Papers by Author: Zhong Qi Wang

Abstract: Tool wear can affect surface quality of the work-piece and frequent tool changing leads to low machining efficiency. Tool life of milling ultrahigh strength steel is thus an important indicator in manufacturing. In this study, we compare Diffuse Approximation (DA) and Kriging method for predicting tool life of milling ultrahigh strength steel. Latin hypercube method is employed as design of experiments after comparing three different designs of experiments (full factorial design, Latin Hypercube Sampling (LHS) and random design). An example with LHS is taken to investigate accuracy of approximation of DA and Kriging method. The results show that the DA provides significant improvement in accuracy of prediction compared with Kriging method. Tool life of milling ultrahigh strength steel predicted by DA is almost close to ‘exact’ values, especial for big mutation of adjacent measured values. The most errors with DA are less than ones with Kriging method.

Abstract: A large number of weakly rigid parts are used in the progress of aircraft assembly, while it’s deviation will affect the quality of the product finally. The assembly variation model of aircraft weakly rigid parts based on influence coefficient method are constructed for controlling assembly accuracy effectively. Based on the linear elastic hypothesis of small deformation, the model carry out the mechanical analysis of aircraft weakly rigid parts in the typical process of positioning, clamping, jointing and spring-back. Influence coefficient matrix of the key features affected by parts manufacturing variation and fixture variation is calculated through the Finite Element method and Monte Carlo simulation, then the assembly variation model is constructed. Finally, based on the above model, an engineering example of assembly variation prediction of aircraft panels was given.

Abstract: Since the bracket deformation caused by its deadweight is too large, and the riveting of aircraft panel is always over-tolerance, a new algorithm for analysis and compensation of bracket deformation is presented in this paper. The algorithm is formed by combining finite element (FE) simulation with analytic method, which is fit for different combinations of supporting plates of bracket system. The formula is constructed through cubic spline interpolation and envelope surface fitting according to the FE simulation data. Meanwhile, a corresponding compensation method is proposed. Finally, a numerical simulation example with the software of ABAQUS shows that the algorithm and its results are valid and feasible.

Abstract: In the process of information semantic integration for product design and manufacturing, it is very important to express the product information semantic. Description logics (DLs) are a family of state-of-the-art knowledge representation languages, and a decidable subset of first-order logic. Firstly, by analyzing the characteristics of product information, proposed a semantic information description framework based on description logics for product information integration, which is divided into three levels: basic description logic, classic extended logic and unusual extended logic. Then, in the framework, reducer was taken for example to illustrate the application of their description logic in product design and manufacturing formal semantic information. Finally, based on description logic, discussed reasoning problems of product design and manufacturing information.

Abstract: In the process of automated riveting, the position between the riveting head and the holes distributed on the stringer and wing skin to be riveted will go beyond the design requirements currently. Using the edge distance determination technology to measure and compensate the deviation in time is one effective method to solve this problem. In the dissertation, after the characteristic of the edge distance determination technology is introduced, the working principle of the edge distance tracer apparatus is developed. Based on the mechanical design solution, a pressure sensor is selected to measure the position relationship between the riveting head and the stringer. Then an edge distance tracer apparatus is struck out to detect the deviation, which is an automatic positioning feedback device that can be fit for many kinds of stringers. And the riveting head is operated to meet the design deviation requirements. By using this technology, the drilling precision of the automated riveting system can be effectively improved.

Abstract: Pulleys and bushing have different linear expansion coefficient, relatively sliding may occur between them when hated, therefore, we have to ensure that there's enough interference volume within pulleys and bushing. First of all, using simplify numerical method calculated theoretical extreme temperature, then taking simulate analysis with ABAQUS finite element analysis software, through the change of CPRESS and COPEN in different temperature field, extract the extremely working temperature of aluminum pulleys. and then determined the limitation and cooperation relationships by comparison.

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: This paper proposes a new efficient iterative algorithm which named flexible iterative algorithm (FIAL) with a general approach suitable for surface form errors prediction in peripheral milling of thin-walled workpiece. First, a FEA-Based model is presented to analyze the surface dimensional errors in peripheral milling of thin-walled workpieces. Then the FIAL is discussed in detail for the procedure of deformation prediction. From FIAL, an iterative scheme for the calculations of tool/workpiece deflections considering the former convergence cutting position are developed，in the scheme a small variable must be included in the calculation of radial cutting depth which never been considered in the literatures before.The proposed approach is validated and proved to be efficient through comparing the obtained numerical results with the test results.

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.