表面缺陷对硅橡胶密封件接触特性的影响

以典型舱门橡胶密封件为研究对象,基于自制的密封接触特性试验装置,研究不同直径表面缺陷对硅橡胶密封件表面接触特性的影响。结果表明:缺陷直径对接触面积和平均接触压力影响较大,缺陷直径越大,接触面积越小,平均接触压力略有增大;缺陷直径对缺陷周围接触效果影响较大,直径越大,接触特性越差;表面缺陷对密封件密封性能影响显著。     

表面缺陷对硅橡胶密封件接触特性影响的试验研究

以典型舱门橡胶密封件为研究对象,基于自制的密封接触特性试验装置,研究不同直径表面缺陷对硅橡胶密封件表面接触特性的影响。结果表明：缺陷直径对接触面积和平均接触压力影响较大,缺陷直径越大,接触面积越小,平均接触压力略有增大;缺陷直径对缺陷周围接触效果影响较大,直径越大,接触特性越差;表面缺陷对密封件密封性能影响显著。     

表面缺陷对硅橡胶密封性能的影响规律研究

采用有限元方法研究金属表面凸起缺陷对硅橡胶密封性能的影响规律。基于ABAQUS软件,建立密封接触过程有限元模型。重点分析表面凸起的高度、半径和位置对密封性能的影响。结果表明:表面凸起缺陷对密封性能影响显著;高度和位置对接触压力和接触面积影响较大,凸起的高度越大、距离接触压力的峰值位置越近时,越容易发生泄漏;而凸起半径对密封性能的影响相对较小。     

安装过盈量和介质压力对旋转轴唇形橡胶密封圈密封性能的影响

以水下工作的旋转轴唇形橡胶密封圈(简称唇形密封圈)为研究对象,基于有限元分析方法研究安装过盈量和介质压力对唇形密封圈密封性能的影响。使用ANSYS软件创建唇形密封圈的三维轴对称有限元分析模型。仿真结果表明:唇口接触宽度与最大接触压力随着安装过盈量的增大而增大,且安装弹簧的唇形密封圈接触宽度和接触压力比未安装弹簧的唇形密封圈大;随着介质压力的增大,唇口最大接触压力增大,接触压力的最大值出现在唇口尖端处,最大接触压力始终大于介质压力。     

机械密封摩擦副端面接触分形模型的修正

分析了原机械密封摩擦副端面接触分形模型存在的问题,并进行了修正,得到了摩擦副端面微凸体承载面积比与端面比压的关系式。修正模型考虑了摩擦副端面间流体膜压的作用、微凸体实际微接触面积与微接触截面积之间的区别,并通过采用一个三次多项式来表达弹塑性变形微凸体的接触压力与接触面积的关系,从而满足了接触微凸体在变形状态转变临界点处的接触面积与接触压力转化皆是连续和光滑的条件。依据修正后的接触分形模型对密封面配对材料为硬质合金YG8-碳石墨M106K的部分平衡型机械密封摩擦副端面微凸体承载面积比的影响因素进行了分析。结果表明,微凸体承载面积比随着弹簧比压的增大近似呈线性增大,随着密封流体压力的增大而非线性单调增大,随着端面分形维数的增大先增大后减小,随着端面特征尺度系数的增大而减小;在正常工作参数范围内,真实接触面积仅占名义接触面积的很小一部分。     

高速列车塞拉门橡胶密封条的结构优化和压缩特性研究

采用两参数Mooney-Rivlin超弹性本构模型,对比不同硬度高速列车塞拉门橡胶密封条的压缩载荷-压缩量的仿真结果与试验结果,确定不同硬度密封条的材料常数;对优化后密封条的压缩特性进行仿真分析和对气密性进行试验验证。结果表明：在4 mm压缩量下,优化前后的密封条与门框压条间的最大接触压力基本相同;与优化前密封条相比,优化后密封条的压缩载荷减小了29.4%,密封性能提高了近1倍。     

轴压作用下缠绕复合材料夹芯圆柱壳力学性能研究

为研究缠绕复合材料夹芯圆柱壳的力学特性,首先开展了缠绕复合材料夹芯圆柱壳模型的轴向压缩试验,得到载荷-位移曲线与应变分布规律;进而,依据复合材料经典层合板理论,将缠绕圆柱壳模型的内外蒙皮均匀化,等效为单向纤维增强复合材料,采用ABAQUS有限元软件对结构模型进行分析,得到不同载荷下的应变规律;最后,将有限元计算结果与试验结果进行对比,轴向刚度误差为10.69%,测点应变值最大误差为12.88%,表明该方法可用于缠绕复合材料夹芯圆柱壳计算,为复合材料夹芯圆柱壳的设计应用提供指导。     

