scholarly journals Numerical Analysis on the Collapse of a RC Frame

2016 ◽  
Vol 12 (4) ◽  
pp. 22-35
Author(s):  
George Bogdan Nica ◽  
Florin Pavel
Keyword(s):  
Numerical Investigation ◽  
Concrete Strength ◽  
Collapse Mechanism ◽  
Rc Frame ◽  
Good Match ◽  
Structural Behaviour ◽  
Collapse Analysis ◽  
Rc Slab ◽  
Applied Element Method ◽  
The Impact

Abstract This paper focuses on the collapse analysis of a planar RC frame. This research is based on an experimental study presented in the literature. The analyses are conducted using a dedicated software based on the Applied Element Method. This numerical method is able to model accurately all the structural behaviour stages leading up to the collapse itself. A very good match between the experimental and numerical results is observed. The numerical investigation highlights several behaviour stages for the model RC frame. Moreover, the contribution of the RC slab and the impact of the concrete strength on the overall collapse mechanism is discussed and evaluated through numerical investigation.

Impact of CEDIT recommendations: An example of health technology assessment in a hospital network

2006 ◽  
Vol 22 (2) ◽  
pp. 161-168 ◽  
Author(s):  
Florence Bodeau-Livinec ◽  
Emmanuelle Simon ◽  
Catherine Montagnier-Petrissans ◽  
Marie-Eve Joël ◽  
Elisabeth Féry-Lemonnier
Keyword(s):  
Decision Making ◽  
Technology Assessment ◽  
Health Technology ◽  
Technological Innovations ◽  
Administrative Staff ◽  
Good Match ◽  
French Hospital ◽  
The Impact ◽  
Widespread Interest

Objectives: The objective of this study is to assess the impact of CEDIT (French Committee for the Assessment and Dissemination of Technological Innovations) recommendations on the introduction of technological innovations within the AP-HP (Assistance Publique–Hôpitaux de Paris), the French hospital network to which this body is attached.Methods: In 2002, a study based on semidirective interviews of fourteen people affected by these recommendations and a case study relating to thirteen recommendations issued between 1995 and 1998 were conducted.Results: The CEDIT is very scientifically reputable among interviewees. There is generally widespread interest for the recommendations. They are used as decision-making tools by administrative staff and as negotiating instruments by doctors in their dealings with management. Based on the case study, ten of thirteen recommendations had an impact on the introduction of the technology in health establishments. One recommendation appears not to have had an impact. Furthermore, the impact of two technologies was impossible to assess.Conclusions: This study highlights the significant impact of recommendations arising from a structure that is attached to a hospital network and the good match between CEDIT's objectives and its assignments.

Numerical Investigation of the Solidity Effect on Linear Compressor Cascades

2014 ◽  
Author(s):  
J. Sans ◽  
M. Resmini ◽  
J.-F. Brouckaert ◽  
S. Hiernaux
Keyword(s):  
Numerical Investigation ◽  
State Of The Art ◽  
Leading Edge ◽  
Operating Conditions ◽  
Compressor Cascade ◽  
Minimum Loss ◽  
Low Speed ◽  
High Mach ◽  
The Stability ◽  
The Impact

Solidity in compressors is defined as the ratio of the aerodynamic chord over the peripheral distance between two adjacent blades, the pitch. This parameter is simply the inverse of the pitch-to-chord ratio generally used in turbines. Solidity must be selected at the earliest design phase, i.e. at the level of the meridional design and represents a crucial step in the whole design process. Most of the existing studies on this topic rely on low-speed compressor cascade correlations from Carter or Lieblein. The aim of this work is to update those correlations for state-of-the-art controlled diffusion blades, and extend their application to high Mach number flow regimes more typical of modern compressors. Another objective is also to improve the physical understanding of the solidity effect on compressor performance and stability. A numerical investigation has been performed using the commercial software FINE/Turbo. Two different blade profiles were selected and investigated in the compressible flow regime as an extension to the low-speed data on which the correlations are based. The first cascade uses a standard double circular arc profile, extensively referenced in the literature, while the second configuration uses a state-of-the-art CDB, representative of low pressure compressor stator mid-span profile. Both profiles have been designed with the same inlet and outlet metal angles and the same maximum thickness but the camber and thickness distributions, the stagger angle and the leading edge geometry of the CDB have been optimized. The determination of minimum loss, optimum incidence and deviation is addressed and compared with existing correlations for both configurations and various Mach numbers that have been selected in order to match typical booster stall and choke operating conditions. The emphasis is set on the minimum loss performance at mid-span. The impact of the solidity on the operating range and the stability of the cascade are also studied.

Altitude Effects on the Performance of Small Radial Turbomachinery: Part I — Compressor Impellers

2016 ◽  
Author(s):  
Dries Verstraete ◽  
Kjersti Lunnan
Keyword(s):  
Reynolds Number ◽  
Performance Analysis ◽  
Rotational Speed ◽  
Pressure Ratio ◽  
Unmanned Aircraft ◽  
Good Match ◽  
One Dimensional ◽  
Design Changes ◽  
Current Article ◽  
The Impact

Small unmanned aircraft are currently limited to flight ceilings below 20,000 ft due to the lack of an appropriate propulsion system. One of the most critical technological hurdles for an increased flight ceiling of small platforms is the impact of reduced Reynolds number conditions at altitude on the performance of small radial turbomachinery. The current article investigates the influence of Reynolds number on the efficiency and pressure ratio of two small centrifugal compressor impellers using a one-dimensional meanline performance analysis code. The results show that the efficiency and pressure ratio of the 60 mm baseline compressor at the design rotational speed drops with 6–9% from sea-level to 70,000 ft. The impact on the smaller 20 mm compressor is slightly more pronounced and amounts to 6–10%. Off-design changes at low rotational speeds are significantly higher and can amount to up to 15%. Whereas existing correlations show a good match for the efficiency drop at the design rotational speed, they fail to predict efficiency changes with rotational speed. A modified version is therefore proposed.

