基于正交试验的楔形橡胶减振器三向刚度研究

利用Solidwork软件建立楔形橡胶减振器三维模型,由单轴压缩试验得到橡胶材料（天然橡胶胶料）的应力-应变曲线,通过有限元仿真结果与试验结果对比确定Mooney-Rivlin模型为橡胶材料本构模型;采用正交试验方法,以橡胶材料邵尔A型硬度、橡胶层厚度、橡胶层倾斜角度及钢板数量为变量因子,研究其对楔形橡胶减振器三向刚度的影响。结果表明：橡胶材料邵尔A型硬度和橡胶层倾斜角度增大,楔形橡胶减振器的轴向和纵向刚度先增大后减小;橡胶层厚度增大,减振器的轴向和纵向刚度减小;钢板数量增多,减振器的轴向和纵向刚度增大;这4个变量因子对减振器的横向刚度影响不大;同时满足减振器三向许用刚度的橡胶材料邵尔A型硬度、橡胶层厚度、橡胶层倾斜角度和钢板数量分别为66度以上、30～35 mm、64°～67°、1—2。     

基于回归分析的机车车辆用橡胶关节径向刚度检测方法

通过数据分析发现,机车车辆用整体式橡胶关节径向刚度(有套筒工装)与轴向刚度(无套筒工装)之间和有/无套筒工装的径向刚度之间具有线性相关性,通过回归分析获得整体式橡胶关节径向刚度与轴向刚度之间和有/无套筒工装径向刚度之间的回归方程。径向预压式橡胶关节及轴向预压式橡胶关节径向刚度与压装刚度也具有线性相关性,可通过回归方程以橡胶关节压装刚度计算其径向刚度。本回归分析方法可以提高橡胶关节径向刚度的检测效率,拟合偏差在±5%以内。     

橡胶-钢球支座刚度的有限元分析

通过非线性有限元方法对橡胶-钢球支座在轴向拉伸、扭转和弯曲的大变形载荷作用下的力学行为进行分析,得出支座的轴向刚度、扭转刚度和弯曲刚度与变形的关系。轴向刚度和弯曲刚度随着变形的增大而减小,扭转刚度随着变形的增大而增大,但总的来说,变化很小。     

轴棒法C／C复合材料微观结构及性能分析

采用轴棒法4D预制体、煤沥青为前驱体,经过常压、高压相结合的液相浸渍一炭化的致密工艺,制备出高密度轴棒法C／C复合材料。研究了轴棒法C／C复合材料的微观结构及其对轴向室温、高温（2800℃）拉伸破坏形式的影响。结果表明：轴棒法C／C复合材料轴向增强体采用炭棒,出现了一个特殊的界面,即炭棒与基体的“间隙”,主要原因是炭棒内部结合较强和纤维、基体的热膨胀系数不匹配而引起的;间隙的存在,使得轴棒法C／C复合材料的轴向室温、高温拉伸破坏形式出现较大差异,室温拉伸由于界面结合强度弱而引起的炭棒完整的拔出,未起到纤维应有的增强作用;高温拉伸却由于受热膨胀,间隙愈合,界面结合变强,试样从有效部位断裂,纤维增强作用明显提高。     

液压悬置橡胶主簧静态力学特性计算与试验研究

运用有限元理论和Abaqus分析软件建立某小型客车动力总成液压悬置橡胶主簧的有限元离散模型,探讨橡胶主簧的轴向与径向静态力学特性的仿真计算方法,对比仿真计算结果与试验结果,验证了有限元分析方法的正确性。计算分析了胶料硬度对橡胶主簧静态力学特性的影响,结果表明,橡胶主簧静态刚度与胶料硬度正相关,且径向刚度对橡胶硬度更为敏感。     

悬架筒式减震器橡胶衬套刚度和拉脱力试验与计算分析

以一款悬架筒式减震器橡胶衬套为例,应用非线性有限元分析软件ABAQUS计算其各向刚度和拉脱力,并与测试值进行对比。计算结果与测试数据吻合证明了分析方法的有效性。另外,还计算和分析了缩径对橡胶衬套各向刚度的影响。结果表明,随着过盈量的增大,橡胶衬套的径向和偏摆刚度显著提高,轴向刚度缓慢降低,扭转刚度基本不变。     

SiC含量对C/C-SiC复合材料弯曲强度及抗氧化性能的影响

选用聚碳硅烷（PCS）为前驱体，对密度分别为1．34g／cm^3，1．52g／cm^3和1．62g／cm^3的针刺炭布C／C材料进行液相致密化处理，制得密度达1．75g／cm^3的C／C-SiC复合材料，并与密度为1．85g／cm^3的同结构高密度C／C材料的弯曲强度和抗氧化性能进行了对比分析。结果表明：密度为1．34g／cm^3的C／C材料经过PCS致密化处理，在保持高密度C／C材料的弯曲强度同时，显著提高了材料的抗氧化性能。     

