Coupled Discrete Element/Finite Element Method for the Analysis of Large Reinforced Concrete Structures Submitted to an Impact

2011 ◽  
Vol 82 ◽  
pp. 284-289
Author(s):  
Laurent Daudeville ◽  
Jessica Haelewyn ◽  
Philippe Marin ◽  
Serguei Potapov
Keyword(s):  
Reinforced Concrete ◽  
Finite Elements ◽  
Heterogeneous Media ◽  
Concrete Slab ◽  
Element Model ◽  
Discrete Element ◽  
Discrete Elements ◽  
Reinforced Concrete Slab ◽  
The Impact ◽  
Element Method

The efficiency of the discrete element method for studying the fracture of heterogeneous media has been demonstrated, but it is limited by the size of the computational model. A coupling between the discrete elements (DEM) and the finite elements (FEM) methods is proposed to handle the simulation of impacts on large structures. The structure is split into two subdomains in each of which the method is adapted to the behavior of the structure under impact. The DEM takes naturally into account the discontinuities and is used to model the media in the impact zone. The remaining structure is modeled by the FEM. We propose an adaptation of the coupling procedure to connect Discrete Element model to shell-type Finite Elements. Finally, the efficiency of this approach is shown on the simulation of a reinforced concrete slab impacted by a tubular impactor.

Calculation of Reinforced Concrete Prismatic Shells by the Finite Element Method Using Variable Elasticity Parameters

2019 ◽  
Vol 945 ◽  
pp. 969-974
Author(s):  
V. Kruglov ◽  
V. Iurchenko
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Finite Elements ◽  
Concrete Slab ◽  
Volume Ratio ◽  
High Strength ◽  
Finite Elements Method ◽  
Software Module ◽  
Reinforced Concrete Slab ◽  
Elastic Characteristics

The paper considers the modification of the generally accepted formulation of the finite elements method by applying in the calculation I.Mileykovski’s refined technical theory of shells that takes into account the deformations of the transverse shear along the thickness of the model. When applying this solution path, it is possible to calculate thick and thin shells (plates) with equal efficiency, taking into account the complex strained state of an anisotropic material. It illustrates the inclusion in the computational algorithm of variable parameters of the elasticity of concrete, allowing more accurate evaluation of the stress-strain state in the finite element under complex (combined) loads. The presence of reinforcement in the material is modeled by dividing the structure into layers and sequentially reduction the elastic characteristics of the material based on the volume ratio of the components. The advantage of the algorithm is the ease of its integration with the conventional finite elements method. All transformations in this case consist in the modification of expressions for determining the elastic characteristics of the construction, calculating the gradient and stiffness matrices, while the sequence of further calculations does not change. This enables to use the proposed algorithm, including as a plug-in software module, expanding the capabilities of existing computing programs. The article demonstrates the application of the method in modeling a reinforced concrete slab made with the use of multi-component high-strength concrete of a heavy class having a prismatic strength under uniaxial compression of more than 110 MPa.

THE EFFECT OF IMPACT LOADS ON PRESTRESSED CONCRETE SLABS

2018 ◽  
Vol 5 (1) ◽  
Author(s):  
Youmn Al Rawi ◽  
Yehya Temsah ◽  
Hassan Ghanem ◽  
Ali Jahami ◽  
Mohamad Elani
Keyword(s):  
Reinforced Concrete ◽  
Prestressed Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
Concrete Slabs ◽  
Shear Mode ◽  
Reinforced Concrete Slab ◽  
Finite Element Program ◽  
Reinforced Concrete Slabs ◽  
The Impact

Many research studies have been conducted on the effect of impact loading on structures, and design procedures were proposed for reinforced concrete (RC) slabs; however the availability of these studies and procedures are limited for prestressed slabs. The proposed research will examine, using numerical analysis, the impact of rock fall on prestressed concrete slabs with equivalent moment capacity reinforced concrete slabs. It is expected that prestressed concrete slabs will have different behavior to resist impact loading compared with traditional reinforced concrete slabs. The thickness of the prestressed concrete slab will be 25cm whereas that of the reinforced concrete slab will be 30cm. The impact loading consists of 500Kg drop weight. The drop height will be 10m, 15m and 20m.The structural analysis is performed using a Finite Element program "ABAQUS". A comparison will be done between both slab types in terms of failure mode, damage, and deflection. It has been found that both slabs failed in punching. However, the RC slab performed better than the prestressed concrete slab with respect to the value of the deflection at mid-span, while both showed punching shear mode of failure.

