Numerical Simulation of Blast Effects on Fibre Grout Strengthened RC Panels

The present paper aims to examine the potential of the Applied Element Method (AEM) in simulating the blast effects in RC panels. The numerical estimates are compared with the results obtained in an experimental campaign designed to investigate the effectiveness of fibre grout for strengthening full scale RC panels by comparing the effects that a similar blast load produces in a reference and the strengthened panel. First, a numerical model of the reference specimen was created in the software Extreme Loading for Structures and calibrated to match the experimental results. With no further calibration, the fibre reinforced grout strengthening was added and the resulting numerical model subjected to the same blast load. The experimental blast effects on both reference and strengthened panels, despite the lack of high speed measurement equipment (pressure, strains and displacements sensors), compare well with the numerical estimates in terms of residual and maximum displacements, showing that, once calibrated, the AEM numerical models can be successfully used to simulate blast effects in RC panels.

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High-speed impact assessment for composite air inlet

International Journal of Structural Integrity ◽

10.1108/ijsi-10-2018-0059 ◽

2019 ◽

Vol 11 (5) ◽

pp. 723-736

Author(s):

Radek Doubrava ◽

Martin Oberthor ◽

Petr Bělský ◽

Jan Raška

Keyword(s):

Numerical Simulation ◽

Composite Structure ◽

High Speed ◽

Numerical Models ◽

Impact Resistance ◽

High Speed Camera ◽

Content Type ◽

High Speed Impact ◽

Air Inlet ◽

Final Design

Purpose The purpose of this paper is to describe the approach for the design of a jet engine composite air inlet for a new generation of jet trainer aircraft from the perspective of airworthiness requirements regarding high-speed impact resistance. Design/methodology/approach Validated numerical simulation was applied to flat test panels. The final design was optimised and verified by validated numerical simulation and verified by testing on a full-scale demonstrator. High-speed camera measurement and non-destructive testing (NDT) results were used for the verification of the numerical models. Findings The test results of flat test panels confirmed the high durability of the composite structure during inclined high-speed impact with a near-real jet inlet load boundary condition. Research limitations/implications Owing to the sensitivity of the composite material on technology production, the results are limited by the material used and the production technology. Practical implications The application of flat test panels for the verification and tuning of numerical models allows optimised final design of the air inlet and reduces the risk of structural non-compliance during verification tests. Originality/value Numerical models were verified for simulation of the real composite structure based on high-speed camera results and NDT inspection after impact. The proposed numerical model was simplified for application in a real complex design and reduced calculation time.

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Numerical Simulation of Failure Characteristics of Reactive Powder Concrete With Steel Fiber

Frontiers in Physics ◽

10.3389/fphy.2021.759513 ◽

2021 ◽

Vol 9 ◽

Author(s):

Xiaohu Zhang ◽

Songyuan Liu ◽

Gan Li ◽

Xiaofei Wang

Keyword(s):

Numerical Simulation ◽

Numerical Model ◽

Failure Modes ◽

Steel Fiber ◽

Numerical Models ◽

Triaxial Compression ◽

Mechanical Tests ◽

Steel Fibers ◽

Reactive Powder Concrete ◽

Reactive Powder

Steel fibers were delivered into the numerical concrete specimens using a mixed congruence method. A coplanar projection method is proposed to solve the problem of discriminating the crossing among steel fibers. Numerical models were built for reactive powder concrete (RPC) cylindrical specimens with 1 and 2% steel fiber. Comparisons between the numerical model and actual specimen slices show that the modified method has a good simulation effect. An improved anchor cable unit was used to simulate the bond–slip behavior between the steel fiber and concrete; the drawing of a single steel fiber was simulated. Then, the uniaxial compression, triaxial compression, and three-point bending of RPC specimens with 1% steel fiber were simulated, reproducing the concrete cracking and steel fiber slipping behaviors of RPC specimens. The failure modes of the numerical RPC specimen under various mechanical tests are consistent with the experimental results, proving the practicability and accuracy of this established numerical model. This study provides a foundation for the numerical simulation of RPC properties.

