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arXiv 2603.08992math.NAcs.NA
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四场混合有限元方法用于不可压缩非线性弹性

Four-field mixed finite elements for incompressible nonlinear elasticity

Monash University(莫纳什大学)

Santiago Badia, Wei Li, Ricardo Ruiz-Baier

AI总结:

本文提出了一种四场混合有限元方法,用于解决不可压缩非线性弹性问题,该方法无需稳定化并具有更高的鲁棒性和收敛性。

摘要:

我们提出了一种稳定的有限元方法,用于不可压缩非线性弹性,该方法基于一种四场混合公式,包括位移、位移梯度、第一Piola-Kirchhoff应力和压力。与现有的四场混合公式不同,如兼容应变混合有限元方法(CSFEM),所提出的方法采用不连续的位移场,并且在2D或3D中都不需要稳定化。推导了牛顿-拉夫森线性化,并识别了满足相关inf-sup条件的有限元配对。为了恢复准确的连续位移场,进一步引入了一种高效的后处理技术。我们建立了线性化连续问题的适定性,并为离散公式建立了先验误差估计。在2D和3D中进行的大量数值实验显示了最优或甚至超收敛速率以及增强的鲁棒性,特别是在3D中,CSFEM通常需要稳定化。

英文摘要:

We present a stable finite element method for incompressible nonlinear elasticity based on a four-field mixed formulation involving the displacement, displacement gradient, first Piola--Kirchhoff stress and pressure. Unlike existing four-field mixed formulations, such as the compatible strain mixed finite element method (CSFEM), the proposed approach employs a discontinuous displacement field and requires no stabilisation in either 2D or 3D. A Newton--Raphson linearisation is derived and finite element pairs satisfying the relevant inf-sup conditions are identified. To recover accurate continuous displacement fields, an efficient postprocessing technique is further introduced. We establish the well-posedness of the linearised continuous problem together with a priori error estimates for the discrete formulation. Extensive numerical experiments in both 2D and 3D demonstrate optimal or even super convergence rates and enhanced robustness, particularly in 3D where CSFEM typically requires stabilisation.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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