基于正交试验的航空叶片精锻模具磨损分析

针对航空叶片模具设计效率低、磨损严重、参数修正困难等问题,在对叶片模具设计过程分析的基础上,基于UG/Open API技术开发了模具CAD系统,实现了模具参数化设计,提高了模具设计效率;基于Archard修正理论,借助Deform-3D软件就模具设计参数对叶片精锻成形的影响进行仿真模拟,通过正交试验分析了锻压速度、成形角度、桥部厚度对叶片模具磨损与寿命的影响,得出了有益于延长模具寿命的最优工艺组合参数,并对该组合参数的设计规则进行了优化,使得模具设计参数的确定更加精确、简单;通过工程实例,对模具磨损与寿命进行了分析,得出试验结果与模拟结果具有较好的一致性。研究结果对航空叶片精锻模具优化设计与磨损分析具有重要的指导意义。     

航空叶片模具设计参数对模具磨损影响分析

为解决航空叶片精锻模具磨损严重,设计参数确定困难等问题,本文在分析模具设计过程和锻造工艺的基础上,基于Archard摩擦理论,借助有限元分析软件对不同设计参数的叶片模具的精锻成形过程进行了模拟仿真,运用正交试验设计方法分析了模具成形角度、桥部厚度、桥部宽度对叶片成形力和模具磨损的影响,得出了有益于叶片成形和减小模具磨损的最优化组合设计参数,并对该参数的计算方法进行了改进,简化了计算过程且参数计算更加精确;最后,通过工程实例对上述过程进行了验证,其实验结果与仿真结果的一致性较好,减小了模具磨损,提高了叶片模具设计效率.     

弹体热冲拔成形工艺数据库研究与开发

在充分总结弹体热冲拔成形知识的基础上,构建了弹体热冲拔成形工艺数据库,开发了数据库管理系统。应用在弹体热成形工艺与模具设计上,实现了工艺数据的积累、共享、重用,达到了优化工艺与模具设计,提高工艺设计水平与效率的目的。     

汽车端盖零件的冲压模具设计

首先对端盖零件进行工艺分析,确定该零件成形工艺和模具设计的要点,并提出了最佳成形工艺方案。重点描述了落料拉深冲孔复合模的设计过程,并解决凸凹模的设计,定位精度和冲裁孔拉深变形等问题,为薄壁零件浅拉深成形的模具设计提供参考。     

炭纤维增强脂基复合材料热压罐成型模具设计知识管理框架

热压罐成型法是大尺寸高质量炭纤维增强树脂基复合材料制件的主要生产方法,其生产工艺过程数字化是其工艺方法研究热点之一.制定生产工艺所需要各项信息的数字化表达是实现其工艺数字化的基础,信息描述的质量直接影响到工艺知识的重用性.在详细分析热压罐成型法生产工艺制定需考虑的设备、工艺、工装等因素的基础上,应用本体技术对炭纤维增强树脂基复合材料热压罐生产所用到的设备能力参数、工艺过程参数、工装模具信息进行了数字化描述,建立主要工艺装备框架式模具设计的知识表达模型框架,开发了基于模拟的模具设计原型系统.研究结果可用于热压罐成型模具设计知识的存储和推理重用.     

板料冲压成形快速分析软件FASTAMP

基于先进的有限元逆算法研制开发了具有独立版权的板料冲压成形快速分析软件FASTAMP,与传统的增量法CAE软件有很大的区别,可以进行快速的优化设计和成形性模拟,主要面向产品设计、工艺设计与模具设计人员.该软件具有一套完整的、独立的前后处理系统,其中包括标准的CAD数据接口、曲面编辑和曲面网格生成器.     

基于知识的板料冲裁工艺与模具设计支持技术

为了提高板料冲裁工艺与模具设计的质量和效率,实现知识的重用和共享,对板料冲裁工艺与三维模具设计的智能化、参数化设计技术进行了系统地研究,提出了以数据库、框架、规则、面向对象和数学模型等混合方法表示工艺设计知识,以几何模型/数据库混合表示法描述结构设计知识;提出了面向工程的动态设计方法,将实际设计知识记录到动态知识库中,成为半标准化的知识,支持系统的智能设计.根据提出的方法,基于Ⅰ-DEAS软件平台,利用宏命令与API接口函数相结合的方法,建立了冲裁工艺与三维模具设计支持系统,具体设计实例表明所建立的系统大大提高了设计的质量和效率.     

