Numerical analysis of damage zones in a bridge

2019 ◽  
Vol 11 (1) ◽  
pp. 1-12
Author(s):  
Mohammed Lamine Moussaoui ◽  
Mohamed Chabaat
Keyword(s):  
Numerical Analysis ◽  
Material Properties ◽  
Data File ◽  
Time Range ◽  
Bridge Structure ◽  
Time Step ◽  
Batch Mode ◽  
Content Type ◽  
Finite Element Software ◽  
Von Mises

Purpose The purpose of this paper is to present a numerical analysis of structural monitoring for damage zones detection. The study is performed with Ansys finite element software, which reads in batch mode programming a previously generated mesh data file and computes the transient dynamic solution for each time-step iteration within an analysis time range. Design/methodology/approach The approach itself is applied on a bridge structure which can be potentially subjected to damage zones due to severe loads cases and or earthquakes vibrations. The ideal Von Mises failure criterion ellipsoid envelope is applied for the detection of overstepped computed stresses and strains. Findings This numerical analysis allows computing, for each time-step iteration, the dynamic displacements at each degree of freedom and the corresponding stresses and strains inside the elements under the action of several times dependent loads cases. Practical implications Several simulations are considered to quantify the external loads. Originality/value The material properties of reinforced concrete RC are calculated for an existing specific bridge structure case. The RC strength is then introduced from the basic compounds material properties using the corresponding volumes fractions.

Fire behaviour and resistance of cold-formed steel beams with sigma cross-sections

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Flávio Arrais ◽  
Nuno Lopes ◽  
Paulo Vila Real
Keyword(s):  
Numerical Analysis ◽  
Cross Section ◽  
Cross Sections ◽  
Failure Modes ◽  
Elevated Temperatures ◽  
Numerical Results ◽  
Lateral Torsional Buckling ◽  
Torsional Buckling ◽  
Content Type ◽  
Finite Element Software

PurposeSigma cross-section profiles are often chosen for their lightness and ability to support large spans, offering a favourable bending resistance. However, they are more susceptible to local, distortional and lateral-torsional buckling, as possible failure modes when compared to common I-sections and hollow cross-sections. However, the instability phenomena associated to these members are not completely understood in fire situation. Therefore, the purpose of this study is to analyse the behaviour of beams composed of cold-formed sigma sections at elevated temperatures.Design/methodology/approachThis study presents a numerical analysis, using advanced methods by applying the finite element software SAFIR. A numerical analysis of the behaviour of simply supported cold-formed sigma beams in the case of fire is presented considering different cross-section slenderness values, elevated temperatures, steel grades and bending moment diagrams. Comparisons are made between the obtained numerically ultimate bending capacities and the design bending resistances from Eurocode 3 Part 1–2 rules and its respective French National Annex (FN Annex).FindingsThe current design expressions revealed to be over conservative when compared with the obtained numerical results. It was possible to observe that the FN Annex is less conservative than the general prescriptions, the first having a better agreement with the numerical results.Originality/valueFollowing the previous comparisons, new fire design formulae are analysed. This new methodology, which introduces minimum changes in the existing formulae, provides at the same time safety and accuracy when compared to the numerical results, considering the occurrence of local, distortional and lateral-torsional buckling phenomena in these members at elevated temperatures.

Numerical analysis of the shear strength of circular reinforced concrete columns subjected to cyclic lateral loads using linear genetic programming

2020 ◽  
Vol 37 (7) ◽  
pp. 2517-2537
Author(s):  
Mostafa Rezvani Sharif ◽  
Seyed Mohammad Reza Sadri Tabaei Zavareh
Keyword(s):  
Numerical Modeling ◽  
Shear Strength ◽  
Reinforced Concrete ◽  
Numerical Analysis ◽  
Genetic Programming ◽  
Linear Genetic Programming ◽  
Rc Columns ◽  
Content Type ◽  
Alternative Approach ◽  
Engineering Problems

Purpose The shear strength of reinforced concrete (RC) columns under cyclic lateral loading is a crucial concern, particularly, in the seismic design of RC structures. Considering the costly procedure of testing methods for measuring the real value of the shear strength factor and the existence of several parameters impacting the system behavior, numerical modeling techniques have been very much appreciated by engineers and researchers. This study aims to propose a new model for estimation of the shear strength of cyclically loaded circular RC columns through a robust computational intelligence approach, namely, linear genetic programming (LGP). Design/methodology/approach LGP is a data-driven self-adaptive algorithm recently used for classification, pattern recognition and numerical modeling of engineering problems. A reliable database consisting of 64 experimental data is collected for the development of shear strength LGP models here. The obtained models are evaluated from both engineering and accuracy perspectives by means of several indicators and supplementary studies and the optimal model is presented for further purposes. Additionally, the capability of LGP is examined to be used as an alternative approach for the numerical analysis of engineering problems. Findings A new predictive model is proposed for the estimation of the shear strength of cyclically loaded circular RC columns using the LGP approach. To demonstrate the capability of the proposed model, the analysis results are compared to those obtained by some well-known models recommended in the existing literature. The results confirm the potential of the LGP approach for numerical analysis of engineering problems in addition to the fact that the obtained LGP model outperforms existing models in estimation and predictability. Originality/value This paper mainly represents the capability of the LGP approach as a robust alternative approach among existing analytical and numerical methods for modeling and analysis of relevant engineering approximation and estimation problems. The authors are confident that the shear strength model proposed can be used for design and pre-design aims. The authors also declare that they have no conflict of interest.

