scholarly journals A numerical approach for evaluating residual capacity of fire damaged concrete members

2020 ◽  
Vol 10 (2) ◽  
pp. 230-242
Author(s):  
Venkatesh Kodur ◽  
Ankit Agarawal
Keyword(s):  
Numerical Model ◽  
Mechanical Response ◽  
Structural Response ◽  
Numerical Approach ◽  
Fire Exposure ◽  
Ambient Conditions ◽  
Concrete Members ◽  
Fire Scenarios ◽  
Residual Capacity ◽  
Residual Response

This paper presents an approach to evaluate residual capacity of fire-damaged concrete structures. The approach involves capturing response in three stages; namely, structural response at ambient conditions (prior to fire exposure), thermo-mechanical response during fire exposure, and post-fire residual response after cooling down of the structural member. The proposed approach is implemented in a comprehensive numerical model developed in the finite element computer program ABAQUS for specifically evaluating residual capacity of an RC beam after exposure to different fire scenarios. Predictions from the numerical model are utilized to highlight importance of each stage of analysis in evaluating realistic residual capacity of fire damaged concrete members.

Dynamic Mechanical Response Validation of Pavement Structural under Complex Stress State

2010 ◽  
Vol 163-167 ◽  
pp. 1645-1650
Author(s):  
Guo Ping Qian ◽  
Shuai Li ◽  
Li Jun Jiang
Keyword(s):  
Stress State ◽  
Model Calculation ◽  
Mechanical Response ◽  
Structural Response ◽  
Complex Stress ◽  
Calculation Model ◽  
Dynamic Strain ◽  
Response Model ◽  
Dynamic Mechanical ◽  
Pavement Structure

Under the heavy traffic, the stress state of asphalt pavement structure has such a complex change that it is difficult for conventional pavement structural response calculation model to deal with. Therefore, "Pavement structure dynamic mechanical response model under complex stress condition" is established in this paper. Kinds of cases are calculated according to the characteristics of heavy vehicle. Then the FWD deflection test and dynamic strain test are carried out. Finally, the rationality of pavement structural response model calculation model is proved by comparing the test results with the theoretical model calculation results.

Research Regarding the Effects of 120 mm HE Mortar Bombs on Advanced Materials

2021 ◽  
Vol 42 ◽  
pp. 128-134
Author(s):  
Daniela Pintilie ◽  
Iuliana Florina Pană ◽  
Adrian Malciu ◽  
Constantin Puică ◽  
Cristina Pupăză
Keyword(s):  
Experimental Data ◽  
Numerical Model ◽  
Initial Velocity ◽  
High Explosive ◽  
Numerical Approach ◽  
Advanced Materials ◽  
Physical Mechanisms ◽  
Shock Wave Generation ◽  
3D Numerical Model ◽  
Experimental Trials

High Explosive Mortar bombs are used on the battlefield for destroying the manpower, non-armoured equipment and shelters. The paper describes an original experimental and numerical approach regarding the potential threats caused by the detonation of 120 mm HE mortar bombs. The evaluation of the bomb effect presumes the fulfillment of experimental trials that focus on two physical mechanisms which appear after the detonation of the cased high explosive. These mechanisms are the shock wave generation and the fragments propulsion, which were also studied by a numerical model that provides results over the bomb fragmentation mode. The novelty of the paper consists in the calibrated 3D numerical model confirmed by the experimental data, which provides information over the fragmentation process of the case and the initial velocity of its fragments, proving that the main threat of this type of ammunition is the effect through metal fragments. The results of numerical simulation and experimental data are used for their comparative analysis and the assessment of the phenomena.

Analysis of the Structural Response of a Mid-span Multi-girder Composite Bridge submitted to different Fire Scenarios

2014 ◽  
Vol 102 (43) ◽  
pp. 71-78
Author(s):  
José Alós Moya ◽  
Ignacio Payá Zaforteza ◽  
Antonio Hospitaler Pérez ◽  
José Aguado López
Keyword(s):  
Structural Response ◽  
Fire Scenarios ◽  
Composite Bridge

Mechanical response of marble epistyles under shear: numerical analysis using an experimentally validated model

2018 ◽  
Vol 27 (3-4) ◽  
Author(s):  
Ermioni D. Pasiou ◽  
Stavros K. Kourkoulis
Keyword(s):  
Numerical Model ◽  
Stress Field ◽  
Mechanical Response ◽  
Specific Problem ◽  
Shear Loading ◽  
Filling Material ◽  
Experimental Protocol ◽  
Loading Mode ◽  
Traditional Design ◽  
Simple Contact

AbstractThe mechanical response of the restored “connections” of the epistyles of the Parthenon Temple on the Acropolis of Athens is studied assuming that the interconnected epistyles are under shear loading mode. The study is implemented by taking advantage of a numerical model, properly validated on the basis of the data of a recent relative experimental protocol. The main difficulty while studying the specific problem is the co-existence of three materials of completely different mechanical behaviors, i.e. the brittle marble of the epistyles, the ductile titanium of the connector and the cement-based material filling the grooves of the marble in which the connector is placed. The interfaces of this three-material-complex are simulated as simple contact with friction, the coefficient of which is, also, experimentally determined. Taking advantage of the data provided by the numerical model the stress field developed in the connector and the surrounding marble volume is described. Moreover, the forces imposed by the connector on the surface of the groove are quantitatively determined. Furthermore, the model permits a quantitative comparison between the mechanical response of the interconnected epistyles in the presence or in the absence of the “relieving space”. It is definitely concluded that the alternative design of the “connections”, according to which a small portion of the connector’s web is left uncovered by the filling material (relieving space), offers serious advantages against the traditional design, in the direction of reducing the intensity of the stress field developed in the marble volume surrounding the connector, thus, contributing to the protection of the authentic building material of the monument in the case of overloading of the epistyles.

