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胡晓东 《机械工人(冷加工)》2009,(6):75-77
1.振动时效原理
振动消除应力简称VSR(Vibratory Stress Relief),它是利用-受控振动能量对金属工件进行处理,达到消除工件残余应力的目的。 相似文献
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《机械设计与制造》2013,(9)
曲轴作为内燃机核心部件,质量的好坏将决定内燃机的性能的高低。而曲轴加工过程中产生的残余应力会直接影响到曲轴的质量。目前常用的曲轴消除残余应力的方式热时效方式的处理时间长、能耗高的缺点一直无法有效解决,特别有些曲轴还无法运用热时效的方式消除残余应力。而振动时效是消除工件残余应力的一种有效手段,避免了热时效的缺点。依据工件内部的残余应力和振动产生的动应力的叠加达到或超过材料屈服强度的"Wozney&Crawmer"准则,求出在激振器以轴弯曲振动固有频率激励下轴类零件产生弯曲振型的主共振,解决现有装置产生动应力达不到消减残余应力要求的难题,且轴两端变形量也有很大提高,同时轴的动应力分布更加均匀,从而能有效地消减轴类零件的残余应力。 相似文献
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针对现有部分振动时效控制系统存在的灵活性差、自动化程度低等问题,对振动时效系统中的数据采集、激振电机控制、变频器控制等方面问题进行了研究,对频谱分析法判定工件固有频率的理论依据进行了推导。采用VB和Matlab混编构建了振动时效控制系统,结合数据采集卡、变频器和激振电机等,开发出了振动时效系统。设计了包括数据采集模块和激振电机模块等硬件系统以及包括人机交互界面、扫频模块、频谱分析模块和时效处理模块的控制系统。利用振动时效前后残余应力实测对比法,对振动时效效果进行了定量评定。研究结果表明,经过该系统处理的试件残余应力平均下降了46.62%,达到了振动时效消除残余应力标准,证明了系统的有效性;并且该系统开发周期短、自动化程度较高。 相似文献
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以某公司生产的大型机床床身铸件为研究对象,研究通过在床身铸件铸造过程中,应用高频振动工艺控制铸件的凝固过程,改善铸件的金相组织和相组成均一性,进而改善床身铸件的尺寸精度。通过高频振动对大型床身铸件进行凝固晶粒细化消除内应力根源,同时应用热处理时效进一步进行应力消除,再利用盲孔法检测铸件的残余应力。利用扫描电镜(SEM)观察材料的显微结构,并进行相应的相结构和成分分析。结果显示,床身铸件应用振动凝固工艺,有效地消除工件内部的残余应力,经振动凝固可有避免凝固过程中的残余应力28.72%。床身铸件经热时效处理后,应力消除92.64%。综合应用振动凝固工艺及热处理时效之后,其II类残余应力有效消除≥95%。它为生产该类型产品提供技术参考和指导。 相似文献
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构件中的残余应力是一种不稳定的力学参量,它的存在使得构件在循环应力或外界条件改变时,工件局部产生大的塑性变形,尤其是大型焊件,从而影响工件的正常使用。而振动时效就是利用激振器以机械的方式向工件辅入能量,并利用共振原理,激迫工件在固有频率附近振动或共振,使振动应力与工件内部应力叠加,使材料晶体内部产生细小的塑性变形,从而降低并均化残余应力,获得类似于热时效的效果。下面就将我们研制成功的纵梁振动时效工艺作一简单的介绍。 相似文献
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论述了振动时效的原理和工艺方法,比较了振动时效和自然时效、热时效在消除工件内部产生的残余应力优缺点,指出了振动时效在各类典型工件中应用的措施和经济效益。 相似文献
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北京翔博科技有限责任公司是一家中外合作企业,拥有目前全球最先进的频谱谐波时效专利技术。研制生产的"领航者频谱谐波时效专家系统"解决了振动消除应力技术起源几十年未解决的障碍性难题,可逐步取代以消除应力为目的的热时效技术。频谱谐波时效技术是通过傅立叶分析方法对金属工件进行频谱分析,找出工件的几十种谐波频率,从中优选出效果最佳的五种不同振型谐波频率进行处理,达到多维消除残余应力的目的,提高尺寸精 相似文献
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In this study, residual stress distribution in multi-stacked film by MEMS (Micro-Electro Mechanical System) process is predicted
using Finite Element method FEMi. We develop a finite element program for residual stress analysis (RESA) in multi-stacked
film. The RESA predicts the distribution of residual stress field in multi-stacked film. Curvatures of multistacked film and
single layers which consist of the multi-stacked film are used as the input to the RESA. To measure those curvatures is easier
than to measure a distribution of residual stress. To verify the RESA. mean stresses and stress gradients of single and multilayers
are measured. The mean stresses are calculated from curvatures of deposited wafer by using Stoney’s equation. The stress gradients
are calculated from the vertical deflection at the end of cantilever beam. To measure the mean stress of each layer in multi-stacked
film, we measure the curvature of wafer with the left film after etching layer by layer in multi-stacked film. 相似文献
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Photoelastic experiment has two significant problems. The first problem is manufacturing a model specimen for complicated
shapes of structures. The second problem is residual stress contained in the photoelastic model material. In this paper, the
stress optic law that can be effecitvely used on photoelastic model materials with residual stress is developed. By using
