ANSYS, the software of construction analysis, is used to analyze static and dynamic performances of a XH2408 gantry style numerical control （NC） milling machining center and optimize its construction using the finit...ANSYS, the software of construction analysis, is used to analyze static and dynamic performances of a XH2408 gantry style numerical control （NC） milling machining center and optimize its construction using the finite element method. First, a finite element model is established and the static and dynamic analysis are completed as constraints and loads applied on the finite element model. It is found that both spindle box and gantry are the worst components of assembly in performance. Secondly, the spindle box and gantry are chosen as objects of optimal design separately, aiming to improve their performance. The optimal plans are accomplished on the basis of the minimum volume for the spindle box and the maximum inherent frequency for the gantry subject to the constrains. Finally, the machine tool improved is analyzed statically and dynamically based on the optimal results of the spindle box and gantry. The results show that optimal design with the finite element method increases static and dynamical performances of the XH2408 gantry style numerical control milling machining center and the technique is effective and practical in engineering applications.展开更多
Permanent magnets with high energy products are widely used in a variety of electromagnetic devices. Such devices can be found in marine, aerospace, and robotic applications which require the minimization of weight an...Permanent magnets with high energy products are widely used in a variety of electromagnetic devices. Such devices can be found in marine, aerospace, and robotic applications which require the minimization of weight and volume of the electromagnetic device. During the magnetizing process, the magnet may not be perfectly magnetized. Therefore, it needs to be demagnetized. Because of high coercivity of some permanent magnets, the demagnetization process requires the intense magnetic fields in close proximity with the magnetic material. The fields must be produced for a short period of time （millisecond range） and they also must be bidirectional in order to overcome the coercivity of magnetic material. Different parameters have been known to affect the demagnetizer operation such as the core shape, core material, turn number, cross section of air gap, magnet type and so on. The amplitude and waveform of the fixture current is obtained from PSPICE simulations and also from experimental measurement. A 2D finite element analysis is developed to simulate the magnetic fields and the mechanical forces. In this paper, the main parameters affecting the optimal design of the demagnetizer are discussed. Simulation results show that the core structure, air gap width, and turn numbers are the most important parameters when designing such a device.展开更多
In this work, investigation of particle rebound characteristics due to impact with surface of a target material is presented. The rebound of a spherical particle after impact on a planar surface was analyzed in detail...In this work, investigation of particle rebound characteristics due to impact with surface of a target material is presented. The rebound of a spherical particle after impact on a planar surface was analyzed in detail. Specifically, the coefficient of restitution of the particle under various impact conditions was investigated numerically. This study has been conducted by carrying out a series of FEM-based (finite element method) simulations using ANSYS Autodyn software. First, a summary about the state of the art and the theoretical models for the elastic collisions were reviewed. Afterwards, the impact of an aluminum oxide particle on an aluminum alloy target surface was modeled. Using the Autodyn tool, the results were compared and validated by the experimental results of Gorham and Kharaz [1]. Selection of an appropriate equation of state (EOS) and a strength model for each material had a strong effect on the results. For both materials, the Shock EOS was applied for the final simulations. As the strength model, the Johnson-Cook and the elastic model were used, respectively. The agreement of the obtained numerical results with the experimental data confirmed that the proposed model can precisely predict the real behavior of the particle after the impact, when the material models are properly chosen. Furthermore, the effects of impact velocity and impact angle on the rebound characteristics of the particle were analyzed in detail. It was found that the selection of the exact value of friction coefficient has a drastic effect on the prediction of restitution coefficient values, especially the tangential restitution coefficient.展开更多
With the development of aeronautic and astronautic techniques, radiation becomes much more significant while the structure is exposed to the higher and higher temperature. Most of the current finite element software p...With the development of aeronautic and astronautic techniques, radiation becomes much more significant while the structure is exposed to the higher and higher temperature. Most of the current finite element software packages treat it using the net-radiation method or absorbed radiation method based on the assumption of isothermal surface with uniform radiation heat flux, which brings the conflict between the precision and the quantity of grids. Using integral method to compute the variable radiation heat flux in higher-order finite element, the precision can be improved greatly while using the same quantity of grids, because it is more consistent with the distribution of real temperature. In this paper, the integral is only processed on the same integral points as those used for solving the finite element equations, so it may be of high efficiency. In an academic testing model, the result is contrast to which get in ANSYS, proving the high precision of the method. Then an actual sandwich panel used in the thermal protection system is analyzed with the method, and the error is comparatively low to the analytical answer while the computation being of high efficiency.展开更多
Based on the use of finite element method(FEM) software ANSYS in electromagnetism, the electromagnetic processing of single winding 2D transformer and double winding 3D transformer are analyzed fully. Two examples, wh...Based on the use of finite element method(FEM) software ANSYS in electromagnetism, the electromagnetic processing of single winding 2D transformer and double winding 3D transformer are analyzed fully. Two examples, which are 2D static field and constant magnetic field, illustrate that the symbolization color vector pictures and curves obtained by ANSYS are not to achieve with other FEM softwares developed by individuals. For a transformer, the forces born by each winding pie and even each turn are analyzed separately under the conditions of unloading, normal load and short circuit. Especially under the condition of short circuit, there are pushing, pressing, suspending and vibrating between winding turns, and then the total winding is probably damaged. Therefore, the detail results give a basis to further fault diagnosis.展开更多
文摘ANSYS, the software of construction analysis, is used to analyze static and dynamic performances of a XH2408 gantry style numerical control （NC） milling machining center and optimize its construction using the finite element method. First, a finite element model is established and the static and dynamic analysis are completed as constraints and loads applied on the finite element model. It is found that both spindle box and gantry are the worst components of assembly in performance. Secondly, the spindle box and gantry are chosen as objects of optimal design separately, aiming to improve their performance. The optimal plans are accomplished on the basis of the minimum volume for the spindle box and the maximum inherent frequency for the gantry subject to the constrains. Finally, the machine tool improved is analyzed statically and dynamically based on the optimal results of the spindle box and gantry. The results show that optimal design with the finite element method increases static and dynamical performances of the XH2408 gantry style numerical control milling machining center and the technique is effective and practical in engineering applications.
