Towards a thermo-magneto-mechanical coupling framework for magneto-rheological elastomers
Towards a thermo-magneto-mechanical coupling framework for magneto-rheological elastomers
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DOI：
10.1016/j.ijsolstr.2017.08.022
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发表时间：
2017-12
影响因子：
3.6
通讯作者：
M. Mehnert;M. Hossain;P. Steinmann
中科院分区：
文献类型：
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作者：
M. Mehnert;M. Hossain;P. Steinmann
磁流变弹性体（MREs）是一类相对较新的智能材料，可以承受由外部磁激励引起的大变形。这些是生产传感器和执行器的有希望的候选者。由于其固有的化学成分，大多数聚合物材料对温度非常敏感。在磁-机械耦合载荷作用下的磁流变磁体上进行实验时，由于各种原因，保持恒定的温度分布是一项非常重要的任务，例如，i)实验需要在可以在整个测试过程中保持规定温度的温度室中进行，ii)内部可能会产生额外的温度梯度。本文基于MREs建模和计算中常用的总能量法，设计了一个热-磁-力耦合本构模型。利用热力学的基本定律推导出相关的本构方程，从而得到热力学一致的公式。我们利用两个非齐次边值问题证明了所提出的热-磁-机械耦合框架的性能。在这两个问题中，轴对称圆柱管在热-磁-力耦合载荷下变形。在第一个例子中，机械变形是轴向拉伸和径向膨胀的结合，而在第二个例子中，圆柱体被置于围绕圆柱体轴的机械扭转载荷和轴向拉伸的结合下。在这两个例子中，都施加了周向磁场和径向温度梯度。结果捕获了各种热-磁-机械耦合与MRE提出的公式。
Magnetorheological elastomers (MREs) are a relatively new class of smart materials that can undergo large deformations resulting from external magnetic excitation. These are promising candidates in producing sensors and actuators. Due to their inherent chemical compositions, most polymeric materials are highly susceptible to temperature. While performing experiments on MREs that are exposed to magneto-mechanically coupled loads, maintaining a constant temperature profile is a non-trivial task for various reasons, e.g., i) experiments need to be performed in a temperature chamber that can maintain a prescribed temperature throughout a test, and ii) additional temperature gradients can be generated internally. In this paper, a thermo-magneto-mechanically coupled constitutive model is devised that is based on the total energy approach frequently used in MREs modelling and computation. Relevant constitutive equations are derived exploiting basic laws of thermodynamics that result in a thermodynamically consistent formulation. We demonstrate the performance of the proposed thermo-magneto-mechanically coupled framework with the help of two non-homogeneous boundary value problems. In both problems an axisymmetric cylindrical tube is deformed under thermo-magneto-mechanically coupled loads. In the first example the mechanical deformation is a combination of axial stretch and radial inflation whereas in the second example the cylinder is put under a mechanical load of torsion around the cylinder axis combined with an axial stretch. In both examples a circumferential magnetic field and a radial temperature gradient are applied. The results capture various thermo-magneto-mechanical couplings with the formulation proposed for MRE.