Geometric Modelling for Virtual Colon Unfolding

A virtual endoscopie view is not necessarily the best way to examine a hollow organ, such us, the colon. The inner surface of the colon is where polyps are located, and therefore what is examined by the physicians. A flight through the colon using a common endoscopie view shows a smal! percentage of the inner surface. Virtually unfolding of the colon can be a more etficient way to look at the inner surface. We propose two methods to unfold the colon : a method that unfolds the colon locally using local projections, and a method that obtains global unfolding of the colon by achieving a suitable parameterization of its surface

非線形ばねで支持された弾性ブロックの連成振動の有限要素解析 : 弱非線形性を有する場合の検討

This paper describes vibration analysis using finite element method for an elastic block supported by a nonlinear concentrated spring. The restoring force of the spring has cubic nonlinearity. Finite element for the nonlinear spring is expressed and is connected to the elastic block modeled by linear solid finite elements. Further, the discretized equations in physical coordinate are transformed into the nonlinear ordinary coupled equations using normal coordinate corresponding to linear natural modes. This transformation yields computation efficiency. Influences of Young's modulus on nonlinear frequency responses for the elastic block are clarified