In-plane Response of a Three-span Simply Supported Bridge to Near-fault Strong Ground Motion

اختصاصی از یارا فایل In-plane Response of a Three-span Simply Supported Bridge to Near-fault Strong Ground Motion دانلود با لینک مستقیم و پرسرعت .

مقاله با عنوان: In-plane Response of a Three-span Simply Supported Bridge to Near-fault Strong Ground Motion
نویسندگان: Milad Veisi , Reza Saleh Jalali
محل انتشار: هشتمین کنگره ملی مهندسی عمران - دانشگاه صنعتی نوشیروانی بابل - 17 و 18 اردیبهشت 93
محور: دینامیک سازه
فرمت فایل: PDF و شامل 8 صفحه به انگلیسی می باشد.

چکیده:
In this paper a simple model of a three-span simply supported bridge excited by the horizontal component of fault-normal pulse with different magnitudes and time lags has been considered. In the considered model the axially rigid mass-less piers are connected at the top to the rigid decks by hinges and at the bottom to the ground by linear rotational springs and dashpots. For determination of the pounding force between decks, the linear viscoelastic model has been chosen. It is assumed that the bridge is near the fault and the excitations at all piers have the same amplitude but differ in terms of phase. The system of equations of motion has been solved by the fourth-order Runge-Kutta method because of its self-starting feature and the long-range stability. For a range of main period of the bridge, the maximum impact force between decks and the minimum gap size required to avoid collision can be determined under fault-normal pulse with different magnitudes and time lags. It could be concluded from the results that time lag plays a very important role in determining maximum impact force and it’s better to use softer piers to reduce the maximum impact force and the minimum gap size required to avoid collision between decks.

** توجه: خواهشمندیم در صورت هرگونه مشکل در روند خرید و دریافت فایل از طریق بخش پشتیبانی در سایت مشکل خود را گزارش دهید. **

Probabilistic Quantification of Incremental Dynamic Analysis Results

اختصاصی از یارا فایل Probabilistic Quantification of Incremental Dynamic Analysis Results دانلود با لینک مستقیم و پرسرعت .

مقاله با عنوان: Probabilistic Quantification of Incremental Dynamic Analysis Results
نویسندگان: Azad Yazdani , Hessan Salehi
محل انتشار: هشتمین کنگره ملی مهندسی عمران – دانشگاه صنعتی نوشیروانی بابل - 17 و 18 اردیبهشت 93
فرمت فایل: PDF و شامل 6 صفحه می باشد.

چکیده:
Incremental Dynamic Analysis (IDA) is a parametric analysis method that has recently emerged in several different forms to estimate more thoroughly structural performance under seismic load. It involves subjecting a structural model to one or more ground motion records. This method considers both inherent randomness and model uncertainty, so it used to probabilistic analysis of structures at high seismic loading. The objective of this study is to improve efficient, but accurate procedures for probabilistic analysis of nonlinear seismic behavior of structure. According to the three-parameter Log-normal distribution more rationally describe maximum story drift ratio at a higher value of spectral acceleration. The traditional method based on two-parameter Log-normal distribution is compared with the presented procedure based on three-parameter Log-normal distribution on analytical data. Improvement in the probabilistic estimation of maximum story drift ratio demand are illustrate with a SAC-9 story, moment resisting frame building exposed to a set of 20 ground motion.

** توجه: خواهشمندیم در صورت هرگونه مشکل در روند خرید و دریافت فایل از طریق بخش پشتیبانی در سایت مشکل خود را گزارش دهید. **

Experimental investigation of sloshing in a rectangular tank using a numerical simulation

اختصاصی از یارا فایل Experimental investigation of sloshing in a rectangular tank using a numerical simulation دانلود با لینک مستقیم و پرسرعت .

مقاله با عنوان: Experimental investigation of sloshing in a rectangular tank using a numerical simulation
نویسندگان: Mohammad Reza Shekari
محل انتشار: هشتمین کنگره ملی مهندسی عمران – دانشگاه صنعتی نوشیروانی بابل - 17 و 18 اردیبهشت 93
فرمت فایل: PDF و شامل 7 صفحه به انگلیسی می باشد.

چکیده:
Pressure variations and 3D effects on liquid sloshing loads in a moving partially filled rectangular tank have been performed numerically. Recently, extensive advances have been made in the development of numerical techniques for investigating the effects of liquid sloshing on large structures. However, there is a lack of experimental data that may be used for validating the analytical and numerical solutions acquired. This paper presents a numerical algorithm which is achieved through the use of finite shell elements for the structure and internal boundary elements for the liquid region. Several configurations of both baffled and unbaffled tanks are considered to show the slosh loads in the cases investigated. It is observed that baffles significantly reduce the fluid motion and accordingly the pressure response.

** توجه: خواهشمندیم در صورت هرگونه مشکل در روند خرید و دریافت فایل از طریق بخش پشتیبانی در سایت مشکل خود را گزارش دهید. **

مقاله ISI با عنوان: Analysis of a bridge failure due to fire using computational fluid dynamics and finite element models

اختصاصی از یارا فایل مقاله ISI با عنوان: Analysis of a bridge failure due to fire using computational fluid dynamics and finite element models دانلود با لینک مستقیم و پرسرعت .

