Applied Mechanics and Materials Vols. 278-280

Abstract: Bimetal composited tube is constituted by two different metals. Comparing with single metal tube, composited tube can make the best of optimum performance of based tube and clad tube. In present research, straight bimetal tubes were taken as the objectives and have been studied deeply. A new hydroform process is introduced in this paper, which can be used to form bimetal composited special tubes. Loading path, loading method, deformation of material, influence of frictional force etc. are studied using numerical simulation fully and the key technique and specialty of this technology were gained. Through simple equipment bimetal composited T-tube has been prepared.

Abstract: The Reissner’s plate bending theory with consideration of transverse shear deformation effects is adopted to study the fundamental fracture problem in functionally graded materials (FGMs) plates for a crack perpendicular to material gradient. The crack-tip higher order asymptotic fields of FGMs plates are obtained by the asymptotic expansion method. This study has fundamental significance as Williams’ solution.

Abstract: The numerical simulation of multi-directional precise contour forging of 6700 steering knuckle was studied in this paper. A 3D thermodynamic coupling finite element method (FEM) was established for each process of the deformation, based on the rigid-viscoplastic finite element method FEM. The results showed that the shape and size of the blanking billet can be optimized and the materials utilization ratio and the dimensional accuracy can be increased dramatically by using multi-directional precise contour forging

Abstract: Cyclic changes of temperature in space may cause thermal deformation and thermal stresses at the silver welding spots on solar cells, which result in the solar array work abnormally. According to the temperature conditions in the thermal vacuum, the thermal stress and deformation at silver welding spot that between solar cell and inter-link chip were analyzed. The result shows that thermal cycling can make the sliver welding spot separated or contacted, which cause the solar array work wrong. The phenomenon of thermal vacuum reliability test was corresponding with these results. This paper could offer some references for the design and manufacture of solar array in the future.

Abstract: Improvement of materials properties induced by constrained groove pressing (CGP) depends largely on deformation homogeneity. Utilizing commercial software DEFORM-3D, a finite element model of multi-pass CGP was established. The distribution and homogeneity evolution of equivalent strain ware analyzed in detail. Based on Taguchi optimization method, the influence of processing parameters (such as groove width, groove angle, friction coefficient and deformation rate) on strain homogeneity was studied numerically and systematically. Within a certain range, the optimum parameter combination is obtained by means of signal to noise ratio analysis. The inhomogeneity factor of the optimum model decreases by about 50 %. The average accumulative equivalent strain is almost twice that of the initial model. Analysis of variance shows that groove angle and groove width are the two most important parameters and effect of friction between dies and sample should not be neglected.

Abstract: To understand relationship between the meso-structure of non-homogeneous materials and the fracture properties, two groups of concrete specimens are designed and tested. For the two groups with the same water-cement ratio and coarse aggregate volume ratio, small and large grain size gravels are used respectively. Since both groups of materials are with the same mass ratio of coarse aggregates, the heterogeneity of the gravels distribution in concrete with larger grain size is higher than the other. The results show that the group with smaller aggregate grain size gains higher material fracture strength and fracture energy than another group. Then the concrete with more homogeneous meso-structure will reach higher fracture properties

Abstract: The friction contact modals on the friction contact are summarized here. Based on Finite Element Method, the contact pressure on rough surface is calculated. The influence of the worn surface on the distribution of contact pressure is also investigated. According to our experimental result of graphite wear rate, we estimate the wear of graphite pebble used in HTGR-10. It shows that the 80% graphite will wear out in 10 years running time.

Abstract: Heat conductive materials, which are widely used in the fields like electronic information, electrical engineering and aerospace, are required high thermal conductivity, excellent electrical insulation, corrosive resistance, chemical stability and so on. In this paper, steel/unsaturated polyester (UP) sandwich composite is designed to use as heat conductive material. The capacity of composite thermal transmission with steel wire arrangements in longitudinal and transverse directions are analyzed by software ANSYS. Finally, equivalent thermal conductivity of composite is calculated. The results show that capacity of composite’s thermal transmission increases quickly with increasing number of steel wire in the longitudinal direction，but it increases slowly with the increasing number of steel wire in the transverse direction.

Abstract: The geometric topography of the engineering surfaces play key roles in many issue of engineering and science including the analysis of friction, wear, lubrication, sealing and contact conductivity, especially microcosmic surface contact, thus the characterization of surface is one of the most important topics of tribology. Using the technology of CAD/CAE, a three-dimensional solid model of the fractal surfaces was established and meshed to provide the computer models for microcosmic contact analysis between two rough surfaces in this paper.

Abstract: There are so many energy-efficient distillation processes that it is difficult to select the best distillation process and achieve optimal design for a mixture of separation. Studying on different energy-efficient distillation processes, and we finally extracted 30 typical energy-efficient distillation processes, and established mathematical models of these processes to optimize and design. The characters and applicable conditions of every flow were obtained. According to the summary, we build a knowledge base for the expert systems. This was main content of the knowledge base of the system software. This expert system software ，based on windows XP system, was installed with Prolog and. Net.