BEHAVIOR OF REINFORCED CONCRETE SLABS UNDER ACCIDENTAL IMPACTS

2018 ◽  
Vol 5 (2) ◽  
Author(s):  
Shamsoon Fareed
Keyword(s):  
Reinforced Concrete ◽  
Impact Loading ◽  
Concrete Slab ◽  
High Mass ◽  
Concrete Slabs ◽  
Reinforced Concrete Slab ◽  
Reinforced Concrete Slabs ◽  
Numerical Predictions ◽  
Operational Life ◽  
The Impact

Loads resulting from activities such as rock fall, heavy drop weights (for e.g. equipment's, heavy machines during installation), missile and aircraft interaction with slabs may results in loading intensity which have higher magnitude as compared to static loading. Based on the velocity of the impacting object at the time of contact, these activities may result in impact loading. Therefore, slabs designed should provide resistance to these accidental loading during their entire operational life. In this study, a dynamic non-linear finite element analyses were conducted to investigate the behavior of the reinforced concrete slabs subjected to high-mass low-velocity impacts. For this purpose, initially an already published impact test results were used to validate the numerical predictions. Following validation, a study was conducted to investigate the influence of the impact velocity on the behavior of the reinforced concrete slab. Based on the numerical investigation, it was found that the velocity of the impacting object has a significant influence on the behavior exhibited by slab under impact loading. Furthermore, it was also found that the behavior of slab under impact is both local and global. Local behavior is associated with the damage caused at the contact area of the slab and the impactor, whereas global behavior refers to the overall deformation of the slab when stress waves move away from the impact zone and travel towards the supports.

Simulation of Failure of a Fixed Beam Subjected to Impact Load Using Quadrilateral Discrete Element Method

2012 ◽  
Author(s):  
Rajesh P. Nair ◽  
C. Lakshmana Rao
Keyword(s):  
Discrete Element Method ◽  
Impact Analysis ◽  
Mechanical Response ◽  
Impact Load ◽  
Discrete Element ◽  
Failure Criteria ◽  
Discrete Elements ◽  
The Impact ◽  
Fixed Beam ◽  
Element Method

Discrete Element Method (DEM) is an explicit numerical scheme to model the mechanical response of solid and particulate media. In our paper, we are introducing Quadrilateral Discrete Element Method (QDEM) for the simulation of the separation of elements in fixed beam subjected to impact load. QDEM results are compared with other DEM results available in literature. Impact loads include two cases: (a) a half sine wave and (b) a penetrator hitting the fixed beam. Separation criteria used for the discrete elements is maximum principal stress failure criteria. In QDEM, convergence study for the response of fixed beam is obtained using MATLAB platform. Validation of quadrilateral elements in fixed beam is being carried out by comparing the results with empirical formula available in literature for the impact analysis.

scholarly journals A discrete element/shell finite element coupling for simulating impacts on reinforced concrete structures

2010 ◽  
pp. 153-164
Author(s):  
Jessica Rousseau ◽  
Philippe Marin ◽  
Laurent Daudeville ◽  
Sergueï Potapov
Keyword(s):  
Finite Element ◽  
Heterogeneous Media ◽  
Element Model ◽  
Discrete Element ◽  
Impact Zone ◽  
Large Structures ◽  
Coupling Procedure ◽  
The Media ◽  
Shell Finite Element ◽  
The Impact

The efficiency of the discrete element method for studying the fracture of heterogeneous media has been demonstrated, but it is limited by the size of the computational model. A coupling between the discrete element and the finite element methods is proposed to handle the simulation of impacts on large structures. The structure is split into two subdomains in each of which the method is adapted to the behaviour of the structure under impact. The DEM takes naturally into account the discontinuities and is used to model the media in the impact zone. The remaining structure is modelled by the FEM. We propose an extension of the coupling procedure to connect the Discrete Element model to shell-type Finite Elements. The efficiency of the coupling method is tested and validated.

scholarly journals CALCULATION OF RELIABILITY OF REINFORCED CONCRETE FLIGHT STRUCTURES

2021 ◽  
pp. 18-25
Author(s):  
Roman Kaplin
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Load Capacity ◽  
Element Model ◽  
Operating Conditions ◽  
Structural Element ◽  
Reinforced Concrete Slab ◽  
Bridge Structures ◽  
Number Of Cycles ◽  
Office Software

