Huang Qingxue

The analysis of new hydraulic rolling shear servo system dynamic characteristics

The hydraulic rolling shear whose hydraulic system is researched in this article is designed based on the theory of rolling shear. This article builds the transfer function of the unsymmetrical valve controlling unsymmetrical cylinder system and gets the expressions of the flow gain and the flow pressure coefficients and then compares them with the system controlled by symmetric valve. After the theoretical analysis, this article compares the control effects between the unsymmetrical valve and symmetric valve with the simulation software HYVOS. The simulation declares that when the unsymmetrical cylinder is controlled by the unsymmetrical valve, its control voltage is one-third of that controlled by the symmetric valve. Using unsymmetrical valve to control the unsymmetrical cylinder is perfect and meets the demands of the rolling shears as shown by the data collected from the field.

Analysis of bearing characteristics of axially heavy-loaded composite nut

A three-dimensional solid model is constructed for the heavy-loaded screw pairs of a nut subjected to axial compressive load and thrust on different sides. The finite element software ANSYS is used to calculate the stress and strain distribution at each thread root of the screw pairs. A composite nut structure is proposed based on the characteristics of the stress and strain distribution. This structure improves the local rigidity of the nut. The finite element method is adopted to calculate the stress and strain distribution at each thread root of the composite nut. The comparison of the measured results and calculated results indicates that the maximum stress and strain at the thread roots of the composite nut decrease significantly while the load distribution becomes considerably even. An experiment is conducted to check the calculated results for the two types of screw pairs. The experimental results verify the appropriateness of the composite nut structure.

Spread Model for TC4 Alloy Rod during the Three-Roll Tandem Rolling Process

Abstract In order to get high-precision TC4 alloy rod during the three-roll tandem rolling process, the spread of rod has been studied. A numerical simulation project was designed by an orthogonal experiment optimization design method. On the FEM software platform of Marc, the influence of rolling process parameters, including the rolling temperature, the rolling velocity, the inscribed circle of pass, the diameter of roller, and the friction coefficient between roller and rod, on the spread was investigated. Moreover, the effect order of above parameters was analyzed. On this basis, the spread model for TC4 alloy rod during three-roll rolling was established. The experiment was done on the self-developed three-roll mill of eight passes with a flat triangle-round sequence. The calculated results of spread model are in good agreement with the on-site data.

The Application of Fast Multipole-BEM for 3-D Elastic Contact Problem with Friction

In this paper, three-dimensional elastic contact problem is discussed. Based on traditional boundary element method (BEM), mixed boundary integral equation is presented to solving several bodies contact problem with friction. It is not only reducing the dimension from domain to boundary, but also solving the displacement and stress independently at the same time. A new judgement criterion of contact state is established to judge the contact state of separate, adhere and slip. Through numerical analysis, the displacement and stress obtained by FM-BEM is better than traditional BEM in calculation time and accuracy. It illustrates that FM-BEM is better than traditional BEM for solving contact problem with friction.

Velocity Field Analysis of Bonding Interface on Cold-Rolled Copper/Aluminum Composite Plate

Abstract The cold-rolled bonding process of copper/aluminum bimetal plate was investigated by the velocity field of finite element method (FEM). At the same time, deformation characteristics of metal were analyzed in the bonding process. The study method was to combine theory calculation with field data. The circumferential velocity of rollers, rolling reduction rate, synchronous rolling of non-equal sized rollers and asymmetrical rolling of non-equal sized rollers were analyzed. Results show that the velocity field can explain the cold-rolled bonding process of copper/aluminum bimetal plate more effectively; the synchronicity of metal flow on bonding surface decreases with the increase of circumferential velocity about rollers near the exit of deformation area, and the bonding strength is reduced; in the process of synchronous rolling about non-equal sized rollers, diameter ratio of the rolls is 1.4∼1.6 with a great synchronicity of metal flow near the exit of deformation area and a high bonding strength; in the process of asymmetrical rolling about non-equal sized rollers, the circumferential velocity rate of rollers is 1.2 with a great synchronicity of metal flow near the exit of deformation area and a high bonding strength.

Research and application of a new cut to length model of rolling shear

Two main problems of cut to length were discussed in order to improve accuracy and efficiency in plate shearing line. And a new cut to length model with dynamic parameter has been put forward, which applies pinch roll drive as a part of control loops completely. In this paper, the key points include the process settings, the method of implementation and dynamic parameter compensation of the control model. The practical application of results indicates the pinch roll can stop in expected position; the accuracy and efficiency of cut to length meets the technological requirements when the set shearing length is different.