Nonlinear Numerical Analysis of SRC Frame Middle Joints

2013 ◽  
Vol 376 ◽  
pp. 231-235
Author(s):  
Cheng Li ◽  
Yun Zou ◽  
Jie Kong ◽  
Zhi Wei Wan
Keyword(s):  
Finite Element ◽  
Numerical Analysis ◽  
Bearing Capacity ◽  
Axial Load ◽  
Load Ratio ◽  
Experimental Results ◽  
Steel Ratio ◽  
Finite Element Software ◽  
Axial Load Ratio ◽  
Hysteretic Performance

Nonlinear numerical analysis for the force performance of frame middle joint is processed in this paper with the finite element software of ABAQUS. Compared with experimental results, numerical analysis results are found to be reasonable. Then the influence of factors such as shaped steel ratio and axial-load ratio are contrastively analyzed. The results show that shaped steel ratio has a greater influence on the bearing capacity and hysteretic performance of the structure, but the axial-load ratio has less influence.

Nonlinear Numerical Analysis of Transfer Column in SRC-RC Hybrid Structure

2014 ◽  
Vol 578-579 ◽  
pp. 936-939 ◽  
Author(s):  
Qian Qian Sun ◽  
Yun Zou ◽  
Qiang Wang
Keyword(s):  
Numerical Analysis ◽  
Axial Load ◽  
Load Ratio ◽  
Hybrid Structure ◽  
Area Ratio ◽  
Experimental Result ◽  
Finite Element Software ◽  
Axial Load Ratio ◽  
Hysteretic Performance ◽  
Extension Length

Nonlinear numerical analysis of the stress performance of SRC-RC transfer columns was carried out in this paper with the finite element software of ABAQUS. Compered with the experimental result , numerical analysis result are found to be reasonable.Then the influence of factors such as extension length of shape steel , area ratio of shape steel and axial-load ratio were contrastively analyzed . The results show that extension length of shape steel and the area ratio of shape steel have a greater influence on the bearing capacity and the hysteretic performance of transfer column ,but axial-load ratio has less influence .

Mechanics of Composite Layered Rough Medium in Contact

2013 ◽  
Vol 703 ◽  
pp. 200-203
Author(s):  
Shao Biao Cai ◽  
Yong Li Zhao
Keyword(s):  
Material Properties ◽  
Three Dimensional ◽  
Shear Stresses ◽  
Normal Loading ◽  
Layered Coatings ◽  
Pressure Profiles ◽  
Tangential Traction ◽  
Von Mises ◽  
Von Mises Stresses ◽  
Tangential Friction

This study presents a first attempt to develop a numerical three-dimensional multilayered (more than 2 composite layered coatings) elasticperfectly plastic rough solids model to investigate the contact behavior under combined normal loading and tangential traction. Contact analyses are performed to study the effects composite thin film layers. Local contact pressure profiles, von Mises stresses, and shear stresses as a function of material properties and applied normal and tangential friction loads are calculated.

Design and topological optimization of rear pressure bulkhead for a typical aircraft

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Marshal Thakran ◽  
Meenakshi ◽  
Jitender Sharma ◽  
Charles Gilbert Martin
Keyword(s):  
Numerical Analysis ◽  
Significant Influence ◽  
Design Methodology ◽  
Structural Integrity ◽  
Topological Optimization ◽  
Content Type ◽  
Iterative Design ◽  
Practical Implications ◽  
Insight Into ◽  
Selection Of

Purpose The purpose of this paper is to evaluate the model of a rear pressure bulkhead with different design optimizations to meet the pressurized cabin requirements of an aircraft. Design/methodology/approach This paper presents the results of the static analysis of a dome-shaped rear pressure bulkhead model designed in Catia-v5. Numerical analysis of model meshed in hyper-mesh and solved using Opti-Struct for iterative design optimizations. Findings All the iterative models are analyzed at 9 Psi. Rear pressure bulkhead designed with L-section stringer shows better results than the model optimized with T-section stringer for the same thickness. The model optimized with L-shaped stinger also reduces the weight of the bulkhead without affecting the structural integrity. Practical implications It has been concluded in this paper that the selection of specific shapes of the stringers shows a significant influence on weight reduction. Originality/value This paper provides a topical, technical insight into the design and development of a rear pressure bulkhead. It also outlines the future development of dome-shaped rear pressure bulkhead.

