模拟钣金冲压成形的计算机软件系统

ＳＭＦＳＳ１由模具设计的ＣＡＤ模块，前处理模块，成形过程仿真模块和后处理模块及接口组成，仿真模块使用有限元方法对成形过程中的接触问题采用了接触搜寻法确定接触对，并使用罚参数法快速准确地球出接触力，前后处理模块使ＣＡＤ系统与仿真模块构成统一的应用系统，应用效率与方便性良好，通过应用实例说明软件的实用性及可应用性。     

EDMI系统拟实制造软件的研究开发

该文在对ＥＤＭＩ系统ＶＭ问题研究的基础上,提出了以高级语言ＣＶＩ为外壳,以作者开发的优化及无缝连接模块为纽带,将动画仿真软件ＳＩＭＡＮ／ＣＩＮＥＭＡ、ＣＡＤ软件ＰＲＯＴＥＬ和作者开发的ＳＭＴ动画仿真模块集成于一体,构成了ＥＤＭＩ系统数据驱动式的ＶＭ软件,目前已基本完成。     

以三维建模引擎为核心的新型建筑CAD系统研究

为了开发建筑设计全过程集成ＣＡＤ系统,提出了一种以三维建模引擎为核心的新建筑ＣＡＤ系统３ＤＭＥＣＡＤ （３Ｄ Ｍｏｄｅｌｉｎｇ Ｅｎｇｉｎｅ Ｂａｓｅｄ Ａｒｃｈｉｔｅｃｔｒｕａｌ ＣＡＤ Ｓｙｓｔｅｍ）。该系统的三维建模引擎是以基于特征的ＣＳＧ与Ｂ－ｒｅｐ混合模型为基础,作为系统的公用数据模块,实现向计算分析、仿真演示、设计成果提交等外部子系统模块的数据转化,同时利用特征识别技术实现各 同步更新     

注塑模具CAE前后处理系统的设计与实现

本文详细分析了塑料模具计算机辅助工程（ＣＡＥ）前、后处理系统的功能及特点，针对有限元和边界元方法解决塑料模具设计仿真分析的特点，设计并实现了塑料模具ＣＡＥ前、后处理系统。该系统不仅能很好满足注塑模具ＣＡＥ的需求，而且具有通用性，建立、修改模型高效简单，可应用于其它领域ＣＡＥ系统的前、后处理系统。     

两组CDV容限参数的流量强制与成形算法

信元时延变化ＣＤＶ对峰值速率警管有很大的影响，文中首先提出基于通用信元速率算法ＧＣＲＡ（Ｔ，δ）的ＣＤＶ成形算法，该算法能有效地成形ＣＤＶ使之符合ＧＣＲＡ（Ｔ，δ）算法对ＣＤＶ容限的要求；在对ＣＤＶ成形算法分析的基础上，进一步提出了两有ＣＤＶ容限参数的流量强制与成形算法ＴＰ－ＥＳＡ，ＴＰ－ＥＳＡ既能成形ＣＤＶ到任意预设的值，又能防止连接对流量的恶意滥用。文中对算法的实现和操作也进行了研究。     

基于知识的,集成工具化的汽车锻件模具设计过程的仿真思想

提出了一个基于知识的，集成ＣＡＤ／ＣＡＭ模块，有限元分析模块，Ｍｏｔｉｆ界面制作模块的汽车锻件模具设计的仿真系统，此系统可推广到其它类似的模具设计过程仿真。     

两级CDV容限参数的流量强制与成形算法

信元时延变化ＣＤＶ对峰值速率警管有很大影响，文中首先提出基于通用信元速率算法ＧＣＲＡ（Ｔ，δ）的ＣＤＶ成形算法，该算法能有效地成形ＣＤＶ使之符合ＧＣＲＡ（Ｔ，δ）算法对ＣＤＶ容限的要求；在对ＣＤＶ成形算法分析的基础上，进一步提出了两级ＣＤＶ容限参数的流量强制与成形算法ＴＰ－ＥＳＡ，ＴＰ－ＥＳＡ既能成形ＣＤＶ到任意预设的值，又能防止连接对流量的恶意滥用。文中对算法的实现和操作也进行了研究。     

串行输出ADC的时序控制及与MCS51单片机的接口

串行输入ＡＤＣ体积小、功耗低将成为设计者关注的焦点，它的使用可以提高系统性能、降低成本和功耗。由于串行输出ＡＤＣ着眼于ＤＳＰ应用系统，因而将其用于工业控制及仪表领域，必须解决如何与通用单片机接口。为了提高其转换性能必须对其转换时的时序进行精确控制。本文给出了串行输出ＡＤＣ－ＭＡＸ１２１与８９Ｃ５１接口及如何用８９Ｃ５１对其时序进行控制的实例     

