共查询到20条相似文献,搜索用时 156 毫秒
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对复杂花纹轿车子午线轮胎进行3D建模和高速生热仿真分析,从热力学角度研究带束层结构对轮胎高速温度场的影响,分析帘布层转向效应与花纹结构耦合延缓或加速材料疲劳失效的机理。结果表明:轮胎高速生热与带束层结构参数的相关性从大到小依次为带束层帘线角度、带束层总宽度和带束层帘线经密度;在考察的轮胎行驶速度区间内,行驶速度每提升20 km·h-1,轮胎各易失效观测点的温度提升幅度均大于3 ℃,且轮胎模型左右两侧相同观测点的温度差值随着行驶速度的提升呈增大趋势;胎面花纹沟槽结构对轮胎内部热量的快速扩散有非常重要的作用,合理的花纹结构能够减缓轮胎高速失效,但胎面花纹结构布置需要考虑帘布转向效应的影响,以避免两者相互耦合加速橡胶材料疲劳破坏。 相似文献
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针对高速场景下起重机轮胎胎肩脱层、生热问题,运用有限元分析方法建立纵向花纹445/80R25工程机械轮胎有限元分析模型,进行数值分析和优化及产品性能改善。通过对比分析原始方案轮胎刚性和接地数据的仿真结果与实测结果,验证有限元模型的准确性;优化胎肩部位材料分布,在此基础上采用不同带束层结构方案对胎肩部位受力进行有限元分析,优化带束层端点受力状态。结果表明:胎肩和胎里曲线优化后的B3带束层方案(1#—4#带束层宽度分别为165,103,138和123mm)轮胎胎肩部位受力状态最优,达到改善设计目标;B3方案轮胎的耐久性能比原始方案轮胎提升17%,接地印痕矩形率增大,耐磨性能提升;海外目标客户测试显示,B3方案轮胎早期行驶10000km无胎肩脱层问题,达到改善目标。 相似文献
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《橡胶工业》2017,(8)
介绍24.00R35全钢工程机械子午线轮胎的设计。结构设计:轮胎外直径2 181 mm,断面宽646 mm,行驶面宽度558 mm,行驶面弧高32.88 mm,胎圈着合直径884 mm,断面水平轴位置(H_1/H_2)0.87;胎面花纹采用等节距设计,花纹深度65 mm,花纹饱和度65.8%。使用Solidworks软件对轮胎进行三维设计,通过有限元分析优化轮胎轮廓和材料分布。施工设计:胎面施工采用挤出胶条热缠绕方式,带束层为4层带束层结构,其中1~#—3~#带束层采用7×7×0.22+0.15HT钢丝帘线,4~#带束层采用高伸长的3×4×0.20HE钢丝帘线,胎体采用7×7×0.22+0.15HT钢丝帘线,钢丝圈采用Φ2.0 mm高强度钢丝。成品轮胎试验结果表明,轮胎外缘尺寸和耐久性能达到国家标准和设计要求。 相似文献
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介绍高性能宽基385/65R22.5全钢子午线轮胎的设计。运用经验设计与仿真分析相结合的方法,对模具轮廓及花纹节距排列进行优化,胎面采用耐磨性良好的低滚动阻力胶料。结构设计:外直径 1 070 mm,断面宽 392 mm,行驶面宽度 300 mm,行驶面弧度高 14.5 mm,胎圈着合直径 572 mm,胎圈着合宽度 324 mm,断面水平轴位置(H1/H2) 1.058,胎面采用4条纵向曲折花纹沟变节距设计,花纹深度 16 mm,花纹周节数 3,花纹饱和度 78.5%。施工设计:胎面采用内嵌式双胶结构,带束层采用4层结构,1#带束层采用3×0.20+6×0.35HT钢丝帘线,2#和3#带束层采用3+8×0.33HT钢丝帘线,4#带束层采用5×0.35HI钢丝帘线,胎体采用0.25+6+12×0.225HT钢丝帘线,采用三鼓成型机成型,B型翻转式双模硫化机硫化。成品性能试验结果表明:轮胎充气外缘尺寸、强度性能、耐久性能和高速性能良好,滚动阻力性能达到B级,噪声性能达到A级,雪地性能达到专业雪地轮胎水平。 相似文献
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Dinesh Singh J. K. Gehlawat Musti S. Rao 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1990,47(2):127-136
Oslefins and diolefins are important intermediates in the petrochemical industry and the future promises a further substantial increase in demand. While several catalysts have been formulated in the past for the abstraction of hydrogen from butenes and propylene, these catalysts are inefficient in the abstraction of first hydrogen from butane. Bismuth molybdates (β and γ-phases) containing iron oxide and supported on alumina are used as catalysts in the present investigation on the oxidative dehydrogenation of n-butane. Effects of catalyst content, temperature and oxygen: n-butane ratio on conversion and selectivity to butadiene and (C4H8 + C4H6) are studied in the following ranges of experimental conditions: β-bismuth molybdate/100 mol support I(K), 3–9; γ-bismuth molybdate/100 mol support I(K), 5-20; temperature, 400–500°C; O2: butane ratio, 0.6:1.7. 相似文献
