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Consistent thermal stress evaluation in finite elements

IR@NAL: CSIR-National Aerospace Laboratories, Bangalore

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Title Consistent thermal stress evaluation in finite elements
 
Creator Prathap, Gangan
Naganarayana, BP
 
Subject Aircraft Design, Testing & Performance
 
Description The computation of thermal stresses in displacement finite elements through a formal theoretical basis using the minimum potential principle leads to oscillating stress predictions. Many finite element packages have therefore used an average temperature in simple elements; thermal stresses were computed only at the centroids of such elements to avoid these problems. In this paper we trace this difficulty to a consistency requirement - requirement that stress fields derived from temperature fields (or initial strains) must be consistent with the total strain field interpolations used in the finite element formulation. The principle governing the problem is developed from the minimum total potential theorem and the Hu-Washizu theorem. This gives it a formal rational basis and leads to an orthogonally condition that provides the procedure for determining consistent, thermal stresses in a variationally correct manner. The principle is demonstrated using some simple problems. A four-noded laminated plane-shell element is also considered to prove the rigour and generality of the approach presented here.
 
Date 1995
 
Type Journal Article
PeerReviewed
 
Identifier Prathap, Gangan and Naganarayana, BP (1995) Consistent thermal stress evaluation in finite elements. Computers and Structures, 54 (3). pp. 415-426.
 
Relation http://nal-ir.nal.res.in/316/