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1.
角接触球轴承在运行过程中的润滑状况至关重要,润滑油直接影响滚动轴承的接触状态。为分析角接触球轴承的润滑状况以及考虑润滑时轴承的机械特性,基于有限元和晶格玻尔兹曼方法,建立了双向流固耦合轴承仿真模型,对角接触球轴承进行动力学有限元仿真和润滑流体仿真,并与轴承拟静力学理论计算结果进行对比,验证模型的准确性。分析结果表明,保持架与滚珠接触并撞击,在轴承腔内油膜压力最大,滚珠与内圈、外圈滚道接触区分别为第二、第三大油膜压力区。润滑油受滚珠公转影响,沿着滚珠转动方向流动,实现对滚珠与内圈、外圈和保持架之间的润滑。滚珠运动和最大接触应力仿真结果与轴承拟静力学理论求解结果一致,即流固耦合仿真模型计算轴承机械特性具有较高的准确性。 相似文献
2.
拉臂机构作为拉臂式垃圾车的关键部位,直接决定整车的可靠运行与人员操作体验,文中在分析拉臂机构的力学特性基础上,计算出在装卸工况下的载荷,利用有限元分析软件,对拉臂机构关键部位进行静态有限元分析与模态分析,分析结果表明拉臂机构符合动态性能要求,但其工作时强度不足,需对此进行结构优化。通过对拉臂机构进行局部修改,采取必要的辅助措施,使其达到符合静态性能要求的目的。在满足拉臂机构静动态性能要求上,装箱工况最大应力降低了23.3%,卸箱工况最大应力降低了24.9%,较好地达到了提高拉臂机构安全性能的目的。 相似文献
3.
Aniruddha Nag Mohammed Asif Ali Jiabei Zhou Makoto Ogawa Tatsuo Kaneko 《大分子材料与工程》2021,306(11):2100459
Aromatic and functional polymers with processibility derived from biobased starting materials are prerequisite considering sustainable society. Poly(2,5-benzimidazole)s are rigid-rod polymers to show ultrahigh thermal stability such as flame retardance, while usually suffer from poor solubility. Here, poly(benzimidazole-co-amide)s are synthesized from two biobased monomers, 3,4-diaminobenzoic acid and a semirigid comonomer, 4-aminohydrocinnamic acid. The copolymers with an amide composition of 80 mol% and higher are soluble in widely used polar solvents to fabricate the films keeping high flame retardance, which is comparable with popular high-performance polymers such as aromatic polyimides, polyetheretherketone, polyphenylene sulfide, etc. 相似文献
4.
5.
对激光选区熔化(Selective laser melting,SLM)成形马氏体时效钢进行固溶及500 ℃时效不同时间的热处理,分析时效时间对其组织性能的影响。结果表明:SLM 18Ni300钢经固溶+时效处理后,其组织为马氏体、逆转变奥氏体和Ni3(Mo, Ti)析出相,随时效时间增加,析出相数量逐渐增加并聚集长大,同时逆转变奥氏体含量增大。随时效时间的增加,其硬度和强度逐渐增加达到峰值后下降,而伸长率不断增加。SLM 18Ni300钢的最佳时效工艺为500 ℃×4 h。 相似文献
6.
Huahai Shen Menglu Li Pengcheng Li Haiyan Xiao Haibin Zhang Xiaotao Zu 《Journal of the American Ceramic Society》2021,104(5):2301-2312
In the past decades, pyrochlores, such as Gd2Zr2O7, have demonstrated great potential to immobilize nuclear wastes such as Pu, which results in the production of Pu2Zr2O7. Due to the high radioactivity of Pu, it is difficult to investigate the radiation response behavior of Pu2Zr2O7 and its physical properties of the damaged state experimentally. Consequently, few related data have been reported in the literature thus far. In this study, first-principles calculations have been carried out to investigate the defect formation and its effect on the thermodynamic properties of Pu2Zr2O7. It reveals that PuZr antisite and O8a interstitial defects are very easy to form in Pu2Zr2O7. In particular, the O8a interstitial defect can be formed spontaneously, while it is mechanically unstable. When vacancy, interstitial or antisite defects are formed in Pu2Zr2O7, and the elastic moduli and Debye temperature are decreased. Besides, better ductility is resulted. As compared with other zirconate pyrochlores, such as Gd2Zr2O7, the Pu2Zr2O7 is suggested to be less resistant to radiation-induced amorphization. This study demonstrates that the created defects due to self-radiation from actinide decay have remarkable influences on the thermophysical properties of Pu2Zr2O7. 相似文献
7.
湿法脱硫排出的废水是燃煤机组废水中最难处理的末端废水之一。热法固化是实现脱硫废水零排放的必然途径。通过构建整个燃煤机组厂级尺度热力系统虚拟仿真模型,从能量流、物料流、水平衡及其之间的相互影响机制的角度对比分析了目前三种主流不同脱硫工艺路线的优劣。在此基础上,提出了基于吸附式热泵和多效蒸馏浓缩,废热用于干燥的新型脱硫工艺,新工艺所需的高温烟气量最小,仅为旁路直喷式的1/5,为目前主流浓缩干燥方案的1/3,在回收水分的同时,极大降低高温烟气的消耗量,降低对主机安全性的影响。相关研究可以为燃煤机组脱硫废水零排放及深度节水提供新的解决思路。 相似文献
8.
Yunhai Zhang Yongsheng Liu Yejie Cao Liyang Cao Jing Wang Yu Pan Ning Wang 《Journal of the American Ceramic Society》2021,104(1):645-653
C/SiC composites prepared by chemical vapor infiltration technique (CVI) have been regarded as thermal structural materials widely. However, these composites still suffer from poor functional properties like low thermal conductivity, especially in thickness direction of the composites, limiting their large-scale applications. Herein, mesophase pitch based carbon fiber (MPCF) and continuous wave laser machining were utilized to construct highly effective heat conductive micro-pipelines within CVI C/SiC composite. The effect of initial density on the final density and thermal conductivity of the as-obtained MPCF-C/SiC composites were investigated. The results revealed that higher initial density would directly enhance the thermal conductivity and reduce the negative impact of the bottle-neck effect. At temperatures between 100°C and 500°C, MPCF-C/SiC composites preserved more than threefold of the thermal conductivity (340%) when compared to reference C/SiC composites. This work provides a highly effective route for enhancing the thermal conductivity of C/SiC, which would broaden their future applications. 相似文献
9.
Thomas Fehn Felix Kugler Beatrice Tübke Rainer Schweppe Phillip Mebert Wolfgang Krcmar Ulrich Teipel 《化学,工程师,技术》2021,93(5):771-780
Due to the growing energy requirements, the proportion of external thermal insulation composite systems (ETICS) installed has increased significantly during the past 50 years. Due to the longevity of these systems, ETICS waste is currently accumulating. Owing to the complex construction as well as a multitude of differently installed materials and substances of the past generations, there are many uncertainties and problems with the clean and low-pollutant processing of such systems. In the frame of this work, the ETICS were processed and sorted before being screened for ingredients or pollutants as well as for the purity of the recovered material fractions. 相似文献
10.