Hu Washizu principle

In continuum mechanics, and in particular in finite element analysis, the Hu-Washizu principle is a variational principle which says that the action

$\underset{V^e}{\int }[\frac{1}{2}{ϵ}^{T}Cϵ-{\sigma }^Tϵ+{\sigma }^T(\mathrm{\nabla }u)-{\overline{p}}^{T}u]dV-\underset{S_{\sigma }^e}{\int }{\overline{T}}^{T}udS$

is stationary, where $C$ is the elastic stiffness tensor. The Hu-Washizu principle is used to develop mixed finite element methods. The principle is named after Hu Haichang and Kyuichiro Washizu.

Further reading

• K. Washizu: Variational Methods in Elasticity & Plasticity, Pergamon Press, New York, 3rd edition (1982)
• O. C. Zienkiewicz, R. L. Taylor, J. Z. Zhu : The Finite Element Method: Its Basis and Fundamentals, Butterworth-Heinemann, (2005).