发射载荷下孔隙形状对变形特性的影响

为了研究发射载荷下战斗部装药内部孔隙的变形过程对发射药安全性的影响,采用ANSYS/LS-DYNA非线性有限元分析软件进行了数值模拟.结果表明,相同体积的椭球形孔隙和球形孔隙的变形特征相差很小.     

不同厚度UHMWPE层合板抗侵彻性能的数值模拟

本文采用软件模拟的计算方法,在ANSYS/LS-DYNA程序的支持下,对不同厚度UHMWPE层合复合材料的抗侵彻性能进行数值模拟。通过弹道极限速度V50和能量吸收Ea分析评定靶板的抗侵彻性能。     

板料冲压成形过程中起皱的数值模拟与实验研究

起皱是板料成形过程中的主要缺陷,起皱的数值模拟作为解决起皱问题的有效方法,越来越受到工业界和学术界的重视。本文利用大型非线性有限元软件ANSYS/LS-DYNA的动态显示算法,对低碳钢冷轧板杯形零件在冲压过程中发生的起皱现象进行数值模拟及实验研究,分析了不同坯料尺寸和不同变形工艺条件下的变形过程。结果表明,模拟结果与实验结果基本吻合,数值模拟结果可靠,具有良好的应用价值。     

复合材料板翅式换热器力学与传热性能数值研究

本文采用数值模拟方法,利用有限元分析软件ANSYS模拟PTFE复合材料用于板翅式换热器时的导热性能以及在各种工况下的受力情况,得到PTFE的热导率与不同温度载倚下的压力和温度图,并进行分析.分析结果可为PTFE复合材料的优化设计提供参考依据.     

CFRP加固钢筋混凝土梁弯曲疲劳性能的有限元分析

本文采用数值模拟方法,利用有限元软件ANSYS对CFRP加固钢筋混凝土梁弯曲疲劳性能进行了分析,研究了钢筋混凝土梁的疲劳机理,得出了CFRP加固钢筋混凝土梁疲劳寿命的提高程度.研究结果表明,采用CFRP加固钢筋混凝土梁能大幅提高其疲劳寿命,并对实际工程起到了一定的指导意义.     

基于虚拟裂纹闭合法计算组合材料的应变能释放率

本文研究了将虚拟裂纹闭合法应用ANSYS有限元计算软件,计算组合材料的应变能释放率。在有限元计算中,为了减小后处理工作量,将弹簧单元施加在裂纹尖端。在实际的有限元计算中,COMBIN14单元被用来建立有限元模型,从而将求解过程和后处理过程联系起来,自动计算出能量释放率。随后,将该方法应用于计算组合材料的应变能释放率,进行数值模拟实验。通过分析比较数值计算结果和理论值,表明该数值分析方法所计算出的应变能释放率与理论值完全符合,该数值分析方法是一种高效,精确的数值分析方法。     

缠绕管件轴压下径向形变和破坏模式的有限元分析与验证

本文采用缠绕工艺制备厚壁碳/环氧复合材料主承力管件,对所制备管件试样进行轴压破坏试验,并采用有限元分析软件ANSYS7.0对试验过程进行模拟分析.分析结果表明轴压管件径向形变最大的位置在距离管件端面20～25mm处,表明该位置容易发生破坏,与实验结果是一致的.     

Ti3SiC2/Al2O3陶瓷基复合材料支护托板结构优化设计

本文以ANSYS优化设计基本理论为基础,以ANSYS为模拟分析软件,通过对Ti3SiC2/A12O3陶瓷基复合材料支护托板进行结构优化设计,最终得到满足强度要求、容易成型、且成本较低的矿用支护托板.为工程上的支护托板的优化设计提供了依据.     

拉压不同弹性模量变厚度圆柱壳基本方程及其应用

本文以变厚度圆柱壳微分单元为分析模型,导出了拉压不同弹性模量复合材料变厚度圆柱壳弯曲问题的平衡微分方程及其关系式.该方程的COLSYS数值解与ANSYS有限元结果比较表明,本文理论公式正确,基本假定合理,可作为复合材料变厚度圆柱壳较为精确的弯曲理论.     

