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 modelsژورنال: 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
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رساله دکتری با عنوان: Dynamic Finite Element Modeling and Analysis of Blast-resistant Sandwich Structures
اختصاصی از یارا فایل رساله دکتری با عنوان: Dynamic Finite Element Modeling and Analysis of Blast-resistant Sandwich Structures دانلود با لینک مستقیم و پرسرعت .
رساله دکتری با عنوان: Dynamic Finite Element Modeling and Analysis of Blast-resistant Sandwich Structuresدانشگاه : University of Connecticut
استاد راهنما: Jeong-Ho Kim
پژوهشگر: Linhui Zhang
سال 2012
فرمت فایل: PDF و شامل 165 صفحه
چکیده:
Blast-resistant composites and structures are gaining more and more academic and industrial interests currently. The metal sandwich structure is proven to perform better than the monolithic plate with the same mass under blast loading. Besides, the foam or foam-like cores with stacking of graded layers can further mitigate the blast effects. In this work, the dynamic responses of corrugated sandwich plates with various homogeneous and graded core arrangements under shock tube loading are investigated by finite element method. By comparing the maximum back face deflection, maximum back face velocity, plastic energy absorption, stress history and contact force, the corrugated sandwich plate with the gradually graded core has a better overall performance.
The parametric study on unit-cell corrugated and trapezoid sandwich structures with given mass and various core arrangements subjected to idealized air-blast loading is also carried out. The sandwich structures with graded cores can prevent the structure to get fully crushed. It is also shown that the trapezoid sandwich structures have larger impact tolerance, but the trapezoid sandwich structures are more sensitive to the initial geometric imperfections than corrugated sandwich structures.
Due to the benefits of the graded cores, a modified rule of mixture and linear strain-rate dependence are used to derive the rate-dependent elastic-plastic constitutive relation for functionally graded (FG) material. The derived constitutive relations are implemented in ABAQUS/Explicit through a VUMAT subroutine to simulate the dynamic response of a FG plate subjected to shock tube loading.
مشاهده آنلاین و دریافت فایل نمونه:
https://drive.google.com/file/d/0B3BBM5yT_t4ZWkUxUGdNRzNLS0k
** توجه: خواهشمندیم در صورت هرگونه مشکل در روند خرید و دریافت فایل از طریق بخش پشتیبانی در سایت مشکل خود را گزارش دهید. **
The Stress Analysis of Pressure Vessels and Pressure Vessel Components
اختصاصی از یارا فایل The Stress Analysis of Pressure Vessels and Pressure Vessel Components دانلود با لینک مستقیم و پرسرعت .
کتابی قدیمی ولی مفید برای طراحی مخازن تحت فشار بر اساس تئوریهای تنش
پاورپوینت درس Contrastive Analysis
اختصاصی از یارا فایل پاورپوینت درس Contrastive Analysis دانلود با لینک مستقیم و پرسرعت .
ارایه درس بررسی مقابله ای کارشناسی آموزش زبان انگلیسی
شامل 12 اسلاید پاورپوینت و توضیح موارد زیر:
The switching function analysis of power electronic circuits
اختصاصی از یارا فایل The switching function analysis of power electronic circuits دانلود با لینک مستقیم و پرسرعت .
