Department of Mechanical and Process Engineering, Swiss Federal Institute of Technology (ETH), Zurich 8092, Switzerland.
Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125, USA.
Phys Rev E. 2016 Jan;93(1):010901. doi: 10.1103/PhysRevE.93.010901. Epub 2016 Jan 12.
The incremental stiffness characterizes the variation of a material's force response to a small deformation change. In lattices with noninteracting vibrational modes, the excitation of localized states does not have any effect on material properties, such as the incremental stiffness. We report that, in nonlinear lattices, driving a defect mode introduces changes in the static force-displacement relation of the material. By varying the defect excitation frequency and amplitude, the incremental stiffness can be tuned continuously to arbitrarily large positive or negative values. Furthermore, the defect excitation parameters also determine the displacement region at which the force-displacement relation is being tuned. We demonstrate this phenomenon experimentally in a compressed array of spheres tuning its incremental stiffness from a finite positive value to zero and continuously down to negative infinity.
增量刚度表征了材料对小变形变化的力响应的变化。在具有非相互作用振动模式的晶格中，局部态的激发对材料性质（如增量刚度）没有任何影响。我们报告说，在非线性晶格中，驱动缺陷模式会引起材料静态力-位移关系的变化。通过改变缺陷激励的频率和幅度，可以连续调节增量刚度到任意大的正值或负值。此外，缺陷激励参数还决定了力-位移关系被调节的位移区域。我们在压缩球体阵列中实验证明了这一现象，将其增量刚度从有限正值调零，并连续调至负无穷大。
