This limit was set because errors in axis calculations can become large for smaller rotations, even though the amount of rotation is well-defined [ 24, 25].
In order to demonstrate the sensitivity of the method to smaller rotations and larger rotations, detailed simulation tests were presented with a smaller range of rotations, including 1°, 2°, 3°,…, 8°.
The lateral region is sensitive to rotation and cannot be trusted to provide valid BMD measurements, but the computer can automatically create a "total" from the 2 regions and give us a valid overall femoral neck BMD that can allow smaller rotations.
It is because from the statistical results (Tables 1 to 3) we can see that high percentage of the rotated blocks have relatively small rotation angles.
On the other hand, static sequences contain blocks with very small rotation.
Geometrical nonlinearities are taken into account on the basis of large displacement and small rotation.
One small rotation angle Helmert transformation (actual case) and one big rotation angle Helmert transformation (simulative case) are studied.
To prevent above potential risk, a flexure-linked biaxial gantry is designed to allow a small rotation angle of the cross-arm.
Numerical examples demonstrate that they are accurate and efficient for large deformation, small rotation nonlinear analysis of thin to moderately thick laminated composite plates.
