Finite Element Analysis of Concrete Frames after Fire with Fiber Model

2012 ◽  
Vol 193-194 ◽  
pp. 372-378 ◽  
Author(s):  
Min Xia ◽  
Jiang Tao Yu ◽  
Zhou Dao Lu ◽  
Li Wen Zhang
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Temperature Fields ◽  
Structural Members ◽  
Concrete Frames ◽  
Element Analysis ◽  
Fiber Model ◽  
Concrete Frame ◽  
Residual Mechanical Properties ◽  
The Cross

In order to analyze the residual mechanical properties of concrete frame structures after fire, a novel numerical model considering the distribution of non-uniform temperature in the cross-sections of structural members and the changing of mechanical properties of materials damaged by fire is developed in this paper by dividing the cross-sections of structural members into a lot of concrete fibers and steel fibers based on the concept of fiber model. Besides, the Analytical System of Fire-damaged Concrete Frame (ASFCF) is established through the secondary development of ABAQUS Software that is completed by the programming language of Python. This system is used to analyze the temperature fields and the nonlinear mechanical performances of a multi-story, multi-span, three-dimensional concrete frame after fire. The results indicate that ASFCF can properly analyze the mechanical properties of concrete frames after fire, and it provides valuable references for assessing the residual mechanical properties of concrete frames after fire.

Numerical Analysis and Simulation of Spatial Concrete Frames after Fire

2012 ◽  
Vol 204-208 ◽  
pp. 3423-3432
Author(s):  
Min Xia ◽  
Jiang Tao Yu ◽  
Zhou Dao Lu
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Numerical Models ◽  
Element Model ◽  
Frame Structures ◽  
Slab Thickness ◽  
Fire Damage ◽  
Concrete Frames ◽  
Concrete Frame ◽  
The Cross

In order to analyze the mechanical properties under three conditions of fire-damage, rehabilitation and strengthening of spatial concrete frame structures after fire, two novel numerical models are developed in this paper by dividing the cross-sections of beams and columns into a lot of concrete fibers and steel fibers and dividing slabs into several layers along the direction of the slab thickness based on the concept of the fiber element model and the layered shell element model. These two models can consider the distribution of non-uniform temperature in the cross-sections of structural members and the changing of mechanical properties of fire-damaged, rehabilitated and strengthened materials. Besides, the Analytical System of Fire-damaged Concrete Frame (ASFCF) is established through the secondary development of ABAQUS Software that is completed by the programming language of Python. This system is used to analyze and compare the mechanical responses under three conditions of fire-damage, rehabilitation and strengthening of a multi-story, multi-span spatial concrete frame after fire. The results indicate that ASFCF can properly analyze the mechanical properties under three conditions of fire-damage, rehabilitation and strengthening of spatial concrete frames after fire, and it provides valuable references for assessing the residual mechanical properties and the mechanical properties after rehabilitation and strengthening of global concrete frame structures after fire.

Comparison of the Cross Sectional Area, the Loss in Volume and the Mechanical Properties of LAE442 and MgCa0.8 as Resorbable Magnesium Alloy Implants after 12 Months Implantation Duration

2010 ◽  
Vol 638-642 ◽  
pp. 675-680 ◽  
Author(s):  
Martina Thomann ◽  
Nina von der Höh ◽  
Dirk Bormann ◽  
Dina Rittershaus ◽  
C. Krause ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Degradation Process ◽  
Cross Sectional Area ◽  
Bending Test ◽  
Sectional Area ◽  
Cross Sectional ◽  
Initial Strength ◽  
Three Point Bending ◽  
The Cross