Problem Diagnosis and Aerodynamic Improvement of a Field Pipeline Compressor

2000 ◽  
Author(s):  
Zheji Liu ◽  
D. Lee Hill ◽  
Yuri I. Biba
Keyword(s):  
Numerical Investigation ◽  
Individual Component ◽  
Field Testing ◽  
Interface Model ◽  
Efficiency Improvement ◽  
Extensive Investigation ◽  
Peak Efficiency ◽  
Aerodynamic Loss ◽  
Design Changes ◽  
The Impact

Abstract An extensive investigation surrounding a performance shortfall of a pipeline compressor is presented. Regions of high aerodynamic loss are identified from an extensive flange-to-flange numerical investigation. Special attention is placed on understanding the impact of the interface model between the rotating and stationary components on the performance of each individual component and the whole machine. This process lead to the redesign of the radial inlet, the diffuser region, and the volute. Upon numerical validation of the proposed design changes, the components were manufactured and installed into the compressor that was already operating in the field. “Field” testing showed the new design to have a peak efficiency improvement of 4 points surpassing the contract guarantee.

scholarly journals Numerical investigation of the fatal 1985 Manchester Airport B737 fire

2017 ◽  
Vol 121 (1237) ◽  
pp. 287-319 ◽  
Author(s):  
E. R. Galea ◽  
Z. Wang ◽  
F. Jia
Keyword(s):  
Wind Speed ◽  
Numerical Investigation ◽  
Computer Simulations ◽  
Potential Benefit ◽  
Fire Plume ◽  
Significant Difference ◽  
Actual Fire ◽  
The Right ◽  
The Impact ◽  
Burn Through

ABSTRACTIn this paper, fire and evacuation computer simulations are used to reconstruct the 1985 Manchester Airport B737 fire that resulted in the loss of 55 lives. First the actual fire and evacuation are reconstructed. Secondly, the impact of exit opening times and external wind on the fire and evacuation are investigated. Finally, the potential benefit offered by modern materials is evaluated. The results suggest that the number of fatalities could have been reduced by 87% had the forward right exit not malfunctioned and by 36% had the right over-wing exit been opened without delay. Furthermore, given the fuel pool size and location, a critical wind speed of 1.5m/s is necessary to cause the fire plume to lean onto the fuselage eventually resulting in fuselage burn-through. Finally, it is suggested that the use of modern cabin materials could have made a significant difference to the fire development and survivability.

Numerical Investigation of a Stiffened Panel Subjected to Low Velocity Impacts

2015 ◽  
Vol 665 ◽  
pp. 277-280 ◽  
Author(s):  
Aniello Riccio ◽  
S. Saputo ◽  
A. Sellitto ◽  
A. Raimondo ◽  
R. Ricchiuto
Keyword(s):  
Numerical Investigation ◽  
Composite Laminates ◽  
Mechanical Response ◽  
Numerical Study ◽  
Fem Analysis ◽  
Matrix Cracking ◽  
Stiffened Panel ◽  
Low Velocity ◽  
Formation And Evolution ◽  
The Impact

The investigation of fiber-reinforced composite laminates mechanical response under impact loads can be very difficult due to simultaneous failure phenomena. Indeed, as a consequence of low velocity impacts, intra-laminar damage as fiber and matrix cracking and inter-laminar damage, such as delamination, often take place concurrently, leading to significant reductions in terms of strength and stability for composite structure. In this paper a numerical study is proposed which, by means of non-linear explicit FEM analysis, aims to completely characterize the composite reinforced laminates damage under low velocity impacts. The numerical investigation allowed to obtain an exhaustive insight on the different phases of the impact event considering the damage formation and evolution. Five different impact locations with the same impact energy are taken into account to investigate the influence on the onset and growth of damage.

scholarly journals Influence of the concrete strength and the type of supports on the stress-strain state of a hyperbolic paraboloid shell footbridge structure

2021 ◽  
Vol 17 (4) ◽  
pp. 379-390
Author(s):  
David Cajamarca-Zuniga ◽  
Sebastian Luna
Keyword(s):  
Thin Shell ◽  
Strain State ◽  
Concrete Strength ◽  
Design Parameters ◽  
Live Load ◽  
Structural Behaviour ◽  
Stress Strain ◽  
Hyperbolic Paraboloid ◽  
Element Analysis ◽  
Stress Strain State

Relevance. This work is the first in a series of publications on the selection of a suitable analytical surface for implementation as a self-supporting structure for a thin shell footbridge. The study on the influence of concrete strength, live load position and support types on the stress-strain state of a hyperbolic paraboloid (hypar) shell is presented. Objective - to define the initial design parameters such as the appropriate concrete strength and the support type that generates the best structural behaviour to perform the subsequent structural design of a thin shell footbridge. Methods. The static finite element analysis was performed for 4 compressive strengths of concrete (28, 40, 80, 120 MPa) which correspond normal, high and ultra-high resistance concrete, 5 different live load arrangements and 3 different support conditions. Results. The shell model with pinned (two-hinged) supports shows the same vertical displacements as the model with fixed supports (hingeless). For the studied shell thickness, in terms of stress behaviour, the model with pinned ends is more efficient. The combination of two-hinged supports with 80 MPa concrete strength shows a better structural performance.

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