For the purpose of quantifying the noise in acoustic elastography, a displacement covariance matrix is derived analytically for the cross-correlation based 3D motion estimator. Static deformation induced in tissue from an external mechanical source is represented by a second-order strain tensor. A generalized 3D model is introduced for the ultrasonic echo signals. The components of the covarian...

The deformation eld commonly used for Euler-Bernoulli beams in structural dynamics is investigated to determine its suitability for use in exible multibody dynamics. It is found that the traditional deformation eld fails to produce an elastic rotation matrix that is complete to second order in the deformation variables. A complete second-order deformation eld is proposed along with the equation...

A beam finite element formulation for large deflection problems in the analysis of flexible multibody systems has been proposed. In this formulation, a set of independent deformation modes are defined for each element that do not change if the element is subjected to rigid body motions. The paper examines the applicability of this deformation mode formulation for a shear-deformable three-dimens...