Nonlinear FE simulations of structural behavior parameters of reinforced concrete beam with epoxy-bonded FRP

2015 ◽  
Vol 24 (1-2) ◽  
pp. 35-46 ◽  
Author(s):  
Saptarshi Sasmal ◽  
S. Kalidoss
Keyword(s):  
Reinforced Concrete ◽  
Numerical Models ◽  
Adhesive Layer ◽  
Control Mode ◽  
Hydraulic Actuator ◽  
Element Analysis ◽  
Interfacial Stresses ◽  
Rc Structures ◽  
Laminate Thickness ◽  
Reinforcement Strain

AbstractIn the present study, investigations on fiber-reinforced plastic (FRP) plated-reinforced concrete (RC) beam are carried out. Numerical investigations are performed by using a nonlinear finite element analysis by incorporating cracking and crushing of concrete. The numerical models developed in the present study are validated with the results obtained from the experiment under monotonic load using the servo-hydraulic actuator in displacement control mode. Further, the validated numerical models are used to evaluate the influence of different parameters. It is found from the investigations that increase in the elastic modulus of adhesive layer and CFRP laminate increases the interfacial stresses whereas increase in laminate modulus decreases the displacement and reinforcement strain of the beam. It is also observed that increase in the adhesive layer can largely reduce the interfacial stresses, whereas increase in laminate thickness increases it. However, increase in laminate thickness decreases the displacement and reinforcement strain of the beam significantly. It is mention worthy that increase in laminate length reduces the interfacial stresses, whereas CFRP width change does not affect the interfacial stresses. The study will be useful for the design and practicing engineers for arriving at the FRP-based strengthening schemes for RC structures judiciously.

scholarly journals Multiobjective optimal design of reinforced concrete frames using two metaheuristic algorithms

2021 ◽  
Vol 9 (4B) ◽  
Author(s):  
Mehdi Babaei ◽  
◽  
Masoud Mollayi ◽  
Keyword(s):  
Reinforced Concrete ◽  
Optimal Design ◽  
Optimization Problem ◽  
Numerical Models ◽  
Steel Structures ◽  
Metaheuristic Algorithms ◽  
Rc Structures ◽  
Weighted Sum Method ◽  
Rc Frames ◽  
Single Objective

Genetic algorithm (GA) and differential evolution (DE) are metaheuristic algorithms that have shown a favorable performance in the optimization of complex problems. In recent years, only GA has been widely used for single-objective optimal design of reinforced concrete (RC) structures; however, it has been applied for multiobjective optimization of steel structures. In this article, the total structural cost and the roof displacement are considered as objective functions for the optimal design of the RC frames. Using the weighted sum method (WSM) approach, the two-objective optimization problem is converted to a single-objective optimization problem. The size of the beams and columns are considered as design variables, and the design requirements of the ACI-318 are employed as constraints. Five numerical models are studied to test the efficiency of the GA and DE algorithms. Pareto front curves are obtained for the building models using both algorithms. The detailed results show the accuracy and convergence speed of the algorithms.

Towards hybridization of composite patch in repair of cracked Aluminum panel

2019 ◽  
Vol 10 (6) ◽  
pp. 868-887
Author(s):  
Alpesh H. Makwana ◽  
A.A. Shaikh
Keyword(s):  
Stress Intensity ◽  
Carbon Fiber ◽  
Hybrid Composite ◽  
Adhesive Layer ◽  
Patch Repair ◽  
Element Analysis ◽  
Interfacial Stresses ◽  
Content Type ◽  
Composite Patch ◽  
Repair Efficiency