飞机舱门密封系统的仿真分析与优化设计

对飞机舱门（简称舱门）密封系统进行仿真分析,通过正交试验对密封带的结构和材料进行优化设计。结果表明：密封带的截面圆角半径对舱门密封系统的应力产生影响,密封带的截面圆角半径为3.5 mm时舱门密封系统的压缩应力最小,最大接触应力最大;密封带的内部增强织物能同时提高舱门密封系统的压缩应力与最大接触应力,但对压缩应力的影响较小;密封带采用35U硅橡胶材料时舱门密封系统的压缩应力与最大接触应力最小,密封带采用75U硅橡胶材料时舱门密封系统的压缩应力与最大接触应力最大;舱门密封系统的压缩应力与最大接触应力随着密封带的硅橡胶材料邵尔A型硬度的增大而增大。当密封带的截面圆角半径为3.5mm、采用邵尔A型硬度为50度的55U硅橡胶材料、内部有增强织物时,舱门密封系统的密封性能最优。     

粉煤灰混凝土的碳化-冻融特性研究

为了分析粉煤灰混凝土的碳化-冻融特性,制备了不同粉煤灰掺量的混凝土样品,利用室内试验方法对混凝土样品迚行冻融循环和碳化,分析混凝土样品的质量损失率、相对动弹性模量和碳化面积随粉煤灰掺量和冻融-碳化周期的变化觃律。研究结果表明:在冻融-碳化条件下,粉煤灰混凝土的质量损失率、弹模损失率以及碳化面积率均随粉煤灰掺量的增大出现了先增大后减小再增大的现象;对比分析结果表明,粉煤灰混凝土的碳化能够在一定程度上提高其抗冻能力;粉煤灰混凝土的碳化面积率随着冻融-碳化循环次数的增加而增大,且当冻融-碳化循环大于一定周期后,碳化面积趋于稳定。     

摩擦对胎面材料单轴压缩力学行为的影响

为获取摩擦因数对胎面材料压缩力学行为的影响规律,进行了准静态单轴压缩试验,并采用ABAQUS有限元分析软件对不同摩擦因数下胎面胶的压缩行为进行研究。结果表明:随着摩擦因数的增大,胎面材料单轴压缩弹性模量增大;橡胶试样上表面的膨胀半径随摩擦因数的增大而减小,而中性面的膨胀半径先增大后减小;接地压力在摩擦因数为0.4左右时趋于最大。     

芳纶短纤维增强硅橡胶阻尼材料的制备及性能研究

以芳纶纤维和苯基硅橡胶为原料,制得芳纶短纤维增强硅橡胶阻尼材料,研究了纤维长度、纤维用量及纤维处理方式对阻尼材料力学性能与阻尼特性的影响。结果表明,硫酸酸蚀处理可增大纤维表面粗糙度,而硅烷偶联剂则附着于纤维表面,实验所涉纤维处理方式中,γ-(甲基丙烯酰氧)丙基三甲氧基硅烷与纤维的结合最好,以其制得的阻尼材料的拉断伸长率最高,达到524%。阻尼材料的弹性模量随纤维长度的增加变化不明显,但随纤维用量的增加而略有增加。纤维长度对阻尼材料的储能模量与损耗因子的影响较小;而随着纤维用量的增加,材料的储能模量与损耗因子增加,使得材料的阻尼性能得到改善。相比于基体硅橡胶,制备的短纤维增强阻尼材料的损耗因子提高明显。     

低模量硅橡胶的配合及性能

通过原材料选择及配合剂的变量试验,探讨了各配合体系对硅橡胶硫化胶性能的影响,并确定了低模量硅橡胶胶料的基本配方。其硫化胶物理性能为:拉伸强度≥7 0MPa,拉伸弹性模量<0 40MPa,剪切强度≥2 4MPa,剪切模量<0 30MPa,基本满足弹性材料力学性能设计指标的要求。     

On the Role of Both Polypropylene Fibers and Silica Nanoparticles on the Viscoelastic Behavior of Silicone Rubber Nanocomposites

In the present study, silica nanoparticles and polypropylene fibers were added to silicone rubber matrix and their effect was investigated on the viscoelastic behavior of silicone rubber composites by dynamic mechanical analysis and compression set test. Bonding of the reinforcements with silicone rubber matrix was studied by Fourier transform infrared spectroscopy (FTIR). The results proved that the role of silica particles on the elastic modulus of silicone rubber was more effective than that of polypropylene at room temperature because of higher stiffness and also partial interaction of polypropylene with matrix.     