The switching function analysis of power electronic circuits
IET 2008
سرفصلها
Part 1 The switching function 1
1 The switching function: Application and properties 3
1.1 Introduction 3
1.2 Application of the switching function technique 3
1.3 Properties of the switching function 6
2 Voltage–current relations in switched circuits 17
2.1 Single switch 18
2.2 Parallel switches 19
2.3 Parallel switched-resistors 20
2.4 Switched-inductors 21
2.5 Parallel switched-capacitors 24
2.6 Kirchoff’s First Law (current law) 27
2.7 Kirchoff’s Second Law (voltage) 27
2.8 Superposition theorem in switched circuits 29
2.9 Current sharing in a parallel RC switched network 31
3 Pulse width modulation 35
3.1 Sinusoidally modulated PWM signal – unipolar 36
3.2 The rectified sine-wave PWM signal 39
3.3 The PWM signal of a composite function 43
3.4 PWM sine-wave – bipolar square wave modulation 45
Part 2 AC to DC conversion 49
4 Analysis of the single phase ac to dc phase controlled converter
with R–L load 51
4.1 Introduction 51
4.2 Mathematical modelling 51
4.3 Analysis 55
5 The single phase full-wave diode rectifier – RC load 65
5.1 Introduction 65
5.2 Mathematical modelling 65
vi Contents
5.3 Analysis 72
5.4 Neutral current in three phase systems 77
6 The three-phase half-wave phase controlled converter 83
6.1 Introduction 83
6.2 Mathematical modelling of the three-phase half-wave
phase controlled converter 83
6.3 Analysis 91
6.4 Results 98
7 The three-phase full-wave phase controlled rectifier 101
7.1 Introduction 101
7.2 The mathematical modelling of the three-phase
full-wave controlled rectifier circuit 101
7.3 Analysis of three-phase full-wave phase controlled
rectifier 111
8 Overlap in ac to dc three-phase converters 121
8.1 Introduction 121
8.2 Operation and modes 122
8.3 Analysis 132
Part 3 DC to DC converters 135
9 The step down converter 137
9.1 Introduction 137
9.2 Mathematical modelling of the step down converter 137
10 The step up or boost converter 145
10.1 Introduction 145
10.2 Mathematical modelling of the dc to dc step up
(boost) converter 145
10.3 Analysis 152
11 The buck boost dc to dc converter 163
11.1 Introduction 163
11.2 Mathematical modelling of the buck boost converter 164
11.3 Analysis of the buck boost converter 168
12 The CUK dc to dc converter 175
12.1 Introduction 175
12.2 Mathematical modelling of the CUK dc to dc
converter 175
12.3 Analysis of the CUK dc to dc converter 180
13 The PWM full bridge dc to dc converter 187
13.1 Introduction 187
13.2 Operation and modes of the PWM full bridge dc to dc
converter: bipolar operation 188
13.3 Analysis of the PWM full bridge dc to dc converter:
bipolar operation 189
13.4 Operation and modes of the PWM full bridge
dc to dc converter: unipolar operation 193
Contents vii
13.5 Analysis of the PWM full bridge dc to dc converter:
unipolar operation 197
Part 4 Frequency changers 203
14 Three by three matrix converter 205
14.1 Introduction 205
14.2 Operation and mathematical model 206
14.3 The modes of operation and the switching functions 208
14.4 Analysis of the matrix converter as a three-phase to
three-phase system 211
14.5 The matrix converter as an ac to dc voltage converter 218
15 The single pulse PWM inverter 223
15.1 Introduction 223
15.2 Operation and modes of the circuit 223
15.3 The mathematical model and analysis 229
16 The sinusoidally PWM inverter 235
16.1 Introduction 235
16.2 Mathematical modelling 235
16.3 Analysis 241
17 The envelope cyclo-converter 245
17.1 Introduction 245
17.2 The mathematical model 245
17.3 The switching functions 246
Part 5 Active filters 249
18 The thyristor-controlled reactor 251
18.1 Introduction 251
18.2 The single reactor arrangement 251
18.3 The two reactor arrangement 257
19 The switched capacitor active filters 263
19.1 Introduction 263
19.2 The general model for the switched-capacitor active
filters 263
19.3 The switching functions 265
19.4 The line current 266
19.5 The double-switch double-capacitor 266
19.6 Reactive power generation 266
20 The inverter configuration active filter 271
20.1 Introduction 271
20.2 Operation and analysis 271
21 Single phase rectification with active line shaping 275
21.1 Mathematical modelling of the active shaping circuit 275
Discussion 289
References 291
Index 293