Publications

2021
Baghdadi M, Dimia MS, Guenfoud M, Bouchair A. An experimental and numerical analysis of concrete walls exposed to fire. Structural Engineering and Mechanics, An Int'l Journal [Internet]. 2021;77 (6) :819-830. Publisher's VersionAbstract

To evaluate the performance of concrete load bearing walls in a structure under horizontal loads after being exposed to real fire, two steps were followed. In the first step, an experimental study was performed on the thermo-mechanical properties of concrete after heating to temperatures of 200-1000oC with the purpose of determining the residual mechanical properties after cooling. The temperature was increased in line with natural fire curve in an electric furnace. The peak temperature was maintained for a period of 1.5 hour and then allowed to cool gradually in air at room temperature. All specimens were made from calcareous aggregate to be used for determining the residual properties: compressive strength, static and dynamic elasticity modulus by means of UPV test, including the mass loss. The concrete residual compressive strength and elastic modulus values were compared with those calculated from Eurocode and other analytical models from other studies, and were found to be satisfactory. In the second step, experimental analysis results were then implemented into structural numerical analysis to predict the post-fire load-bearing capacity response of the walls under vertical and horizontal loads. The parameters considered in this analysis were the effective height, the thickness of the wall, various support conditions and the residual strength of concrete. The results indicate that fire damage does not significantly affect the lateral capacity and stiffness of reinforced walls for temperature fires up to 400oC.

Baghdadi M, Dimia MS, Guenfoud M, Bouchair A. An experimental and numerical analysis of concrete walls exposed to fire. Structural Engineering and Mechanics, An Int'l Journal [Internet]. 2021;77 (6) :819-830. Publisher's VersionAbstract

To evaluate the performance of concrete load bearing walls in a structure under horizontal loads after being exposed to real fire, two steps were followed. In the first step, an experimental study was performed on the thermo-mechanical properties of concrete after heating to temperatures of 200-1000oC with the purpose of determining the residual mechanical properties after cooling. The temperature was increased in line with natural fire curve in an electric furnace. The peak temperature was maintained for a period of 1.5 hour and then allowed to cool gradually in air at room temperature. All specimens were made from calcareous aggregate to be used for determining the residual properties: compressive strength, static and dynamic elasticity modulus by means of UPV test, including the mass loss. The concrete residual compressive strength and elastic modulus values were compared with those calculated from Eurocode and other analytical models from other studies, and were found to be satisfactory. In the second step, experimental analysis results were then implemented into structural numerical analysis to predict the post-fire load-bearing capacity response of the walls under vertical and horizontal loads. The parameters considered in this analysis were the effective height, the thickness of the wall, various support conditions and the residual strength of concrete. The results indicate that fire damage does not significantly affect the lateral capacity and stiffness of reinforced walls for temperature fires up to 400oC.

Baghdadi M, Dimia MS, Guenfoud M, Bouchair A. An experimental and numerical analysis of concrete walls exposed to fire. Structural Engineering and Mechanics, An Int'l Journal [Internet]. 2021;77 (6) :819-830. Publisher's VersionAbstract

To evaluate the performance of concrete load bearing walls in a structure under horizontal loads after being exposed to real fire, two steps were followed. In the first step, an experimental study was performed on the thermo-mechanical properties of concrete after heating to temperatures of 200-1000oC with the purpose of determining the residual mechanical properties after cooling. The temperature was increased in line with natural fire curve in an electric furnace. The peak temperature was maintained for a period of 1.5 hour and then allowed to cool gradually in air at room temperature. All specimens were made from calcareous aggregate to be used for determining the residual properties: compressive strength, static and dynamic elasticity modulus by means of UPV test, including the mass loss. The concrete residual compressive strength and elastic modulus values were compared with those calculated from Eurocode and other analytical models from other studies, and were found to be satisfactory. In the second step, experimental analysis results were then implemented into structural numerical analysis to predict the post-fire load-bearing capacity response of the walls under vertical and horizontal loads. The parameters considered in this analysis were the effective height, the thickness of the wall, various support conditions and the residual strength of concrete. The results indicate that fire damage does not significantly affect the lateral capacity and stiffness of reinforced walls for temperature fires up to 400oC.

