scholarly journals Numerical Approximation of Blast Loads on Confined Dry-Stacked Masonry Wall

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Muhammad Ishfaq ◽  
Azmat Ullah ◽  
Awais Ahmed ◽  
Sarfraz Ali ◽  
Syed Muhmmad Ali ◽  
...  
Keyword(s):  
Numerical Model ◽  
Time History ◽  
Experimental Tests ◽  
Masonry Wall ◽  
Experimental Results ◽  
Charge Weight ◽  
Test Cases ◽  
Pressure Time ◽  
Out Of Plane ◽  
A Charge

This research intends to numerically study the out-of-plane behaviour of confined dry-stacked masonry (CDSM) walls against blast loading. CDSM is a mortarless interlocking masonry system consisting of Hydraform blocks laid in stretcher bond with reinforced concrete (RC) confining elements. A nonlinear numerical model is developed using advanced finite element hydrocode ANSYS-Autodyn to study the response of CDSM walls subjected to explosive loads. Four different test cases using a charge weight of 4 kg, 8 kg, 12 kg, and 16 kg of Wabox explosive are investigated numerically. The results obtained from numerical simulation are validated with the experimental tests results. The numerical results are found in good agreement with the experimental results. The ability of the numerical model is studied to correctly predict the pressure-time history in pressure gauges installed on walls and compared with experimental data. Peak incident overpressures obtained in these numerical tests ranged from 240 to 1000 kPa. Likewise, the damage patterns obtained from the numerical simulations are compared with available experimental results which show a satisfactory agreement. This study helps to check the response of CDSM structures against blast load which can be used for the construction of blast resisting design of buildings.

Mechanical Properties of Various Models of Interlocking Concrete Blocks under In-Plane and Out-of-Plane Loads

2021 ◽  
Vol 881 ◽  
pp. 149-156
Author(s):  
Mochamad Teguh ◽  
Novi Rahmayanti ◽  
Zakki Rizal
Keyword(s):  
Mechanical Properties ◽  
Building Material ◽  
Experimental Tests ◽  
Concrete Block ◽  
Masonry Wall ◽  
Masonry Walls ◽  
Plane Shear ◽  
Out Of Plane ◽  
Concrete Blocks ◽  
Local Materials

Building material innovations in various interlocking concrete block masonry from local materials to withstand lateral earthquake forces is an exciting issue in masonry wall research. The block hook has an advantage in the interlocking system's invention to withstand loads in the in-plane and out-of-plane orientations commonly required by the masonry walls against earthquake forces. Reviews of the investigation of in-plane and out-of-plane masonry walls have rarely been found in previous studies. In this paper, the results of a series of experimental tests with different interlocking models in resisting the simultaneous in-plane shear and out-of-plane bending actions on concrete blocks are presented. This paper presents a research investigation of various interlocking concrete blocks' mechanical properties with different hook thicknesses. Discussion of the trends mentioned above and their implications towards interlocking concrete block mechanical properties is provided.

Applied Element Method Simulation of Fiber Reinforced Polymer and Polypropylene Composite Retrofitted Masonry Walls

2014 ◽  
Vol 17 (11) ◽  
pp. 1567-1583 ◽  
Author(s):  
Saleem M. Umair ◽  
Muneyoshi Numada ◽  
Kimiro Meguro
Keyword(s):  
Numerical Model ◽  
Research Work ◽  
Masonry Wall ◽  
Fiber Reinforced Polymer ◽  
Bending Test ◽  
Fiber Reinforced ◽  
Reinforced Polymer ◽  
Out Of Plane ◽  
Applied Element Method ◽  
Element Method

In current research work, an attempt is made to simulate the behavior of a newly proposed composite material using 3-D Applied Element Method (AEM). Fiber Reinforced Polymer (FRP) being a strong material provides a significant increase in shear strength. Polypropylene band (PP-band) not only holds the masonry wall system into a single unit but also provides a fairly high deformation capacity at a very low cost of retrofitting. A composite of FRP and PP-band is proposed and applied on the surface of masonry wall. Verification of the proposed numerical model is achieved by conducting experiments on twelve masonry wallets. Out of twelve, six masonry wallets were tested in out of plane bending test and six were tested under in-plane forces in the form of diagonal compression test. Same wallet retrofitting scheme was selected for in-plane and out of plane experiments and all of them were analyzed using proposed 3-D AEM numerical simulation tool. Proposed numerical model has served satisfactory and has shown a fairly good agreement with experimental results which encourages the use of 3D-AEM to numerically simulate the behavior of non-retrofitted and retrofitted masonry wallets.

scholarly journals Experimental Study on the Damage Characteristics of Polymer Slabs Subjected to Air Contact and Close-In Explosions

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Zhidong Liu ◽  
Xiaohua Zhao ◽  
Hongyuan Fang ◽  
Xueming Du ◽  
Binghan Xue ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Shock Wave ◽  
Failure Mode ◽  
Explosive Charge ◽  
Time History ◽  
Dynamic Mechanical Properties ◽  
Charge Weight ◽  
Pressure Time ◽  
Static Mechanical ◽  
Air Explosion

