Structural Behaviour Evaluation by Numerical Simulations for Innovative Solutions of Hybrid Lintels - Part 2: FEM Analysis

2017 ◽  
Vol 21 ◽  
pp. 286-293
Author(s):  
Cristina E. Lanivschi ◽  
Oana Neculai ◽  
Dorina Nicolina Isopescu
Keyword(s):  
Reference Model ◽  
Fem Analysis ◽  
Steel Reinforcement ◽  
Interface Model ◽  
Structural Behaviour ◽  
Weak Bond ◽  
Innovative Solutions ◽  
Frictional Interface ◽  
Service State ◽  
Concrete Component

The paper presents a detailed analysis on the performance of reinforced concrete (RC)/ aerated autoclaved concrete (AAC) hybrid lintels, studied using finite element method (FEM), through numerical modelling. The analyzed lintels are a combination of modules, made of AAC and RC or pre-stressed concrete, which can be used for closing any span of windows or doors, for any wall thickness. To simulate the hybrid modules lintels in their service state, FEM modelling was used, together with rigorous numerical calculus, in order to better understand their flexural behaviour, the AAC-RC interface area and the way the material properties affect the structural performance of the analyzed lintels. The numerical analysis was initiated with validation of the reference model with analytically determined efforts in concrete component of the lintel. A subsequent model was constructed by adding the steel reinforcement and AAC component to the reference model. The analysis was conducted for two scenarios of a perfect and possibly very weak bond of RC/ AAC interface on “bonded interface model”, BIM and respectively “frictional interface model”, FIM models. The results showed that steel reinforcement had greater effect on the lintel`s stiffness than AAC component, while the effect of AAC is almost cancelled in the case of a weak bond of the interface. Future investigation needs to be developed considering an analytical model based on FIM model calibrated with laboratory measurements.

scholarly journals Numerical and Experimental Investigation on the Structural Behaviour of a Horizontal Stabilizer under Critical Aerodynamic Loading Conditions

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
R. Sepe ◽  
R. Citarella ◽  
A. De Luca ◽  
E. Armentani
Keyword(s):  
Fem Analysis ◽  
Experimental Tests ◽  
Aerodynamic Load ◽  
Honeycomb Core ◽  
Structural Behaviour ◽  
Research Activity ◽  
Composite Sandwich ◽  
Load Vector ◽  
Definition Of ◽  
Transfer Moulding

The aim of the proposed research activity is to investigate the mechanical behaviour of a part of aerospace horizontal stabilizer, made of composite materials and undergoing static loads. The prototype design and manufacturing phases have been carried out in the framework of this research activity. The structural components of such stabilizer are made of composite sandwich panels (HTA 5131/RTM 6) with honeycomb core (HRH-10-1/8-4.0); the sandwich skins have been made by means of Resin Transfer Moulding (RTM) process. In order to assess the mechanical strength of this stabilizer, experimental tests have been performed. In particular, the most critical inflight recorded aerodynamic load has been experimentally reproduced and applied on the stabilizer. A numerical model, based on the Finite Element Method (FEM) and aimed at reducing the experimental effort, has been preliminarily developed to calibrate amplitude, direction, and distribution of an equivalent and simpler load vector to be used in the experimental test. The FEM analysis, performed by using NASTRAN code, has allowed modelling the skins of the composite sandwich plates by definition of material properties and stack orientation of each lamina, while the honeycomb core has been modelled by using an equivalent orthotropic plate. Numerical and experimental results have been compared and a good agreement has been achieved.

scholarly journals CALCULATING THE CARRYING CAPACITY OF FLEXURAL PRESTRESSED CONCRETE BEAMS WITH NON-METALLIC REINFORCEMENT

2010 ◽  
Vol 2 (6) ◽  
pp. 5-13
Author(s):  
Mantas Atutis
Keyword(s):  
Prestressed Concrete ◽  
Concrete Beams ◽  
Steel Reinforcement ◽  
Elastic Response ◽  
Structural Behaviour ◽  
Moment Capacity ◽  
Calculation Results ◽  
Fibre Reinforced Polymer ◽  
Frp Reinforcement ◽  
Metallic Reinforcement

The article reviews moment resistance design methods of prestressed concrete beams with fibre-reinforced polymer (FRP) reinforcement. FRP tendons exhibit linear elastic response to rupture without yielding and thus failure is expected to be brittle. The structural behaviour of beams prestressed with FRP tendons is different from beams with traditional steel reinforcement. Depending on the reinforcement ratio, the flexural behaviour of the beam can be divided into several groups. The numerical results show that depending on the nature of the element failure, moment resistance calculation results are different by using reviewed methods. It was found, that the use of non-metallic reinforcement in prestressed concrete structures is effective: moment capacity is about 5% higher than that of the beams with conventional steel reinforcement.