网格式整体壁板增量弯曲工艺知识库研究

针对网格式整体壁板数字化加工制造的需求,建立了自适应增量弯曲工艺知识库系统,阐述了系统的体系结构与实现方法.基于增量成形以及自适应控制的基本理论,提出了自适应增量弯曲成形工艺知识库参数获取方法(直接法、单特征法、双特征法、三特征法、多点回归求解法),在此基础上,建立了一种基于工艺特征方程的自适应增量弯曲工艺知识库系统.研究表明,所设计的系统能够按照一定的计算法则,给出待加工零件的弯曲工艺参数,实现了网格式整体壁板增量弯曲成形过程中的工艺参数自动预测与调整,并在实际应用中进行了验证.     

发动机同步带轮粉末冶金成形模具设计

针对发动机同步带轮的粉末冶金成形工艺,根据同步带轮的结构特点和粉末冶金模具设计原理,采用成形速度和成形速率相等原理设计同步带轮成形模具;采用变模数设计法设计成形中模;对定位孔提出采用成形芯棒的设计方案;将设计的模具图建立模具组立图,理论分析所设计模具方案的可行性;通过模具装机实验,验证成形模具设计的合理性。结果表明,试生产的同步带轮经过烧结等工艺达到了客户在精度、性能等方面的技术指标,并且提高了齿形精度和模具的使用寿命,成功开发了发动机同步带轮成形模具。     

带弧形槽成形件冲压工艺分析及模具设计

在分析了某汽车上带R24弧形槽成形件结构和工艺特点的基础上,利用Dynaform软件进行CAE模拟分析,确定了成形工艺。介绍了带R24弧形槽成形件冲压工艺方案的选择、排样设计和模具设计要点。     

铝合金弹壳成形及失效分析

随着现代化战争对武器轻量化的迫切需要,高强轻质铝合金弹壳的研制已成为世界各国的重点研究方向。铝合金弹壳成形工艺一般有拉深变薄、挤压和旋压等方法,其在制备成形过程中的失效方式复杂多变,失效原因多种多样。基于自主开发的高强高韧铝合金弹壳,介绍了铝合金弹壳材料制备技术和模具冲压成形技术,综述了铝合金弹壳的成形工艺、失效方式和性能特征,分析了金属弹壳的失效原因和解决措施,展望了轻质铝合金弹壳的发展趋势。     

基于实例的CAPP策略

从充分利用工艺规程编制实例的角度出发，提出了用基于实例的推理改进ＣＡＰＰ推理方法的策略，并具体介绍了将基于实例的推理与基于知识的推理有机结合的混合推理系统的具体结构、实例的表示、提取方法以及基于知识、实事库的正确性维护与版本管理的实例修改策略。     

基于实例推理的镀膜机快速设计研究

目的研究大规模定制模式下镀膜机的快速设计方法。方法阐述了基于实例推理技术的基本原理和关键技术,将基于实例推理的快速设计技术应用到镀膜机的设计过程中;研究了镀膜机的实例表示、检索和修正的具体实现方法,即采用数据库表的实例表示方法构建了镀膜机的实例库,运用最相邻策略法进行镀膜机实例的检索,采用基于框架的方案变换方法对检索的最相似实例进行修正。结果以Pro Engineer 5.0为开发平台,开发了基于实例推理的镀膜机快速设计系统,实现了资源的整合和重复利用。通过测试,该系统使设计效率提高了30%。结论将基于实例推理的快速设计技术引入到镀膜机的设计中,能够提高产品的设计效率和缩短产品的开发周期,从而解决客户个性化需求与大批量生产之间的矛盾,提高企业的市场竞争力。     

铝合金弹壳的发展历程和研究现状

介绍了国内外铝合金弹壳的发展历程和研究现状,论述了铝合金弹壳的特点和优势,重点介绍了目前铝合金弹壳的制备方法和工艺流程,展望了铝合金弹壳的发展方向和应用前景。     

Intelligent process design system for the transfer moulding of electronic packages

Currently, mould design and the setting of the process parameters of transfer moulding for electronic packages are done manually in a trial-and-error manner. The effectiveness of the setting of parameters is largely dependent on the experience of engineers. The paper describes an intelligent process design system for transfer moulding of electronic packages that is used to determine optimal mould design parameters and the setting of the process parameters mainly based on case-based reasoning, artificial neural networks and a multiobjective optimization scheme. The system consists of two modules: a case-based reasoning module and a process optimization module. The former module is used to determine initial mould design parameters and the setting of the process parameters while the latter module is used to determine optimal mould design parameters and the setting of the process parameters. Implementation of the intelligent system has demonstrated that the time for the determination of optimal mould design parameters and the setting of the process parameters can be greatly reduced, and the setting of parameters recommended by the system can contribute to the good quality of moulded packages.     

