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The existence of viscosity effect at the interface of double dissimilar materials has an important impact on the distribution of the interface crack-tip field and the properties variety of the interface itself. The singularity and viscosity are considered in the crack-tip. The elastic-viscoplastic governing equations of double dissimilar materials at the interface crack-tip field are established. The displacement potential function and boundary condition of interface crack-tip are introduced. The numerical analysis of elastic-viscoplastic/rigid interface for mode Ⅲ is worked out. The stress-strain fields are obtained at the crack-tip and the variation rules of solutions are discussed according to each parameter. The numerical results show that the viscosity effect is a main factor of the interface propagating in the crack-tip field, and the interface crack-tip is a viscoplastic field governed by the viscosity coefficient, Mach number (Ma), and singularity exponent. 相似文献
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An elastic-viscoplastic mechanics model is used to investigate asymptotically the mode Ⅲ dynamically propagating crack tip field in elastic-viscoplastic materials. The stress and strain fields at the crack tip possess the same power-law singularity under a linear-hardening condition. The singularity exponent is uniquely determined by the viscosity coefficient of the material. Numerical results indicate that the motion parameter of the crack propagating speed has little effect on the zone structure at the crack tip. The hardening coefficient dominates the structure of the crack-tip field. However, the secondary plastic zone has little influence on the field. The viscosity of the material dominates the strength of stress and strain fields at the crack tip while it does have certain influence on the crack-tip field structure. The dynamic crack-tip field degenerates into the relevant quasi-static solution when the crack moving speed is zero. The corresponding perfectly-plastic solution is recovered from the linear-hardening solution when the hardening coefficient becomes zero. 相似文献
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线性硬化材料中稳恒扩展裂纹尖端场的粘塑性解 总被引:1,自引:0,他引:1
采用弹粘塑性力学模型,对线性硬化材料中平面应变扩展裂纹尖端场进行了渐近分析.假设人工粘性系数与等效塑性应变率的幂次成反比,通过量级匹配表明应力和应变均具有幂奇异性,奇异性指数由粘性系数中等效塑性应变率的幂指数唯一确定.通过数值计算讨论了Ⅱ型动态扩展裂纹尖端场的分区构造随各材料参数的变化规律.结果表明裂尖场构造由硬化系数所控制而与粘性系数基本无关.弱硬化材料的二次塑性区可以忽略,而较强硬化材料的二次塑性区和二次弹性区对裂尖场均有重要影响.当裂纹扩展速度趋于零时,动态解趋于相应的准静态解;当硬化系数为零时便退化为HR(Hui-Riedel)解. 相似文献
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高酸度条件下单波长、双峰双波长分光光度法测定铬(Ⅵ) 总被引:1,自引:0,他引:1
铬(Ⅵ)的测定,在金属材料的分析中具有重要意义。目前,铬的测定仍采用二苯卡巴肼法,该法的灵敏度虽较高(ε=34600),但由于显色剂的稳定性很差,显色剂溶液和工作曲线需当天配制和绘制,除给操作带来许多麻烦外,还造成大量试剂的浪费。 相似文献
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利用幂软化损伤模型,对Ⅲ型裂纹进行了详细的研究。给出了本构方程及渐近方程。位移、应变和应力用对数级数展开,揭示了场的渐近特性。其结果表明,应力和应变分别具有如下的奇异性:σ-(lnR/r)^1/n+1,ε-(LnR/r)^n/n+1。 相似文献
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双材料界面中存在材料黏性效应, 对界面裂纹尖端场的分布和界面本身性能
的变化起着重要的影响. 考虑裂纹尖端的奇异性, 建立了双材料界面扩展裂纹尖端的弹黏塑
性控制方程. 引入界面裂纹尖端的位移势函数和边界条件, 对刚性-弹黏塑性界面I型界面
裂纹进行了数值分析, 求得了界面裂纹尖端应力应变场, 并讨论了界面裂纹尖端场随各影响
参数的变化规律. 计算结果表明, 黏性效应是研究界面扩展裂纹尖端场时的一个主要因素,
界面裂纹尖端为弹黏塑性场, 其场受材料的黏性系数、马赫数和奇异性指数控制. 相似文献
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在硫酸介质中,钛与水杨基荧光酮及CTMAB可以形成两种颜色不同的络合物。当水杨基荧光酮过量时,络合物呈红紫色(λmax=540nm);当钛过量时,络合物呈蓝紫色(λmax=610nm)。本文系统研究了红紫色络合物的生成条件及其在测定钛中的应用。试验证明,钛-水杨基荧光酮-CTMAB的红紫色络合物具有较高的灵敏度ε640=1.64*10~5. 常见阳离子中除钨(Ⅵ)以外,绝大部分阳离子均不干扰钛的测定或可用适当掩蔽剂消除干扰。有色溶液在钛含量为0—5生克/25毫升时,遵守比尔定律。本法可以不经任何分离,直接快速测定某些合金钢及纯金属材料(如铝)中的微量钛并得到了比较满意的结果。 相似文献