As a new antiseepage reinforcement material, polyurethane grouting material has been widely studied in terms of its static mechanical properties. However, research on its dynamic mechanical properties is relatively rare. In this research, considering the influence of the explosive charge weight, the air contact and close-in explosion experiments of polymer slabs were carried out. The failure mode and damage spatial distribution characteristics of polymer slabs were explored. Pressure time history curve of air shock wave was obtained using an air shock wave tester. The influence of polymer slabs on the propagation of air explosion shock wave was compared and analyzed. The results show that, under the air contact explosion, the polymer slab mainly suffers local damage, while under close-in explosion, overall damage is the main damage mode. With the increase of the explosive charge weight, the failure mode of the polymer slab transits from surface crack and slight spalling to local and whole crushing.

scholarly journals Attaining a Beam-Like Behavior with FRP Strips and CAM Ribbons

2018 ◽  
Vol 2 (3) ◽  
pp. 6-16 ◽  
Author(s):  
Elena Ferretti
Keyword(s):  
Ultimate Load ◽  
Masonry Wall ◽  
Experimental Results ◽  
Seismic Retrofitting ◽  
Masonry Walls ◽  
Less Invasive ◽  
Entire Height ◽  
Out Of Plane ◽  
Seismic Forces ◽  
Frp Strips

Abstract One of the major concerns in the seismic retrofitting of masonry walls is that of increasing the ultimate load for out-of-plane forces. In multi-story buildings, these forces may originate from the hammering actions of floors, when the earthquake direction is orthogonal to the wall. A possibility for counteracting the out-of-plane displacements is retaining the wall by building some buttresses, that is, some beams lean against the wall and disposed vertically. Another possibility is to make the buttress in the thickness of the wall. In this second case, we must cut the wall for its entire height, realize the buttress, and restore the masonry wall around it. In both cases, the interventions are highly invasive. The first intervention also leads to increments of mass that enhance the attraction of seismic forces. The aim of this paper is to find a less invasive and lighter alternative for realizing buttresses. We proposed to use FRP strips and steel ribbons in a combined fashion, so as to realize an ideal vertical I-beam embedded into the wall, without requiring to cut the masonry. We also provided some experimental results for verifying the effectiveness of the model.

scholarly journals Attaining a Beam-Like Behavior with FRP Strips and CAM Ribbons

2018 ◽  
Vol 2 (3) ◽  
pp. 7 ◽  
Author(s):  
Elena Ferretti
Keyword(s):  
Ultimate Load ◽  
Masonry Wall ◽  
Experimental Results ◽  
Seismic Retrofitting ◽  
Masonry Walls ◽  
Less Invasive ◽  
Entire Height ◽  
Out Of Plane ◽  
Seismic Forces ◽  
Frp Strips

One of the major concerns in the seismic retrofitting of masonry walls is that of increasing the ultimate load for out-of-plane forces. In multi-story buildings, these forces may originate from the hammering actions of floors, when the earthquake direction is orthogonal to the wall. A possibility for counteracting the out-of-plane displacements is retaining the wall by building some buttresses, that is, some beams lean against the wall and disposed vertically. Another possibility is to make the buttress in the thickness of the wall. In this second case, we must cut the wall for its entire height, realize the buttress, and restore the masonry wall around it. In both cases, the interventions are highly invasive. The first intervention also leads to increments of mass that enhance the attraction of seismic forces. The aim of this paper is to find a less invasive and lighter alternative for realizing buttresses. We proposed to use FRP strips and steel ribbons in a combined fashion, so as to realize an ideal vertical I-beam embedded into the wall, without requiring to cut the masonry. We also provided some experimental results for verifying the effectiveness of the model.

scholarly journals Simulations and Experiments of a Nonlinear Aircraft Braking System With Physical Dispersion

2010 ◽  
Vol 132 (4) ◽  
Author(s):  
Fabrice Chevillot ◽  
Jean-Jacques Sinou ◽  
Nicolas Hardouin ◽  
Louis Jezequel
Keyword(s):  
Time History ◽  
Experimental Tests ◽  
Experimental Results ◽  
Dynamic Equations ◽  
Experimental Conditions ◽  
Braking System ◽  
Nonlinear Dynamic Equations ◽  
The Coefficient Of Friction ◽  
Time History Response ◽  
Good Agreement

This paper deals with the simulation of nonlinear vibration induced by friction in an aircraft braking system. Experimental tests reveal that in similar experimental conditions the mechanism can generate vibrations of various amplitudes. The aim of this study is to simulate the behavior of the brake by taking into account the dispersion of parameters, which produce the variability of the response. A nonlinear model of the brake is presented. The time-history response is obtained by integration of the full set of nonlinear dynamic equations. Based on experimental results, the dispersions of the coefficient of friction and of the damping configuration are introduced. Monte Carlo simulations are performed and show a very good agreement with the experimental results.