Purpose The maintenance of aircraft structure with lower cost is one of the prime concerns to regulatory authorities. The carbon fiber-reinforced polymer (CFRP) patches are widely used to repair the cracked structure. The demands and application of CFRP compel its price to increase in the near future. A distinct perspective of repairing the cracked aluminum panel with the hybrid composite patch is presented in this paper. The purpose of this paper is to propose an alternative patch material in the form of a hybrid composite patch which can provide economical repair solution. Design/methodology/approach The patch hybridization is performed by preparing the hybrid composite from tows of carbon fiber and glass fiber. Rule of hybrid mixture and modified Halpin–Tsai’s equation are used to evaluate the elastic constant. The stress intensity factor and interfacial stresses are determined using finite element analysis. The debonding initiation load is evaluated after testing under mode-I loading condition. Findings The hybrid composite patch has rendered the adequate performance for reduction of stress intensity in the cracked panel and control of interfacial stresses in the adhesive layer. The repair efficiency and repair durability of the composite patch repair was ensured by incorporation of the hybrid composite patch. Originality/value The studies involving patch hybridization for the application of composite patch repair are presently lacking. The influence of the patch stiffness, methodology to prepare the hybrid composite patch and effects of hybridization on the performance of composite patch repair is presented in this paper.

A Discrete Model for an Electrostatically Driven Micro-Hydraulic Actuator

2014 ◽  
Author(s):  
Behrouz Shiari ◽  
Mahdi M. Sadeghi ◽  
Ali Darvishian ◽  
Khalil Najafi
Keyword(s):  
Discrete Model ◽  
Numerical Models ◽  
Dynamic Performance ◽  
Hydraulic Actuator ◽  
Element Analysis ◽  
Time Operation ◽  
Discrete Dynamic Model ◽  
Dynamic Forces ◽  
Physical Phenomena ◽  
Fully Coupled

High-force, large-deflection actuators are critical for devices such as valves and pumps used in micro-fluidic systems. The major technical impediment in improving the performance of the micro-actuators lies in the lack of understanding the physical phenomena and their interactions of electric, mechanical, and fluidic fields for performing their intended functions. Because of the complexity of the actuator, the fully coupled numerical analysis such as finite element analysis is extremely expensive. Here, we introduce a discrete model of an Electrostatic Micro-Hydraulic (EMH) actuator. The model considers all dynamic forces which are involved in a time operation of the hydraulic actuator cell and covers three major physics: electrostatic, mechanical and fluidic. The physics have been coupled together to investigate the dynamic of the device. The discrete dynamic model developed in this work may be used for simple yet accurate predictions of dynamic performance of such actuators, and is preferable to more complicated and very expensive coupled numerical models. The analysis relies on physics-based equations and can be modified to accommodate different chamber geometries, different material properties and different working fluids. Results from the analytical model compare favorably with experimental measurements.

scholarly journals A Comparative Study of the Performance of Slender Reinforced Concrete Columns with Different Cross-Sectional Shapes

Fibers ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 35
Author(s):  
Safaa Qays Abdualrahman ◽  
Alaa Hussein Al-Zuhairi
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Slenderness Ratio ◽  
Structural Performance ◽  
Element Analysis ◽  
Cross Sectional ◽  
Rc Structures ◽  
Section Size ◽  
Concentric Loading ◽  
Rectangular Columns

Most reinforced concrete (RC) structures are constructed with square/rectangular columns. The cross-section size of these types of columns is much larger than the thickness of their partitions. Therefore, parts of these columns are protruded out of the partitions. The emergence of columns edges out of the walls has some disadvantages. This limitation is difficult to be overcome with square or rectangular columns. To solve this problem, new types of RC columns called specially shaped reinforced concrete (SSRC) columns have been used as hidden columns. Besides, the use of SSRC columns provides many structural and architectural advantages as compared with rectangular columns. Therefore, this study was conducted to explain the structural performance of slender SSRC columns experimentally and numerically via nonlinear finite element analysis. The study is based on nine RC specimens tested up to failure, as well as eighteen finite element (FE) models analyzed by Abaqus soft wear program. The use of SSRC columns led to increase strength by about 12% and reduce deformations, especially with slenderness ratio more than 40 as compared with equivalent square-shaped columns. Two design formulas were proposed to determine the compressive strength of SSRC columns under concentric loading. The results obtained indicate a good structural performance of SSRC columns when compared with equivalent square-shaped columns.