Current research focuses on magnesium based alloys in the course of searching a resorbable osteosynthetic material which provides sufficient mechanical properties besides a good biocompatibility. Previous studies reported on a favorable biocompatibility of the alloys LAE442 and MgCa0.8. The present study compared the degradation process of cylindrical LAE442 and MgCa0.8 implants after 12 months implantation duration. Therefore, 10 extruded implants (2.5 x 25 mm, cross sectional area 4.9 mm²) of both alloys were implanted into the medullary cavity of both tibiae of rabbits for 12 months. After euthanization, the right bone-implant-compound was scanned in a µ-computed tomograph (µCT80, ScancoMedical) and nine uniformly distributed cross-sections of each implant were used to determine the residual implants´ cross sectional area (Software AxioVisionRelease 4.5, Zeiss). Left implants were taken out of the bone carefully. After weighing, a three-point bending test was carried out. LAE442 implants degraded obviously slower and more homogeneously than MgCa0.8. The mean residual cross sectional area of LAE442 implants was 4.7 ± 0.07 mm². MgCa0.8 showed an area of only 2.18 ± 1.03 mm². In contrast, the loss in volume of LAE442 pins was more obvious. They lost 64 % of their initial weight. The volume of MgCa0.8 reduced clearly to 54.4 % which corresponds to the cross sectional area results. Three point bending tests revealed that LAE442 showed a loss in strength of 71.2 % while MgCa0.8 lost 85.6 % of its initial strength. All results indicated that LAE442 implants degraded slowly, probably due to the formation of a very obvious degradation layer. Degradation of MgCa0.8 implants was far advanced.

Non-Dimensional Kinetoelastostatic Maps for Compliant Mechanisms

2013 ◽  
Author(s):  
Santosh D. B. Bhargav ◽  
Harish I. Varma ◽  
G. K. Ananthasuresh
Keyword(s):  
Cross Sections ◽  
Compliant Mechanisms ◽  
Compliant Mechanism ◽  
Slenderness Ratio ◽  
Element Analysis ◽  
Output Displacement ◽  
Static Responses ◽  
Slender Beams ◽  
Applied Forces ◽  
The Cross

How do we assess the capability of a compliant mechanism of given topology and shape? The kinetoelastostatic maps proposed in this paper help answer this question. These maps are drawn in 2D using two non-dimensional quantities, one capturing the nonlinear static response and the other the geometry, material, and applied forces. Geometrically nonlinear finite element analysis is used to create the maps for compliant mechanisms consisting of slender beams. In addition to the topology and shape, the overall proportions and the proportions of the cross-sections of the beam segments are kept fixed for a map. The finite region of the map is parameterized using a non-dimensional quantity defined as the slenderness ratio. The shape and size of the map and the parameterized curves inside it indicate the complete kinetoelastostatic capability of the corresponding compliant mechanism of given topology, shape, and fixed proportions. Static responses considered in this paper include input/output displacement, geometric amplification, mechanical advantage, maximum stress, etc. The maps can be used to compare mechanisms, to choose a suitable mechanism for an application, or re-design as may be needed. The usefulness of the non-dimensional maps is presented with multiple applications of different variety. Non-dimensional portrayal of snap-through mechanisms is one such example. The effect of the shape of the cross-section of the beam segments and the role of different segments in the mechanism as well as extension to 3D compliant mechanisms, the cases of multiple inputs and outputs, and moment loads are also explained. The effects of disproportionate changes on the maps are also analyzed.

scholarly journals EFFECT OF MICROSTRUCTURE OF CARDBOARD ON ITS MECHANICAL PROPERTIES

2021 ◽  
pp. 361-371
Author(s):  
Nikolay Petrovich Midukov ◽  
Viktor Sergeyevich Kurov
Keyword(s):  
Mechanical Properties ◽  
Cross Sections ◽  
Contact Lines ◽  
Modern Computer ◽  
Fiber Contact ◽  
Breaking Length ◽  
The Cross ◽  
Prediction Of Mechanical Properties ◽  
Almost All ◽  
Compression Resistance

