Authors: Shu Yuan Zhang, Yun Xin Wu
Abstract: A mathematical model has been developed to predict the residual stresses level in pre-stretched aluminum alloy plate. This is based on force balances of the residual stress, theory of plastoelasticity and a new conception of free length. The model is relatively simple because only rolling direction residual stress is taken into account, but provides a clear illustration of stress relief mechanism in stretching process. With this model, residual stress distributions of stretched beam can be determined directly by knowing the specimen dimensions, material properties and the original stress. The model offers an useful tool to show the effect of varying tension ratio on the final residual stress level, thus makes it possible to predict stress relief and control residual stresses. An example of using the model is presented by applying published data while showing mechanism of stress relief during stretching. Analysis indicates that it is stretch-caused convergence of the free lengths of strips in beam that lead to reduction in the residual stresses.
3187
Authors: Qiong Fen Wang, Yuan Cai Liu, Liang Cao, Ji Yao, Jian Feng Huang
Abstract: Calculations of the end-plate semi-rigid joints are carried out with a FE-program ANSYS. Some results of the calculations are introduced in this paper. The influences of the joints semi-rigidity on the deformation, the bending capacity and the internal force of the structure are researched; the initial rotational stiffness, the elastic ultimate moment and the plastic ultimate moment of the steel joints and the composite joints are compared. Some results may be useful for the design of the end-plate semi-rigid joints.
1625
Authors: Jing Feng Wang, Bo Wang, Zhong Ming Zheng
Abstract: To research the mechanical behaviour of the novel composite beam with concrete filled steel tubular (CFST) truss, an experimental study of simple composite beam subjected to monotonic loading is described. A test program was developed to investigate failure models and working mechanism of the typed composite structure. Load-deformation curves, deflection regulation, strain distribution of beam were analyzed and asserted. The experimental and analytic results show that the typed composite beam has high strength, excellent ductility, and torsion performance. It can be used the large span bridges and high rise buildings.
1680
Abstract: In order to meet the necessity of the code for seismic design of buildings: Principle for strong connections and feebleness member. The exernal steel tube of column and steel beam are joining with three kinds of style. Containing two strengthen styles T-style stiffening plate and appending haunch. The result reveals that the two strengthen connections ultimate load are much bigger, good ductility, better seismic behavior. The deformation of the column and the region of the connection is smaller when it was broken, Indicating the connections’s globality is better and the stiffness is bigger. It avoids brittleness for breaking styles when they are given more load.
3269
Authors: K. Venkata Rao, S. Raja, T. Munikenche Gowda
Abstract: A two noded active sandwich beam element is formulated by employing layerwise Timoshenko’s beam theory. Displacement continuity conditions are imposed between different layers of the sandwich. This element is used to model an adaptive sandwich beam with macro-fiber composite (MFC) as extension actuator and shear actuated fiber composite (SAFC) as shear actuator. Influence of thickness and volume fraction of the active fiber (PZT-5A and single crystal PMN-PT) in the composite actuators on the actuation performance of the sandwich beam is investigated. Based on several numerical experiments, it is found that the PMN-PT based shear actuators give maximum actuation authority for the volume fraction of the fibers in the range of 80%-85%, whereas in case of PZT-5A based shear actuators the actuation authority remains maximum for the fiber volume fractions 80% and above.
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