An isogeometric Timoshenko curved beam element with an enhanced representation of concentrated loads

Abstract

Isogeometric analysis directly employs CAD geometry representation. This approach is very convenient for the analysis of curved beams, since the arbitrarily-curved beams can be analysed with no geometry approximation errors (as far as the CAD model is concerned). CAD models typically use NURBS basis functions, which also introduce higher continuity along an entire computational domain. Although this continuity can be beneficial for analysis in many aspects, it also causes oscillations in numerical solutions when concentrated load is applied inside a domain. This paper extends approach introduced for straight beams based on basis extension to the generally curved Timoshenko beams using adaptive basis enrichment. Extension functions are proposed and the superior performance over standard IGA is documented.