Chemorheological Relaxation, Residual Stress, and Permanent Set Arising in Radial Deformation of Elastomeric Hollow Spheres
Chemorheological Relaxation, Residual Stress, and Permanent Set Arising in Radial Deformation of Elastomeric Hollow Spheres
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弹性空心球径向变形中产生的化学流变松弛、残余应力和永久变形
DOI：
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发表时间：
1996
期刊：
影响因子：
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通讯作者：
K. Rajagopal
中科院分区：
文献类型：
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作者：
H. E. Huntley;A. Wineman;K. Rajagopal
最近，人们发展了一种橡胶类材料的本构理论，该理论认为在不同的变形水平下，应力产生于不同的微观机制。对于小变形，应力由通常的橡胶弹性理论给出。随着变形量的增加，大分子微观结构中的一些结点发生断裂。然后，结合部进行改造，产生新的微观结构。本构方程允许随着变形量的增加而连续断裂原始结点并形成新的结点。大分子断裂导致应力降低，称为化学流变学松弛。这种新的大分子结构导致了在释放外部载荷时的永久定形。本文考虑了由这种材料组成的空心球，它也被假定为不可压缩和各向同性，在径向拉力作用下受轴对称变形。它形成了具有原始微观结构的材料的外层区域和经历了大分子断裂的材料的内部区域，由半径随着变形而增加的球形界面隔开。确定了释放牵引力时的应力分布、径向载荷膨胀响应、残余应力分布和永久变形。结果表明，在球体内边界处的薄层材料中会出现高压应力的残余状态。
Recently, a constitutive theory for rubber-like materials has been developed by which stress arises from different micromechanisms at different levels of deformation. For small deformations, the stress is given by the usual theory of rubber elasticity. As the deformation increases, there is scission of some junctions of the macromolecular microstructure. Junctions then reform to generate a new microstructure. The constitutive equation allows for continuous scission of the original junctions and formation of new ones as deformation increases. The macromolecular scission causes stress reduction, termed chemorheological relaxation. The new macromolecular structure results in permanent set on release of external load. The present work considers a hollow sphere composed of such a material, also assumed to be incom-pressible and isotropic, which undergoes axisymmetric deformation under radial traction. There develops an outer zone of material with the original microstructure and an inner zone of material having undergone macromolecular scission, separated by a spherical interface whose radius increases with the deformation. The stress distribution, radial load-expansion response, residual stress distribution, and permanent set on release of traction are determined. It is found that a residual state of high compressive stress can arise in a thin layer of material at the inner boundary of the sphere.