数据采集与监控系统(SCADA系统)在煤气调度中的应用

介绍了由ＥＬＰＲＯ公司ＴＬＣ系列模块组成的ＳＣＡＤＡ系统在煤气调度中的应用,具体介绍了系统的结构与配置、软件系统（ＣＩＴＥＣＴ）、ＲＴＵ的组成及特点、无线通信等技术问题。     

智能过程控制系统的概念模型

以ＫＡＤＳ原理为基础，基于模型的智能过程控制系统ＭＩＰＣＳ的构造过程被分为知识分析和系统实现两个阶段，知识分析阶段建立ＭＩＰＣＳ的概念模型，系统实现阶段则根据概念模型建造一个面向特定应用问题的智能过程控制系统ＭＩＰＣＳ，概念模型从知识一级描述了智能过程控制系统ＭＩＰＣＳ所具有知识与使用这些知识的策略，知识表示为模型，模型按ＫＡＤＳ原理组织成四层框架形式，本文描述了上述内容。     

Analysis of sheet metal extrusion process using finite element method

Sheet bulk metal forming processes have been widely developed to the facilitate manufacture of complicated 3D parts. However, there is still not enough know-how available. In this paper, as one of the typical sheet bulk metal forming processes, the sheet metal extrusion process was studied. A reasonable finite element method (FEM) model of sheet metal extrusion process taking the influence of flow-stress curve with wide range of plastic strain and ductile damage into consideration was established and simulated by an arbitrary Lagrangian-Eulerian (ALE) FEM implemented in MSC. Marc. Validated by comparing the results with experiment, some phenomenological characteristics, such as metal flow behavior, shrinkage cavity, and the influence of different combinations of diameter of punch, diameter of extrusion outlet, and diameter of pre-punched hole were analyzed and concluded, which can be used as theoretical fundamental for the design of the sheet metal extrusion process.     

Automatic recognition of features from freeform surface CAD models

This paper reports the design and implementation of a system for automatic recognition of features from freeform surface CAD models of sheet metal parts represented in STL format. The developed methodology has three major steps viz. STL model preprocessing, Region segmentation and automated Feature recognition. The input CAD model is preprocessed to get a healed and topology enriched STL model. A new hybrid region segmentation algorithm based on both edge- and region-based approaches has been developed to segment the preprocessed STL model into meaningful regions. Geometrical properties of facets, edges and vertices such as gauss and mean curvature at vertices, orientations of facet normals, shape structure of triangles, dihedral edge angle (angle between facets), etc. have been computed to identify and classify the regions. Feature on a freeform surface is defined as a set of connected meaningful regions having a particular geometry and topology which has some significance in design and manufacturing. Feature recognition rules have been formulated for recognizing a variety of protrusion and depression features such as holes, bends, darts, beads, louvres, dimples, dents, ridges/channels (blind and through) etc. occurring on automotive sheet metal panels. The developed system has been extensively tested with various industrial sheet metal parts and is found to be robust and consistent. The features data can be post processed and linked to various downstream CAD/CAM applications like automated process planning, sheet metal tool design, refinement of FEM meshes and product redesign.     

板料成形模拟后处理中的截面物理量的显示技术*

在自行开发的板料成形有限元后置处理系统FASTAMP_POST中,采用了动态获取截面物理量的算法,实现了截面物理量实时显示功能。该功能真实反映了网格物理量的大小及其变化趋势,具有原理简单、易实现、执行速度快的优点。     

Deep Learning in Sheet Metal Bending With a Novel Theory-Guided Deep Neural Network

Sheet metal forming technologies have been intensively studied for decades to meet the increasing demand for lightweight metal components. To surmount the springback occurring in sheet metal forming processes, numerous studies have been performed to develop compensation methods. However, for most existing methods, the development cycle is still considerably time-consumptive and demands high computational or capital cost. In this paper, a novel theory-guided regularization method for training of deep neural networks (DNNs), implanted in a learning system, is introduced to learn the intrinsic relationship between the workpiece shape after springback and the required process parameter, e.g., loading stroke, in sheet metal bending processes. By directly bridging the workpiece shape to the process parameter, issues concerning springback in the process design would be circumvented. The novel regularization method utilizes the well-recognized theories in material mechanics, Swift’s law, by penalizing divergence from this law throughout the network training process. The regularization is implemented by a multi-task learning network architecture, with the learning of extra tasks regularized during training. The stress-strain curve describing the material properties and the prior knowledge used to guide learning are stored in the database and the knowledge base, respectively. One can obtain the predicted loading stroke for a new workpiece shape by importing the target geometry through the user interface. In this research, the neural models were found to outperform a traditional machine learning model, support vector regression model, in experiments with different amount of training data. Through a series of studies with varying conditions of training data structure and amount, workpiece material and applied bending processes, the theory-guided DNN has been shown to achieve superior generalization and learning consistency than the data-driven DNNs, especially when only scarce and scattered experiment data are available for training which is often the case in practice. The theory-guided DNN could also be applicable to other sheet metal forming processes. It provides an alternative method for compensating springback with significantly shorter development cycle and less capital cost and computational requirement than traditional compensation methods in sheet metal forming industry.      