the stress optic law as developed in this research, we can obtain good results in photoelastic experiments using model material
in which residual stress is contained. It is assured that the stress optic law developed in this research is useful. Therefore,
it is suggested that the stress optic law considering residual stress can be applied to the photoelastic experiment for the
stress analysis of the composite materials or bi-materials in which the residual stress is easily contained. 相似文献
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Shang Hyon Shin 《Journal of Mechanical Science and Technology》2005,19(10):1885-1890
The contour method relies on deformations that occur when a residually stressed component is cut along a plane. The method
is based on the elastic superposition principle. When plasticity is involved in the relaxation process, stress error in the
resulting measurement of residual stress would be caused. During the cutting the specimen is constrained at a location along
the cut so that deformations are restrained as much as possible during cutting. With proper selection of the constraining
location the plasticity effect can also be minimized. Typical patterns of longitudinal welding residual stress state were
taken to assess the plasticity effect along with constraining locations. 相似文献
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选用不同的覆盖率对Q345钢试样进行超声波喷丸强化处理.试验结果表明:随着喷丸覆盖率的增加,Q345钢试样表层组织晶粒逐渐变细,显微硬度和表面残余压应力值均不断提高,而表面粗糙度值却随着覆盖率的增加而降低. 相似文献
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微机电系统中热分析的几个问题 总被引:1,自引:0,他引:1
本文针对微传热学及其热分析给出一个理论描述 ,以期促进 MEMS设计理论及研究方法的发展 ,适应设计与制造技术趋于一体化研究的需要。 相似文献
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对液压挖掘机主平台底板和立板T型焊接头的焊接温度场和应力场进行了数值模拟,并对主平台的模型进行了网格划分和工艺参数的确定,结合实际工艺提出了不同的焊接顺序方案,通过计算,分析了不同方案对焊接结构件残余应力的影响,从而为实际生产提供了可靠的数值预测依据。 相似文献
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The demand for high quality and fully automated production, coupled with advances in alloy development, focuses attention on the surface condition of products, especially the residual stresses on the machined surface because of its effect on component performance, longevity, and reliability. Although stainless steel is an important, material with wide application, it is not easy to obtain favorable surface condition, due to its sensitivity to thermal and mechanical operations. In order to obtain favorable surface conditions in a stainless steel component, it is necessary to have practical data which include information concerning tool wear, surface roughness and surface residual stress. In the research toward developing a machinability chart which can provide suitable cutting parameters for the high production rate and good quality surface, and can be used in computer controlled machining tools, surface residual stress distributions in the turning process for stainless steel were studied. Austenitic 304 stainless steel bars were selected as the workpieces and uncoated carbide tools were used in the tests. The obtained results will show residual stress conditions on the machined stainless steel components varying according to cutting conditions. 相似文献
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加工基准对车轴表面加工质量有一定影响,为了定量分析由于偏心切削造成的影响程度,从理论上对加工基准误差与加工后车轴表面残余应力的相对关系进行了分析,针对偏心切削对表面残余应力的影响规律进行了研究。设计了在不同偏心量下的切削加工试验,对切削后试件轴表面残余应力进行了测量,试验结果表明,偏心切削对表面残余应力存在一定影响,但是影响程度不是很大。 相似文献