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The phenomenon of stress softening observed in the cyclic inflation of spherical balloons or membranes is quantitatively and qualitatively examined. A new measure of the stress softening extent is proposed which correctly captures the main feature of this phenomenon. This measure of the stress softening is related to the relevant response functions in the constitutive models proposed in the literature to describe this effect. Using these relationships, the predictive capability of the theoretical models is examined. It is shown that only those theoretical models which admit a non-monotone character of the stress softening can properly describe this phenomenon. 相似文献
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The Compression Deformation Mechanism of a Metallic Rubber 总被引:1,自引:0,他引:1
H. Zuo Y. H. Chen H. B. Bai H. Sun 《International Journal of Mechanics and Materials in Design》2005,2(3-4):123-131
In this paper, the microcompression deformation mechanisms of a porous wire-like metallic body, designated metallic rubber, in uniaxial compression loading along the direction of cold stamping, have been investigated by conducting the macroscopic compressing tests and microscopic observation of the deformed material. The stress/strain relation suggest that the stress/strain relation curve could be divided into three distinct stages depending upon the variation in the stiffness with the compression deformation. The results which reveal that there exist different microscopic compression deformation mechanisms in each distinct stage: In the first stage, referred to as stage I, the elastic deformation, owing to the elastic bending of each small segments of metallic wire, occurs in the body piece by piece. In the second stage, referred to as stage II, the elastic deformation of all small segments of the metallic wire and crossed sliding friction operating in the contacted surfaces of the wire represent the main deformation mode of this stage. The third stage is the re-strengthening stage, referred to as stage III. In this case, the deformation due to nonlinear elastic bending of a series of small segments of metallic wire coils and extruded sliding friction operating in the contacted surfaces of wire coils govern the behaviour of the metallic rubber. 相似文献
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金属橡胶弹性阻尼元件各向异性特性的实验研究 总被引:3,自引:0,他引:3
研究了金属橡胶构件在不同方向的载荷作用下表现出来的各向异性,提出了用于分析金属橡胶材料内部结构的物理假设,并根据假设确定了各向异性研究的主要参数,然后通过实验研究进行了验证。实验结果表明,如果改变金属橡胶元件的相对高度,增加径向尺寸可以在很大范围内改变金属橡胶隔振器的径向刚度;要使金属橡胶隔振器的力学特性更近于线性,应让隔振器在径向范围内工作;如果隔振系统中含有多个承受压载荷的金属橡胶隔振器,则可以使其工作在与成型压力方向相垂直的方向。当相同结构和尺寸的钢元件和金属橡胶元件在承受剪切载荷作用时,这两种材料表现出了相同的刚度变化趋势。 相似文献
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A finite-element solution for rubber composite shells is presented. Sandwich laminates with a rubber core have also been studied. Incompressibility of a rubber matrix and complexity of composite shells bring forth the need for a sound numerical model to describe the behavior of such engineering materials. The developed model was applied to a degenerate shell element within the limits of the first- and third-order shear deformation theories. The model allows to predict with a sufficient accuracy the nonlinear behavior of sandwich shells with composite skins and rubber cores and composite shells with a rubber matrix. 相似文献