弹性车轮橡胶块疲劳寿命分析及刚度设计

采用Mooney-Rivlin模型,建立了弹性车轮橡胶块非线性有限元本构模型,并仿真分析和计算了橡胶块运行过程中各工况下的应力和应变;研究了弹性车轮整体刚度与橡胶块使用寿命的关系。结果表明,为保证弹性车轮的使用安全性和经济性,弹性车轮径向刚度和轴向刚度设计范围应在100～200 MN/m和10～20 MN/m之间。     

致密化工艺对C/C复合材料性能的影响

以三种致密化工艺对2D炭布针刺预制体进行致密，得到三组C／C复合材料，对其进行力学、热学性能检测及微观结构分析，并用C／C复合材料抗热震指标对三种致密化工艺所制备试样的性能进行综合评价，考察并比较了不同致密化工艺对C／C复合材料性能的影响。结果表明，采用化学气相沉积、沥青高压浸渍炭化及树脂常压炭化工艺所制备的RLS试样具有较好的综合性能。     

炭基体结构状态对C/C复合材料抗烧蚀性能的影响

碳基体在C／C复合材料的组成中占有很大的比重，因此炭基体不同的结构状态往往对C／C复合材料的各项性能有显著的影响。本文利用不同的原料和加工工艺制备出了三种具有不同炭基体的C／C复合材料，这三种碳基体分别是热解炭，沥青炭以及解热炭－树脂炭混合炭基体。对这三种材料多项性能的测试结果表明，炭基体的结构状态如石墨化度，炭片层结构的取向度的不同对C／C复合材料的各项性能均有显著的影响；基本趋势是C／C材料的石墨化度越高，材料的导电性能，导热性能以及抗烧蚀性能越好，压缩强度越低。三种炭基体中沥青炭基体沿纤维轴向的取向度最低，其抗烧蚀性能最差。     

橡胶Mooney-Rivlin模型力学性能常数的确定

用非线性有限元分析法和轴向压缩试验确定橡胶材料Mooney—Rivlin模型力学性能常数C1和C2。先由橡胶材料硬度计算出C1与C2之和，再通过非线性有限元分析法模拟不同C2／C1下橡胶材料的压缩应力-应变曲线并与实测曲线比较，与实测曲线重合性最好的模拟曲线的C2／C1即为橡胶材料的实际C2／C1，进而求得C1和C2。     

油浸式电抗器用阻尼橡胶材料压缩阻尼特性与本构模型

通过对油浸式电抗器器身-油箱间阻尼橡胶材料进行轴向压缩滞回性能试验,研究了其阻尼特性;依据实验数据并结合ABAQUS数值模拟结果,校正了适用于油浸式电抗器器身-油箱间阻尼橡胶材料的Mooney-Rivlin和Yeoh本构模型参数。结果表明,相比普通抗振橡胶试件,丁腈橡胶试件的轴向压缩刚度更大,滞回曲线更饱满,耗能能力更强;Mooney-Rivlin模型和Yeoh模型均适用于NBR试件的小变形和大变形行为,其中Mooney-Rivlin模型参数和Yeoh模型参数计算结果最大误差分别为-11.31%和-12.21%。     

Strain-induced crystallization of natural rubber as studied by high-resolution solid-state C NMR spectroscopy

A series of high-resolution solid-state ¹³C NMR experiments were performed on both unstretched and in situ stretched natural rubber samples. From the ¹³C CP/MAS spectra, it was found that natural rubber does form small crystals at room temperature though the degree of crystallinity is very small. Furthermore, from the ¹³C DD/MAS spectra, the crystalline signals were found to increase with the increase of draw ratio. ¹³C spin-lattice relaxation time (T₁) and ¹H spin-spin relaxation time (T₂) of in situ stretched natural rubber were measured for the first time, which provided further evidences for the conclusion that there exist crystals in both stretched and unstretched natural rubber samples. Quantitative ¹³C NMR measurements indicated that strain-induced crystallization occurs when the draw ratio reaches about 2.0 and the maximum crystallinity of our natural rubber samples can be as high as 19.3% upon stretching.     

树脂对硅橡胶性能的影响

研究了PS树脂、2112树脂、C5/C9石油树脂等3种树脂时硅橡胶混炼胶力学性能和阻尼性能的影响.结果表明,加入PS树脂可提高硅橡胶的力学性能,加入C5/C9石油树脂或2112树脂对硅橡胶力学性能无明显影响;加入C5/G9石油树脂和2112树脂对硅橡胶阻尼性能无明显影响,但加入PS树脂对硅橡胶高温阻尼性能有一定改善作用;加入C5/C9石油树脂和2112树脂对硅橡胶的高低温模量变化影响不大,但加入PS树脂使硅橡胶的高低温模量变化超过2个数量级,影响其模量稳定性,不利于在高低温环境下减振材料的实际应用.     

