A Six-Node Curved Triangular Element and a Four-Node Quadrilateral Element for Analysis of Laminated Composite Aerospace Structures

Martin, C. Wayne and Breiner, David M. (2004) A Six-Node Curved Triangular Element and a Four-Node Quadrilateral Element for Analysis of Laminated Composite Aerospace Structures. Technical Report NASA/CR-2004-210725, Research Engineering, NASA Dryden Flight Research Center.

Full text available as: PDF - Requires Adobe Acrobat Reader or other PDF viewer.

Abstract

Mathematical development and some computed results are presented for Mindlin plate and shell elements, suitable for analysis of laminated composite and sandwich structures. These elements use the conventional 3 (plate) or 5 (shell) nodal degrees of freedom, have no communicable mechanisms, have no spurious shear energy (no shear locking), have no spurious membrane energy (no membrane locking) and do not require arbitrary reduction of out-of-plane shear moduli or under-integration. Artificial out-of-plane rotational stiffnesses are added at the element level to avoid convergence problems or singularity due to flat spots in shells. This report discusses a 6-node curved triangular element and a 4-node quadrilateral element. Findings show that in regular rectangular meshes, the Martin-Breiner 6-node triangular curved shell (MB6) is approximately equivalent to the conventional 8-node quadrilateral with 2 x 2 integration. The 4-node quadrilateral (MB4) has very good accuracy for a 4-node element, and may be preferred in vibration analysis because of narrower bandwidth. The mathematical developments used in these elements, those discussed in the seven appendices, have been applied to elements with 3, 4, 6, and 10 nodes and can be applied to other nodal configurations.

EPrint Type:	NASA Contractor Report
Keywords:	Aerospace engineering, Composites, Curved elements, Finite element, Structural design
Subjects:	(01 - 09) Aeronautics: (05) Aircraft Design, Testing And Performance
ID Code:	375
Deposited On:	13 January 2005
Additional Information:	58 pages. This work was done as partial fulfillment for contract numbers NAS4-97007, NAS4-50079, NCA2-318, and NCA2-497 ranging from 1991–1998. NASA Technical Monitor – Kajal K. Gupta, NASA Dryden Flight Research Center.