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Experimental and Numerical Evaluation of UHPFRC Slabs Subjected to Contact and Close-In Explosion

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.309.180 ◽

2020 ◽

Vol 309 ◽

pp. 180-185

Author(s):

Ondřej Janota ◽

Marek Foglar

Keyword(s):

Numerical Simulation ◽

Reinforced Concrete ◽

Numerical Model ◽

High Performance ◽

Numerical Evaluation ◽

Numerical Models ◽

Blast Resistance ◽

Near Field ◽

Fibre Reinforced Concrete ◽

High Performance Fibre

This paper presents achievements in the field of the numerical simulation of the fibrere reinforced concrete (FRC) and ultra-high performance fibre reinforced concrete (UHPFRC). The numerical simulations were performed to verify results of two experimental programmes focused on the blast resistance of FRC and UHPFRC. The response of the FRC and UHPFRC slabs to the contact and near-field blast was studied in these two experiments. As the detail behaviour of specimens could not be observed because of the blast load, the numerical models were prepared. The accuracy of the numerical models was evaluated based on the comparison of numerical and experimental results. Different approaches for blast simulation were tested and compared. The results indicate that the various phenomena (e.g. overpressure propagation, stress cumulation, crack propagation and damage extend) can be successfully simulated. However, the comparison of the soffit velocity, measured with the PDV unit and numerical model showed shortcomings of the numerical model. These numerical model inaccuracies are discussed and their reasons presented.

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Combined Experimental and Numerical Study for Multiple Microchannel Heat Transfer System

2010 14th International Heat Transfer Conference, Volume 6 ◽

10.1115/ihtc14-22235 ◽

2010 ◽

Cited By ~ 5

Author(s):

Jingru Zhang ◽

Yogesh Jaluria ◽

Tiantian Zhang ◽

Li Jia

Keyword(s):

Experimental Data ◽

Numerical Simulation ◽

Steady State ◽

Numerical Model ◽

Initial Conditions ◽

Numerical Study ◽

Numerical Models ◽

Three Dimensional ◽

Variation Versus ◽

Heat Transfer System

Multiple microchannel heat sinks for potential use for electronic chip cooling are studied experimentally and numerically to characterize their thermal performance. The numerical simulation is driven by experimental data, which are obtained concurrently, to obtain realistic, accurate and validated numerical models. The ultimate goal is to design and optimize thermal systems. The experimental setup was established and liquid flow in the multiple microchannels was studied under different flow rates and heat influx. The temperature variation versus time was recorded by thermocouples, from which the time needed to reach steady state was determined. Temperature variations under steady state conditions were compared with three-dimensional steady state numerical simulation for the same boundary and initial conditions. The experimental data served as input parameters for the validation of the numerical model. In case of discrepancy, the numerical model was improved. A fairly good agreement between the experimental and simulation results was obtained. The numerical model also served to provide input that could be employed to improve and modify the experimental arrangement.

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Numerical Study of the Pulsation Process of Spark Bubbles under Three Boundary Conditions

Journal of Marine Science and Engineering ◽

10.3390/jmse9060619 ◽

2021 ◽

Vol 9 (6) ◽

pp. 619

Author(s):

Chunlong Ma ◽

Dongyan Shi ◽

Chao Li ◽

Dongze He ◽

Guangliang Li ◽

...

Keyword(s):

