MODELING OF CONTROL FORCES FOR KINEMATICAL CONSTRAINTS IN MULTIBODY SYSTEMS DYNAMICS - A NEW APPROACH

1991-01-01
IDER, SK
Conventionally kinematical constrains in multibody systems are treated similar to geometrical constraints and are modeled by constraint reaction forces which are perpendicular to constraint surfaces. However, in reality, one may want to achieve the desired kinematical conditions by control forces having different directions in relation to the constraint surfaces. In this paper the conventional equations of motion for multibody systems, subject to kinematical constraints, are generalized by introducing general direction control forces. Conditions for the selection of the control force directions are also discussed. A redundant robotic system subject to prescribed end-effector motion is analyzed to illustrate the methods proposed.
COMPUTERS & STRUCTURES

Suggestions

EXTENSION OF THE RESIDUAL VARIABLE METHOD TO PROPAGATION PROBLEMS AND ITS APPLICATION TO THE WAVE-EQUATION IN CYLINDRICAL COORDINATES
AKKAS, N; Tokdemir, Turgut (Elsevier BV, 1992-08-03)
Consider a partial differential equation with cylindrical coordinates describing a dynamic process in an infinite medium with an inner cylindrical boundary. If an analytical solution to the problem is not possible, then one resorts to numerical techniques. In this case it becomes necessary to discretize the infinite domain even if the solution is required on the inner cylindrical surface or at a limited number of points in the domain only. The residual variable method (RVM) circumvents the difficulty associ...
The theorems of structural variation for rectangular finite elements for plate flexure
Saka, MP (Elsevier BV, 2005-11-01)
The theorems of structural variation predict the forces and displacements throughout a structure without the need of fresh analysis when the physical properties of one or more members are altered or even its topology is changed due to removal of one or more of its elements. It has been shown that a single linear elastic analysis of a parent structure under the applied loads and a set of unit-loading cases is sufficient to determine the elastic, non-linear elastic and even elasticplastic response of number o...
ISOPARAMETRIC ELEMENTS WITH UNEQUALLY SPACED EDGE NODES
UTKU, M; CITIPITIOGLU, E; OZKAN, G (Elsevier BV, 1991-01-01)
In the isoparametric finite element formulation, mapping of equally spaced nodes on the boundary of the master element to unequally spaced locations on the physical elements results in an unacceptable distortion. This type of distortion is defined as 'node mapping distortion' and a technique for its elimination is presented. Simple test cases demonstrate the utility of the new formulation.
ANALYSIS OF FRAMES WITH NONPRISMATIC MEMBERS
ELMEZAINI, N; BALKAYA, C; CITIPITIOGLU, E (American Society of Civil Engineers (ASCE), 1991-06-01)
The linear elastic behavior of frames with nonprismatic members is investigated by using isoparametric plane stress finite elements. It is determined that the conventional methods of analysis for these types of structures lead to erroneous results. Comparison of the fixed end moments, stiffness, and carry-over factors of nonprismatic members available in the literature with those computed by finite element analysis reveals large discrepancies. Based on an extensive study, sources and magnitudes of errors...
A SHEAR FLEXIBLE FINITE-ELEMENT FOR NONUNIFORM, LAMINATED COMPOSITE BEAMS
Oral, Süha (Elsevier BV, 1991-01-01)
A shear flexible finite element is formulated for linearly tapered, symmetrically laminated composite beams. The element has three nodes and 18 degrees of freedom. The three-node configuration is obtained from a five-node parent element by constraining the shear angle variation to be linear. The bending in two planes, twisting and stretching are considered. The performance of the element is tested with isotropic and composite materials, constant and variable cross-sections, and straight and curved geome...
Citation Formats
S. IDER, “MODELING OF CONTROL FORCES FOR KINEMATICAL CONSTRAINTS IN MULTIBODY SYSTEMS DYNAMICS - A NEW APPROACH,” COMPUTERS & STRUCTURES, pp. 409–414, 1991, Accessed: 00, 2020. [Online]. Available: https://hdl.handle.net/11511/63604.