Non-Linear Seismic Assessment of AGRs: Incorporation of Aged Graphite Material Properties

Many existing reinforced concrete buildings were designed in Southern European countries before the introduction of modern seismic codes and thus they are potentially vulnerable to earthquakes. Consequently, simplified methodologies for the seismic assessment and retrofitting of existing structures are required. In this study, a displacement based procedure using non-linear static analyses is applied to a four-storey RC frame in order to obtain an initial estimation of the overall inadequacy of the original structure as well as the extent of different retrofitting interventions. Accurate numerical models are developed to reproduce the seismic response of the RC frame in the original configuration. The effectiveness of three different retrofitting solutions countering structural deficiencies of the RC frame is examined through the displacement based approach. Non-linear dynamic analyses are performed to assess and compare the seismic response of the frame in the original and retrofitted configurations.

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Rheological Properties of a Natural Estuarine Mud

Applied Rheology ◽

10.1515/arh-2003-0010 ◽

2003 ◽

Vol 13 (3) ◽

pp. 142-149 ◽

Cited By ~ 3

Author(s):

Thierry Aubry ◽

Tolotrahasiina Razafinimaro ◽

Ricardo Silva Jacinto ◽

Philippe Bassoulet

Keyword(s):

Rheological Properties ◽

Material Properties ◽

Mechanical Response ◽

Oscillatory Shear ◽

Cohesive Sediments ◽

Exponential Functions ◽

Non Linear

Abstract In this paper, the linear and non-linear rheological properties of estuarine cohesive sediments were investigated. The density of the sediments has been determined by pycnometry. Creep and oscillatory shear measurements have been performed in order to determine i) the transitions in mechanical response to creep and oscillatory shear and ii) the material properties of these natural fluids as a function of their density. For all samples tested, four different rheological transitions have been determined and all material properties have been shown to be satisfactorily fitted by exponential functions of the density.

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Designing Optimal Volume Fractions For Functionally Graded Materials With Temperature-Dependent Material Properties

Journal of Applied Mechanics ◽

10.1115/1.2712231 ◽

2006 ◽

Vol 74 (5) ◽

pp. 861-874 ◽

Cited By ~ 17

Author(s):

Florin Bobaru

Keyword(s):

Functionally Graded Materials ◽

Material Properties ◽

Volume Fraction ◽

Effective Properties ◽

Functionally Graded ◽

Dominant Factor ◽

Temperature Dependent ◽

Graded Materials ◽

Critical Stresses ◽

Non Linear

We present a numerical approach for material optimization of metal-ceramic functionally graded materials (FGMs) with temperature-dependent material properties. We solve the non-linear heterogeneous thermoelasticity equations in 2D under plane strain conditions and consider examples in which the material composition varies along the radial direction of a hollow cylinder under thermomechanical loading. A space of shape-preserving splines is used to search for the optimal volume fraction function which minimizes stresses or minimizes mass under stress constraints. The control points (design variables) that define the volume fraction spline function are independent of the grid used in the numerical solution of the thermoelastic problem. We introduce new temperature-dependent objective functions and constraints. The rule of mixture and the modified Mori-Tanaka with the fuzzy inference scheme are used to compute effective properties for the material mixtures. The different micromechanics models lead to optimal solutions that are similar qualitatively. To compute the temperature-dependent critical stresses for the mixture, we use, for lack of experimental data, the rule-of-mixture. When a scalar stress measure is minimized, we obtain optimal volume fraction functions that feature multiple graded regions alternating with non-graded layers, or even non-monotonic profiles. The dominant factor for the existence of such local minimizers is the non-linear dependence of the critical stresses of the ceramic component on temperature. These results show that, in certain cases, using power-law type functions to represent the material gradation in FGMs is too restrictive.

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Water vapor transport to material surfaces-Simplified analytical expressions for non-linear material properties

MATEC Web of Conferences ◽

10.1051/matecconf/201928202002 ◽

2019 ◽

Vol 282 ◽

pp. 02002

Author(s):

Carl-Eric Hagentoft

Keyword(s):

Material Properties ◽

Building Materials ◽

Accurate Estimate ◽

Water Vapor Transport ◽

Material Surface ◽

Vapor Permeability ◽

Moisture Profile ◽

Material Surfaces ◽

Non Linear ◽

Linear Material

The water vapour transfer between the indoor air and material surfaces is of importance for the moisture balance of the room. It can also be important for the moisture content and durability of the material surface layer such as artefacts in churches and historical buildings. For most building materials the penetration depth due to short time fluctuations, such as diurnal ones, is very limited. For these cases the assumption of semi-infinite analysis gives accurate results even for a rather thin material layer. In the paper, the moisture profile and surface moisture uptake are modelled in detail for isothermal cases and strongly non-linear material properties for the sorption isotherm and vapor permeability. An approximative formula is given for a quite accurate estimate of the moisture up take for a demonstration case with a strongly non-linear material.

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Dropped Object Analysis Using Non-Linear Dynamic FE Analysis

Volume 4A: Structures, Safety and Reliability ◽

10.1115/omae2014-23333 ◽

2014 ◽

Cited By ~ 2

Author(s):

Kwanghyun Ahn ◽

Minsung Chun ◽

Sangmin Han ◽

Kibok Jang ◽

Yongsuk Suh

Keyword(s):

Material Properties ◽

Failure Criteria ◽

Offshore Structures ◽

Linear Analysis ◽

Fe Analysis ◽

Structural Safety ◽

Design Consideration ◽

Linear Dynamic ◽

Non Linear

For the last few decades, necessity of direct non-linear FE analysis has been increasing for the accidental events at the vessel/offshore structures. One of major areas for the accidental design, dropped object analysis using non-linear analysis is indispensable for the verification of structural safety at the design process. This paper is concerned with the methodology, conditions, and design consideration of dropped object analysis using dynamic FE analysis. By comparing the results from direct FE analyses to those from simplified energy method described in DNV-RP-C204, necessities and advantages of direct non-linear analysis can be verified. In this paper, the effect of analysis condition is investigated using parametric study. The results are influenced by the application of failure criteria according to the rule requirements, application of material properties, dropping position, condition of the object, and so on. This study can suggest appropriate determination of the methodology and condition for the dropped object analysis using direct FE analysis.

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