高温换热器多场耦合数值模拟研究

建立了高温换热器流动和传热的数值模型,对5种不同工况条件下的换热器进行了数值模拟,得到换热器的流动和传热特性;在ANSYS软件中建立换热器管束三维有限元模型,通过ANSYS CFX-POST准确的将前面FLUENT计算得到的温度场、压力场映射到ANSYS结构模型中,对换热器进行多场耦合分析;通过热-结构应力分析,得到换热器管束的等效应力和位移分布状况,并确定了最大应力发生的位置和具体数值,对换热器进行强度评价。     

Analysis of non-linear consolidation of soft clay by differential quadrature method

Due to the complexity of the non-linear consolidation of soft clay, numerical method is always adopted to its solution. The differential quadrature method (DQ method) equaling to a high precision finite difference method can obtain highly accurate numerical solutions of differential equations using less grid points. This numerical method is always used to solve the complicated nonlinear physical problem governed by partial equations. In this paper, DQ method is implemented to one dimensional non-liner consolidation equation and the boundary conditions. Euler forward scheme is used to solve the discrete equation, and the pore pressure and consolidation curves are prepared. The present numerical results are compared with the analytical solutions. Compared with the other numerical method, the method of solving the non-linear consolidation equation by the DQ method in this paper is very simple and reasonable. The DQ method is successfully implemented to the soft clay consolidation analysis and can assure satisfied numerical results with less grid points.     

软模/真空灌注成型带复杂孔圆盘的工艺探讨

为解决复杂复合材料构件的整体一次成型问题,提高复合材料制品的整体性能,降低生产成本,本文采用硅橡胶制备软模,利用其柔韧性解决常规模具无法一次成型的问题。并通过软模/真空灌注工艺制备了带复杂孔圆盘,以验证其工艺可行性。通过比较与其他工艺制备的复合材料性能,探讨其使用前景。结果表明,采用软模/真空灌注工艺可一次整体成型带复杂孔圆盘等复杂构件,制品性能稳定。     

A new discretization of space for the solution of multi-dimensional population balance equations

In this work, a novel radial grid is combined with the framework of minimal internal consistency of discretized equations of Chakraborty and Kumar [2007. A new framework for solution of multidimensional population balance equations. Chemical Engineering Science 62, 4112-4125] to solve n-dimensional population balance equations (PBEs) with preservation of (n+1) instead of 2ⁿ properties required in direct extension of the 1-d fixed pivot technique of Kumar and Ramkrishna [1996a. On the solutions of population balance equation by discretization-I. A fixed pivot technique. Chemical Engineering Science 51, 1311-1332]. The radial grids for the solution of 2-d PBEs are obtained by intersecting arbitrarily spaced radial lines with arcs of arbitrarily increasing radii. The quadrilaterals obtained thus are divided into triangles to represent a non-pivot particle in 2-d space through three surrounding pivots by preserving three properties, the number and the two masses of the species that constitute the newly formed particle. Such a grid combines the ease of generating and handling a structured grid with the effectiveness of the framework of minimal internal consistency. A new quantitative measure to supplement visual comparison of two solutions is also introduced. The comparison of numerical and analytical solutions of 2-d PBEs for a number of uniform and selectively refined radial grids shows that the quality of solution obtained with radial grids is substantially better than that obtained with the direct extension of the 1-d fixed pivot technique to higher dimensions for both size independent and size dependent aggregation kernels. The framework of Chakraborty and Kumar combined with the proposed 2-d radial grid, which offers flexibility and achieves both reduced numerical dispersion and the ease of implementation, appears as an effective extension of the widely used 1-d fixed pivot technique to solve 2-d PBEs.     

Time-implicit fixed and deforming grid solutions for compression mold filling

A general governing equation for tracking the filling free surface during compression molding is derived. From this equation, with appropriate choice of parameters, a time-implicit fixed grid solution and a time-implicit deforming grid solution are obtained. Numerical results of several test problems reveal that both solutions reach the same level of accuracy. The fixed grid scheme, however, is more robust and can solve problem with complex geometrical features.     