Effects of clay on phase morphology and mechanical properties in polyamide 6/EPDM-g-MA/organoclay ternary nanocomposites

In this study, both organoclay and EPDM-g-MA rubber were used to simultaneously improve the toughness and stiffness of polyamide 6 (PA6). We first prepared PA6/EPDM-g-MA/organoclay ternary nanocomposites using melt blending. Then the composites were subjected to traditional injection molding and so-called dynamic packing injection molding. The dispersion of clay, phase morphology, crystallinity and orientation of PA6 as well the mechanical properties were characterized by WAXD, SEM, DSC, 2D-WAXS and mechanical testing, respectively. The effects of clay on phase morphology and mechanical properties of PA6/EPDM-g-MA blends could be summarized as follows: (1) weakening interphase adhesion between PA6 and EPDM-g-MA rubber particles, resulted in increasing of rubber particle size, as the clay and rubber contents are low; (2) preventing coalescence of rubber domains, arisen in decreasing of rubber particle size, as the clay and rubber contents are high; (3) the blocking effect on the overlap of stress volume around rubber particles caused broadening of the brittle-ductile transition region and decrease of toughness, and (4) the effective stress transfer leading a better reinforcement when the interparticle distance is smaller than the critical value.     

测试条件对微孔橡胶垫板动刚度及动静比的影响

建立了微孔橡胶垫板结构简化模型,对动静比与能量损耗的关系进行了定性分析,并考察了测试频率和加载力值对动刚度和动静比的影响。结果表明,在外力作用下,橡胶垫板的内耗越大,则动刚度和动静比越大;随着测试频率和加载力值的增加,动刚度和动静比均增大。     

两种石油树脂对再生胶性能影响的研究

研究了C5石油树脂和C9石油树脂用量对再生胶性能的影响。结果表明,加入C9石油树脂的再生胶具有较短正硫化时间、较低门尼粘度和较高拉断伸长率。当C9石油树脂用量为3~5份时,再生胶具有较好综合性能。     

炭前驱体形态对C/C复合材料导热系数的影响

利用热塑性中间相沥青为黏结剂,短炭纤维.增强体,一步热压成型制备C/C导热复合材料.采用SEM和偏光显微镜观察等分析手段,研究了2∶1,2.5∶1和3∶1三种不同管径比对C/C复合材料的影响.结果表明:通过热压模具空腔结构的改变可以引起炭前驱体挤出形态的变化,使得轴向基体炭有序生长与短炭纤维增强体呈现有序排列,其中间相液晶分子垂直和平行于模压压力方向均排列成纤维状长程有序结构,短切纤维呈现出与压力平行方向排布.当空腔管径比为3:1,轴向导热系数由86.2 W/(m·K)增大至115.5 W/(m· K),各向异性比由1.6减小为1.2.由此所得块体C/C复合材料具有显著的二维取向结构,轴径向导热系数趋于平衡.     

Hygroscopic-aging behavior of pure and NaCl-filled polyurethane rubber

The aging phenomenon of highly filled rubber in humid environment was investigated. HTPBD was reacted with MDI and mixed with salt at the same time. The mixture was then hot-pressed for 24 h at 90°C to prepare the sample. The changes in mechanical properties and glass transition temperature of the sample were followed when they were subjected to different humidity at 30°C for 7 days. Furthermore, the effects of humidity on chemical structures were studied with IR. The results showed that unfilled rubber suffered no changes in mechanical properties after 7 days in environment of high humidity (RH 97). However, for NaCl-Filled rubber, its strength decreased because of a loss of stiffness of salt after salt deliquesced. The glass transition temperature of unfilled rubber seems not to be affected by various humid conditions, but the T_g of filled rubber decreased slightly. From SEM pictures, we observed that interior holes were left after salt deliquesced. This was the main cause for the reduction in mechanical properties of filled rubber.     

Rubber toughening of nylon 6 nanocomposites

The rubber toughening of nylon 6 nanocomposites prepared from an organoclay was examined as a means of balancing stiffness/strength versus toughness/ductility. Nine different formulations varying in montmorillonite, or MMT, and maleated ethylene/propylene rubber or EPR-g-MA rubber content were made by mixing of nylon 6 and organoclay in a twin screw extruder and then blending the nanocomposites with the rubber in a single screw extruder. In this sequence, the MMT platelets were efficiently dispersed in the nylon 6 matrix. The MMT platelets did not penetrate into the rubber phase. The addition of clay affected the dispersion of the rubber phase resulting in larger and more elongated rubber particles. The tensile properties and impact strength of these toughened nanocomposites are discussed in terms of the MMT and rubber contents and morphology. There is a clear trade-off between stiffness/strength versus toughness/ductility.