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91.
体积成形有限元模拟软件CASFORM的开发研究 总被引:6,自引:0,他引:6
简要介绍了作者自主开发的体积成形有限元模拟软件CASFORM及其关键技术,并给出了大量的实例分析。CASFORM主要由前处理模块,有限元分析模块,后处理模块,有限元网格生成模块和网格再划分及数据传递模块以及材料数据库和模拟数据库等构成,该软件能够分析各种体积成形工艺,包括锻造、挤压、拉拔等。能够预测缺陷的生成,验证和优化工艺/模具设计方案,该软件既能模拟等温成形过程,也可以模拟非等温成形过程,即可进行单工位成形分析,也可进行多工位成形分析。该软件界面友好,使用方便,可靠性和自动化程度高,是模具和工艺设计方案验证和优化的有力工具。 相似文献
92.
Distortion Engineering - Identification of Causes for Dimensional and Form Deviations of Bearing Rings 总被引:1,自引:0,他引:1
Distortion of power transmission parts after heat treatment is influenced by each step of the process chain, ranging from material production to hard-machining. However, an experimental analysis for each production step in the manufacture of bearing rings has shown that distortion is significantly influenced by turning before heat treatment. Elastic ring deformation caused by fixing the workpiece in the chuck leads to a variation of the depth of cut and polygonal form deviations occur after machining. In addition the cutting process induces locally varying residual stresses which also contribute to dimensional and form deviations of machined rings. In this paper results from experimental investigations of the principle physical causes for the distortion of bearing rings are presented and discussed. Finally, strategies for the minimization of distortion are derived. 相似文献
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95.
利用Pro/E三维模型与二维图形双向关联功能可以快速生成工程图,但由于在视图表达上有些方面不符合我国制图标准而影响其有效使用.本文针对Pro/E制作工程剖视图时所存在的与制图国标不相符合的问题,提出了解决这些问题的方法和技巧. 相似文献
96.
在产品的协同设计过程中,每个项目都要涉及到众多的工作人员和大量的网络资源。协调好各个人员的工作并且有效、安全地使用网络资源是保证产品设计顺利进行的关键。本文提出并研究了采用活动目录技术来实现协同设计系统的服务层上的项目人员管理需求模式,开发了相应的项目人员管理工具,并且在基于知识的注塑模具和冲压模具设计系统中得到应用。 相似文献
97.
大型露天矿在由山坡型转入深凹型开采后,随着运输条件的恶化,将单一的准轨铁路运输,改变为铁路—汽车联合运输,以延长铁路运输的服务年限,为此,需要解决提高电力机车运输性能、改造运输线路系统等问题。 相似文献
98.
《Information and Software Technology》2014,56(10):1219-1232
ContextScientific software plays an important role in critical decision making, for example making weather predictions based on climate models, and computation of evidence for research publications. Recently, scientists have had to retract publications due to errors caused by software faults. Systematic testing can identify such faults in code.ObjectiveThis study aims to identify specific challenges, proposed solutions, and unsolved problems faced when testing scientific software.MethodWe conducted a systematic literature survey to identify and analyze relevant literature. We identified 62 studies that provided relevant information about testing scientific software.ResultsWe found that challenges faced when testing scientific software fall into two main categories: (1) testing challenges that occur due to characteristics of scientific software such as oracle problems and (2) testing challenges that occur due to cultural differences between scientists and the software engineering community such as viewing the code and the model that it implements as inseparable entities. In addition, we identified methods to potentially overcome these challenges and their limitations. Finally we describe unsolved challenges and how software engineering researchers and practitioners can help to overcome them.ConclusionsScientific software presents special challenges for testing. Specifically, cultural differences between scientist developers and software engineers, along with the characteristics of the scientific software make testing more difficult. Existing techniques such as code clone detection can help to improve the testing process. Software engineers should consider special challenges posed by scientific software such as oracle problems when developing testing techniques. 相似文献
99.
《Information and Software Technology》2014,56(1):6-19
ContextIn the era of globally-distributed software engineering, the practice of global software testing (GST) has witnessed increasing adoption. Although there have been ethnographic studies of the development aspects of global software engineering, there have been fewer studies of GST, which, to succeed, can require dealing with unique challenges.ObjectiveTo address this limitation of existing studies, we conducted, and in this paper, report the findings of, a study of a vendor organization involved in one kind of GST practice: outsourced, offshored software testing.MethodWe conducted an ethnographically-informed study of three vendor-side testing teams over a period of 2 months. We used methods, such as interviews and participant observations, to collect the data and the thematic-analysis approach to analyze the data.FindingsOur findings describe how the participant test engineers perceive software testing and deadline pressures, the challenges that they encounter, and the strategies that they use for coping with the challenges. The findings reveal several interesting insights. First, motivation and appreciation play an important role for our participants in ensuring that high-quality testing is performed. Second, intermediate onshore teams increase the degree of pressure experienced by the participant test engineers. Third, vendor team participants perceive productivity differently from their client teams, which results in unproductive-productivity experiences. Lastly, participants encounter quality-dilemma situations for various reasons.ConclusionThe study findings suggest the need for (1) appreciating test engineers’ efforts, (2) investigating the team structure’s influence on pressure and the GST practice, (3) understanding culture’s influence on other aspects of GST, and (4) identifying and addressing quality-dilemma situations. 相似文献
100.
《Information and Software Technology》2014,56(5):477-494
ContextAlthough Agile software development models have been widely used as a base for the software project life-cycle since 1990s, the number of studies that follow a sound empirical method and quantitatively reveal the effect of using these models over Traditional models is scarce.ObjectiveThis article explains the empirical method of and the results from systematic analyses and comparison of development performance and product quality of Incremental Process and Agile Process adapted in two projects of a middle-size, telecommunication software development company. The Incremental Process is an adaption of the Waterfall Model whereas the newly introduced Agile Process is a combination of the Unified Software Development Process, Extreme Programming, and Scrum.MethodThe method followed to perform the analyses and comparison is benefited from the combined use of qualitative and quantitative methods. It utilizes; GQM Approach to set measurement objectives, CMMI as the reference model to map the activities of the software development processes, and a pre-defined assessment approach to verify consistency of process executions and evaluate measure characteristics prior to quantitative analysis.ResultsThe results of the comparison showed that the Agile Process had performed better than the Incremental Process in terms of productivity (79%), defect density (57%), defect resolution effort ratio (26%), Test Execution V&V Effectiveness (21%), and effort prediction capability (4%). These results indicate that development performance and product quality achieved by following the Agile Process was superior to those achieved by following the Incremental Process in the projects compared.ConclusionThe acts of measurement, analysis, and comparison enabled comprehensive review of the two development processes, and resulted in understanding their strengths and weaknesses. The comparison results constituted objective evidence for organization-wide deployment of the Agile Process in the company. 相似文献