scholarly journals Dislocation–grain boundary interactions: recent advances on the underlying mechanisms studied via nanoindentation testing

2021 ◽  
Author(s):  
Farhan Javaid ◽  
Habib Pouriayevali ◽  
Karsten Durst
Keyword(s):  
Grain Boundary ◽  
Mechanical Response ◽  
Displacement Curve ◽  
Ambient Conditions ◽  
Recent Advances ◽  
Slip Transfer ◽  
Depth Analysis ◽  
Dislocation Interactions ◽  
Underlying Mechanisms ◽  
Insight Into

Abstract To comprehend the mechanical behavior of a polycrystalline material, an in-depth analysis of individual grain boundary (GB) and dislocation interactions is of prime importance. In the past decade, nanoindentation emerged as a powerful tool to study the local mechanical response in the vicinity of the GB. The improved instrumentation and test protocols allow to capture various GB–dislocation interactions during the nanoindentation in the form of strain bursts on the load–displacement curve. Moreover, the interaction of the plastic zone with the GB provides important insight into the dislocation transmission effects of distinct grain boundaries. Of great importance for the analysis and interpretation of the observed effects are microstructural investigations and computational approaches. This review paper focused on recent advances in the dislocation–GB interactions and underlying mechanisms studied via nanoindentation, which includes GB pop-in phenomenon, localized grain movement under ambient conditions, and an analysis of the slip transfer mechanism using theoretical treatments and simulations. Graphical abstract

Efficient numerical modelling for the design of friction damped braced steel plane frames

1989 ◽  
Vol 16 (3) ◽  
pp. 211-218 ◽  
Author(s):  
A. Filiatrault ◽  
S. Cherry
Keyword(s):  
Numerical Modelling ◽  
Performance Index ◽  
Load Distribution ◽  
Structural Response ◽  
Computer Time ◽  
Numerical Approach ◽  
Braced Frames ◽  
Friction Damping ◽  
Braced Frame ◽  
Brake Lining

A novel friction damping system for the aseismic design of framed buildings has been proposed by Canadian researchers. The system has been shown experimentally to perform very well and is an exciting development in earthquake resistant design.The design of a building equipped with the friction damping system is achieved by determining the optimum slip load distribution to minimize structural response. The optimum slip load distribution is usually determined using the general nonlinear dynamic computer program DRAIN-2D, which requires extensive computer time and is not practical for most design offices.This paper describes a new, efficient, numerical modelling approach for the design of friction damped braced frames. The hysteretic properties of the friction devices are derived theoretically and included in a friction damped braced frame analysis program, which is adaptable to a microcomputer environment. The optimum slip load distribution is determined by minimizing a relative performance index derived from energy concepts. The new numerical approach is much more economical to use than DRAIN-2D and is of great value for the practical design of friction damped braced frames. Key words: braced frames, brake lining, performance index, damping, dynamics, earthquakes, energy, friction.

Potential Insights from Performance-Based Design of Fire Protection in Tall Buildings

2019 ◽  
Author(s):  
Pierre Ghisbain ◽  
Jenny Sideri ◽  
Reyhaneh Abbasi ◽  
Luciana Balsamo ◽  
Reza Imani ◽  
...  
Keyword(s):  
Fire Protection ◽  
Mechanical Response ◽  
Tall Buildings ◽  
Element Model ◽  
Fire Effects ◽  
Design Fire ◽  
Fire Engineering ◽  
Fire Scenarios ◽  
Fire Loading ◽  
The Impact

<p>Analysis of the structural performance under realistic fire scenarios makes Performance Based Fire Engineering (PBFE) particularly suited to design fire protection of tall buildings. In this paper, the impact of using the PBFE method is studied using a standard tall building as an example. The parametric temperature- time curves recommended in Eurocode 1 are used to define the fire loads. The thermal and mechanical response of the building to the imposed fire loading is subsequently analyzed by means of a finite element model of the mixed-use tower. Particular care is devoted to analyzing the performance of a steel truss at a transfer level, to study potential global effects of a local fire, effects that are not studied or understood within the prescriptive design framework.</p>

Analysis, Design, and Optimization of Thermal In-Plane Microactuator—Chevron Type

2011 ◽  
Vol 8 (3) ◽  
pp. 102-109
Author(s):  
K.B. Puneeth ◽  
K.N. Seetharamu
Keyword(s):  
Neural Network ◽  
Mechanical Response ◽  
Thermal Response ◽  
Structural Response ◽  
Design Tool ◽  
Thermal Actuator ◽  
Coupled Models ◽  
Element Analysis ◽  
Design And Optimization ◽  
Analysis Design

A predictive model of thermal actuator behavior has been developed and validated that can be used as a design tool to customize the performance of an actuator to a specific application. Modeling thermal actuator behavior requires the use of two sequentially or directly coupled models, the first to predict the temperature increase of the actuator due to the applied voltage and the second to model the mechanical response of the structure due to the increase in temperature. These models have been developed using ANSYS for both thermal response and structural response. Consolidation of FEA (finite element analysis) results has been carried out using an ANN (artificial neural network) in MATLAB. It is seen that an ANN can be successfully employed to interpolate and predict FEA results, thus avoiding necessity of running FEA code for every new case. Furtheroptimization of geometry for maximum actuation length has been carried out using a GA (genetic algorithm) in MATLAB. The results of the GA were verified against the ANN and FEA results.

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