自适应模糊神经网络在板料弯曲回弹预测中的应用

回弹是板料冲压成形中影响工件质量的重要因素，因为它是一个多变量相互作用的高度非线性问题，至今在解析和数值方法中未能找到一个很有效的解决途径。该文提出利用自适应模糊神经网络(ANFIS)对非线性问题的良好逼近能力，采用基于有限元方法获得训练样本，经训练后得到具有回弹预测能力的ANFIS模型。实验验证了该方法的有效性。     

The effect of non-linear recovery on springback prediction

Numerical prediction of springback remains one of the major problems in sheet metal forming. The quality of springback prediction for a sheet metal forming process depends on a precise estimation of the stress distribution all over the metal sheet. In particular, the decrease of the unloading elastic modulus (non-linear recovery) with increasing plastic prestrain during stress reversals, observed by several authors, was commonly not taken into account in FE analysis. A model is proposed which takes the elastic modulus evolution with plastic prestrain and the unloading stress into account. Numerical simulations show that this model coupled with a non-linear kinematic hardening model can accurately predict the springback amount.     

一种基于高压水射流的金属板材柔性渐进成形技术

本文提出了一种新型的金属板材无模成形方法,即高压水射流柔性渐进成形方法,并基于此方法设计出一套五轴成形装置,其中喷嘴具有二个旋转自由度,工作台具有三个平动自由度,具有很好的柔性,非常适合多品种小批量产品的生产和新产品的试制。对高压水射流柔性渐进成形装置的各个子系统进行了详细的介绍,并对成形过程提出了一种新的仿真分析方法,将比较复杂的流固耦合问题,简化为加载等效压强的方法。最后通过单点水柱成形的仿真分析,揭示射流压力和板厚对金属板材成形性能的影响。     

Porting an industrial sheet metal forming code to a distributed memory parallel computer

The parallel version of the sheet metal forming semi-implicit finite element code ITAS3D has been developed using the domain decomposition method and direct solution methods at both subdomain and interface levels. IBM Message Passing Library is used for data communication between tasks of the parallel code. Solutions of some sheet metal forming problems on IBM SP2 computer show that the adopted DDM algorithm with the direct solver provides acceptable parallel efficiency using a moderate number of processors. The speedup 6.7 is achieved for the problem with 20000 degrees-of-freedom on the 8-processor configuration.     

Quadratic programming method in numerical simulation of metal forming process

In this paper, a quadratic programming (QP) model based on a parametric variational principle is proposed for elastic–plastic (EP) finite element analysis of metal forming processes. The contact problem with friction between blank and tools is treated in the same way as in plastic analysis. The penalty factors, which are normally introduced into the algorithm for contact analysis, have a direct influence on accuracy of solution. There is no available rule for choosing a reasonable value of these factors for simulation of metal forming, and they are therefore cancelled through a special technique so that the numerical results can be of high accuracy. The algorithms for contact analysis and plastic analysis are established in one frame and consistent with each other. Compared with the conventional EP FEM, the newly developed method requires no tedious iterative procedures, and has no convergence problems. To apply this method easily to simulation of metal forming, detailed forms of some key matrices or vectors for 2D FEM and 3D FEM are presented, and a parametric loading algorithm for the QP model is developed, which is suitable for QP problem with free variables, and can decrease memory cost by avoiding the introduction of additional slack variables and improve the solution efficiency to some extent. Finally the proposed QP model is validated by two examples, analysis of V-notched tension test and analysis of the drawing of a square box––one of the benchmarks proposed at NUMISHEET93. It can be seen that the accuracy of solution of the new EP FEM based on QP is better than that of the conventional EP FEM based on iteration. To make the new EP FEM more applicable to metal forming industries, It is necessary to develop a more efficient QP algorithm that is suitable for large-scale problems.     

有限元法在板料二次成形中的应用

本文建立了板料成形动力显式有限元模拟，采用四节点退化壳单元对板料进行离散化，利用中心差分法离散时间域，建立显式计算格式，采用罚函数法和修正库仑定理计算接触力和摩擦力。对二次成形过程，建立了有限元分析计算模型。通过Dynaform对板料成形进行仿真得出最后结论。