Baghdadi M, Dimia MS, Guenfoud M, Bouchair A. An experimental and numerical analysis of concrete walls exposed to fire. Structural Engineering and Mechanics, An Int'l Journal [Internet]. 2021;77 (6) :819-830. Publisher's VersionAbstract

To evaluate the performance of concrete load bearing walls in a structure under horizontal loads after being exposed to real fire, two steps were followed. In the first step, an experimental study was performed on the thermo-mechanical properties of concrete after heating to temperatures of 200-1000oC with the purpose of determining the residual mechanical properties after cooling. The temperature was increased in line with natural fire curve in an electric furnace. The peak temperature was maintained for a period of 1.5 hour and then allowed to cool gradually in air at room temperature. All specimens were made from calcareous aggregate to be used for determining the residual properties: compressive strength, static and dynamic elasticity modulus by means of UPV test, including the mass loss. The concrete residual compressive strength and elastic modulus values were compared with those calculated from Eurocode and other analytical models from other studies, and were found to be satisfactory. In the second step, experimental analysis results were then implemented into structural numerical analysis to predict the post-fire load-bearing capacity response of the walls under vertical and horizontal loads. The parameters considered in this analysis were the effective height, the thickness of the wall, various support conditions and the residual strength of concrete. The results indicate that fire damage does not significantly affect the lateral capacity and stiffness of reinforced walls for temperature fires up to 400oC.

Boudjelal S, Fourar A, Massouh F. Experimental and numerical simulation of free surface flow over an obstacle on a sloped channel. Modeling Earth Systems and Environment [Internet]. 2021;8 :1025–1033. Publisher's VersionAbstract

In the present study, both experimental and numerical were conducted on a free surface flow over an obstacle. Numerical simulations were performed using the Renormalization Group (RNG-k-ɛ) based Reynolds-Averaged Navier–Stokes (RANS) turbulence model coupled with the Volume OF Fluid (VOF) method in FLUENT Software to investigate the effect of the channel slope on the flow pattern upstream, above and downstream the obstacle. Respectively, 5%, 7%, 8%, 10%, 20% and 50% channel slopes were considered. Numerical simulation has showed a good agreement compared against experimental results. Effect of the slope on the flow is observed particularly upstream of the obstacle where the flow takes the vertical direction after hitting the upstream wall. The more the slope becomes steeper, the higher the level of the water is. Recirculation zones in the case of a horizontal channel are elongated downstream the weir, whereas in the case of a sloped channel, they are localized just at the foot of the downstream wall.

Boudjelal S, Fourar A, Massouh F. Experimental and numerical simulation of free surface flow over an obstacle on a sloped channel. Modeling Earth Systems and Environment [Internet]. 2021;8 :1025–1033. Publisher's VersionAbstract

In the present study, both experimental and numerical were conducted on a free surface flow over an obstacle. Numerical simulations were performed using the Renormalization Group (RNG-k-ɛ) based Reynolds-Averaged Navier–Stokes (RANS) turbulence model coupled with the Volume OF Fluid (VOF) method in FLUENT Software to investigate the effect of the channel slope on the flow pattern upstream, above and downstream the obstacle. Respectively, 5%, 7%, 8%, 10%, 20% and 50% channel slopes were considered. Numerical simulation has showed a good agreement compared against experimental results. Effect of the slope on the flow is observed particularly upstream of the obstacle where the flow takes the vertical direction after hitting the upstream wall. The more the slope becomes steeper, the higher the level of the water is. Recirculation zones in the case of a horizontal channel are elongated downstream the weir, whereas in the case of a sloped channel, they are localized just at the foot of the downstream wall.

Boudjelal S, Fourar A, Massouh F. Experimental and numerical simulation of free surface flow over an obstacle on a sloped channel. Modeling Earth Systems and Environment [Internet]. 2021;8 :1025–1033. Publisher's VersionAbstract

In the present study, both experimental and numerical were conducted on a free surface flow over an obstacle. Numerical simulations were performed using the Renormalization Group (RNG-k-ɛ) based Reynolds-Averaged Navier–Stokes (RANS) turbulence model coupled with the Volume OF Fluid (VOF) method in FLUENT Software to investigate the effect of the channel slope on the flow pattern upstream, above and downstream the obstacle. Respectively, 5%, 7%, 8%, 10%, 20% and 50% channel slopes were considered. Numerical simulation has showed a good agreement compared against experimental results. Effect of the slope on the flow is observed particularly upstream of the obstacle where the flow takes the vertical direction after hitting the upstream wall. The more the slope becomes steeper, the higher the level of the water is. Recirculation zones in the case of a horizontal channel are elongated downstream the weir, whereas in the case of a sloped channel, they are localized just at the foot of the downstream wall.

