Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w h...Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w hich is axial feeding distance as related to the applied internal pressure. Due to the complicated nature of plastic deformation, a optimum loading path which w ill guarantee good hydroformed parts free of winkle and fracture has often to be determined by finite element analysis. In order to save trials and errors, adap tive FEM simulation method has been developed. To effectively apply the adaptive simulation method, we have to know the applicability of the method. In this pap er, a classification of tube hydroforming (THF) processes based on sensitivity to loading parameters has been suggested. Characteristics of the classification have been analyzed in terms of failure mode, dominant loading parameters and th eir working windows. It was discussed that the so called pressure dominant THF p rocess is the most difficult process for both simulation in FEM analysis and pra ctical operation in real manufacturing situation. To effectively find out the op timum loading path for pressure dominant THF process, adaptive FEM simulation st rategies are mostly needed.展开更多
构建"厌氧池"和"短程好氧生物滤池"串联而成的短程氮磷无机化反应器,利用陶粒、火山岩和煤渣作为短程好氧生物滤池的填料,通过考察了不同COD容积负荷下三种生物填料的氮、磷无机化效能和有机物去除效果,以及填料表...构建"厌氧池"和"短程好氧生物滤池"串联而成的短程氮磷无机化反应器,利用陶粒、火山岩和煤渣作为短程好氧生物滤池的填料,通过考察了不同COD容积负荷下三种生物填料的氮、磷无机化效能和有机物去除效果,以及填料表层生物膜量沿程变化,筛选出利于短程好氧生物滤池实现农村污水氮磷资源化利用的生物填料和COD容积负荷组合。结果表明,在常温25~35℃下,当COD容积负荷=0.8 kg COD/(m^3·d)时,陶粒和火山岩填料均能达到较好的氮、磷无机化效能和COD去除效果,但通过研究填料生物量的沿程分布,发现火山岩填料上层具有较高的非活性物质,上层易堵塞,不利于连续稳定运行,所以选取陶粒填料较合适;此时,陶粒填料短程好氧生物滤池有机氮无机化率η_(Org-N)和氨氮减少百分比分别为46.78%和23.84%,有机磷无机化增长率Δ_(ηP)和COD去除率分别为13.99%和80.56%,具有良好的除碳保磷保氮的效果,利于农村污水的氮磷资源化利用。展开更多
文摘Tube hydroforming process is a relative new process f or production of structural parts of low weight and high rigidity. The successfu lness of the process depends largely on the a proper selection of loading path w hich is axial feeding distance as related to the applied internal pressure. Due to the complicated nature of plastic deformation, a optimum loading path which w ill guarantee good hydroformed parts free of winkle and fracture has often to be determined by finite element analysis. In order to save trials and errors, adap tive FEM simulation method has been developed. To effectively apply the adaptive simulation method, we have to know the applicability of the method. In this pap er, a classification of tube hydroforming (THF) processes based on sensitivity to loading parameters has been suggested. Characteristics of the classification have been analyzed in terms of failure mode, dominant loading parameters and th eir working windows. It was discussed that the so called pressure dominant THF p rocess is the most difficult process for both simulation in FEM analysis and pra ctical operation in real manufacturing situation. To effectively find out the op timum loading path for pressure dominant THF process, adaptive FEM simulation st rategies are mostly needed.
文摘构建"厌氧池"和"短程好氧生物滤池"串联而成的短程氮磷无机化反应器,利用陶粒、火山岩和煤渣作为短程好氧生物滤池的填料,通过考察了不同COD容积负荷下三种生物填料的氮、磷无机化效能和有机物去除效果,以及填料表层生物膜量沿程变化,筛选出利于短程好氧生物滤池实现农村污水氮磷资源化利用的生物填料和COD容积负荷组合。结果表明,在常温25~35℃下,当COD容积负荷=0.8 kg COD/(m^3·d)时,陶粒和火山岩填料均能达到较好的氮、磷无机化效能和COD去除效果,但通过研究填料生物量的沿程分布,发现火山岩填料上层具有较高的非活性物质,上层易堵塞,不利于连续稳定运行,所以选取陶粒填料较合适;此时,陶粒填料短程好氧生物滤池有机氮无机化率η_(Org-N)和氨氮减少百分比分别为46.78%和23.84%,有机磷无机化增长率Δ_(ηP)和COD去除率分别为13.99%和80.56%,具有良好的除碳保磷保氮的效果,利于农村污水的氮磷资源化利用。
