Coupled thermal- and deformation-induced degradation in planar rubber membranes under radial loading
Coupled thermal- and deformation-induced degradation in planar rubber membranes under radial loading
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径向载荷下平面橡胶膜的耦合热和变形引起的降解
DOI：
10.1177/1081286519829513
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发表时间：
2019
影响因子：
2.6
通讯作者：
J. Shaw
中科院分区：
文献类型：
--
作者：
A. Wineman;J. Shaw
在高温下，弹性体由于其大分子网络中的断裂、重卷和重交联而发生微观结构变化。这导致了基于化学的应力松弛和永久固定。在以前的工作中，开发了用于此类弹性体热-机械响应的本构方程，该方程推广了Tobolsky双网络理论并结合了实验程序的结果。一个实验结果是，断裂过程似乎不受拉伸的影响，在适度的拉伸。有迹象表明，较大的变形会影响断裂过程。本工作的目的是修改以前发展的本构理论，以允许这一点。本构理论包含材料性质，代表断裂、重卷和重交联的化学动力学，用活化能表示。这里考虑的前提是，受到文献中力学-化学讨论的启发，变形的增加降低了活化能，导致更快的化学应力松弛。本文介绍了一种会计方法。然后将合成本构理论应用于平面环形薄板在其外边界受牵引力作用下的径向平面变形的模拟。选择这种特殊的几何形状有两个原因：(1)它便于实验研究；(2)内圆边界附近的拉伸浓度会引起更快的化学基应力松弛，这是很容易观察到的。
Elastomers at elevated temperatures can undergo microstructural changes owing to the scission, re-coiling, and re-crosslinking in their macromolecular network. These result in chemically based stress relaxation and permanent set. In previous work, a constitutive equation was developed for the thermo-mechanical response of such elastomers that generalized the Tobolsky two-network theory and incorporated results from an experimental program. One experimental result was that the scission process appeared to be unaffected by stretch, to within moderate stretches. There are indications that larger deformations affect the scission process. The purpose of the present work is to modify the previously developed constitutive theory to allow for this. The constitutive theory contains material properties, representing the chemical kinetics of scission, re-coiling, and re-crosslinking, that are expressed in terms of activation energies. The premise considered here, motivated by the mechano-chemical discussion in the literature, is that an increasing deformation decreases the activation energy and results in faster chemical stress relaxation. A method for accounting for this is introduced. The resultant constitutive theory is then used in the simulation of the radial planar deformation of a planar annular sheet by tractions at its outer boundary. This particular geometry is chosen for two reasons: (1) its convenience for experimental study; (2) the stretch concentration near the inner circular boundary will cause faster chemically based stress relaxation there, which could be readily observable.