金属橡胶/橡胶复合叠层耗能器动力学模型及参数识别

采用电液伺服材料试验机的位移加载方式,对金属橡胶/橡胶复合叠层耗能器进行动态特性研究,在此基础上结合理论分析建立了耗能器的动力学模型,并利用傅里叶级数展开技巧辨识出模型中的未知参数,对比理论与试验结果表明,所建模型可靠且参数识别精度能够满足工程应用的要求.     

金属橡胶/橡胶复合叠层耗能器试验建模与参数辨识

通过试验与理论相结合的方法,对金属橡胶/橡胶复合叠层耗能器进行动态特性研究,建立了耗能器的非线性弹性复合阻尼模型,该模型将恢复力分解为非线性弹性力和非线性阻尼力两部分,并辨识出了模型中的参数。对比理论与试验结果表明:所建模型能够很好地描述耗能器的非线性迟滞特性,为耗能器动力设计及动力优化奠定了良好基础。     

金属橡胶/橡胶复合叠层耗能器的阻尼测试

采用电液伺服材料试验机的位移加载方式,对金属橡胶／橡胶复合叠层耗能器进行动态试验研究。基于耗能相等原则及正交函数的性质,提出一种精度高、便于工程应用的粘弹等效阻尼测试方法,该方法可以通过实测耗能器恢复力数据方便地计算出损耗因子。依据这一方法对耗能器进行测试,结果表明金属橡胶／橡胶复合叠层耗能器具有很好的阻尼减振性能。     

金属橡胶/碟簧叠层复合结构阻尼特性及其非对称迟滞模型参数识别

针对碟簧(disc springs, DS)、橡胶–碟簧等结构的阻尼性能差以及抗高温等恶劣环境能力弱,采用正弦力激励法对添加弹性阻尼金属橡胶(entangled metallic wire material, EMWM)后的叠层复合结构进行试验研究。以耗能量、损耗因子和动态平均刚度为评价指标,分析了不同激励条件和不同金属橡胶密度对金属橡胶/碟簧叠层复合结构阻尼性能的影响。基于迹法等效阻尼模型,考虑弹性恢复力和阻尼力随变形幅值、频率的变化规律,用参数分解识别法建立该复合结构在一定载荷下的非对称迟滞模型。结果表明,预测的滞回曲线与实测曲线吻合度高,参数识别精度能够满足工程应用的要求。     

基于SMA复合橡胶支座的建筑结构自适应隔震

提出一种应用形状记忆合金拉索耗能器复合普通橡胶支座(简称SMA复合橡胶支座)的新型建筑结构自适应隔震体系,给出了该隔震支座的详细构造和工作机理,研究了SMA复合橡胶座的智能性,分析了基础隔震结构计算模型.验证了形状记忆合金在建筑结构自适应隔震方面的有效性与适用性.     

小型叠层橡胶支座水平刚度的实验研究

本文对小型叠层橡胶支座(D<100mm)进行了压剪试验研究,并总结了这类支座的一些基本性能。试验表明:当用现有的大型叠层橡胶支座水平刚度计算公式对小型叠层橡胶支座的水平刚度进行计算时,其计算结果偏小,必须经过适当修正后,才能计算小型叠层橡胶支座的水平刚度。同时,从开发新产品的角度出发,本文还对一组锡芯叠层橡胶支座进行了初步的试验研究。实验成果在一定程度上弥补了这一研究领域内的不足。     

基于形状记忆合金的桥梁隔震

本文提出了一种应用形状记忆合金耗能器和叠层橡胶支座的新型桥梁隔震体系，给出了该隔震支座的详细构造，并建立起了其恢复力理论模型。     

金属橡胶非线性隔振器试验研究与参数分析

研究了变激励条件下金属橡胶非线性隔振器的参数变化。以某型隔振器为研究对象,对其进行了静态试验及不同正弦激励条件下动态试验。借助双折线泛函本构关系的本构模型,利用粒子群优化算法对不同激励条件下的隔振器模型参数进行了识别,通过识别参数的对比得到了隔振器各参数在不同激励情况下的变化趋势。结果显示对金属橡胶非线性隔振系统进行动力学分析时,必须首先对实际工况下隔振器进行动态试验。再通过参数识别获取隔振器准确的数学模型,才能对金属橡胶隔振系统进行准确的动力学分析。为金属橡胶隔振系统的动力学分析提供了一般方法。     

橡胶减振器非线性动态特性的试验研究

采用电动振动台对橡胶减振器的非线性动态特性进行了试验研究,利用正逆傅立叶变换对试验数据进行了处理.建立了橡胶减振器的动力学模型,运用Runge-Kutta法和模型曲线重构法论证了模型对单一工况参数识别的有效性.利用该模型对试验工况逐一进行识别,得到了不同工况下橡胶减振器的刚度和阻尼.分析发现识别的刚度和阻尼与振幅和频率之间呈曲面关系,表明橡胶减振器在较大振幅下的动态特性已不能用简单的曲线来描述.     