Effects of infill patterns on the strength and stiffness of 3D printed topologically optimized geometries

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nadim S. Hmeidat ◽  
Bailey Brown ◽  
Xiu Jia ◽  
Natasha Vermaak ◽  
Brett Compton
Keyword(s):  
Material Properties ◽  
Failure Modes ◽  
Mechanical Anisotropy ◽  
Failure Behavior ◽  
Fused Filament Fabrication ◽  
Content Type ◽  
Orthotropic Composite ◽  
Material Extrusion ◽  
Specific Material ◽  
Strength And Stiffness

Purpose Mechanical anisotropy associated with material extrusion additive manufacturing (AM) complicates the design of complex structures. This study aims to focus on investigating the effects of design choices offered by material extrusion AM – namely, the choice of infill pattern – on the structural performance and optimality of a given optimized topology. Elucidation of these effects provides evidence that using design tools that incorporate anisotropic behavior is necessary for designing truly optimal structures for manufacturing via AM. Design/methodology/approach A benchmark topology optimization (TO) problem was solved for compliance minimization of a thick beam in three-point bending and the resulting geometry was printed using fused filament fabrication. The optimized geometry was printed using a variety of infill patterns and the strength, stiffness and failure behavior were analyzed and compared. The bending tests were accompanied by corresponding elastic finite element analyzes (FEA) in ABAQUS. The FEA used the material properties obtained during tensile and shear testing to define orthotropic composite plies and simulate individual printed layers in the physical specimens. Findings Experiments showed that stiffness varied by as much as 22% and failure load varied by as much as 426% between structures printed with different infill patterns. The observed failure modes were also highly dependent on infill patterns with failure propagating along with printed interfaces for all infill patterns that were consistent between layers. Elastic FEA using orthotropic composite plies was found to accurately predict the stiffness of printed structures, but a simple maximum stress failure criterion was not sufficient to predict strength. Despite this, FE stress contours proved beneficial in identifying the locations of failure in printed structures. Originality/value This study quantifies the effects of infill patterns in printed structures using a classic TO geometry. The results presented to establish a benchmark that can be used to guide the development of emerging manufacturing-oriented TO protocols that incorporate directionally-dependent, process-specific material properties.

Dynamic Analysis of the Joined-Wing Configuration in High-Altitude Long-Endurance Aircraft Using Fluid-Structure Interaction Model

2007 ◽  
Author(s):  
Prabu Ganesh Ravindren ◽  
Kirti Ghia ◽  
Urmila Ghia
Keyword(s):  
Finite Element ◽  
High Altitude ◽  
Fluid Structure Interaction ◽  
Structural Deformation ◽  
Time Step ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Finite Element Software ◽  
Joined Wing ◽  
Long Endurance

Recent studies of the joined-wing configuration of the High Altitude Long Endurance (HALE) aircraft have been performed by analyzing the aerodynamic and structural behaviors separately. In the present work, a fluid-structure interaction (FSI) analysis is performed, where the fluid pressure on the wing, and the corresponding non-linear structural deformation, are analyzed simultaneously using a finite-element matrix which couples both fluid and structural solution vectors. An unsteady, viscous flow past the high-aspect ratio wing causes it to undergo large deflections, thus changing the domain shape at each time step. The finite element software ANSYS 11.0 is used for the structural analysis and CFX 11.0 is used for the fluid analysis. The structural mesh of the semi-monocoque joined-wing consists of finite elements to model the skin panel, ribs and spars. Appropriate mass and stress distributions are applied across the joined-wing structure [Kaloyanova et al. (2005)], which has been optimized in order to reduce global and local buckling. The fluid region is meshed with very high mesh density at the fluid-structure interface and where flow separation is predicted across the joint of the wing. The FSI module uses a sequentially-coupled finite element equation, where the main coupling matrix utilizes the direction of the normal vector defined for each pair of coincident fluid and structural element faces at the interface [ANSYS 11.0 Documentation]. The k-omega turbulence model captures the fine-scale turbulence effects in the flow. An angle of attack of 12°, at a Mach number of 0.6 [Rangarajan et al. (2003)], is used in the simulation. A 1-way FSI analysis has been performed to verify the proper transfer of loads across the fluid-structure interface. The CFX pressure results on the wing were transferred across the comparatively coarser mesh on the structural surface. A maximum deflection of 16 ft is found at the wing tip with a calculated lift coefficient of 1.35. The results have been compared with the previous study and have proven to be highly accurate. This will be taken as the first step for the 2-way simulation. The effect of a coupled 2-way FSI analysis on the HALE aircraft joined wing configuration will be shown. The structural deformation history will be presented, showing the displacement of the joined-wing, along the wing span over a period of aerodynamic loading. The fluid-structure interface meshing and the convergence at each time step, based on the quantities transferred across the interface will also be discussed.

