b******v 发帖数: 1493 | 1 在Incompressible Elasticity里,能量泛函有如下表达式
E(u,p) = \int_{\Omega} W(F)-p(detF-1)-f*u -\int_{\Gamma} g*u
做一阶变分,能够得到Euler-Lagrange方程
\int_{\Omega} [dW/dF-p d(detF)/dF]:grad(v)-fv -\int_{\Gamma} g*v = 0
\int_{\Omega} -q(detF-1) = 0
再做一次变分,能够得到Euler-Lagrange方程的线性化方程,
这是一个saddle point system
a(w, v) + b(p, v) = L1(v)
b(q, w) = L2(q)
其中a(w,v) = \int_{\Omega} [(d^2W/dF^2-p*d^2(detF)/dF^2)grad(w)]:grad(v)
而b(q,v) = \int_{\Omega}-q*d(detF)/dF:grad(v)
根据熟知的理论,上述saddle point system是well-posed的充要条件是
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