In this paper, based on a tangential interpolation function and an adaptively increasing penalty-factor strategy(TIPS), a novel parameterization method with a self-penalization scheme aimed for the topology optimizati...In this paper, based on a tangential interpolation function and an adaptively increasing penalty-factor strategy(TIPS), a novel parameterization method with a self-penalization scheme aimed for the topology optimization of metallic antenna design is proposed. The topology description is based on the material distribution approach.The proposed tangential interpolation function aims to associate the material resistance with design variables, in which the material resistance is expressed in the arctangent scale and the arctangent resistance is interpolated with the design variables using the rational approximation of material properties. During the optimization process, a strategy with an adaptively increasing penalty factor is used to eliminate the remaining gray scale elements, as illustrated in examples,in the topology optimization based on the proposed tangential interpolation function. Design results of typical examples express the effectiveness of the proposed TIPS parameterization.展开更多
A new numerical method to predict the initial blank geometry from the desiredobjective shape of parts is presented. Based on the conditions that the deformations in materialare most evenly distributed and that the vol...A new numerical method to predict the initial blank geometry from the desiredobjective shape of parts is presented. Based on the conditions that the deformations in materialare most evenly distributed and that the volume remains constant, a positive definite functional forblank design is constructed. The functional is minimized by an iterative scheme of finite element,and then the optimal initial configuration is obtained. The method is easy and expedient to use. Theresults of numerical simulation of forming process and multi-point forming experiments for sheetmetal demonstrate that good precision is achieved by the proposed method.展开更多
The architecture of digital sheet metal manufacturing system is proposed based on the classification of sheet metal manufacturing information.The essence of digital manufacturing is the definition,management and trans...The architecture of digital sheet metal manufacturing system is proposed based on the classification of sheet metal manufacturing information.The essence of digital manufacturing is the definition,management and transfer of information,and the key technologies are brought forward and described.It is pointed out that knowledge-based manufacturing elements design is necessary to make digital technology efficient.The management of all kinds of sheet metal manufacturing element information is to build single source of manufacturing data.Multi-state model-based digital transfer and coordination method is designed to provide a foundation for digital manufacturing of aircraft sheet metal part.The application of digital sheet metal manufacturing is exemplified with an aircraft sheet metal part.The application result is compared to that of the traditional analog transfer technology.It is shown that the developed technology can improve part quality,shorten manufacturing time and lower manufacturing cost.展开更多
The metallic antenna design problem can be treated as a problem to find the optimal distribution of conductive material in a certain domain. Although this problem is well suited for topology optimization method, the v...The metallic antenna design problem can be treated as a problem to find the optimal distribution of conductive material in a certain domain. Although this problem is well suited for topology optimization method, the volumetric distribution of conductive material based on 3D finite element method (FEM) has been known to cause numerical bottlenecks such as the skin depth issue, meshed 'air regions' and other numerical problems. In this paper a topology optimization method based on the method of moments (MoM) for configuration design of planar metallic antenna was proposed. The candidate structure of the planar metallic antenna was approximately considered as a resistance sheet with position-dependent impedance. In this way, the electromagnetic property of the antenna can be analyzed easily by using the MoM to solve the radiation problem of the resistance sheet in a finite domain. The topology of the antenna was depicted with the distribution of the impedance related to the design parameters or relative densities. The conductive material (metal) was assumed to have zero impedance, whereas the non-conductive material was simulated as a material with a finite but large enough impedance. The interpolation function of the impedance between conductive material and non-conductive material was taken as a tangential function. The design of planar metallic antenna was optimized for maximizing the efficiency at the target frequency. The results illustrated the effectiveness of the method.展开更多
Laser forming is a new type of flexible manufacturing process that has become viable for the shaping of metallic components. Process designing of laser forming involves finding a set of process parameters, including l...Laser forming is a new type of flexible manufacturing process that has become viable for the shaping of metallic components. Process designing of laser forming involves finding a set of process parameters, including laser power, laser scanning paths, and scanning speed, given a prescribed shape. To date, research has focused on process designing for rectangular plates, and only a few studies are presented for axis-symmetric geometries like circular plates. In the present study, process designing for axis-symmetric geometries--with focus on class of shapes--is handled using a formerly proposed distance-based approach. A prescribed shape is achieved for geometries such as quarter-circular and half-circular ring plates. Experimental results verify the applicability of the proposed method for a class of shapes.展开更多
The contact pressure acting on the sheet/tools interface has been studied because of growing the concern about the wear of tools. Recent studies make use of numerical simulation software to evaluate and correlate this...The contact pressure acting on the sheet/tools interface has been studied because of growing the concern about the wear of tools. Recent studies make use of numerical simulation software to evaluate and correlate this pressure with the friction and wear generated. Since there are many studies that determine the coefficient of friction in sheet metal forming by bending under tension (BUT) test, the contact pressure between the pin and the sheet was measured using a film that has the ability to record the applied pressure. The vertical force applied to pin was also measured. The results indicate that the vertical force is more accurate to set the contact pressure that using equations predetermined. It was also observed that the contact area between the sheet and the pin is always smaller than the area calculated geometrically. The friction coefficient was determined for the BUT test through several equations proposed by various authors in order to check if there is much variation between the results. It was observed that the friction coefficient showed little variation for each equation, and each one can be used. The material used was the commercially pure aluminum, alloy Al1100.展开更多
基金supported by the National Natural Science Foundation of China (Grants 11332004, 11372063, and 11572073)the 111 Project (Grant B14013)
文摘In this paper, based on a tangential interpolation function and an adaptively increasing penalty-factor strategy(TIPS), a novel parameterization method with a self-penalization scheme aimed for the topology optimization of metallic antenna design is proposed. The topology description is based on the material distribution approach.The proposed tangential interpolation function aims to associate the material resistance with design variables, in which the material resistance is expressed in the arctangent scale and the arctangent resistance is interpolated with the design variables using the rational approximation of material properties. During the optimization process, a strategy with an adaptively increasing penalty factor is used to eliminate the remaining gray scale elements, as illustrated in examples,in the topology optimization based on the proposed tangential interpolation function. Design results of typical examples express the effectiveness of the proposed TIPS parameterization.
