Li Gang Cai

Comparison of Adomian Decomposition Method and Differential Transformation Method for Vibration Problems of Euler-Bernoulli Beam

In this paper, we compare the Differential transformation method and Adomian decomposition method to solve Euler-Bernoulli Beam vibration problems. The natural frequencies and mode shapes of the clamped-free uniform Euler-Bernoulli equation are calculated using the two methods. The Adomian decomposition method avoids the difficulties and massive computational work inherent in Differential transformation method by determining the very rapidly convergent analytic solutions directly. We found the solution between the two methods to be quite close. According to calculation of eigenvalues, natural frequencies and mode shapes, we compare the convergence of Differential transformation method and Adomian decomposition method. The two methods can be alternative ways to solve linear and nonlinear higher-order initial value problems.

Adaptable Design Methodology of Heavy Duty Machine Tool for Green Remanufacturing

In order to achieve the remanufacturers and utility extension of the old heavy-duty machine tool, an adaptable design method of the heavy machine tool that oriented to the green remanufacturing is proposed in this paper. The guiding ideology of the adaptable design is integrated into the green design and product development. The present status of research at home and abroad is summarized, and then the existing problems are analyzed. Axiomatic design is introduced to be the research principal line and the four design domains are extended to five ones including regeneration domain. By full analysis, the three future research directions including the adaptable modular design, the adaptable platform design and the adaptable interface design of the heavy-duty machine tool, are proactively introduced.

Gear Fault Diagnosis Method Based on the Integration of Empirical Mode Decomposition and Cepstrum Analysis

Gear is the most common mechanical transmission equipment. Therefore, gear fault diagnosis is of much significance. In this article, a gear fault diagnosis method based on the integration of empirical mode decomposition and cepstrum is proposed by introducing empirical mode decomposition and cepstrum into gear fault analysis. Firstly EMD is used to decompose the gear vibration signal finite number of intrinsic mode functions and a residual error item. To do gear fault diagnosis, cepstrum analysis is carried upon those intrinsic mode functions to extract feature information from the vibration signal. The results of the study on simulated and experimental signals show that this method is better than the cepstrum method and it can precisely locate the site of gear failure.

The Thermal Characteristics Analysis of a Super Hydrostatic Guideway

This paper established the finite element model of a hydrostatic guideway. Based on the thermal characteristic simulation analysis, the temperature field and thermal deformation of the guideway were obtained. The analysis results show that the oil film temperature increment will cause thermal deformation of the guideway and processing errors. The errors will influence the machining accuracy of machine tools. The analysis results provide certain theory basis for the research on the above influence. And then the results also give certain reference for the research on the thermal error compensation of machine tools.

Heat - Stress Analysis and Structural Improvement of High Temperature Eutectic Fixed-Point Crucible

When the metal - carbon eutectic gets phase transition, the graphite crucible will be effect by the thermal stress and the phase transformation stress, which often make the crucible rupture, fail to achieve durability requirements, and then affect the research of high temperature eutectic fixed-point’s long-term stability and reproducibility. In order to improve the durability of crucible, the finite element software ANSYS and direct coupling method were used in this paper to analyze the heat-stress of Pt-C fixed-point crucible with sleeve (graphite sleeve) during the solidification. Based on the results of the simulation, we analyze the reasons of the breakdown of the crucible and propose two measures to improve the durability of crucible, which are adding graphite cloth or graphite foil between the crucible and the sleeve. Then we use ANSYS to analyze the two improved crucibles, and prove the effectiveness of these two measures.

The Study of High Strength Bolt Preload with Hydraulic Tensioner Installation

Preloading the high strength bolt using hydraulic extension method is a fast and efficient method for bolt installation. Hydraulic bolt tension device can guarantee the initial tension of bolt well. However, if the relation of initial tension and the final remaining preload of bolt cannot be determined, the preload on the bolts still cannot be guaranteed. This paper uses theoretical analysis method to research the relation between the eventual preload and the initial tension of high strength bolts on Heavy-duty Gantry beams. Then we proposes a set of calculation method of bolt installation preload and the initial tension and provides theoretical basis for the installation of heavy-duty segmented beam.

Simulation Analysis and Experiment Research for a Large Span and Heavy Load Crossbeam

Aiming at solving issues of load bearing deformation compensation and sympathetic vibration, this paper takes a large span and heavy load crossbeam of a domestic heavy-type numerical control milling planer for research object, the final purpose is to improve machining precision and stability of the heavy machine tool product. The load curve considering the influence of columns deformation, natural frequency and vibration model are obtained, respectively by the dynamic and static simulation analysis of the crossbeam with the finite element analysis method. Then, the modal analysis results are verified through the model experiment. Lastly, this paper presents an approach by estimating the load curve to improve machining precision, points out the weak links, and provides guidance for crossbeam structure design, optimization and reverse manufacture.

Numerical Simulation Analysis of Ink Temperature Field in the Printing Process

Ink is one of the important material in printing process, its features, to a great extent, decide the printing quality, and ink viscosity is one of the main parameters, the value of the ink viscosity directly affects the quality of printing. In the case of other conditions are determined, the main factor of influencing the ink viscosity is temperature. In this paper, by using the Workbench CFX fluid simulation software, the ink temperature field of two extrusion ink rollers in printing press is analyzed by numerical simulation , the influence of the ink roller speed on ink temperature and the influence of ink roller thermal conductivity on the ink temperature are analyzed,.

Detection and Compensation of Positioning Accuracy Based on the Laser Interferometer

The positioning accuracy of CNC machine tool is the best moving position accuracy which the machine tool can reach under the control of CNC control system. The principles of frequency laser interferometer measurement are described in this paper, and pitch error is compensated by taking DAHE V1500 CNC machine with FANUC system as example. The result shows that the precision of CNC machine tool is effectively improved.

An Improvement Geometric Error Identification Method of CNC Machine Tool Based on Double Ball Bar

The double ball bar is widely used because it can quickly, easily and cost-effectively detect and evaluate the accuracy of CNC machine tools. But since the error recognition algorithm based on the double ball bar ignores the quadratic item, its recognition accuracy would be reduced. In this paper, an improved CNC verticality error and position error identification formula, combined with the machine tool error model to deduce a new error recognition model of double ball bar measurement is proposed. It can be drawn that the accuracy of the model are better than the existing methods because it keeps the second item in the derivation process of the model.