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This paper presents a unified novel technique for enforcing nonlinear beam-to-shell, beam-to-solid, and shell-to-solid constraints in explicit finite element formulations. The limitations of classical multi-point constraint approaches are examined at length, particularly in the context of explicit solution schemes. Novel formulation of a generalized constraint method that ensures proper element coupling is then presented, and its computer implementation in explicit integration algorithms is discussed. Crucial in this regard is the accurate and efficient representation of finite rotations, accomplished using an incremental rotation tensor. The results of some illustrative test cases show the accuracy and robustness of the newly developed algorithm for a wide range of deformation, including that in which large rotations are encountered. When compared to existing works, the salient features of the current method are in evidence.

Brown & Root's BARBOX concept is an alternative, purpose-built, deep-draft monohull system for floating production, storage, and offloading (FPSO). This FPSO system concept has been designed for worldwide applications including West Africa, the North Sea and the Gulf of Mexico environments. The BARBOX's stiffened flat plate construction gives it a low capital investment cost compared to systems with minimum water plane hull types (e.g.. semi-submersible, SPAR, TLP) and ship-shaped FPSO. The BARBOX's dynamic motion characteristics are similar or better than those of comparable ship-shaped FPSO configurations. This paper also considers construction of the BARBOX hull in the Gulf of Mexico region. A recent Brown & Root study indicated that the Gulf coast fabrication yards were technically capable to fabricate the BARBOX hull and they could be cost competitive against worldwide shipyards. P. 249

No abstract

This work presents a novel technique for enforcing the beam-to-shell, beam-to-solid, and shell-to-solid family of constraints in explicit finite element formulations. The limitations of classical multipoint constraint approaches are examined at length, with robustness and accuracy examined through numerical examples. Novel formulation of the new constraint method is presented, and its implementation in the explicit finite element computational cycle discussed. The results of some illustrative test cases employing the newly proposed method are given, showing excellent accuracy even in the presence of large rotations. When compared to existing works, the salient features of the current method are in evidence.