Laouche M, Karech T, Rangeard D, Martinez J. Experimental Study of the Effects of Installation of Sand Columns in Compressible Clay Using a Reduced Model. Geotechnical and Geological Engineering [Internet]. 2021;39 :2301-2312. Publisher's VersionAbstract

The present study focuses on the investigation of the behaviour of a reduced model of a reinforced soil massif by a sand column tested in the laboratory. These tests involved the installation of sand columns in clay specimens (kaolin) by different methods. The specimens thus obtained are subjected to the same oedometric loading program. The first part of this work aims to study the effect of the intensity of the compaction stress of the sand columns on the surrounding soil and the effect on the behaviour of the soil-column massif. The sand columns were installed with the soil replacement method and with compacting of the columns (WR_WC). Three different compaction stresses were used to install the columns. In the second part, a sand column 20 mm in diameter was installed by two methods: one with replacement of the soil (WR) and without compaction and the other with displacement of the soil (WD). A comparison between the two methods has been established. By determining the equivalent characteristics for the soil-column massif, this study made it possible to characterize the effect of the installation method of the columns on the settlements, the void ratioe of kaolin, the equivalent void ratio eeq of the massif soil-column and on the compressibility parameters of the massif (equivalent compression index Cceq and swelling index Cseq), by comparing the results obtained with those of the unreinforced soils that constitute the reference case. The results obtained showed that the techniques used for the installation of columns have significant effects on the behaviour of reinforced massifs.

Laouche M, Karech T, Rangeard D, Martinez J. Experimental Study of the Effects of Installation of Sand Columns in Compressible Clay Using a Reduced Model. Geotechnical and Geological Engineering [Internet]. 2021;39 :2301-2312. Publisher's VersionAbstract

The present study focuses on the investigation of the behaviour of a reduced model of a reinforced soil massif by a sand column tested in the laboratory. These tests involved the installation of sand columns in clay specimens (kaolin) by different methods. The specimens thus obtained are subjected to the same oedometric loading program. The first part of this work aims to study the effect of the intensity of the compaction stress of the sand columns on the surrounding soil and the effect on the behaviour of the soil-column massif. The sand columns were installed with the soil replacement method and with compacting of the columns (WR_WC). Three different compaction stresses were used to install the columns. In the second part, a sand column 20 mm in diameter was installed by two methods: one with replacement of the soil (WR) and without compaction and the other with displacement of the soil (WD). A comparison between the two methods has been established. By determining the equivalent characteristics for the soil-column massif, this study made it possible to characterize the effect of the installation method of the columns on the settlements, the void ratioe of kaolin, the equivalent void ratio eeq of the massif soil-column and on the compressibility parameters of the massif (equivalent compression index Cceq and swelling index Cseq), by comparing the results obtained with those of the unreinforced soils that constitute the reference case. The results obtained showed that the techniques used for the installation of columns have significant effects on the behaviour of reinforced massifs.

Laouche M, Karech T, Rangeard D, Martinez J. Experimental Study of the Effects of Installation of Sand Columns in Compressible Clay Using a Reduced Model. Geotechnical and Geological Engineering [Internet]. 2021;39 :2301-2312. Publisher's VersionAbstract

The present study focuses on the investigation of the behaviour of a reduced model of a reinforced soil massif by a sand column tested in the laboratory. These tests involved the installation of sand columns in clay specimens (kaolin) by different methods. The specimens thus obtained are subjected to the same oedometric loading program. The first part of this work aims to study the effect of the intensity of the compaction stress of the sand columns on the surrounding soil and the effect on the behaviour of the soil-column massif. The sand columns were installed with the soil replacement method and with compacting of the columns (WR_WC). Three different compaction stresses were used to install the columns. In the second part, a sand column 20 mm in diameter was installed by two methods: one with replacement of the soil (WR) and without compaction and the other with displacement of the soil (WD). A comparison between the two methods has been established. By determining the equivalent characteristics for the soil-column massif, this study made it possible to characterize the effect of the installation method of the columns on the settlements, the void ratioe of kaolin, the equivalent void ratio eeq of the massif soil-column and on the compressibility parameters of the massif (equivalent compression index Cceq and swelling index Cseq), by comparing the results obtained with those of the unreinforced soils that constitute the reference case. The results obtained showed that the techniques used for the installation of columns have significant effects on the behaviour of reinforced massifs.

Laouche M, Karech T, Rangeard D, Martinez J. Experimental Study of the Effects of Installation of Sand Columns in Compressible Clay Using a Reduced Model. Geotechnical and Geological Engineering [Internet]. 2021;39 :2301-2312. Publisher's VersionAbstract

The present study focuses on the investigation of the behaviour of a reduced model of a reinforced soil massif by a sand column tested in the laboratory. These tests involved the installation of sand columns in clay specimens (kaolin) by different methods. The specimens thus obtained are subjected to the same oedometric loading program. The first part of this work aims to study the effect of the intensity of the compaction stress of the sand columns on the surrounding soil and the effect on the behaviour of the soil-column massif. The sand columns were installed with the soil replacement method and with compacting of the columns (WR_WC). Three different compaction stresses were used to install the columns. In the second part, a sand column 20 mm in diameter was installed by two methods: one with replacement of the soil (WR) and without compaction and the other with displacement of the soil (WD). A comparison between the two methods has been established. By determining the equivalent characteristics for the soil-column massif, this study made it possible to characterize the effect of the installation method of the columns on the settlements, the void ratioe of kaolin, the equivalent void ratio eeq of the massif soil-column and on the compressibility parameters of the massif (equivalent compression index Cceq and swelling index Cseq), by comparing the results obtained with those of the unreinforced soils that constitute the reference case. The results obtained showed that the techniques used for the installation of columns have significant effects on the behaviour of reinforced massifs.

