A general format for a third-order gradient elasto-plasticity under finite deformations is suggested. The basic assumptions are the principle of Euclidean invariance and the isomorphy of the elastic behaviour before and after yielding. The format allows for isotropy and anisotropy. Both the elastic and the plastic laws include the second and third deformation gradient. The starting point is an objective expression for the stress power. By applying the Clausius-Duhem inequality, necessary and sufficient conditions for thermodynamic consistency are derived for this format.

中文翻译：

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有限三阶梯度弹塑性和热塑性

提出了有限变形下三阶梯度弹塑性的一般格式。基本假设是欧氏不变性原理和屈服前后弹性行为的同构。该格式允许各向同性和各向异性。弹性和塑性定律都包括第二和第三变形梯度。起点是应力功率的客观表达。通过应用 Clausius-Duhem 不等式，可以为这种格式推导出热力学一致性的充分必要条件。