An Enhanced Interface Model for Friction Fatigue Problems of Axially Loaded Piles

2019 ◽  
Author(s):  
Borana Kullolli ◽  
Matthias Baeßler ◽  
Pablo Cuéllar ◽  
Shilton Rica ◽  
Frank Rackwitz
Keyword(s):  
Cyclic Loading ◽  
Dominant Role ◽  
Normal Pressure ◽  
Interface Model ◽  
Structural Behaviour ◽  
Confining Stress ◽  
Cyclic Mobility ◽  
Axially Loaded ◽  
Bulk Model ◽  
Axially Loaded Piles

Abstract The shaft bearing capacity often plays a dominant role for the overall structural behaviour of axially loaded piles in offshore deep foundations. Under cyclic loading, a narrow zone of soil at the pile-soil interface is subject to cyclic shearing solicitations. Thereby, the soil may densify and lead to a decrease of confining stress around the pile due to micro-phenomena such as particle crushing, migration and rearrangement. This reduction of radial stress has a direct impact on the shaft capacity, potentially leading in extreme cases to pile failure. An adequate interface model is needed in order to model this behaviour numerically. Different authors have proposed models that take typical interface phenomena in account such as densification, grain breakage, normal pressure effect and roughness. However, as the models become more complex, a great number of material parameters need to be defined and calibrated. This paper proposes the adoption and transformation of an existing soil bulk model (Pastor-Zienkiewicz) into an interface model. To calibrate the new interface model, the results of an experimental campaign with the ring shear device under cyclic loading conditions are here presented. The constitutive model shows a good capability to reproduce typical features of sand behaviour such as cyclic compaction and dilatancy, which in saturated partially-drained conditions may lead to liquefaction and cyclic mobility phenomena.

scholarly journals Shear resistance of clamped deck slabs assessed using design equations and FEM analysis

2019 ◽  
Author(s):  
Aleksandar Vidaković ◽  
Jaroslav Halvonik
Keyword(s):  
Fem Analysis ◽  
Concentrated Loads ◽  
Structural Behaviour ◽  
Element Analysis ◽  
Deck Slabs ◽  
Load Carrying ◽  
Bridge Structures ◽  
Bridge Deck Slabs ◽  
Rc Slabs ◽  
Improved Methods

Reinforced concrete (RC) slabs without shear reinforcement are commonly used in the existing bridge structures. An ability of RC slabs to distribute the concentrated loads due to the wheel pressure in transverse direction is an important property for their verification. The aim of this paper is to investigate the effect of redistribution of shear forces and bending moments on the load carrying capacity of RC slabs subjected to concentrated loads. Two methods of the assessment are used: simplified analytical formulations and linear finite element analysis (LFEA). The obtained results are consequently compared with the test results taken from three experimental campaigns. The analyses show big differences among the results obtained from the simplified analytical methods that are based on the design equations introduced in the relevant standards. Improved methods, such as LFEA combined with analytical post-processing method, reflect the structural behaviour in a better way and provide more accurate load-bearing capacity prediction of the bridge deck slabs.

scholarly journals Simulation of Transient Nonlinear Friction-Induced Vibrations Using Complex Interface Modes: Application to the Prediction of Squeal Events

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
J.-J. Sinou ◽  
S. Besset
Keyword(s):  
Finite Element ◽  
Nonlinear Analysis ◽  
Reference Model ◽  
Element Model ◽  
Modal Reduction ◽  
Modal Synthesis ◽  
Complex Modes ◽  
Complex Eigenvalues ◽  
Frictional Interface ◽  
The Subject

During the past decades, the problem of friction-induced vibration and noise has been the subject of a huge amount of works. Various numerical simulations with finite elements models have been largely investigated to predict squeal events. Although a nonlinear analysis is more predictive than Complex Eigenvalues Analysis, one of the main drawbacks of the time analysis is the need of large computational efforts. In view of the complexity of the subject, this approach appears still computationally too expensive to be used in industry for finite element models. In this study, the potential of a new reduced model based on a double modal synthesis (i.e., a classical modal reduction via Craig and Bampton plus a condensation at the frictional interface based on complex modes) for the prediction of self-excited vibrations of brake squeal is discussed. The effectiveness of the proposed modal reduction is tested on a finite element model of a simplified brake system. It will be shown that numerical results of times analysis by applying the proposed reduction correlate well with those of the nonlinear analysis based on a reference model, hence demonstrating the potential of using adapted modal reductions to predict the squeal propensity and to estimate self-excited vibrations and noise.