The article is devoted to the prediction of mechanical properties on the study of the microstructure of the cross section of cardboard. The results of the work in the future can be used as an addition to standard methods for evaluating the mechanical properties of cardboard. On the basis of images of the microstructure of the cross sections of the two-layer test liner cardboard and their graphic processing using modern computer programs, the lengths of fiber contacts were determined. Guided by the fact that the most significant indicator of all geometric parameters of the microstructure is the length of fiber contacts, the main mechanical properties of cardboard were determined (bursting strength and compression resistance, breaking length, bending stiffness, interlayer strength)produced according to various technologies (conventional method of preparing recovered paper stock, dry defibration of recovered paper with aerodynamic formation of the top layer, dry defibration of recovered paper with subsequent supply of fibers to the stock and dry defibration of recovered paper with subsequent grinding in the stock). Each of the technologies allows to obtain cardboard with different mechanical parameters. It has been established that almost all mechanical indicators depend directly proportionally on the length of the fiber contact lines. The obtained dependencies can be used to predict the mechanical properties of cardboard in its production at industry enterprises.

Cross-section optimization of thin-walled open-section composite column for maximizing its ultimate strength

2021 ◽  
pp. 146442072110462
Author(s):  
Prashant K Choudhary ◽  
Prashanta K Mahato ◽  
Prasun Jana
Keyword(s):  
Finite Element ◽  
Ultimate Strength ◽  
Cross Section ◽  
Cross Sections ◽  
Ultimate Load ◽  
Material Failure ◽  
Element Analysis ◽  
Composite Column ◽  
Thin Walled ◽  
The Cross

This paper focuses on the optimization of thin-walled open cross-section laminated composite column subjected to uniaxial compressive load. The cross-section of the column is parameterized in such a way that it can represent a variety of shapes including most of the regular cross-sections such as H, C, T, and I sections. The objective is to obtain the best possible shape of the cross-section, by keeping a constant total material volume, which can maximize the ultimate load carrying capacity of the column. The ultimate strength of the column is determined by considering both buckling instability and material failure. For material failure, Tsai-Wu composite failure criterion is considered. As analytical solutions for these parameterized column models are not tractable, the ultimate loads of the composite columns are computed through finite-element analysis in ANSYS. And, the optimization is carried out by coupling these finite-element results with a genetic algorithm based optimization scheme developed in MATLAB. The optimal result obtained through this study is compared with an equivalent base model of cruciform cross-section. Results are reported for various lengths and boundary conditions of the columns. The comparison shows that a substantial increase of the ultimate load, as high as 610%, can be achieved through this optimization study. Thus, the present paper highlights some important characteristics of open cross-sections that can be useful in the design of thin-walled laminated column structures.

scholarly journals Cross-Sectional Performance of Hollow Square Prisms with Rounded Edges

Symmetry ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 996
Author(s):  
Hiroyuki Shima ◽  
Nao Furukawa ◽  
Yuhei Kameyama ◽  
Akio Inoue ◽  
Motohiro Sato
Keyword(s):  
Mechanical Properties ◽  
Mathematical Model ◽  
Cross Sections ◽  
Cross Sectional ◽  
Hollow Section ◽  
Buckling Resistance ◽  
The Cross ◽  
The Stability ◽  
External Forces ◽  
Sectional Shape

Hollow-section columns are one of the mechanically superior structures with high buckling resistance and high bending stiffness. The mechanical properties of the column are strongly influenced by the cross-sectional shape. Therefore, when evaluating the stability of a column against external forces, it is necessary to reproduce the cross-sectional shape accurately. In this study, we propose a mathematical method to describe a polygonal section with rounded edges and vertices. This mathematical model would be quite useful for analyzing the mechanical properties of plants and designing plant-mimicking functional structures, since the cross-sections of the actual plant culms and stems often show rounded polygons.

scholarly journals Two-Dimensional Nonlinear Finite Element Analysis of CMC Microstructures

2011 ◽  
Author(s):  
Subodh K. Mital ◽  
Robert K. Goldberg ◽  
Peter J. Bonacuse
Keyword(s):  
Silicon Carbide ◽  
Finite Element ◽  
Cross Sections ◽  
Effective Properties ◽  
Ceramic Matrix Composites ◽  
Two Dimensional ◽  
Element Analysis ◽  
Damage Pattern ◽  
Damage Initiation ◽  
The Cross

