设计了包含双层空竹的超表面,通过调节其晶格周期实现了不同阶晶格模式与超表面本征模式间的耦合,获得了3个强耦合区,并在两个晶格周期处实现了弗里德里希–温特根型连续域束缚态(Friedrich-Wintgen bound states in the continuum,FW-B...设计了包含双层空竹的超表面,通过调节其晶格周期实现了不同阶晶格模式与超表面本征模式间的耦合,获得了3个强耦合区,并在两个晶格周期处实现了弗里德里希–温特根型连续域束缚态(Friedrich-Wintgen bound states in the continuum,FW-BIC)。基于耦合模理论对其进行分析,理论分析结果与模拟结果吻合,进一步证明了结构的有效性。讨论了在介质间隔层中基于强耦合和FW-BIC的局域磁场增强,发现最大磁场强度是入射太赫兹波磁场强度的41 209倍,且该值是单纯的由超表面电磁共振产生的磁场强度的4倍。这项研究将为强场太赫兹产生和太赫兹非线性研究提供参考。展开更多
木材作为一种天然的非均质材料,在荷载作用下同一纹理方向会表现出拉、压性能不对称的现象。为了更好地描述拉压性能不同的木材非线性力学行为,在一种用于描述木材受压的双参数本构模型的基础之上,通过引入Drucker-Prager塑性理论的静...木材作为一种天然的非均质材料,在荷载作用下同一纹理方向会表现出拉、压性能不对称的现象。为了更好地描述拉压性能不同的木材非线性力学行为,在一种用于描述木材受压的双参数本构模型的基础之上,通过引入Drucker-Prager塑性理论的静水压概念,建立了能够描述拉压性能不同的木材非线性统一本构模型。实验验证结果表明:模型描述的应力–应变曲线与实验结果吻合较好,运用本文中所建立的本构模型能够很好地描述木材在载荷作用下的非线性力学行为,而且考虑了木材同一纹理方向拉伸和压缩性能的差异。As a natural heterogeneous material, wood exhibits asymmetric tensile and compressive properties in the same texture direction under load. In order to better describe the nonlinear mechanical behavior of wood with different tensile and compressive properties, based on a two parameter constitutive model used to describe wood under compression, a nonlinear unified constitutive model of wood that can describe different tensile and compressive properties was established by introducing the concept of hydrostatic pressure from Drucker Prager plasticity theory. The experimental verification results show that the stress-strain curve described by the model is in good agreement with the experimental results. The constitutive model established in this paper can well describe the nonlinear mechanical behavior of wood under load, and consider the differences in tensile and compressive properties of wood in the same texture direction.展开更多
文摘设计了包含双层空竹的超表面,通过调节其晶格周期实现了不同阶晶格模式与超表面本征模式间的耦合,获得了3个强耦合区,并在两个晶格周期处实现了弗里德里希–温特根型连续域束缚态(Friedrich-Wintgen bound states in the continuum,FW-BIC)。基于耦合模理论对其进行分析,理论分析结果与模拟结果吻合,进一步证明了结构的有效性。讨论了在介质间隔层中基于强耦合和FW-BIC的局域磁场增强,发现最大磁场强度是入射太赫兹波磁场强度的41 209倍,且该值是单纯的由超表面电磁共振产生的磁场强度的4倍。这项研究将为强场太赫兹产生和太赫兹非线性研究提供参考。
文摘木材作为一种天然的非均质材料,在荷载作用下同一纹理方向会表现出拉、压性能不对称的现象。为了更好地描述拉压性能不同的木材非线性力学行为,在一种用于描述木材受压的双参数本构模型的基础之上,通过引入Drucker-Prager塑性理论的静水压概念,建立了能够描述拉压性能不同的木材非线性统一本构模型。实验验证结果表明:模型描述的应力–应变曲线与实验结果吻合较好,运用本文中所建立的本构模型能够很好地描述木材在载荷作用下的非线性力学行为,而且考虑了木材同一纹理方向拉伸和压缩性能的差异。As a natural heterogeneous material, wood exhibits asymmetric tensile and compressive properties in the same texture direction under load. In order to better describe the nonlinear mechanical behavior of wood with different tensile and compressive properties, based on a two parameter constitutive model used to describe wood under compression, a nonlinear unified constitutive model of wood that can describe different tensile and compressive properties was established by introducing the concept of hydrostatic pressure from Drucker Prager plasticity theory. The experimental verification results show that the stress-strain curve described by the model is in good agreement with the experimental results. The constitutive model established in this paper can well describe the nonlinear mechanical behavior of wood under load, and consider the differences in tensile and compressive properties of wood in the same texture direction.
