一种钢车轮辐底高耐久性设计方法研究

轮辐由辐底非回转体和辐底之外的回转体结构两部分组成,它们共同决定了轮辐的疲劳强度和刚度,本文主要研究一种钢车轮辐底高耐久性设计方法,利用HS高压感压纸对辐底进行安装面拓印试验,然后以试验结果为参考依据,通过对轮辐5段外安装面采用轴向摆角度、周向带高度差设计;螺栓孔凸包、尾筋与轮辐外安装面呈断开设计,以此来提升辐底疲劳强度和刚度,使试验失效点避开辐底,后续通过对样件进行试验验证,证明了该设计方法的可靠性。本文以东风本田2WB项目为研究对象,结果表明:采用该设计方法后,失效位置从辐底转变为辐顶区域,疲劳寿命从26.5万次提升至76万次,通过了整车性能试验评价,获得了项目定点开发资格,研究结果可以为其它同类产品设计提供参考。

Investigation of thermal radiation effect on optical dome of sapphire coated yttrium oxide

Compared to traditional optical domes, domes of sapphire coated with films can effectively reduce emissivity and increase transmittance. The purpose of this work is to investigate the thermal radiation effect on sapphire optical dome coated with yttrium oxide by a radio frequency mag- netron sputtering method. The emissivity of sapphire coated with Y203 films is studied by both numerical and experi- mental methods. The results indicate that the emissivity of sapphire substrate is reduced effectively with increasing the thickness of the Y203 film. In addition, a finite element model is developed to simulate the radiation intensity of the optical dome. The thermal responses indicate that the max- imum temperature is reduced apparently compared with the uncoated sapphire as Y203 film thicknesses increase. The average irradiance distribution at different film thicknesses with time shows that the self-thermal radiation disturbance of sapphire optical dome delays 0.93 s when the thickness of Y203 film is 200μm, which can guarantee the dome works properly and effectively even in a harsh environment.

日本大地震之后

北京时间3月11日14时46分,日本东北部宫城县以东太平洋海域发生日本迄今震级最高地震——里氏9.0级地震,震源深度20公里,地震引发了高达10米的海啸,整个日本东北部海岸遭遇不同程度的海啸袭击。东京有强烈震感,仙台大部分地区被海啸淹没。据日本警察厅证实,截至3月28日,日本地震和海啸已经造成28550人遇难或失踪。其中,10901人已被证实遇难,登记在册的失踪者为17649人。除重大人员及财产损失外,在地震和海啸中受损的福岛核电站发生爆炸,令核危机成为日本民众和全球舆论关注的焦点。此外,大地震还撼动全球金融、资本和商品市场,造成股市下跌,国债上涨,原油价格滑落,令复苏中的全球经济充满变数。