Confinement of reinforced concrete columns with fibre-reinforced composite sheets - an experimental study

1999 ◽  
Vol 26 (2) ◽  
pp. 226-241 ◽  
Author(s):  
M Demers ◽  
K W Neale
Keyword(s):  
Reinforced Concrete ◽  
Fibre Composite ◽  
Concrete Strength ◽  
Practical Interest ◽  
Plain Concrete ◽  
Concrete Columns ◽  
Steel Reinforcement ◽  
Structural Behaviour ◽  
Reinforced Concrete Columns ◽  
Reinforced Composite

The wrapping of fibre-reinforced composite sheets around concrete columns is a promising method for structural strengthening and repair. This rehabilitation technique is of practical interest, as the lay-up of the sheets is rather easy; it does not require specialized tools, and the epoxy resins employed cure at ambient temperatures. Here, results of an experimental investigation are reported for 16 round reinforced concrete columns 300 mm in diameter and 1200 mm high. These columns were confined by means of carbon-epoxy sheets and loaded concentrically in axial compression. The effects of various parameters on the structural behaviour of the confined concrete columns are investigated. These parameters included the concrete strength, longitudinal steel reinforcement, steel stirrups, steel corrosion, and concrete damage. The test results show that composite confinement can considerably enhance the structural performance of concrete columns, especially with regard to ductility. The potential to restore the full strength of severely damaged columns is also demonstrated, as retrofitted columns exhibit axial load carrying capacities equal or superior to those of undamaged columns, along with significant increases in ductility. The contribution of the transverse steel reinforcement is seen to be minimal, as long as the stirrup spacing is medium to large. For such cases tests on plain concrete cylinders are sufficient for further investigations of this retrofit method, as the key parameters which really affect strength and ductility are the concrete strength, composite fibre type, and sheet thickness.Key words: fibre composite sheets, confinement, concrete, column repair, rehabilitation, strengthening.

scholarly journals TOWARDS A DIFFERENT WORLD – ON THE POTENTIAL OF THE INTERNET OF EVERYTHING

2019 ◽  
Vol 9 (2) ◽  
pp. 8-11
Author(s):  
Mirosław Płaza ◽  
Radosław Belka ◽  
Zbigniew Szcześniak
Keyword(s):  
Reference Model ◽  
The Internet ◽  
Technological Revolution ◽  
Internet Of Everything ◽  
Innovative Solutions

Internet-based technologies are moving faster and faster into many spheres of our lives and at the same time are a key component of the ongoing technological revolution, which is why there are many ongoing scientific projects aimed at their development. The article presents a discussion on the development of Internet-based technologies known as the Internet of Everything (IoE). The paper presents the areas in which these technologies are most often used. A multi-layered reference model and a procedure for subsequent actions in designing innovative solutions in this area are presented.

scholarly journals IMPROVING THE STRUCTURAL BEHAVIOUR RC PRECAST CONCRETE BEAMS MADE OF RECYCLED AGGREGATE CONCRETE

2016 ◽  
Vol 22 (2) ◽  
pp. 234-242 ◽  
Author(s):  
Andrzej LAPKO ◽  
Robert GRYGO
Keyword(s):  
Precast Concrete ◽  
Fem Analysis ◽  
Random Variable ◽  
Recycled Aggregate Concrete ◽  
Recycled Aggregate ◽  
Structural Behaviour ◽  
Aggregate Concrete ◽  
Flexural Members ◽  
Positive Effects ◽  
Increased Risk

The application of concrete waste for recycled aggregate concrete (RAC) used in structural members is as­sociated with an increased risk for the structure due to, e.g. pollutions in the old crushed concrete and random variable strength. A new concept of RC flexural members like beams and slabs made of RAC with strengthening inclusion was elaborated and presented in the paper based on application of precast concrete inserts made of HSC, located in the com­pression zone of the members. The paper presents the results of experimental and numerical (FEM) analysis carried out on such composite beams. The results of experimental research on the behavior of such beams and numerical simula­tions using Diana computer program reveal some positive effects, such as higher stiffness and flexural capacity of the innovative beams compared to the reference beams made fully of RAC.

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