Prola, Luis CarlosRuben, Rui Miguel BarreirosMonteiro, Cristiano Alexandre Garcia2024-06-212024-06-212024-01-03http://hdl.handle.net/10400.8/9731This work aims to present a proposal for verifying the safety of thin-walled profiles based on the concept of effective elasticity modulus. This method has the advantage, compared to the classical Effective Width method, of not requiring the alteration of geometric properties of the section to account for the effects of post-buckling resistance on local and distortional instability modes. Furthermore, it maintains theoretical consistency by considering the variation of post-buckling average stresses relative to deformations. The dissertation begins with a literature review on plate instability. Then a literature review on section instability is conducted to demonstrate the consistency of applying the concept of effective modulus to post-buckling resistance, illustrating examples of effective elasticity modulus distributions in the post-buckling stage of columns and beams. Following this, an algorithm for calculating the resistance of columns and beams based on the concept of Effective Elasticity Modulus is proposed. Initially, an innovative criterion for post-buckling resistance of plates without imperfections is introduced, using a new relationship between stresses and deformations, where the post-buckling resistance of the plate is reached when the average stress corresponds to yield deformations, by means an effective elasticity modulus. Subsequently, as a comprehensive parametric study has not yet been conducted to calibrate the equations of effective modulus for local and distortional instability modes, reduction coefficients of modulus equivalent to the well-known Direct Strength Method are employed. The proposed calculation algorithm for the Effective Modulus Method is then tested in comparison with experimental and numerical results available in the literature. The method is applied to take into account the interaction of local, distortional, and global instability modes in columns and local and distortional modes in beams.engEngenharia civilMódulo de elasticidade efetivoColunas de aço formadas a frioModos de flambagem de interaçãoColunas de aço de paredes finasMétodo do módulo efetivomaster thesis203652533