文摘Permanent magnets with high energy products are widely used in a variety of electromagnetic devices. Such devices can be found in marine, aerospace, and robotic applications which require the minimization of weight and volume of the electromagnetic device. During the magnetizing process, the magnet may not be perfectly magnetized. Therefore, it needs to be demagnetized. Because of high coercivity of some permanent magnets, the demagnetization process requires the intense magnetic fields in close proximity with the magnetic material. The fields must be produced for a short period of time （millisecond range） and they also must be bidirectional in order to overcome the coercivity of magnetic material. Different parameters have been known to affect the demagnetizer operation such as the core shape, core material, turn number, cross section of air gap, magnet type and so on. The amplitude and waveform of the fixture current is obtained from PSPICE simulations and also from experimental measurement. A 2D finite element analysis is developed to simulate the magnetic fields and the mechanical forces. In this paper, the main parameters affecting the optimal design of the demagnetizer are discussed. Simulation results show that the core structure, air gap width, and turn numbers are the most important parameters when designing such a device.
文摘In this work, investigation of particle rebound characteristics due to impact with surface of a target material is presented. The rebound of a spherical particle after impact on a planar surface was analyzed in detail. Specifically, the coefficient of restitution of the particle under various impact conditions was investigated numerically. This study has been conducted by carrying out a series of FEM-based (finite element method) simulations using ANSYS Autodyn software. First, a summary about the state of the art and the theoretical models for the elastic collisions were reviewed. Afterwards, the impact of an aluminum oxide particle on an aluminum alloy target surface was modeled. Using the Autodyn tool, the results were compared and validated by the experimental results of Gorham and Kharaz [1]. Selection of an appropriate equation of state (EOS) and a strength model for each material had a strong effect on the results. For both materials, the Shock EOS was applied for the final simulations. As the strength model, the Johnson-Cook and the elastic model were used, respectively. The agreement of the obtained numerical results with the experimental data confirmed that the proposed model can precisely predict the real behavior of the particle after the impact, when the material models are properly chosen. Furthermore, the effects of impact velocity and impact angle on the rebound characteristics of the particle were analyzed in detail. It was found that the selection of the exact value of friction coefficient has a drastic effect on the prediction of restitution coefficient values, especially the tangential restitution coefficient.
文摘With the development of aeronautic and astronautic techniques, radiation becomes much more significant while the structure is exposed to the higher and higher temperature. Most of the current finite element software packages treat it using the net-radiation method or absorbed radiation method based on the assumption of isothermal surface with uniform radiation heat flux, which brings the conflict between the precision and the quantity of grids. Using integral method to compute the variable radiation heat flux in higher-order finite element, the precision can be improved greatly while using the same quantity of grids, because it is more consistent with the distribution of real temperature. In this paper, the integral is only processed on the same integral points as those used for solving the finite element equations, so it may be of high efficiency. In an academic testing model, the result is contrast to which get in ANSYS, proving the high precision of the method. Then an actual sandwich panel used in the thermal protection system is analyzed with the method, and the error is comparatively low to the analytical answer while the computation being of high efficiency.
文摘Based on the use of finite element method(FEM) software ANSYS in electromagnetism, the electromagnetic processing of single winding 2D transformer and double winding 3D transformer are analyzed fully. Two examples, which are 2D static field and constant magnetic field, illustrate that the symbolization color vector pictures and curves obtained by ANSYS are not to achieve with other FEM softwares developed by individuals. For a transformer, the forces born by each winding pie and even each turn are analyzed separately under the conditions of unloading, normal load and short circuit. Especially under the condition of short circuit, there are pushing, pressing, suspending and vibrating between winding turns, and then the total winding is probably damaged. Therefore, the detail results give a basis to further fault diagnosis.