橡胶隔振器刚度和阻尼本构关系的试验研究

对橡胶隔振器的动态特性进行了试验研究,利用傅立叶变换分析了采集的试验信号,采用神经网络法拟合了试验曲线,利用曲线重构方法验证了神经网络曲线拟合的可行性。根据神经网络输出的数据,采用最小二乘优化方法对描述橡胶隔振器动态特性的多项式模型进行参数识别,识别结果表明橡胶隔振器的刚度和阻尼与振幅和频率之间呈曲面关系。利用最小二乘曲面拟合方法对刚度和阻尼曲面进行了拟合,得到了描述橡胶隔振器刚度和阻尼的本构关系。     

Conductive rubber composites from different blends of ethylene-propylene-diene rubber and nitrile rubber

Conductive rubber composites were derived from different blends of ethylene-propylene-diene monomer (EPDM) rubber and acrylonitrile butadiene rubber (NBR) containing acetylene black. The electrical and mechanical properties of these composites were measured. The percolation limit for achieving high conductivity of conductive filler depends on the viscosity of the blend. The higher the viscosity, the higher is the percolation limit. The conductivity rises with increasing temperature, and the activation energy of conduction increases with the decrease in the loading of conductive filler and percentage of NBR in the blend. Electrical hysteresis and an electrical resistivity difference during the heating-cooling cycle are observed for these systems, which is mainly due to some kind of irreversible change occurring in the conductive networks during heating. The mechanisms of conduction of these systems were discussed in the light of different theories. It was found that the degree of reinforcement by acetylene black in blends compares with those in the pure components NBR and EPDM. This is due to incompatibility of two elastomers in the blend. This revised version was published online in November 2006 with corrections to the Cover Date.     

硅橡胶/丁基橡胶共混体系的相容性研究

采用机械共混法制备了硅橡胶/丁基橡胶共混材料。通过理论分析、红外、动态力学性能、扫描电镜等初步考察了共混体系中硅橡胶和丁基橡胶的相容性。结果表明:硅橡胶/丁基橡胶共混体系属于热力学不相容体系,当丁基橡胶用量为50份时,硅橡胶呈连续相,丁基橡胶为分散相,随丁基橡胶用量的增加,硅橡胶和丁基橡胶呈部分双相连续的状态。     

Feasible incorporation of devulcanized rubber waste in virgin natural rubber

Devulcanized rubber waste produced from end-of-life passenger tyres by continuous shear flow stage control reaction technology was used both as filler and as part of rubber in a natural rubber matrix to develop the use of the rubber compound and lower the cost. The measurements of cure characteristics, swelling behaviour, crosslink density and dynamic and mechanical properties were carried out in our laboratory. In the present study it was found that using devulcanized rubber as part of rubber yields much better properties than using it as filler. Up to 15 phr devulcanized rubber used as filler and up to as much as 50 phr devulcanized rubber used as part of rubber can be incorporated in a new product without any noteworthy deterioration in performance arising.     

Investigations on the addition of styrene butadiene rubber in natural rubber and dichlorocarbene modified styrene butadiene rubber blends

This paper focuses on the use of styrene butadiene rubber (SBR) as a viscosity modifier in novel blends of natural rubber (NR) and dichlorocarbene modified styrene butadiene rubber (DCSBR). The processing characteristics, vulcanisation kinetics, stress-strain behaviour, mechanical properties and low temperature transition of the blends have been examined in order to analyse the influence of SBR in the blends. The change in cross-link density values from stress strain behaviour and equilibrium swelling data has been correlated with the technological properties of the blends. The excellent mechanical properties and the increased cross-link density in blends in the presence of 5—10 phr of styrene butadiene rubber reveals the viscosity modifying action of SBR in NR/DCSBR blends. The variation in viscosities of these blends with the addition of SBR is reflected in the DSC thermograms. The resulting blends show very high resistance to thermal ageing as compared to those without SBR.     