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Instability analysis of the large deformation of three-layered fiber-reinforced anisotropic rubber tubes subjected to an inner pressure combined with torsion and axial stretch is examined within the framework of finite elasticity. Based on a fiber-reinforced incompressible hyper-elastic material model, the relation between the principal stretch and the inner pressure, torsion and axial stretch is obtained. It is shown that there exists a critical thickness for the tubes. For a thin-walled tube which is thinner than the critical thickness, the tube under-goes a uniform stable inflation when the inner pressure is small. However, the tube may under-go a strikingly non-uniform deformation when the inner pressure is larger than a certain critical value. One portion of the tube may become highly distended as a bubble and it is proved that this deformation is unstable. While a thick-walled tube which is thicker than the critical thickness, always under-goes a uniform inflation. The critical thickness of the tube to take unstable deformation is given based on the deformation curve and its slope. Furthermore, the effect of axial stretch, torsion and the distribution angle or the strength of the fiber on the deformation and the stress of the tube are discussed. 相似文献
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制备了海泡石增强橡胶密封复合材料(SRRC),对其横向压缩力学性能进行了测试。采用扫描电子显微镜观察了试样断面上的海泡石纤维分布状况,建立了单分散和多分散纤维体系的代表性体积单元(RVE)模型。通过Abaqus有限元软件建立了SRRC的计算模型,采用连续的网格重划技术,预测了SRRC的大变形行为。结果表明,当纤维体积分数较小时,压缩应力随应变呈线性增加;当纤维体积分数达到42%时,随着应变的增加,应力-应变曲线呈明显的非线性;增加海泡石纤维的体积分数,能够有效提高SRRC的弹性模量和压缩强度。通过对RVE模型进行2次网格重划,可使模型的压缩应变达到0.4。相比于单分体系,多分散体系RVE模型的预测结果与实验值更为接近。 相似文献
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超声分散制备天然橡胶/丁苯橡胶/炭黑/碳纳米管纳米复合材料 总被引:4,自引:0,他引:4
通过超声分散制备了分散均匀的碳纳米管(CNTs)/天然橡胶母料,利用母料制备了天然橡胶(NR)/丁苯橡胶(SBR)/炭黑(CB)/碳纳米管复合材料。通过比较常规搅拌、双辊混炼和超声分散三种方法对碳纳米管的分散及对复合材料性能的影响,表明超声分散能实现碳纳米管在基体中均匀分散,CNTs和CB的协同作用提高了复合材料的力学性能,当CB/CNTs之比为37/3时力学性能最高,与未加CNTs增强的体系相比,拉伸强度提高了6.4%。当CNTs含量为7phr,与未加CNTs的体系相比,压缩模量提高了20%。 相似文献
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实验以过硫酸钾(KPS)/亚硫酸氢钠(SHS)为氧化还原引发体系,采用化学接枝的方法改性天然胶乳,合成出天然橡胶与丙烯酰胺接枝共聚物NR-g-PAM,并在反应过程中加入无机膨润土(BT),制备一种吸水膨胀天然橡胶(WSNR)。探究单体配比、引发剂用量对接枝反应的影响,膨润土用量对WSNR吸水率、吸水速率、重复吸水率的影响,并对WSNR保水性、耐矿化盐水能力及热失重过程进行分析。结果表明,吸水单体与天然橡胶的质量比为0.8,引发剂用量为单体质量分数的0.75%时接枝率及接枝效率最高。膨润土均匀分布于WSNR网络骨架中,吸水速率随膨润土用量增加而减慢,耐矿化盐水能力提高;重复吸水率及保水性均优异于未添加膨润土的WSNR,膨润土的加入使WSNR在较高温度下才会蒸发失水,自由水含量减少,结合水含量增多。 相似文献
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利用自行建立的疲劳试验系统,以单向聚酯/橡胶复合材料和人造丝/橡胶复合材料为研究对象,揭示了在周期载荷作用下橡胶复合材料的疲劳损伤累积特性,给出了疲劳寿命预报方程,研究了频率对像复合材料疲劳寿命的影响以及材料表面温度的变化规律。发现:橡胶复合材料疲劳过程中伴有较高的热生成,这是橡胶复合材料与其他脆性复合材料最大的不同。疲劳过程中,聚酯/橡胶复合材料的表面温度可达100℃,人造丝/橡胶复合材料的表面温度可达40℃。频率对不同橡胶复合材料的疲劳寿命具有不同的影响。对滞后损失较大的聚酯/橡胶复合材料,增加频率其疲劳寿命明显降低;而对于滞后损失较小的人造丝/像胶复合材料,频率对其疲劳寿命的影响不明显。 相似文献
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液聚合合成橡胶节能技术和节能型橡胶的开发 总被引:1,自引:0,他引:1
总结了燕山石化溶液聚合合成橡胶节能技术和节能型橡胶的开发情况。通过改进催化体系,提高反应速度,提高反应器的生产能力,并在聚合反应器中采用带刮刀的搅拌器,同时改进聚合、凝聚、溶剂回收的部分工艺及设备,燕山石化顺丁橡胶的能耗不断下降,达到世界先进水平。溶液聚合合成橡胶凝聚过程热泵技术的工业化,使生产每吨胶可节约1MPa的低压蒸汽0.72t。橡胶溶液直接脱挥,聚丁二烯橡胶气相聚合工艺技术开发,溶聚丁苯橡胶(SSBR)、中乙烯基聚丁二烯橡胶、苯乙烯-异戊二烯-丁二烯橡胶(SIBR)、苯乙烯-丁二烯热塑性弹性体(SBS)等新型节能型合成橡胶的技术开发也在进行中,其中SSBR、SBS技术已经工业化。 相似文献
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控制振动、降低噪音,已成为当今社会急需解决的问题。文中对橡胶减震材料最近的研究动态作了概述,内容涉及橡胶阻尼减震机理和阻尼减震性能的影响因素。影响橡胶阻尼性能的最主要因素是橡胶的分子结构,其次为填充体系、硫化体系、增塑体系等。文中介绍了阻尼橡胶的改性方法,包括共混、互穿网络技术和填充填料等方法,并指出减震橡胶材料今后的研究方向。 相似文献
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丁腈橡胶和氢氧化铝对氯化丁基橡胶阻尼性能的影响 总被引:3,自引:0,他引:3
通过对各阶复合损耗因子的测定 ,考察了加入耐油配合胶丁腈橡胶和阻燃剂氢氧化铝对氯化丁基橡胶体系阻尼性能的影响。试验结果表明 ,加入丁腈橡胶 ,阻尼体系在 70Hz、2 0 0Hz和 40 0Hz下的复合损耗因子均下降。加入氢氧化铝可改善体系的阻尼性能 ,随着氢氧化铝用量的增加 ,体系在上述频率下的复合损耗因子有一定程度的提高 ,但在与橡胶的质量比达 4∶10的用量时 ,体系的阻尼性能转而下降 相似文献
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废橡胶超声波再生的研究 总被引:1,自引:0,他引:1
废旧橡胶的再生,是关系到环保和资源综合利用的重要课题,超声波再生法,被认为是最具发展前途的再生方法之一,本文对废旧轮胎胶粉的超声波脱硫过程进行了实验研究。结果表明,超声波能有效地对硫化胶进行脱硫再生,超声波的振幅和作用间隙对脱硫过程起关键作用。 相似文献
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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。 相似文献