Probabilistic Design for Deteriorating Reinforced Concrete Structures with Time-Variant Finite Element Analysis

2019 ◽  
Author(s):  
Tsuyoshi Kouta ◽  
Christian Bucher
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Structural Reliability ◽  
Fe Analysis ◽  
Structural Safety ◽  
Illustrative Case ◽  
Probabilistic Design ◽  
Element Analysis ◽  
Rc Structures ◽  
Chloride Induced Corrosion

<p>In this study, a probabilistic design method using time-variant three-dimensional finite element (FE) analysis is presented to predict the structural reliability of deteriorating reinforced concrete (RC) structures due to chloride-induced corrosion. First, models of probabilistic corrosion due to chloride-induced corrosion are briefly reviewed. Then, FE modeling methods for corroded RC structures are presented, followed by validation with reference to experimental tests. In the methods, concrete and reinforcing steels are separately modeled, and the degradation in mechanical behavior of both components is considered. Finally, as an illustrative case study for the proposed FE analysis, the time-variant structural safety of a box-girder bridge is calculated over its lifetime of 50 yrs. The results of this study indicate that the proposed methods can be used to estimate the long-term structural safety of deteriorating RC structures.</p>

New design for reducing interfacial stresses of reinforced structures with FRP plates

2019 ◽  
Vol 37 (2) ◽  
pp. 196-207 ◽  
Author(s):  
Youssouf Belabed ◽  
Bachir Kerboua ◽  
Mostapha Tarfaoui
Keyword(s):  
Composite Structures ◽  
Adhesive Layer ◽  
Design Solution ◽  
Element Analysis ◽  
Interfacial Stresses ◽  
Reinforced Polymers ◽  
Content Type ◽  
Lag Effects ◽  
Frp Composites ◽  
Optimal Configurations

Purpose The sustainability of the structures is not only a technical goal, but also a matter of social and environmental values. This requires the researchers to use very rigid, highly durable and corrosion-resistant composite structures in order to achieve the technical, environmental and social goals. The purpose of this paper is to present an original work on reducing the interfacial stresses of bonded structures with fibre-reinforced polymers (FRP) plates based on new taper design. Design/methodology/approach In this proposed concept, the effect of combined taper is investigated on reducing interfacial stresses, attempting to enhance the structure performance and address the debonding problem that comes with reinforcing techniques. This research is carried out by using finite element analysis, incorporating many new parameters. Findings As a result, a new solution is discovered that combined taper in both adhesive layer and composite laminate, which significantly reduces the interfacial stresses at the end of the FRP plate. Additionally, a parametric study is carried out in order to determine the optimal configurations of taper dimensions as well as other parameters that influence the stress concentration distribution at the edge of the adherends. Practical implications This new design regarding the reduction of interfacial stresses will help in increasing the lifespan of damaged structures reinforced by FRP composites, preserving thus its technical, historical and social values. Originality/value The paper uses straight, concave and convex fillets with inverse taper as a new design solution with new parameters including thermo-mechanical loads and pre-stressed FRP plate with multi-layer, fibre orientation and shear-lag effects.

Effect of Crack on Interfacial Stresses of RC Beam Strengthened with CFRP

2011 ◽  
Vol 462-463 ◽  
pp. 559-562
Author(s):  
Yong Chang Guo ◽  
Han Lin Huang ◽  
Li Juan Li ◽  
Jun Deng ◽  
Gen Quan Zhong
Keyword(s):  
Failure Modes ◽  
Weight Ratio ◽  
Adhesive Layer ◽  
High Strength ◽  
Tensile Failure ◽  
Interface Debonding ◽  
Rc Beam ◽  
Longitudinal Stress ◽  
Interfacial Stresses ◽  
Rc Structures

External bonding of fiber reinforced polymer (FRP) plates or sheets, because of their advantages, such as high strength to weight ratio and good resistance to corrosion, has become a popular technique for the strengthening and upgrading of structurally inadequate or damaged reinforced concrete (RC) structures. Interface debonding failure is one of the most common failure modes of the FRP strengthened RC structures. In this paper, the damaged concrete constitutive model is established and the effects of crack on the interfacial stresses of RC beam strengthened with CFRP are investigated. Longitudinal stress in the CFRP, shear stress in the adhesive layer and the first principal stress in the concrete at the crack tips of the retrofitted RC beams with cracks at different locations are analyzed. The results show that when cracks locate at the loading position, the longitudinal stress in the CFRP is the largest and the tensile failure of the CFRP is the most likely occurred.