基金This project is supported by the 10th Five-Year National S&T Program of China (No. 2001BA203B11).
文摘A new numerical method to predict the initial blank geometry from the desiredobjective shape of parts is presented. Based on the conditions that the deformations in materialare most evenly distributed and that the volume remains constant, a positive definite functional forblank design is constructed. The functional is minimized by an iterative scheme of finite element,and then the optimal initial configuration is obtained. The method is easy and expedient to use. Theresults of numerical simulation of forming process and multi-point forming experiments for sheetmetal demonstrate that good precision is achieved by the proposed method.
文摘The architecture of digital sheet metal manufacturing system is proposed based on the classification of sheet metal manufacturing information.The essence of digital manufacturing is the definition,management and transfer of information,and the key technologies are brought forward and described.It is pointed out that knowledge-based manufacturing elements design is necessary to make digital technology efficient.The management of all kinds of sheet metal manufacturing element information is to build single source of manufacturing data.Multi-state model-based digital transfer and coordination method is designed to provide a foundation for digital manufacturing of aircraft sheet metal part.The application of digital sheet metal manufacturing is exemplified with an aircraft sheet metal part.The application result is compared to that of the traditional analog transfer technology.It is shown that the developed technology can improve part quality,shorten manufacturing time and lower manufacturing cost.
基金supported by the National Natural Science Foundation of China (Grants 11332004, 11372063, and 11572073)111 Project (Grant B14013)the Fundamental Research Funds for the Central Universities (Grant DUT15ZD101)
文摘The metallic antenna design problem can be treated as a problem to find the optimal distribution of conductive material in a certain domain. Although this problem is well suited for topology optimization method, the volumetric distribution of conductive material based on 3D finite element method (FEM) has been known to cause numerical bottlenecks such as the skin depth issue, meshed 'air regions' and other numerical problems. In this paper a topology optimization method based on the method of moments (MoM) for configuration design of planar metallic antenna was proposed. The candidate structure of the planar metallic antenna was approximately considered as a resistance sheet with position-dependent impedance. In this way, the electromagnetic property of the antenna can be analyzed easily by using the MoM to solve the radiation problem of the resistance sheet in a finite domain. The topology of the antenna was depicted with the distribution of the impedance related to the design parameters or relative densities. The conductive material (metal) was assumed to have zero impedance, whereas the non-conductive material was simulated as a material with a finite but large enough impedance. The interpolation function of the impedance between conductive material and non-conductive material was taken as a tangential function. The design of planar metallic antenna was optimized for maximizing the efficiency at the target frequency. The results illustrated the effectiveness of the method.
文摘Laser forming is a new type of flexible manufacturing process that has become viable for the shaping of metallic components. Process designing of laser forming involves finding a set of process parameters, including laser power, laser scanning paths, and scanning speed, given a prescribed shape. To date, research has focused on process designing for rectangular plates, and only a few studies are presented for axis-symmetric geometries like circular plates. In the present study, process designing for axis-symmetric geometries--with focus on class of shapes--is handled using a formerly proposed distance-based approach. A prescribed shape is achieved for geometries such as quarter-circular and half-circular ring plates. Experimental results verify the applicability of the proposed method for a class of shapes.
文摘The contact pressure acting on the sheet/tools interface has been studied because of growing the concern about the wear of tools. Recent studies make use of numerical simulation software to evaluate and correlate this pressure with the friction and wear generated. Since there are many studies that determine the coefficient of friction in sheet metal forming by bending under tension (BUT) test, the contact pressure between the pin and the sheet was measured using a film that has the ability to record the applied pressure. The vertical force applied to pin was also measured. The results indicate that the vertical force is more accurate to set the contact pressure that using equations predetermined. It was also observed that the contact area between the sheet and the pin is always smaller than the area calculated geometrically. The friction coefficient was determined for the BUT test through several equations proposed by various authors in order to check if there is much variation between the results. It was observed that the friction coefficient showed little variation for each equation, and each one can be used. The material used was the commercially pure aluminum, alloy Al1100.