Direct laser etching of hierarchical nanospheres on silicon rubber surface with robust dynamic superhydrophobic stability

Silicone rubbers with high dynamic superhydrophobic stability have an extensive application prospect. Applying direct laser etching technology, a fast and efficient method is proposed for the preparation of silicone rubber surfaces with hierarchical nanospheres and robust dynamic superhydrophobicity. A 4 μl water droplet on the laser modified silicone rubber surface exhibits a contact angle (CA) of 154 ± 3° and a roll-off angle (RA) of 5 ± 1°, there is a 65.6% increase in CA compared with the pristine silicon rubber. Moreover, the modified surface can stabilize its superhydrophobic state under a dynamic pressure of 1960.2 Pa. Interestingly, no significant change in the contacting time for the droplets with different impacting speed is found, which means that the stabilized contact time and robust dynamic superhydrophobicity are induced on the modified silicone rubber surface. The self-cleaning and anti-icing properties on the modified surface can effectively reduce the damage caused by surface pollution, ice formation, and other natural factors when applied to power lines, sealing elements, and automotive.     

Non-linear mechanical behaviour of carbon black reinforced elastomers: experiments and multiscale modelling

Abstract

Antivibrating parts in automotives are often made of natural rubber reinforced by carbon black. This reinforcement, which comes from the filler–filler and filler–rubber interactions, leads to an increase in the elastic modulus, the tensile strength and the hysteresis. The aim of this work is to develop a micromechanical model within a generalised self-consistent scheme for filled rubber in the moderate elongation range (|?|≤0·5). A complex morphological pattern, representative of the microstructure of the material, and which takes into account the occluded rubber, the bound rubber and a percolating network, is proposed and the effective elastic properties are compared with experimental results obtained in both uniaxial and oedometric compression. The influence of the specific surface of the filler is investigated, using N330 and N650 carbon blacks. The model is extended to the non-linear accommodation of the stress heterogeneities between the phases. Model predictions are compared with experimental values in compression and simple shear.     

PP-硅橡胶-LLDPE三元共聚物的合成及性能研究

以聚丙烯(PP)为基体树脂,硅橡胶为增韧剂,线性低密度聚乙烯( LLDPE)为辅增韧剂,制备了一系列的PP/硅橡胶LLDPE的三元共聚物,考察了PP填充不同配比的硅橡胶共混物的力学性能.结果表明,随着硅胶含量不断的增加,样条的断裂伸长率,弹性模量,冲击强度逐渐增加,样条的拉伸强度随着硅胶的增加而逐渐减少;LLDPE的加入量为15％时,PP/硅橡胶/LLDPE的三元共混体系力学性能最佳;硅橡胶的加入量为20％时,PP/硅橡胶/LLDPE的三元共混体系具有良好的拉伸性能和冲击强度.     

Structure and properties of closed‐cell foam prepared from irradiation crosslinked silicone rubber

Silicone rubber foam was prepared through crosslinking with electron beam irradiation and foaming by the decomposing of blowing agent azobisformamide (AC) in hot air. The crosslinking and foaming of silicone rubber was carried out separately, which was different from the conventional method of chemical crosslinking and foaming. After foaming, the silicone rubber foam was irradiated again to stabilize the foam structure and further improve its mechanical properties. The effects of irradiation dose before and after foaming, and the amount of blowing agents on the structure and properties of silicone rubber foam were studied. The experimental results show that with the increase of AC content, the average cell diameter of silicone rubber foam increases a little, the foam density decreases to a minimum value when AC content is 10 phr. With the increase of irradiation dose before foaming from 10 to 17.5 kGy, the cell nucleation density of silicone rubber foam increases, the average cell diameter decreases, and the foam density increases. With the increase of irradiation before foaming, the tensile strength, tensile modulus, and the elongation at break of the silicone rubber foam increase. Through irradiation crosslinking again after foaming, the foam density is decreased and the mechanical properties of silicone foam are further improved. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

配合剂对硅橡胶性能的影响

研究了混炼工艺和补强剂、结构控制剂、硫佛剂等配合剂对硅橡胶性能的影响。结果表明，混炼胶贮存和结构控制剂ＤＳ可有效降低硅橡胶模量，改善力学性能。     

Mechanical behavior of starch/silicone oil/silicone rubber hybrid electric elastomer

Two types of electric elastomers were prepared by dispersing a uniform mixture of starch particles and silicone oil into 107 silicone rubber in the absence and presence of a curing electric field, respectively. The elastic modules were tested with dynamic mechanical analysis with the round disk compression clamp. The results indicate that the storage modulus sensitivity attains a maximum value of 0.55 at a mass ratio of 1 between silicone oil and 107 silicone rubber with the given starch concentration. When the mass ratio is 1 and the starch concentration is 10 wt%, the storage modulus of the A-elastomer without the electric field is 37.1 kPa, while that of the B-elastomer with the electric field is 127.9 kPa. The storage modulus sensitivity attains a maximum value of 2.44.