Papers by Author: Cheng Yu Jiang

Abstract: A wet etching method for preparing silicon nanowires on silicon substrates at near room temperature is presented. The effect of experiment parameter on the silver nanoparticle forming including concentration of AgNO₃, immersing time and solution temperature, and the effect of etching time on the length of silicon nanowires are investigated. It is concluded that solution temperature has more impact to diameter of silicon nanowires than concentration of AgNO₃ and immersing time and longer etching time may result in longer silicon nanowires.

Abstract: The form of blank holder and the manner of blank holder force (BHF) on the complicated parts forming are very important. The blank holder of rectangle box forming was divided long straight segments, short straight segments and corners. The forming process simulation of rectangular box was conducted by FEM based on explicit algorithm, including single-piece blank holder with constant BHF, single-piece blank holder with variable BHF, segmented blank holder with constant BHF, segmented blank holder with variable BHF. The results were analyzed according to the thinnest level of the parts. The displacement in the Z direction of blank holder in the simulation was considered, and the method of determining segmented variable blank holder force (VBHF) was proposed. Finally rectangular box was obtained by rectangular box drawing system of segmented variable BHF on the basis of the simulation result.

Abstract: The sheet forming simulation of rectangular box was conducted by finite element method (FEM), the forming process experiment, further, was investigated, so as to understand the effect of the form of blank holder and the manner of blank holder force (BHF) on the complicated parts forming. In my study, a kind of low carbon steel was investigated, and its mechanical properties were obtained by simple tension tests. The outermost contour of the blank shape was determined by “one step method”. Furthermore, the finite element model was constructed by ANSYS parametric design language (APDL), which has characteristic of grid meshing by Belytschko-Tsay (BT) shell element, applying anisotropic constitutive equation of Barlat yield criterion, dealing contact by penalty function method and using adaptive mesh algorithm in the simulation process. Then the forming process simulation of rectangular box with segmented variable BHF was conducted. On the basis of analyzing the work principle and technical parameters of XP3CEF-100 hydraulic press, the rectangular box drawing system of segmented VBHF was established, which was made of hydraulic press, rectangular box drawing die of segmented blank holder, hydraulic part of blank holder and control part. Finally the low carbon steel forming tests were fulfilled by the rectangular box drawing system on the basis of the simulation result.

Abstract: An efficient flexible iterative algorithm with a general approach is presented for calculations of surface form errors in peripheral milling of thin-walled workpiece. An efficient finite-element model for tool/workpiece is presented to analyze the surface dimensional errors in peripheral milling of aerospace thin-walled workpieces. The efficient flexible iterative algorithm is proposed to calculate the deflections and the maximum surface form errors as contrasted with the rigid iterative algorithm used in the literatures. Meanwhile, some key techniques such as the finite-element modeling of the tool-workpiece system; the determinant algorithm to judge instantaneous immersion boundaries between a cutter element and the workpiece; iterative scheme for the calculations of tool-workpiece deflections considering the former convergence cutting position are developed and the method for calculating the position and magnitude of the maximum surface form errors are developed and presented in detail. The proposed approach is validated and proved to be efficient through comparing the obtained numerical results with the test results.

Abstract: This paper constructs the organization model of manufacture information resource (MIR) using the granularity structure (GS) analysis method. Based on the model, the expression technique of MIR based on metadata and the coding realization technique are analyzed. MIR expression mode achieves flexibility unification using the object-oriented (O-O) coding structure solution. The result proves that the technique of analyzing and coding to MIR based on GS has provided an effective method to standardize the MIR organization under the development mode of product life cycle (PLC).

Abstract: Radio frequency identification (RFID) is a new material identification technology. RFID has a greater number of benefits than its predecessor, the bar code. It is not universally adopted in many industries due to its high cost hitherto. Whereas, RFID is advantageous because it does not require line-of-sight scanning, it acts to reduce labor levels, enhances visibility, and improves inventory management. This article briefly introduced component, principle and characteristic of the RFID technology, and analyzed and introduced more foregroundful application of RFID in modern logistics. RFID technology is combined with network technical and database technology, it will be extensively applied in stock tache, storage tache, transportation tache, retail tache of logistics system. In addition, this paper also discussed the factors which restrain RFID technology from being broadly applied. The uppermost problem faced by RFID technology is the cost of RFID chip, then it comes to the potential intervention of people’s privacy incurred by the use of RFID technology. Otherwise, lack of uniform criteria definitely affects the development of RFID technology.

Abstract: A new approach is proposed to model the milling force based on the cutting force shape characteristics in end milling. The relationship between the cutting force shape characteristics and the cutting depths is analyzed and milling forces are classified into 10 types according to the combination of cutting depths. Further, force indices are extracted and then the real cutting depths are detected based on the changes of force curve characteristics via the force indices in end milling process. Then, bring forward a method of modeling cutting force based on the different types, and the use of real cutting depth makes the model to be more accurately. More important, experiments designed on the classification of milling forces strengthen the pertinence, and makes the experiment data more reliable. The approach is validated through experiments on aluminum alloy 7050-T7451.

Abstract: Micro-Electromechanical Systems (MEMS) has been regarded as one of the most promising technologies for the 21st Century. Recently, some highlight areas attract great attention including Inertial MEMS, Optic MEMS, RF MEMS, BioMEMS, Power MEMS, and NEMS. The state of arts on MEMS research in China is briefly introduced and research activities in Northwestern Polytechnical University such as MEMS CAD tool, inertial MEMS devices, flexible substrate for MEMS integration, micro mirror, micro battery and three dimension measurement are demonstrated.