软模/真空灌注成型内翻法兰半球的工艺探讨

为解决复杂复合材料构件的整体一次成型问题,提高复合材料制品的整体性能,降低生产成本,本文采用硅橡胶制备软模,利用其柔韧性解决常规模具无法一次成型的问题。并通过软模/真空灌注工艺制备了带内翻法兰半球,以验证其工艺可行性。通过比较与其他工艺制备的复合材料的性能,探讨其使用前景。结果表明:采用软模/真空灌注工艺可一次整体成型内翻法兰半球等复杂构件,制品的性能稳定。     

Effects of preform deformation behavior on the properties of the poly(ethylene terephthalate) bottles

Plastics bottles made out of poly(ethylene terephthalate) (PET) are usually produced by injection stretch blow molding. Optimization of the process parameters is necessary to achieve bottles with adequate top load and burst strength. However, doing so experimentally is time‐consuming and costly. To overcome this difficulty, simulation packages based on finite element analysis methods have been developed. In this study, process optimization of a 350‐mL PET fruit juice bottle was carried out by means of BlowView and ANSYS simulation packages. BlowView was used for the ISBM process simulation and ANSYS for structural analysis of the bottles. The bottles were produced under different process conditions where the timing of the stretch rod movement was varied in relation to the activation of the blow pressure. The simulation results obtained through the both simulation packages were compared with experimental results. It was found that bottles of highest quality were produced if the sequencing of axial stretching and radial inflation results in simultaneous biaxial deformation of the preform. Truly biaxial orientation of PET molecules improved both top‐load and burst resistances of the bottles. The structural simulation studies performed by the ANYSYS simulation package validated most of our experimental findings. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

A new framework for solution of multidimensional population balance equations

A new framework is proposed in this work to solve multidimensional population balance equations (PBEs) using the method of discretization. A continuous PBE is considered as a statement of evolution of one evolving property of particles and conservation of their n internal attributes. Discretization must therefore preserve n+1 properties of particles. Continuously distributed population is represented on discrete fixed pivots as in the fixed pivot technique of Kumar and Ramkrishna [1996a. On the solution of population balance equation by discretization—I. A fixed pivot technique. Chemical Engineering Science 51(8), 1311-1332] for 1-d PBEs, but instead of the earlier extensions of this technique proposed in the literature which preserve 2ⁿ properties of non-pivot particles, the new framework requires n+1 properties to be preserved. This opens up the use of triangular and tetrahedral elements to solve 2-d and 3-d PBEs, instead of the rectangles and cuboids that are suggested in the literature. Capabilities of computational fluid dynamics and other packages available for generating complex meshes can also be harnessed. The numerical results obtained indeed show the effectiveness of the new framework. It also brings out the hitherto unknown role of directionality of the grid in controlling the accuracy of the numerical solution of multidimensional PBEs. The numerical results obtained show that the quality of the numerical solution can be improved significantly just by altering the directionality of the grid, which does not require any increase in the number of points, or any refinement of the grid, or even redistribution of pivots in space. Directionality of a grid can be altered simply by regrouping of pivots.     

ON A SYSTEMATIC DESIGN PROCEDURE FOR SINGLE COMPONENT WATER UTILIZATION SYSTEMS IN PROCESS PLANTS

This paper presents a robust methodology to obtain an optimal design of the single component water/wastewater allocation problem in process plants. The method uses a concentration grid water allocation procedure to obtain preliminary optimal structures. A merging procedure provides the final structures. The use of different water allocation strategies shows that the problem has several alternative solutions.     

Solving distillation problems by terrain methods

This paper clearly shows that the recently proposed terrain methodology of Lucia and Yang (2003) can be used to solve steady-state distillation problems in a reliable and efficient manner. Numerical results are presented that show that terrain methods are superior to Newton’s method and homotopy-continuation for distillation examples with multiple solutions.     

基于ANSYS/LS-DYNA对薄壁壳屈曲分析

利用有限元分析软件ANSYS/LS-DYNA,通过实体建模对薄壁壳进行仿真计算.借助ANSYS/LSDYNA程序从网格密度、材料属性、单元类型、接触类型、沙漏控制等五个方面,讨论了薄壁壳在轴向冲击力作用下的屈曲变化情况,并得到了钢管不同时刻的变形情况、应力分布情况、应变分布情况.结果表明,采用该软件模拟薄壁壳屈曲分析是...