Detailed two-dimensional finite element analyses of the cross-sections of a model CVI (chemical vapor infiltrated) SiC/SiC (silicon carbide fiber in a silicon carbide matrix) ceramic matrix composites are performed. High resolution images of the cross-section of this composite material are generated using serial sectioning of the test specimens. These images are then used to develop very detailed finite element models of the cross-sections using the public domain software OOF2 (Object Oriented Analysis of Material Microstructures). Examination of these images shows that these microstructures have significant variability and irregularity. How these variabilities manifest themselves in the variability in effective properties as well as the stress distribution, damage initiation and damage progression is the overall objective of this work. Results indicate that even though the macroscopic stress-strain behavior of various sections analyzed is very similar, each section has a very distinct damage pattern when subjected to inplane tensile loads and this damage pattern seems to follow the unique architectural and microstructural details of the analyzed sections.

Long Term Monitoring of Timber Bridges - Assessment and Results

2013 ◽  
Vol 778 ◽  
pp. 749-756 ◽  
Author(s):  
Bettina Franke ◽  
Steffen Franke ◽  
Andreas Müller ◽  
Mareike Vogel ◽  
Florian Scharmacher ◽  
...  
Keyword(s):  
Moisture Content ◽  
Cross Section ◽  
Cross Sections ◽  
Climate Changes ◽  
Material Behavior ◽  
Natural Material ◽  
Structural Members ◽  
The Cross ◽  
Timber Bridges

Timber bridges have been built for decades all around the world. The hygroscopic material behavior of wood leads to the change of the moisture content of the wood and the dimensions depending on the climate. Therefore in regular inspections following questions arise: what happens with the wood due to the climate changes? Are there major changes of the moisture content? Are there differences between the natural material axes or within the cross section of the structural members? To answer these questions, traffic timber bridges with big cross sections are long term monitored within a research project. The results of the moisture contents measured and a comparison between the different measuring groups and positions are presented. The analyses confirm that the moisture content in the wood follows the climate changes delayed and with smaller amplitude against the calculated equilibrium moisture content. In first steps, a different behavior of the change of the moisture content could be determined over the cross section and along the span of the member.

The cross sections for different channels in heavy ion nuclear reactions

1971 ◽  
Vol 32 (1) ◽  
pp. 7-9 ◽  
Author(s):  
J. Galin ◽  
D. Guerreau ◽  
M. Lefort ◽  
X. Tarrago
Keyword(s):  
Cross Sections ◽  
Nuclear Reactions ◽  
Heavy Ion ◽  
The Cross

Experimental Studies Of Multilayer Glass Structures On Compression, Compression With Bending And Simple Bending

2019 ◽  
pp. 22-30
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Applied Load ◽  
Experimental Studies ◽  
Strength Properties ◽  
Research Topic ◽  
Normative Values ◽  
Laminated Glass ◽  
The Cross ◽  
Experimental Values

The work of multilayer glass structures for central and eccentric compression and bending are considered. The substantiation of the chosen research topic is made. The description and features of laminated glass for the structures investigated, their characteristics are presented. The analysis of the results obtained when testing for compression, compression with bending, simple bending of models of columns, beams, samples of laminated glass was made. Overview of the types and nature of destruction of the models are presented, diagrams of material operation are constructed, average values of the resistance of the cross-sections of samples are obtained, the table of destructive loads is generated. The need for development of a set of rules and guidelines for the design of glass structures, including laminated glass, for bearing elements, as well as standards for testing, rules for assessing the strength, stiffness, crack resistance and methods for determining the strength of control samples is emphasized. It is established that the strength properties of glass depend on the type of applied load and vary widely, and significantly lower than the corresponding normative values of the strength of heat-strengthened glass. The effect of the connecting polymeric material and manufacturing technology of laminated glass on the strength of the structure is also shown. The experimental values of the elastic modulus are different in different directions of the cross section and in the direction perpendicular to the glass layers are two times less than along the glass layers.

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