General curved beam elements based on the assumed strain fields

Abstract

Simple two-noded and three-noded general curved beam elements have been formulated on the basis of assumed strain fields and Timoshenko's beam theory. The two-noded element is formulated from constant strain fields and the three-noded one is from linear strain fields. These curved beam elements, designed in a local curvilinear coordinate system, are transformed into a global cartesian coordinate system in order to analyze effectively the general curved beam structures located arbitrarily in space. Since strain functions are assumed independently, these elements are free from any locking phenomena. Through various numerical tests, it is shown that the suggested general curved beam elements give better convergent characteristics than the modified isoparametric curved beam elements that have been shown in existing studies. These elements are also easy to formulate due to their consistent form of strain fields.