafer with free defects, free contamination and below nanometer level roughness. Test project of CMP slurry is main contain of these detections such as pH value, chelating agent content, SiO2 gel particle size, ζ-potential detection and the observation by Transmission electron microscopy (TEM). End point detection method of pattern wafer CMP usually includes the non destructive optical measurement, motor current feedback measurement and polishing pad temperature test. The main problems of the measurement for pattern wafer CMP are critical dimension (CD), section, film thickness, defects and particles measurement. Some of the new type of testing technology, such as atomic force profiler (AFP), can be used to compare CMP effect, such as dishing, erosion, tungsten plugs, the height of steps and flatness of the wafer, which is significant for wafer CMP research.

Abstract: Based on the principle of conservation of energy，technological process that using butt weld to control the transformational relation between welding deformation and residual stress is carried out. The arrangement measures of critical closure section welds are discussed. In addition, some problems in welding about High-strength steel and Heterogeneous steel are pointed out. And the causes and solution of lamellar tearing problem are put forward through the example of Baosteel NO.2 shaft furnace.

Abstract: This document explained and demonstrated the crack growth of unidirectional glass fiber-reinforced composites (UD-GFRP) using the fracture mechanics theory during the process of machining. The models of fracture mechanics were established at antidromic cutting and direct cutting. The result is obtained that mode-I crack and mode-II crack transform each other during cutting and the complex crack is come into being. The propagation of complex crack makes the material fracture. The quality of machined surface at direct cutting is better than the quality at antidromic cutting.

Abstract: When common epoxy coatings were applied directly on high temperature (usually about 70°C) steel surface, some defects would occur in coating film, such as bubbles, pinholes, loosen and poor quality flow leveling property, etc. These defects lead to reduction in coating’s adhesion, physical properties and anti-penetrability, shorten service life of coatings greatly, making coating losing their protection function. Main reasons for those defects were analyzed briefly in this paper. In high temperature environment, solvents or other volatile organic compounds (VOC) in coatings will volatilize faster than in normal temperature environment, coating may undergo poor quality flow leveling properties, which couldn’t be fixed by itself. Research and development of a new type epoxy coating were introduced in this paper. Several methods were proposed, including selecting suitable resins, adding high boiling point solvent into coating, using leveling agent and other additives. After these modifications, coating’s construction adaptability was improved and could be applied directly on high temperature steel surface. The scanning electron microscopy (SEM) results show that the coating film prepared in high temperature condition have equivalent fine structure with film prepared in normal condition. The physical properties, anti-penetrability and anti-corrosion were also discussed in this paper