A large number of bridges are operated on the roads of Ukraine. The increase in the intensity and speed of traffic leads to qualitative changes in the operating conditions of bridge structures, which is characterized by a sharp increase in the number of cycles under load of bridge elements, and to the development of damage in them. For trouble-free operation and efficient use of bridge structures it is very important to have reliable estimates of the actual load capacity and resource, taking into account the loads, material quality, nature of the structure. The solution of the problem in this statement is possible only on the basis of the theory of reliability. However, its application to specific assessments of durability and reliability of structures is associated with the solution of a set of issues: the identification of patterns of change of various parameters, the accumulation of reliable and easy to calculate statistics on loads and mechanical characteristics of materials, etc. It is necessary to know that the strength of the material (sample) of the structural element and the structure as a whole are completely different things. The article considers a new design of reinforced concrete girder structure, using perforated metal elements and an effective reinforced concrete slab of the carriageway. On its basis, a computational model in the form of a finite-element model built in the SCAD-Office software package is formed. As a result of calculations, the components of the stress-strain state of the structure are obtained. Based on the obtained results, the reliability of the structure was calculatedunder the influence of modern regulatory loads. 

scholarly journals Long-term study of the impact of temperature changes, material aging and service load on the strains of a reinforced concrete structure

2018 ◽  
Vol 66 ◽  
pp. 02006
Author(s):  
Adam Kanciruk
Keyword(s):  
Reinforced Concrete ◽  
Concrete Slab ◽  
Reinforced Concrete Structure ◽  
Reinforced Concrete Slab ◽  
Temperature Changes ◽  
Long Term Study ◽  
Monitoring Process ◽  
Service Load ◽  
The Impact

The article discusses five year long measurements of strains of a concrete floor of a hangar. That hangar, originally meant for servicing light military aircraft, was rebuilt with a view to making it fit for servicing larger and heavier passenger planes. As part of that redevelopment, a new floor - reinforced concrete slab, capable of withstanding the weight of the planes - was constructed. In the areas of the floor where the greatest loads occur, ie. in the areas of the concrete slab on which the wheels of the three undercarriage legs rest, three strain rosettes were installed so that the slab strains could be measured. The rosettes were connected to two meters - dataloggers. The latter were programmed in such a way as to register the measured strains and additionally temperatures many times during every 24 hours. The monitoring process, conducted in such an automatic way, demonstrated the occurrence of strains resulting from service load, aging of the reinforced concrete, as well as changes in its temperature.

3D Adaptive Combined DE/FE Algorithm for Analyzing Impact Fracture of Laminated Glass

2019 ◽  
Vol 16 (04) ◽  
pp. 1850101 ◽  
Author(s):  
Wei Xu ◽  
Mengyan Zang ◽  
Jiro Sakamoto ◽  
Shupei Zhang
Keyword(s):  
Finite Element ◽  
Finite Elements ◽  
Adaptive Algorithm ◽  
Discrete Element ◽  
Impact Fracture ◽  
Laminated Glass ◽  
Discrete Elements ◽  
Simulation Results ◽  
The Impact ◽  
Glass Beam

Laminated glass has been wildly employed in automobile windshields, modern buildings, etc. thanks to its security and durability performance. A novel 3D adaptive combined DE/FE algorithm is proposed to research its impact fracture mechanical properties if the fracture region is small relative to a specimen while the cracks are propagating at a random position. The proposed method can automatically convert the distorted finite elements into the spherical discrete elements during simulating the impact fracture of laminated glass. In this method a system is completely discretized into the finite elements at the initial moment without any discrete element existing until part of the finite elements becoming severely deformed. Subsequently each finite element, whose maximum tensile stress exceeds a user-specified conversion criterion, is converted into eight spherical discrete elements. At the same time the system is fragmented into two subdomains, the finite element (FE) and the discrete element (DE) subdomains. An extrinsic cohesive fracture model is adaptively adopted only in the DE subregion to capture the crack propagation when the normal stress between the DEs equals or exceeds the cohesive strength. The impact fracture of a glass beam is simulated by the adaptive algorithm and the discrete element method, respectively. Beside of the micro-cracks and cohesive zone, almost the same crack patterns are captured by both the numerical methods. Fortunately, the efficiency of the proposed method is much higher (10 times in this case) than that of the pure DEM. A satisfactory agreement of the simulation results certified the feasibility and effectiveness of such an adaptive algorithm. Finally, the impact fracture simulation is performed by the adaptive algorithm on a laminated glass beam which has the same size as the experimental specimens. Besides of the differences on the cracks occurrence and propagation angle, a similar agreement of the fracture patterns is observed as the experimental results. The common conclusions on the role of PVB interlayer can be obviously obtained by analyzing the simulation results, the same by analyzing the experimental ones. The proposed method is hopeful to be employed to analyze the impact fracture of an automobile windshield subjects to the head impact for the protection of pedestrians safety, the traffic accident reconstruction and the structural optimization of windshield.

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