scholarly journals Women leadership barriers in healthcare, academia and business

2017 ◽  
Vol 36 (5) ◽  
pp. 457-474 ◽  
Author(s):  
Stavroula Kalaitzi ◽  
Katarzyna Czabanowska ◽  
Sally Fowler-Davis ◽  
Helmut Brand
Keyword(s):  
Equal Opportunity ◽  
Educational Background ◽  
Work Environments ◽  
Time Range ◽  
Gender Inequalities ◽  
International Studies ◽  
Theoretical Frameworks ◽  
Women Leadership ◽  
Content Type ◽  
Context Specific

Purpose The purpose of this paper is to map the barriers to women leadership across healthcare, academia and business, and identify barriers prevalence across sectors. A barriers thematic map, with quantitative logic, and a prevalence chart have been developed, with the aim to uncover inequalities and provide orientation to develop inclusion and equal opportunity strategies within different work environments. Design/methodology/approach A systematic literature review method was adopted across five electronic databases. Rigorous inclusion/exclusion criteria were applied to select relevant publications, followed by critical appraisal of the eligible articles. The geographical target was Europe, with a publication time range spanning the period from 2000 to 2015. Certain specialized international studies were also examined. The key themes were identified using summative content analysis and the findings were analyzed using qualitative meta-summary method to formulate hypotheses for subsequent research. Findings In total, 26 barriers were identified across the aforementioned sectors. A high degree of barriers commonalities was identified, with some striking differences between the prevalence of barriers across sectors. Research limitations/implications The results of this study may need further validation using statistical methodology given the knowledge base gaps regarding the range of barriers and the differences in their prevalence. Bias and interpretation in reporting anchored in different theoretical frameworks ought to be further examined. Additional variables such as ambiguously stated barriers, sector overlap, women’s own choices, cultural and educational background and analysis in the context of the economic crisis, ensuing austerity and migratory pressure, are also worth exploring. Practical implications Women’s notable and persisting underrepresentation in top leading positions across sectors reflects a critical drawback in terms of organizational and societal progress particularly regarding inclusion and balanced decision making. Practice-related blind spots may need to be further examined and addressed through specific policies. Originality/value The comparative nature of barriers to women leadership across three sectors allows the reader to contrast the differences in gender inequalities and to comprehend inclusion challenges in healthcare, academia and business. The authors draw attention to varying degrees of barriers prevalence that have been understudied and deserve to be further explored. This gap in knowledge extends to policy, thus, highlighting the need to address the gender equality and inclusion challenges in a context-specific manner across work environments.

Influence of hard rolling and the cooling lubricant on the material properties and the rolling strength of PM gears

2019 ◽  
Vol 71 (3) ◽  
pp. 406-410
Author(s):  
Fritz Klocke ◽  
Thomas Bergs ◽  
Christoph Löpenhaus ◽  
Philipp Scholzen ◽  
Tim Frech
Keyword(s):  
Boundary Layer ◽  
Carrying Capacity ◽  
Material Properties ◽  
Rolling Process ◽  
Surface Zone ◽  
Load Carrying Capacity ◽  
Content Type ◽  
Load Carrying ◽  
Phosphorous Content ◽  
Cooling Lubricant

Purpose The lower density of powder metallurgical (PM) gears compared to solid steel gears leads to not only a lower weight but also a lower load-carrying capacity. Therefore, PM gears are cold rolled before hardening to increase the density in the highly stressed surface zone and, thus, the flank load-carrying capacity. A further approach to increase the flank load-carrying capacity is the reduction of friction and wear in the tooth contact. The purpose of this paper is to analyze the hard rolling process as a new manufacturing step in the PM process chain to influence the boundary layer. Design/methodology/approach The investigation includes the new process of hard rolling, the variation of the cooling lubricant in the hard rolling process and the evaluation of its influence on the material properties and the flank load-carrying capacity. Therefore, the additives of the cooling lubricant are varied regarding the sulfur and phosphorous content. The load-carrying capacity is evaluated on disk-on-disk test rig and the material properties are evaluated by metallographic tests and boundary layer. Findings The results of the specimen characteristics in the micro and nano range show a significant influence of hard rolling on the residual stresses and the chemical surface composition. Because of hard rolling, residual compressive stresses as well as roughness are reduced and the flank load-carrying capacity is increased by high phosphorous content of the cooling lubricant. Originality/value This paper investigates a new manufacturing step to increase resource efficiency by increasing the flank load-carrying capacity of spur gears.

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