نتایج جستجو برای: fracture mechanics

تعداد نتایج: 233213  

This study investigates propagation of mode I crack in B70 pre-stressed concrete sleepers by fracture mechanics approach. A new experimental analysis is done for notched B70 pre-stressed concrete sleepers with Replica test and image analysis. A scanning electron microscope test (SEM) and an image analysis are applied for the Replica test in order to determine crack length and crack mouth openin...

Journal: :international journal of transportation engineering 0
seyed mohammad farnam department of civil engineering, bu-ali sina university, hamedan, iran freydoon rezaie department of civil engineering, bu-ali sina university, hamedan, iran

this study investigates propagation of mode i crack in b70 pre-stressed concrete sleepers by fracture mechanics approach. a new experimental analysis is done for notched b70 pre-stressed concrete sleepers with replica test and image analysis. a scanning electron microscope test (sem) and an image analysis are applied for the replica test in order to determine crack length and crack mouth openin...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه تربیت مدرس - دانشکده فنی 1393

انجام عملیات شکست هیدرولیکی سهم قابل توجهی در افزایش تولید نفت و گاز در دنیا داشته است. اگرچه بیش از 60 سال است که در صنعت نفت دنیا شکست هیدرولیکی با موفقیت اجرا می شود، اما در ایران گزارشی از اجرای موفق این عملیات ارایه نشده است. همین امر لزوم توجه هر چه بیشتر دانشمندان ایرانی به این مهم را آشکارتر می سازد. در مدل ایجاد شده توسط نرم افزار آباکوس، مدل سازی چاه به صورت استوانه ای درون بلوک سه ب...

1999
John A. Nairn

Many composites fail by fracture events, such as fiber breaks or matrix cracks, rather than by continuous crack growth. Conventional fracture mechanics deals with predicting crack growth. This paper suggests that conventional fracture mechanics can be extended to predict fracture events by using finite fracture mechanics. In finite fracture mechanics, the next fracture event is assumed to occur...

Journal: :The Journal of Bone and Joint Surgery. British volume 1961

Rapid development of engineering activities expands through a variety of rock engineering processes such as drilling, blasting, mining and mineral processing. These activities require rock dynamic fracture mechanics method to characterize the rock behavior. Dynamic fracture toughness is an important parameter for the analysis of engineering structures under dynamic loading. Several experimental...

Journal: :مکانیک هوافضا 0
احسان براتی یونس علیزاده جمشید آقازاده

in this paper, the mean value of strain energy density criterion has been used to predict the critical fracture load in specimens with u-shaped notch under bending loads. an equation for calculation of averaged strain energy density in this zone has been presented. bending loads under mode i have been considered. two cases have been studied: 1) the control volume only includes the semicircular ...

The fracture mechanics examines the development and expansion of cracks in solids and how they affect the deformation of materials. The stress intensity factors at the tip of the crack and the critical stress intensity factors or fracture toughness of materials are considered in the relevant criteria. There are three main modes of applying forces to a crack including the tensile mode, shear mod...

Journal: :journal of mechanical research and application 2009
mehdi pourmahmoud

modelling of crack propagation by finite element method under mixed mode conditions is of prime importance in fracture mechanics. this paper describes an application of finite element method to the analysis of mixed mode crack growth in linear elastic fracture mechanics. crack growth process is simulated by an incremental crack-extension analysis based on the maximum principal stress criterion,...

Journal: :international journal of advanced design and manufacturing technology 0
masoud nikbakht naghdali choupani

in recent years, the application of composite materials in aircraft and space vehicle structural components has become increasingly popular. preventing failure of composite structural systems has been an important issue in engineering design. due to the lack of through-the-thickness reinforcement, structures made from laminated composite materials and adhesively bonded joints are highly suscept...

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