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- Alhasawi, Anas, et al.
(författare)
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Co-rotational planar beam element with generalized elasto-plastic hinges
- 2017
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Ingår i: Engineering structures. - : Elsevier. - 0141-0296 .- 1873-7323. ; 151, s. 188-205
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Tidskriftsartikel (refereegranskat)abstract
- Slender elements in framed structures may undergo large displacement and experience highly nonlinear behavior. This paper presents a two-node co-rotational flexible beam with generalized elasto-plastic hinges at the beam ends. A Condensation procedure is used to remove the internal degrees of freedom so that the formulation is easily incorporated with the standard co-rotational approach. A family of asymmetric and convex yield surfaces of super-elliptic shape is considered for the plastic behavior of the hinges. By varying the roundness factor, an infinite number of yield surfaces are obtained making it possible to select the yield function that best fit experimental data of any type of cross-section and material. The nonlinear response of bolted connections subjected to both bending and axial forces are conveniently modeled with such a yield surface. Discrete constitutive equations for the hinge plastic deformations are derived using the implicit scheme for both smooth and non-smooth cases. Numerical examples demonstrate the accuracy of the model in predicting the large displacement inelastic response of framed structures. Effect of the roundness factor on the ultimate load strongly depends on the structure typology. It was observed that cyclic loading produces pinching effect, cyclic softening and ductile behavior. Those effects are more pronounced with anisotropic yield criteria.
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| 2. |
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| 3. |
- Heng, Piseth, et al.
(författare)
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Co-rotating rigid beam with generalized plastic hinges for the nonlinear dynamic analysis of planar framed structures subjected to impact loading
- 2019
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Ingår i: Finite elements in analysis and design (Print). - : ELSEVIER SCIENCE BV. - 0168-874X .- 1872-6925. ; 157, s. 38-49
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this paper is to model the nonlinear dynamical response of steel frame structures subjected to impact loading. A 2D co-rotational rigid beam element with generalized elasto-plastic hinges is presented. The main idea is to integrate the concept of the generalized elasto-plastic hinge into the standard co-rotational framework by performing a static condensation procedure in order to remove extra internal nodes and their corresponding degrees of freedom. In addition, impact loading is applied through a contact model that is described in the rigorous framework of non-smooth dynamics. In this framework, equations of motion are derived using a set of differential measures and convex analysis tools, whereas Newton's impact law is imposed by means of a restitution coefficient in order to accommodate energy losses. An energy and momentum conserving scheme is adopted to solve the dynamical equations. The main interest of the current model is the ability to evaluate the geometrically nonlinear inelastic behaviour of steel structures with semi-rigid connections subjected to impact in a simple and efficient way, using only a few number of elements. The accuracy of the proposed formulation is assessed in three numerical applications.
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