تهيه ي مدل رفتاري واحدهاي آجركاري معمول در ساختمان هاي بنايي جهت استفاده در تحليل هاي ديناميكي

چكيده انگليسي :

Isfahan University of Technology Department of Civil Engineering Constitutive Modeling of Masonry Units in Masonry Structures to Be Implemented in Dynamic Numerical Analysis By Negar Naeimi Supervisor A M Halabian Abstract Masonry is one of the oldest materials used in construction During thousands of years prominent features of construction masonry such as abundance compatibility with most climate conditions no need for expert labor in the building conditions process and durability and stability have made it a favorable choice for construction Although a major part of the existing buildings in Iran and other places around the world are of masonry engineers knowledge and apprehension of these kinds of structures are not sufficient and effective Therefore further research towards a toward more extensive understanding of masonry behavior is still indispensable The widespread and irreparable indispensable damages inflicted on inhabitants of masonry structures during the recent earthquakes in Iran evidently prove structures this fact In the analysis of structures above all a constitutive model capable of simulating the behavior of materials is needed It is crystal clear that due to natural variables involved providing a precise constitutive model is clear involved se impossible The complexity of the mechanical behavior of masonry and lack of an adequate set of material data has made analysis of masonry structures much more difficult in comparison to steel and concrete structures structures Providing a cyclic constitutive model present an even greater challenge compared to a monotonic one presents one This study is concerned with the extending of an existing monotonic constitutive model into a cyclic constitutive one The existing monotonic constitutive model based on the plasticity concept is able to simulate the hardening model and softening behavior of masonry It utilizes two different yield surfaces a Rankine type criterion and a Hill surfaces type criterion in order to predict different failure mechanisms in tension and compression respectively compression According to this constitutive model masonry is considered as an anisotropic homogenous material which shows different behaviors along each of the material axes parallel and normal to bed joints To extend the existing material s monotonic constitutive model into the cyclic one the concept of equivalent strain is used in order to utilize the ic one uniaxial stress strain relations in the determination of unloading and reloading paths Unloading and reloading paths curves are considered to be linear in tension In compression unloading and reloading curves are considered to n tension be nonlinear and linear respectively Furthermore the hypothesis of linear elastic unloading and reloading is Furthermore assumed for the shear component The developed cyclic constitutive model is implemented in a finite element software with the ability of del element programming and then it is verified by comparing the predicted numerical responses with the behavior measured in reliable experiments As a result this model has the capability of predicting the main characteristics of hysteresis curves such as stiffness and strength degradation residual relative displacements at zero stress crack degradation stress closing and reopening and energy dissipation Hence it can be implemented in macro modeling simulation of dissipation modeling simulati masonry structures under both monotonic and cyclic loading loading Keywords Masonry in plane behavior macro modeling hysteresis curve finite element method modeling PDF created with pdfFactory trial version www pdffactory com

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تهيه ي مدل رفتاري واحدهاي آجركاري معمول در ساختمان هاي بنايي جهت استفاده در تحليل هاي ديناميكي

مصالح بنايي , رفتار درون صفحه اي , مدل رفتاري ماكرو , منحني هيسترزيس , روش اجزاء محدود