scholarly journals Numerically Efficient Three-Dimensional Model for Non-Linear Finite Element Analysis of Reinforced Concrete Structures

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1578
Author(s):  
Sławomir Dudziak
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Shear Failure ◽  
Load Capacity ◽  
Model Verification ◽  
Element Analysis ◽  
Rc Structures ◽  
Linear Finite Element ◽  
Non Linear

The paper concerns the non-linear finite element analysis (NLFEA) of Reinforced Concrete (RC) structures for engineering applications. The required level of complexity of constitutive models for such analysis was discussed and non-linear elastic models combined with the smeared cracking approach proved to be efficient. A new constitutive hypoelastic-brittle model of concrete based on these assumptions was proposed. Moreover, a method including the tension stiffening effect (TS) was developed. This phenomenon is connected with the bond properties between concrete and steel and, in some situations, has significant influence on the deflections of RC structures. It is often neglected by or included in the constitutive model of concrete. In the paper, an alternative approach was presented, in which this phenomenon is taken into account by generalising the material model of reinforcing steel. This approach is consistent with modern design standards and has solid physical foundations. The proposed models were implemented in the Abaqus code via UMAT user’s procedure coded in FORTRAN. Model verification and validation were presented in four case studies, concerning: a Willam’s test (examination on material point level), a beam with bending failure, and two beams with shear failure (with and without stirrups). The obtained results were compared with experimental outcomes and numerical results obtained by other researchers. The presented approach enables the accurate prediction not only of load capacity but of structural deformability, due to the precise description of TS. Thus, it promises to be a useful engineering tool.

Evaluation and comparison of concrete constitutive models in numerical simulation of reinforced concrete slabs under blast load

2021 ◽  
pp. 204141962110489
Author(s):  
Hani Mahdavi Talaromi ◽  
Farhad Sakhaee
Keyword(s):  
Reinforced Concrete ◽  
Numerical Models ◽  
Concrete Slab ◽  
Constitutive Models ◽  
Computation Time ◽  
Material Model ◽  
Reinforced Concrete Slab ◽  
Rc Structures ◽  
Reinforced Concrete Slabs ◽  
Concrete Damage

Numerical models have been used recently to analyze concrete structures subjected to high-impulsive loads. A material model that can well capture the mechanical behaviors is crucial to obtain reliable results. Present study, focused on reinforced concrete slab as a major load carrying element of the RC structures under blast loading. By performing several simulations in popular and powerful concrete constitutive models, including concrete damage R3, HJC, CSCM, and Winfrith the accuracy of these models was investigated. Maximum deflections have been compared with each other and expanded further to compare with experiments. Result showed all models have an acceptable accuracy in estimating maximum slab deflection. Concrete Damage R3 presented the highest accuracy. HJC has the second rank and CSCM and Winfrith have the third and the fourth places, respectively. HJC needed the minimum computation time. CSCM had minimum input parameters but includes maximum calculation time. Winfrith had the lowest accuracy, however this model presented very conservative results. Uniaxial compressive and tensile stress-strain curves showed that the models which presented higher values of strength, evaluated lower maximum values of deflection.

Concrete Material Models in LS-DYNA for Impact Analysis of Reinforced Concrete Structures

2014 ◽  
Vol 566 ◽  
pp. 173-178
Author(s):  
M.A.K.M. Madurapperuma ◽  
Kazukuni Niwa
Keyword(s):  
Reinforced Concrete ◽  
High Speed ◽  
Impact Analysis ◽  
Material Model ◽  
Material Behavior ◽  
Single Element ◽  
Element Analysis ◽  
Material Models ◽  
Concrete Material ◽  
Rc Structures

Performance of three widely used concrete material models available in LS-DYNA is compared using experimental results of drop-weight impact on a reinforced concrete (RC) beam and high speed aircraft engine missile impact on an RC wall. An overview of these material models and typical concrete material behavior shown by these models using single element analysis are also presented. The study is useful for users who have limited experience on the selection of an appropriate material model for concrete in impact simulation of RC structures.

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