In the fracture study of softening materials, the damage area of crack tip is regarded as a piece of nonlinear crack with cohesive force.

在混凝土类软化材料断裂研究中，裂纹端部损伤区被简化为具有黏聚应力分布的非线性裂纹，该黏聚力对裂纹扩展有阻抗作用。

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But to date no materials have exhibited strong enough nonlinear response to protect sensitive optical elements from laser-induced damage. , we researched the Graded Density Limiter and Tandem limiter.

为解决现有非线性材料的非线性不能达到有效激光防护效果的问题，我们又研究了串列光限幅器件及浓度剃度光限幅器件的光限幅效率的影响因素。

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