Wang Jin W, Witten Thomas A
James Franck Institute, University of Chicago, Chicago, Illinois 60637, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2009 Oct;80(4 Pt 2):046610. doi: 10.1103/PhysRevE.80.046610. Epub 2009 Oct 29.
We use the angular deficit scheme [V. Borrelli, F. Cazals, and J.-M. Morvan, Comput. Aided Geom. Des. 20, 319 (2003)] to determine the distribution of Gaussian curvature in developable cones (d-cones) [E. Cerda, S. Chaieb, F. Melo, and L. Mahadevan, Nature (London) 401, 46 (1999)] numerically. These d-cones are formed by pushing a thin elastic sheet into a circular container. Negative Gaussian curvatures are identified at the rim where the sheet touches the container. Around the rim there are two narrow bands with positive Gaussian curvatures. The integral of the (negative) Gaussian curvature near the rim is almost completely compensated by that of the two adjacent bands. This suggests that the Gauss-Bonnet theorem which constrains the integral of Gaussian curvature globally does not explain the spontaneous curvature cancellation phenomenon [T. Liang and T. A. Witten, Phys. Rev. E 73, 046604 (2006)]. The locality of the compensation seems to increase for decreasing d-cone thickness. The angular deficit scheme also provides a way to confirm the curvature cancellation phenomenon.
我们使用角亏方案[V. 博雷利、F. 卡扎尔斯和J.-M. 莫尔万,《计算机辅助几何设计》20,319(2003年)]来数值确定可展锥(d-锥)[E. 塞尔达、S. 谢伊卜、F. 梅洛和L. 马哈德万,《自然》(伦敦)401,46(1999年)]中高斯曲率的分布。这些d-锥是通过将一张薄弹性片材压入一个圆柱形容器而形成的。在该片材接触容器的边缘处识别出负高斯曲率。在边缘周围有两条具有正高斯曲率的窄带。边缘附近(负)高斯曲率的积分几乎完全被两条相邻带的积分所补偿。这表明全局约束高斯曲率积分的高斯-博内定理并不能解释自发曲率抵消现象[T. 梁和T. A. 维滕,《物理评论E》73,046604(2006年)]。对于减小的d-锥厚度,补偿的局部性似乎增加。角亏方案还提供了一种确认曲率抵消现象的方法。