Numerical Simulation ◽

Numerical Model ◽

Nonlinear Interaction ◽

Cavitation Bubble ◽

High Speed ◽

Free Field ◽

Experimental Results ◽

High Speed Camera ◽

Cavitation Bubbles ◽

Bubble Pulsation

In this study, a compressible three-phase homogeneous model was established using ABAQUS/Explicit. These models can numerically simulate the pulsation process of cavitation bubbles in the free field, near the flat plate target, and near the curved boundary target. At the same time, these models can numerically simulate the strong nonlinear interaction between the cavitation bubble and its nearby wall boundaries. The mutual flow of liquid and gas and fluid solid coupling were solved by the Euler domain in simulation. The results of the numerical simulation were verified by comparing them with the experimental results. In this study, we used electric spark bubbles to represent cavitation bubbles. A high-speed camera was used to record the pulsation process of cavitation bubbles. This study first verified the pulsation process of cavitation bubbles in the free field, because it was the simplest case. Then we verified the interaction process between cavitation bubbles and different wall boundaries. In order to further confirm the credibility of the numerical simulation results, for each wall surface, this study used two burst distances (10 mm and 25 mm) for simulation verification. The numerical model established in this study could effectively simulate the pulsation characteristics of cavitation bubbles, such as the formation of jets and annular bubbles. After verification, the simulated cavitation bubble was almost the same as the cavitation bubble captured by the high-speed camera in the experiment in terms of time, volume, and shape. In this study, a detailed velocity field of the cavitation bubble collapse stage was obtained, which laid down the foundation for the study of the strong nonlinear interaction between the cavitation bubble and the target plates of different shapes. Compared with the experimental results, we found that the numerical model established by the simulation could accurately simulate the bubble pulsation and jet formation processes. In the experiment, the interval time for the bubble pictures taken by the high-speed camera was 41.66 μs per frame. Using a numerical model, the bubble pulsation process can be simulated at an interval of 1 µs per frame. Therefore, the numerical model established by the simulation could show the movement characteristics of the cavitation bubble pulsation process in more detail.

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Validation of SPH-FE Numerical Modeling of the Interaction between a High-Speed Water Jet and a PMMA Target by CEL Model and Experimental Study

International Journal of Nonlinear Sciences and Numerical Simulation ◽

10.1515/ijnsns-2017-0282 ◽

2020 ◽

Vol 21 (3-4) ◽

pp. 227-238

Author(s):

I. Ben Belgacem ◽

L. Cheikh ◽

E.M. Barhoumi ◽

W. Khan ◽

W. Ben Salem

Keyword(s):

Numerical Simulation ◽

Numerical Model ◽

High Speed ◽

Water Jet ◽

Fe Method ◽

Sph Method ◽

Impact Surface ◽

Particle Hydrodynamics ◽

Spherical Head ◽

The Impact

AbstractIn this paper, we present a numerical simulation of a round impacting jet using coupled Smoothed Particle Hydrodynamics (SPH) and Finite Element (FE) methods. Numerical results are compared with the results of another simulation carried out by the CEL (Coupled Eulerian-Lagrangian) method. A water jet with a spherical head was used at an initial speed of 570 m/s to impact a flat plate made of Polymethyl-Methacrylate (PMMA). To model the entire process, the SPH method was used to model the water jet and the FE method for the PMMA structure. The distribution of the pressure on the impact surface and the resulting deformation of the structure were discussed. A Numerical model was developed using ABAQUS/Explicit version 6.14. Results of the coupled SPH-FE simulation were further validated. It is demonstrated that the CEL method presents smoother curves compared to the SPH method. These comparisons serve not only to validate the numerical simulation but also to give guidance in formulating the SPH-FEM numerical model.

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Numerical Simulation of Linear Explosive Formed Penetrator by Endpoint Initiating Manner

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.538-541.534 ◽

2012 ◽

Vol 538-541 ◽

pp. 534-537 ◽

Cited By ~ 1

Author(s):

Rui Jun Gou ◽

Shu Hai Zhang ◽

Kai Fan

Keyword(s):

Numerical Simulation ◽

Theoretical Model ◽

Numerical Model ◽

Velocity Vector ◽

Distribution Curve ◽

Numerical Models ◽

Shaped Charge ◽

Velocity Change ◽

Linear Shaped Charge ◽

Tip Velocity

The formation of linear explosion formed penetrator(LEFP) from linear shaped charge detonated from one end point was studied both theoretically and experimentally, and a numerical simulation was also carried out. By decomposing the detonation velocity vector into spherical and slide components, the theoretical model described the tip velocity change of LEFP. The numerical model illustrated the formation of LEFP and the tip velocity agreed with the theoretical model. The validation of the theoretical and numerical models was verified by experiment, in which steel targets were used to show the effect of LEFP. The results showed that average tip velocity was 2658.4 m/s at 100 mm to the charge mouth. The theoretical and numerical velocity values and distribution curve were very close to the experimental ones. This work may further develop the theory of LEFP and linear shaped charge.

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