مقاله ISI با عنوان: Analysis of a bridge failure due to fire using computational fluid dynamics and finite element models
ژورنال: Engineering Structures
محتوای مقاله: آنالیز شکست پل در اثر حریق
پژوهشگران: J. Alos-Moya, I. Paya-Zaforteza, M.E.M. Garlock, E. Loma-Ossorio, D. Schiffner, A. Hospitaler
سال 2014
فرمت فایل: PDF و شامل 15 صفحه

چکیده:
Bridge fires are a major concern because of the consequences that these kind of events have and because they are a real threat. However, bridge fire response is under researched and not covered in the codes. This paper studies the capabilities of numerical models to predict the fire response of a bridge and provides modeling guidelines useful for improving bridge design. To reach this goal, a numerical analysis of the fire of the I-65 overpass in Birmingham, Alabama, USA in 2002 is carried out. The analyses are based on computational fluid dynamics (CFD) for creating the fire model, and finite element (FE) software for obtaining the thermo-mechanical response of the bridge. The models are validated with parametric studies that consider heat release rate of the spilled fuel, discretization of the fire temperature in the transition from CFD to FE modeling, and boundary conditions. The validated model is used in a study to evaluate the influence of fire scenario (CFD versus standard fires), and live load. Results show that numerical models are able to simulate the response of the bridge and can be used as a basis for a performance-based approach for the design of bridges under fire. Additionally, it is found that applying the Eurocode standard and hydrocarbon fires along the full length of the bridge does not adequately represent a real bridge fire response for medium-long span bridges such as this case study. The study also shows that live loads essentially do not influence the response of the bridge.


لینک مقاله در سایت www.sciencedirect.com :
http://www.sciencedirect.com/science/article/pii/S0141029614001151


** نحوه سفارش مقالات ISI: پس از پیدا کردن مقالات درخواستی خود از پایگاه‌های علمی همانند sciencedirect.com لینک مقالات مورد نظر خود را به ایمیل [e-mail] ارسال کرده پس از قرار گرفتن مقالات در سایت می توانید به صورت آنلاین اقدام به خرید و دریافت مقاله نمایید. **

** توجه: خواهشمندیم در صورت هرگونه مشکل در روند خرید و دریافت فایل از طریق بخش پشتیبانی در سایت مشکل خود را گزارش دهید. **

رساله دکتری با عنوان: Fracturing of layered reservoir rocks

اختصاصی از یارا فایل رساله دکتری با عنوان: Fracturing of layered reservoir rocks دانلود با لینک مستقیم و پرسرعت .

رساله دکتری با عنوان: Fracturing of layered reservoir rocks
دانشگاه : The University of Oklahoma
استاد راهنما: Dr. Ze’ev Reches
پژوهشگر: Seth Busetti
سال 2009
فرمت فایل: PDF و شامل 272 صفحه

چکیده:
The development of fractures in rock layers reflects a history of complex, non-linear, time-dependent mechanical processes. The processes strongly depend on the rock rheology, particularly the behavior during progressive deformation, layering effects such as the mechanical stratigraphy, and the local stress conditions. In the past, the complex mechanics associated with fracture initiation and propagation contributed to the application of simplified models based on linear rheology and using quasi-static solutions. While this approach is effective in solving infinitesimal strain problems, it provides no explanation for strain localization, damage accumulation and rock failure, and it oversimplifies fracture propagation. The objective of the present work is to contribute to the understanding of these processes.
The approach of this study is as follows. (Chapter 1) Theoretical advancements on fracturing and the concept of continuum damage mechanics are compared with rock mechanics experiments to understand progressive deformation, failure, and fracture propagation for rock. It is demonstrated that non-local (away from the crack-tip) yielding behavior must be considered to understand complex fracturing. (Chapter 2) A numerical rheology based on the elastic-plastic-damage properties of Berea sandstone is developed and calibrated to experimental rock mechanics data. A method for translating the stress-strain curve and acoustic emissions data into a material model included in the commercial finite element code Abaqus is presented. Two rock mechanics experiments are simulated in 3-D to test the rheology model. (Chapter 3) The rheology is implemented into finite element models based on classical hydraulic fracturing configurations. The explicit dynamic finite element method is used to simulate damage and transient propagation of a hydrofracture segment. It is shown that the complexity of fracturing depends on the local stress-strain response, which is controlled by the evolving damage pattern. The dynamical characteristics of arrest, rupture, branching, and segmentation of the fracture are described in terms of damage evolution. (Chapter 4) An analytical model for natural fracture reactivation is paired with the finite element simulations to understand the development of complex hydraulic fracture networks in the subsurface. The models' predictions are compared with data from hydraulically stimulated wells in the Barnett Shale. Recommendations are made for optimizing hydrofracture operations in wells for different states of stress (Chapter 5). The occurrence of zones of anomalously high fracture density is characterized in a carbonate sequence near Cedar Mountain Utah, and in Jackfork Group sandstone layers in Oklahoma and Arkansas. The results indicate that fracture density should be examined as a function of the evolving rock properties of the host layer in addition to the layer thickness.
The investigation contributes to understanding the process of damage and fracturing during the deformation of rock layers. The results describe the development of mechanical inhomogeneity in fractured rock layers and can be applied to explain the formation of complex hydraulic fractures in unconventional reservoirs.


مشاهده آنلاین و دریافت فایل نمونه:
https://drive.google.com/file/d/0B3BBM5yT_t4ZcmpQUjBiZmR3WW8


** توجه: خواهشمندیم در صورت هرگونه مشکل در روند خرید و دریافت فایل از طریق بخش پشتیبانی در سایت مشکل خود را گزارش دهید. **