TY - EJOU AU - Gotou, Humihiko AU - Kuwataka, Takashi AU - Nishihara, Terumasa AU - Iwakuma, Tetsuo TI - Finite Displacement Analysis Using Rotational Degrees of Freedom about Three Right-angled Axes T2 - Computer Modeling in Engineering \& Sciences PY - 2003 VL - 4 IS - 2 SN - 1526-1506 AB - The stiffness equation in finite displacement problems is often derived from the virtual work equation, partly in order to avoid the complicated formulation based on the potential functional. Describing the virtual rotational angles by infinitesimal rotational angles about three axes of the right-angled Cartesian coordinate system, we formulate tangent stiffness equations whose rotational degrees of freedom are described by rotational angles about the three axes. The rotational degrees of freedom are useful to treat three rotational components in nodal displacement vectors as vector components for coordinate transformation, when non-vector components like Euler's angles are used to describe finite rotations. In this paper accuracy of the formulations is numerically demonstrated. KW - Euler's angles KW - rotational pseudo-vector KW - rotational degrees of freedom DO - 10.3970/cmes.2003.004.319