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考登钢作为一种高耐候结构钢,广泛应用于各个领域。在火力发电方面,考登钢主要应用在工作环境比较恶劣的烟气加热器和空气预热器中。考登钢表面涂搪的目的就是进一步提高其耐腐蚀性能,延长使用寿命。为了提高考登钢元件的使用寿命,对考登钢表面涂搪瓷的可行性、密着性能、瓷釉、工艺控制、质量保证等方面进行了研究。 相似文献
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A viscometer used to measure the viscosity of 10 μl of a liquid, must be miniaturized down, and the liquid velocity gradient in the channel used to determine the viscosity coefficient. Two major factors that affect the liquid velocity are the mechanical forces exerted by the mechanical motors and electromagnetic forces. In this study, electrowetting on dielectric (EWOD) is adopted to drive liquids. Variously sized electrodes on a chip, and two shapes of channel are employed to measure the velocity gradient to determine the viscosity coefficient. The device is fabricated by microelectromechanical system (MEMS) technology. The dielectric layer used in EWOD has a high dielectric constant, BST (Ba0.7Sr0.3TiO3), to reduce the required applied voltage; its surface is coated with hydrophobic polymer, polytetrafluoro-ethylene (PTFE, Teflon® AF DuPont). Experimental results demonstrate that liquids can be pulled at 660 μm/s in linear channels by applying a voltage of 15 V. 相似文献
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采用实验方法考察工艺参数对沉降斑的影响。基于一个带凸台的平板模具,采用L27(313)正交矩阵进行实验,研究了几何尺寸、熔体温度、注射时间、保压压力及保压时间对厚度突变处沉降斑形成的影响,同时还考虑了熔体温度和注射时间以及保压压力和注射时间之间的交互作用影响;通过性噪比分析和F检验优化成型工艺条件并对工艺参数的影响进行显著性分析。结果表明,对于厚度突变的平板制品,厚度突变的程度对其沉降斑形成的影响最大,其次为熔体温度,保压压力,保压时间等;采取减小厚度变化,降低熔体温度或增加保压压力和保压时间等措施,可以减小厚度突变处沉降斑,从而减少其对外观质量的影响;因素之间的交互作用对制品沉降斑的形成有一定的影响,熔体温度B和注射时间C之间的交互作用影响较为明显,而保压压力D和注射时间C之间的交互作用对该质量指标的影响最小,可以并入误差。 相似文献
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In reexamining medium effects on photochemical reactions, we have emphasized those on unequilibrated excited species such as the Franck-Condon species. Despite recent advances in femtochemistry, such a discussion in molecular photochemistry is uncommon, and the problem remains challenging on account of the extremely short-lived excited species. However, in such cases, a small perturbation resulting from, for example, weak guest-host interactions could turn into a determining factor in dictating the course of a photochemical channel of deactivation. Examples of medium-directed diabatic processes have been examined with this idea in mind. A modified view on rhodopsin photoisomerization is presented along with the consideration that confinement does not necessarily lead to inhibition of reactions of the trapped substrate. 相似文献
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研究了温度和pH值对漆酶酶活以及漆酶处理纤维压制纤维板性能的影响。结果表明,pH较低、温度较高时漆酶酶活较高,压制的纤维板强度性能较好。但温度太高(60~80℃),延长加热时间,漆酶稳定性变差,酶活明显降低,压制纤维板的强度下降。 相似文献