基于实例推理的航空产品机加工工装设计相似性研究

针对航空产品的零件结构特点,将实例推理应用于航空结构零件机械加工工装设计.提出考虑工件信息、工艺信息和装夹信息的工装设计信息表示方法,来表达设计任务信息和以往设计实例信息.将工装设计实例分解为各属性,并按照一定方法对属性间的相似度进行量化,计算实例间的相似度值.结合分层检索的相似性评价算法,得到与设计任务匹配程度高的实例方案,并通过实例修正,达到新设计任务的快速实现.     

A semi-quantitative reasoning methodology for filtering and ranking HAZOP results in HAZOPExpert

Hazard and Operability (HAZOP) analysis is the most widely used and recognized as the preferred Process Hazards Analysis (PHA) approach in the chemical process industry. Recently, a diagraph-model based framework and an expert system called HAZOPExpert was developed for automating this analysis. Upon testing the performance of the system on various industrial case studies. HAZOPExpert was found to successfully mimic the human expert's reasoning and identify the hazards. But, with the increasing complexity of the processes, the HAZOPExpert system generated a large number of consequences compared to those identified by a team of experts. This is mainly due to the strict qualitative reasoning approach implemented in the HAZOPExpert system. In order to filter and rank the consequences generated by the HAZOPExpert system, a semi-quantitative reasoning methodology is proposed using additional quantitative knowledge in the form of design and operating specifications of the process units, and process material property values. This filtering approach combines the qualitative digraph-based HAZOP models and the quantitative knowledge to eliminate the unrealizable consequences. Significant reduction in the number of consequences was obtained using this approach on an ethylene process plant HAZOP case study.     

Model reduction and process control of thermomechanical behaviour of non-linear material deformation

This paper describes a design procedure for metal forming processes by using the controllable subspace of the full system. The velocity profile of the moving die is designed using the reduced order system. The metal forming processes are simulated using non-linear finite element methods based on the rigid viscoplastic flow formulation. The balanced model reduction technique is applied to reduce the full state space model to a reduced order model that retains the controllable subspace of the thermomechanical system. The linear quadratic regulator theory with output tracking is used as an off-line design tool to design the die velocity schedule. The process design is carried out to maintain the strain rate of the critical portion of the billet at a desired value. The procedure for designing the process parameters is demonstrated using two case studies.     

Neuro-Knowledge-Based Expert System (NKBES) for Optimal Scheming of Die Casting Process

We develop a neuro-knowledge-based expert system (NKBES) frame in this work. The system mainly concerns with decision of gating system and die casting machine based on a neuro-inference engine launched under the MATLAB software environment. For enhancement of reasoning agility, an error back-propagation neural network was applied. A rapidly convergent adaptive learning rate (ALR) and a momentum-based error back-propagation algorithm was used to conduct neuro-reasoning. The working effect of the system was compared to a conventional expert system that is based on a two-way (forward and backward) chaining inference mechanism. As the reference, the present paper provided the neural networks sum-squared error (S5E) and ALR vs iterative epoch curves of process planning case mentioned above. The study suggests that the neuro-modeling optimization application to die casting process design has good feasibility, and based on that a novel and effective intelligent expert system can be launched at low cost.     

A methodology for evaluation of metal forming system design and performance via CAE simulation

In the current metal forming product development paradigm, product cost, time-to-market and product quality are three overriding issues, which determine the competitiveness of the developed products. In the up front design process, the first 20% of design activities commits to about 80% of product development cost and product quality issues. How to conduct ‘right the first time’ design is critical to ensure low development cost, high product quality and short time-to-market. To address these issues, state of the art technologies are needed. Traditionally, computer-aided design (CAD) and computer-aided manufacturing (CAM) technologies provide solutions for representation of design intent and realization of design solution physically. However, it is difficult to address some critical issues in the design of forming process, tooling structure, material selection and properties configuration, and finally the product quality control and assurance. Computer-aided engineering (CAE) technology fills this gap as it helps practitioners generate, verify, validate and optimize design solutions before they are practically implemented and physically realized. In this paper, a methodology for evaluation of metal forming system design and performance via CAE simulation is developed. The concept of metal forming system and its design is first articulated and how the CAE technology helps design and design solution evaluation is then presented. To assess and evaluate the performance of metal forming systems, quantitative design evaluation criteria are developed. Through industrial case study, how the developed methodology helps metal forming system design and evaluation is illustrated and its efficiency and validity is finally verified.