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张力柱是卧式铝挤压机预应力框架的重要组成结构,其使用性能直接影响框架整体性和安全性。基于叠板式“T”型钩头张力柱自重挠曲变形分析,提出了叠板组挠曲变形预紧前校正方法,构建了以叠板式张力柱为主要特征的叠板式全预紧封闭框架结构,建立了该框架结构的整体全接触有限元分析模型,通过预紧力逐级施加,在满足承载最大挤压工作载荷时各接触区域无开缝状态条件下,确定了框架预紧力大小和叠板式“T”型钩头处半圆键下垫板厚度。工程应用表明,叠板式全预紧封闭框架承载时各叠板组整体性和使用一致性较好,能够有效提升重型卧式铝挤压机预应力框架的整体性和安全性。 相似文献
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在大型挤压机上,为了增加机架的整体刚性,增加机架的抗疲劳性能,预应力结构机架应用非常普遍。挤压机挤压吨位的增加,必然会使挤压机拉杆增加很大,预紧螺母重量的增加也给加工和装配带来了新的问题。本文就预紧螺母的受力情况进行了分析,得出了发生粘结的几种可能性,并有针对性地提出了解决办法。 相似文献
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680MN多功能模锻挤压机是集模锻与挤压功能一体化的多功能液压机,其主要受力部件活动横梁组件在不同工况下受力情况十分复杂.针对以上问题,680 MN多功能模锻挤压机的动梁采用由4个动梁剖分组件组成动梁主体,通过钢丝和螺栓共同预紧方式进行设计.采用ABAQUS 6.10有限元分析软件对动梁的设计模型进行不同工况、不同受力情况分析.为了保证动梁在钢丝预紧过程中所受预紧力达到设计要求,采用在缠绕过程中动梁组件上的单向应力区粘贴应变片的方案,同时对压机动梁受力情况进行监测分析.有限元分析和实验表明,采用以上设计的680MN多功能模锻挤压机可以达到使用要求. 相似文献
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介绍了SolidWorks二次开发的技术原理与关键技术、挤压机框架预紧受力原理及计算过程。参数化设计过程分为技术路线的确定、参数化模型的确定、参数的确定、人机界面的确定,最后,编制程序实现参数化设计功能。参数的确定是设计过程中的核心,决定了模型建立的内在逻辑以及最终人机界面的友好程度。采用主程序、附属程序以及手动修改相结合的方法,利用VB编程,将产品内部参数间的关联性融入二次开发的程序中,通过SolidWorks API驱动SolidWorks软件,实现了挤压机框架的三维参数化设计,并增加了一些人性化和实用性的功能,以方便设计人员的使用。在保证设计准确率的前提下,使设计效率提高了50%以上。 相似文献
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分析了太原重工设计、生产、制造的全系列金属挤压机的辅助设备和主机设备,主要介绍了挤压机坯锭自动供给系统、预应力框架、液压缸省力机构、短行程机构、快速更换系统等结构特点,该金属挤压机穿孔系统采用内置式结构、挤压筒移动缸布置在后梁上等新技术,不仅满足挤压工艺要求,而且提高了生产率。 相似文献
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液压拉伸器是一种先进的螺栓预紧和拆卸工具,已广泛用于大直径螺栓的预紧,文中给出了液压拉伸器的正确使用与维护方法。 相似文献
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将广义模块化设计应用到液压机预应力机架的有限元分析中,提出了广义有限元模块和广义有限元模块接口的概念.阐述了ANSYS软件中有限元模块数据库的建立方法、有限元模块装配成整机分析模型的具体装配方法和预紧力载荷的模拟方法,用ANSYS参数化设计语言编制了组装有限元模块、预紧单元法施加预紧力和施加问隙导向约束的通用程序模块.最后以45 MN液压机预应力机架的有限元分析为例,详细说明了广义模块设计中分析环节的实施过程和此类液压机设计的注意事项,为同类机架的设计提供了参考和指导. 相似文献
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本文对航空用高强薄壁2024合金型材进行拉弯试制与研究,保证试验单一变量原则,通过对比多组拉弯试验的测量结果,分析1%~3%预拉伸量对固溶状态下型材拉弯回弹变形及褶皱的影响。试验成果可用来确定产品实际生产所需的最优预拉伸力。 相似文献
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Investigations on stress corrosion cracking of prestressing steels (bars) at increased prestressing level The application of prestressing methods using bars lead to additional bending stresses or internal stresses when plastic deformation takes place at curvatures. These stresses are superimposed by the well-planned prestressing. The probability for hydrogen-induced stress corrosion cracking in corrosive media (especially water in the metal sheath) is considerably increased in the presence of internal stresses and if the prestressing level is enlarged. The permissible prestressing levels of the EU guidelines are higher than the values fixed in DIN 4227 with the same permissible radii of curvature. In order to find out if there is an increased risk of stress corrosion cracking, exposure tests were performed with prestressing bars grade St 900/1030 and St 1080/1230, respectively, in an electrolyte simulating metal sheath conditions. All specimens withstood the 2000 h lasting exposure test without fracture which means that the risk of hydrogen-induced brittle fracture could be excluded under practical conditions provided that the current state of the art has been considered. Tensile tests after the exposure revealed a reduction of strain values due to the exposure. Fracture analysis by means of SEM did not show any signs of embrittlement for the materials tested. 相似文献
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Corrosion and cracking-corrosion of prestressing steels Summarizing report about extent and causes of damages of prestressing steels caused by hydrogen cracking-corrosion. Fundamental research of cracking-corrosion of prestressing steel. Results of cracking-corrosion tests with stressed materials in not pure water, in such moistened sand and of water condensating tests. Hereby consideration of contents of chlorides and sulfates as existing in unfilled tubes; partly little addition of the hydrogen-promotor rhodanide. Result that under practical conditions prestressing steels prefer hydrogen induced cracking-corrosion while hereby especially oxygen-poor electrolytes and local corrosion attacks (pitting scars) tend to this hydrogen reception and therefore to failure. These effects are for example often caused by the conditions of crevice-corrosion and by contact with moistened mineral phases (sands). Such is resulting that sensitive prestressing steels are exposed to the danger of failure already before being embedded with mortar. 相似文献
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Sudden collapses of structural components due to fractures of the prestressing steel have occurred. The paper describes the successful application of a nondestructive testing method to identify defective structures. The remanent magnetism method makes it possible to localize fractures of single prestressing steel bars in postensioned tendons. The tendons need not be accessible at any point, not even at the jacking ends. The ferromagnetic properties of the prestressing steel are used in this process. Characteristic magnetic leakage fields are caused by fractures. The magnetic field, measured at the concrete surface along the projection of the tendon profile, allows conclusions concerning existing fractures. Also the extent of damage (number of broken steel bars) can be evaluated. 相似文献