دانلود رایگان مقاله لاتین معادل خطی مدل الاستیک از سایت الزویر
عنوان فارسی مقاله:
معادل خطی مدل الاستیک چسبناک آلیاژ حافظه دار برای سازه های جدا شده
عنوان انگلیسی مقاله:
Equivalent linear elastic-viscous model of shape memory alloy for isolated structures
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Structures can be protected from the damaging effects of earthquakes by isolating them at ground level. A passive isolation system is one of the most effective and simplest representations to implement the above idea. By providing an isolation device between the superstructure and substructure, the time period of a base-isolated structure is elongated and shifted away from the energetic frequency content of an earthquake. Apart from the required flexibility, the isolation system also have an adequate energy dissipating mechanism and re-centering capacity. Further, it should be able to withstand under the action of vertical load coming from the weight of superstructure, and should provide lateral rigidity against in-service load condition, such as wind or blast or low intensity earthquake. The isolation bearings can be broadly classified into two categories: elastomeric type and sliding type. Elastomeric bearings provide a flexible interface (rubber like material) between the structure and foundation. These bearings are also supplemented by lead core to enhance hysteretic damping and to provide lateral stiffness. Elastomeric rubber bearings (ERB) and lead rubber bearings (LRB) are the examples of this category. Sliding type isolation systems provide an interface to allow a structure to slide when the lateral load exceeds a threshold value. Friction pendulum systems (FPS) and resilient friction bearing isolators (RFBI) are the examples of this category. Commercially available traditional isolation bearings such as ERB, LRB, FPS, RFBI etc. have some difficulty in replacing any device component after a strong seismic event. Moreover, they undergo large as well as residual deformations. Isolator displacement is the decision making parameter for the design of an isolation system. Large isolator displacement leads to failure of an isolation system, especially when it is subjected to a near fault earthquake. In order to over come these problems, American Association of State Highway and Transportation Officials (AASHTO) recommends that additional damping can be used to control the large isolator displacement. In this context, many investigations were carried out by researchers to control displacement of isolation bearings using semiactive Magnetorheological (MR) dampers [1–4]. The MR damper may partially solve the above-mentioned problem, but may not be entirely eliminated. Recently, many researchers have used SMA in the isolation systems to reduce its vulnerability against near fault motions [5–14]. SMA has many desirable properties such as super elasticity, durability and fatigue resistance. In addition to this, SMA has also an ability to reduce design displacement as well as recentering capacity. Ozbulut et al. [15] have presented an excellent literature review on the super-elasticity of SMA and its applications in structural vibration control particularly in the area of seismic isolation.
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کلمات کلیدی:
PDF]Equivalent viscous damping equations for direct ... - ROSE School www.roseschool.it/files/get/id/4339 A comparison of the displacements obtained from a non-linear time-history ... SDOF model was designed for five different levels of ductility (2 to 6) and ... order to separate the effects of elastic-viscous and hysteretic damping the ...... where φi is the inelastic mode shape which are often very similar to the elastic mode shape ... [PDF]Basic Elasticity and viscoelasticity - Princeton University Press press.princeton.edu/chapters/s9774.pdf rigid; or it can feed the energy into large changes in shape (the main mechanism in ..... Its equivalence to the shear modulus can be seen in Eq. 1.9; its definition is ... by the viscosity of the material, the stress, the temperature, and the time for which .... applies linear, small- strain models to nonlinear, large- strain materials. Seismic Design and Retrofit of Bridges https://books.google.com/books?isbn=047157998X M. J. N. Priestley, F. Seible, G. M. Calvi - 1996 - Technology & Engineering Viscous damping is physically correct only for an oil-filled dashpot and is difficult to ... the elastic strain energy stored in an equivalent linear elastic system under static ... force-displacement hysteresis loop shapes for various bridge members are ... FORCE g y Energy eff A_ = Elastic Strain DISPLACEMENT 174 MODELING ... Standard linear solid model - Wikipedia https://en.wikipedia.org/wiki/Standard_linear_solid_model The standard linear solid (SLS) model, also known as the Zener model, is a method of modeling the behavior of a viscoelastic material using a linear combination of springs and dashpots to represent elastic and viscous .... Although this model can be used to accurately predict the general shape of the strain curve, as well as ... Life-Cycle Civil Engineering: Proceedings of the International ... https://books.google.com/books?isbn=0203885309 Fabio Biondini, Dan Frangopol - 2008 - Technology & Engineering We start with the definition of the structural deformed shape (i), linear in this case, ... of the equivalent viscous damping, adopted by DDBD to represent the elastic and ... models: the one adopted for this research is the Takeda model (Figure 2), ... [PDF]Linear response of materials: elastic, viscous ... - Docenti.unina https://www.docenti.unina.it/downloadPub.do?tipoFile=md&id=63917 Thus linear elasticity of amorphous materials is characterized by 2 material constants only. For the ... isotropic stress due to a change in volume at constant shape. ..... model is equivalent to a viscoelastic liquid with the modulus: G(t) = G ...