Styrene-butadiene rubber/halloysite nanotubes composites modified by epoxidized natural rubber

The reinforcement effects of halloysite nanotubes on styrene-butadiene rubber and the modification effect of epoxidized natural rubber on styrene-butadiene rubber/halloysite nanotubes composites were studied. The structure, morphology and properties of styrene-butadiene rubber/halloysite nanotubes composites before and after the incorporation of epoxidized natural rubber were investigated. The results indicated that epoxidized natural rubber can promote the dispersion and orientation of halloysite nanotubes in styrene-butadiene rubber matrix at nanoscale and strengthen interfacial combination between halloysite nanotubes and styrene-butadiene rubber by the formation of covalent bonds and hydrogen bonds between epoxidized natural rubber and halloysite nanotubes. Consequently epoxidized natural rubber can improve the mechanical properties of the vulcanizates of styrene-butadiene rubber/halloysite nanotubes composites. Besides epoxidized natural rubber can decrease the rolling resistance of the vulcanizates and increase the wet grip property of the vulcanizates.     

环保型水切割胶粉对天然橡胶力学性能和动态性能的影响

采用环保型水切割胶粉及力化学改性胶粉（MRP）与天然橡胶（NR）复合制备胶粉-NR复合胶,并探讨了胶粉用量对复合胶力学性能和动态性能的影响。通过红外和热失重分析确定了胶粉的主要成分为NR和丁苯橡胶（SBR）,且改性后胶粉大分子链结构未发生明显变化。通过橡胶加工分析仪研究了胶粉用量及改性对复合胶加工性能的影响。采用炭黑分散仪研究并观察了胶粉在NR中的分散情况。结果表明,胶粉改性后与NR的相容性提高,二者界面结合力增大,MRP-NR复合胶加工性能改善。炭黑分散结果表明,胶粉用量越多,其分散性越差,改性后胶粉的分散性提高,MRP-NR复合胶的力学性能最优,拉伸强度为27.9 MPa。     

橡胶相尺度对亚微米或纳米橡胶颗粒填充环氧复合材料性能的影响

对比研究了由液体橡胶在环氧树脂中原位形成的亚微米橡胶/环氧复合材料和在环氧树脂中直接添加纳米橡胶颗粒形成的纳米橡胶/环氧复合材料的性能。研究表明：未固化混合物的黏度随着纳米橡胶相的加入逐渐增加,但随着亚微米橡胶相含量的增加而降低;橡胶/环氧复合材料的玻璃化转变温度随着纳米橡胶颗粒的加入逐渐增加,但随着亚微米橡胶相含量的增加而降低;两种橡胶相的添加均使复合材料的弹性模量降低,断裂延伸率增加;在较低含量时,纳米橡胶颗粒可以提高环氧的拉伸强度;两种橡胶填充的橡胶/环氧复合材料均显示出明显的增韧效果。微观形貌分析表明,两种橡胶均可以在应力作用下脱粘并促进裂纹尖端的塑性变形。     

Influence of carbon blacks on butadiene rubber/high styrene rubber/natural rubber with nanosilica: Morphology and wear

The effect of fillers on morphology and wear characteristics are studied in butadiene rubber (PBR)/high styrene rubber (HSR)/natural rubber (NR) blends with different types of carbon black. SAF N110 with SRF N774 type of carbon black shows a significant effect on curing studies and mechanical properties by reacting at the interface between PBR, HSR and NR matrix. Blends containing the same carbon blacks show high abrasion resistant properties against Du-Pont abrader, DIN abrader and different mining rock surfaces and also is found to be the toughest rubber against all types of rock.     

An analogy between radially-loaded rubber bush mountings and axially-loaded bonded rubber blocks

The validity of the widely-quoted experimental data for the reduced radial stiffness of a cylindrical rubber bush mounting of finite length is discussed by proposing an analogy between such a bush and two tandem cylindrical rubber blocks of circular cross-section which are axially loaded. Previously-derived expressions for the radial stiffness of a finite-length cylindrical bush and the apparent Young’s modulus of an axially-loaded bonded rubber block of circular cross-section are exploited. This leads to an adaptation of the data that incorporates the possible failure of the bushes due to internal rupture. The analytically-derived values of this stiffness are demonstrated to have improved agreement with these appropriately modified data. Representative numerical results are presented for a range of bushes in tabular and graphical forms.