Fluid Structure Interaction Analysis of Liquid Tanks by the Coupled SPH - FEM Method with Experimental Verification

2019 ◽  
Vol 391 ◽  
pp. 152-173 ◽  
Author(s):  
Marina Sunara Kusić ◽  
Jure Radnić ◽  
Nikola Grgić ◽  
Alen Harapin
Keyword(s):  
Numerical Model ◽  
Interaction Analysis ◽  
Plastic Material ◽  
Fluid Structure Interaction ◽  
Experimental Tests ◽  
Experimental Results ◽  
Shaking Table ◽  
Fluid Structure ◽  
Partition Scheme ◽  
Structure Interaction

The paper presents the comparison of the results between the numerical model developed for the simulation of the fluid-structure interaction problem and the experimental tests. The model is based on the so called “partition scheme” in which the equations governing the fluid’s pressures and the equations governing the displacement of the structure are solved separately, with two distinct solvers. The SPH (Smoothed Particle Hydrodynamics) method is used for the fluid and the standard FEM (Finite Element Method), based on shell elements, is used for the structure. Then, the two solvers are coupled to obtain the coupled behaviour of the fluid structure system. The elasto plastic material model for the structure includes some important nonlinear effects like yielding in compression and tension. Previously experimentally tested (on a shaking table) rectangular tanks with rigid and deformable walls were used for the verification of the developed numerical model. A good agreement between the numerical and the experimental results clearly shows that the developed model is suitable and gives accurate results for such problems. The numerical model results are validated with the experimental results and can be a useful tool for analyzing the behaviour of liquid tanks of larger dimensions.

scholarly journals Experimental Testing and Numerical Modeling of Robust Unreinforced and Reinforced Clay Masonry Infill Walls, With and Without Openings

2020 ◽  
Vol 6 ◽  
Author(s):  
Francesca da Porto ◽  
Marco Donà ◽  
Nicolò Verlato ◽  
Giovanni Guidi
Keyword(s):  
Experimental Testing ◽  
Experimental Tests ◽  
Experimental Results ◽  
Infill Walls ◽  
Masonry Infill ◽  
Masonry Infill Walls ◽  
Rc Frames ◽  
Reinforced Masonry ◽  
Out Of Plane ◽  
Degradation Models

This paper presents an overview of the experimental results obtained by combined in-plane/out-of-plane (IP/OOP) tests carried out on robust clay masonry infill walls. The combined tests were carried out on eight full-scale one-bay, one-story infilled reinforced concrete (RC) frames, plus one reference RC bare frame. In four cases, the masonry walls fully fill the RC frame: two walls are made of unreinforced masonry (URM), whereas the other two are made of reinforced masonry (RM), with both vertical and horizontal reinforcement. Each pair of specimens was tested up to different levels of IP drift before carrying out the OOP tests. Four other specimens, still made of URM and RM walls, are characterized by the presence of a central opening, and in one case, the effect of a lintel is analyzed. On the basis of the tests carried out, an analytical model was developed for the analysis of the OOP behavior. It was used to calibrate IP damage degradation models based on the experimental results to define limits for the applicability of well-known flexural and arching mechanism models for the evaluation of the OOP capacity of the infill walls and to evaluate the efficiency of vertical reinforcement. In this work, the experimental campaign is presented, and the results of both experimental tests and numerical analyses are discussed.

Yaw Galloping of a TLWP Platform Under High Speed Currents by Analytical Methods and its Comparison With Experimental Results

2017 ◽  
Author(s):  
Francisco Lamas ◽  
Miguel A. M. Ramirez ◽  
Antonio Carlos Fernandes
Keyword(s):  
High Speed ◽  
Production Systems ◽  
Experimental Tests ◽  
Experimental Results ◽  
Analytical Methodology ◽  
New Approach ◽  
Laboratory Facilities ◽  
Polynomial Curve ◽  
Computational Fluid Dynamics Cfd ◽  
Cfd Analyses

Flow Induced Motions are always an important subject during both design and operational phases of an offshore platform life. These motions could significantly affect the performance of the platform, including its mooring and oil production systems. These kind of analyses are performed using basically two different approaches: experimental tests with reduced models and, more recently, with Computational Fluid Dynamics (CFD) dynamic analysis. The main objective of this work is to present a new approach, based on an analytical methodology using static CFD analyses to estimate the response on yaw motions of a Tension Leg Wellhead Platform on one of the several types of motions that can be classified as flow-induced motions, known as galloping. The first step is to review the equations that govern the yaw motions of an ocean platform when subjected to currents from different angles of attack. The yaw moment coefficients will be obtained using CFD steady-state analysis, on which the yaw moments will be calculated for several angles of attack, placed around the central angle where the analysis is being carried out. Having the force coefficients plotted against the angle values, we can adjust a polynomial curve around each analysis point in order to evaluate the amplitude of the yaw motion using a limit cycle approach. Other properties of the system which are flow-dependent, such as damping and added mass, will also be estimated using CFD. The last part of this work consists in comparing the analytical results with experimental results obtained at the LOC/COPPE-UFRJ laboratory facilities.

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