BOUGOFFA LAZHAR, MENNOUNI ABDELAZIZ, WAZWAZ ABDUL-MAJID. FAMILIES OF EXACT SOLITON SOLUTIONS TO THE AB NONLINEAR SYSTEM. ROMANIAN REPORTS IN PHYSICS [Internet]. 2021;74 (106). Publisher's VersionAbstract

In this paper, the exact solutions to the AB nonlinear system are investigated. This system is reduced via two different transformations to a sine-Gordon equation and a quasilinear equation for a new dependent variable ϕ. Solutions to a sineGordon equation and a quasilinear equation are found. Hence, the original system can well be solved for such ϕ. Also, a similar approach is proposed to solve analytically an eventual extension system for the case of variable coefficients.

BOUGOFFA LAZHAR, MENNOUNI ABDELAZIZ, WAZWAZ ABDUL-MAJID. FAMILIES OF EXACT SOLITON SOLUTIONS TO THE AB NONLINEAR SYSTEM. ROMANIAN REPORTS IN PHYSICS [Internet]. 2021;74 (106). Publisher's VersionAbstract

In this paper, the exact solutions to the AB nonlinear system are investigated. This system is reduced via two different transformations to a sine-Gordon equation and a quasilinear equation for a new dependent variable ϕ. Solutions to a sineGordon equation and a quasilinear equation are found. Hence, the original system can well be solved for such ϕ. Also, a similar approach is proposed to solve analytically an eventual extension system for the case of variable coefficients.

BOUGOFFA LAZHAR, MENNOUNI ABDELAZIZ, WAZWAZ ABDUL-MAJID. FAMILIES OF EXACT SOLITON SOLUTIONS TO THE AB NONLINEAR SYSTEM. ROMANIAN REPORTS IN PHYSICS [Internet]. 2021;74 (106). Publisher's VersionAbstract

In this paper, the exact solutions to the AB nonlinear system are investigated. This system is reduced via two different transformations to a sine-Gordon equation and a quasilinear equation for a new dependent variable ϕ. Solutions to a sineGordon equation and a quasilinear equation are found. Hence, the original system can well be solved for such ϕ. Also, a similar approach is proposed to solve analytically an eventual extension system for the case of variable coefficients.

Bazi S, Benzid R, Bazi Y, Rahhal MMA. A Fast Firefly Algorithm for Function Optimization: Application to the Control of BLDC Motor. SensorsSensors. 2021;21 :5267.
Bazi S, Benzid R, Bazi Y, Rahhal MMA. A Fast Firefly Algorithm for Function Optimization: Application to the Control of BLDC Motor. SensorsSensors. 2021;21 :5267.
Bazi S, Benzid R, Bazi Y, Rahhal MMA. A Fast Firefly Algorithm for Function Optimization: Application to the Control of BLDC Motor. SensorsSensors. 2021;21 :5267.
Bazi S, Benzid R, Bazi Y, Rahhal MMA. A Fast Firefly Algorithm for Function Optimization: Application to the Control of BLDC Motor. SensorsSensors. 2021;21 :5267.
Ameddah H, Lounansa S, Mazouz H. Fatigue Behavior Study of the Biodegradable Cardiovascular Stent. International Conference on Advanced Materials Mechanics & Manufacturing [Internet]. 2021 :42-48. Publisher's VersionAbstract
In recent years the development of health science to improve people’s lives and reduce the death rate from cardiovascular disease, researchers have invested in the solution of stents to treat cardiovascular disease. Usually a permanent implant (metal stent) is used to treat a temporary disease, effective on elastic recoil and negative remodeling, but promoting intimate proliferation. This is combated by an active stent, which nevertheless induces chronic inflammation and delayed healing (because of active drugs), with the risk of late thrombosis. The idea of resolution leads to the study of the behavior of temporary stent biodegradable and bioresorbable, once the healing process is completed. The purpose of this study is to reduce the disadvantages of metal stents, to do this; a biodegradable material (polylactic acid) is used. The fatigue behavior of a stent after its placement using geometric parameters selected from clinical cases (diastole and systole). A finite element numerical study in the field of biomaterial fatigue is proposed in order to investigate and understand the biodegradable behavior of the stent. The results of the numerical study show the predicted lifetime of the biodegradable fragrance.
Ameddah H, Lounansa S, Mazouz H. Fatigue Behavior Study of the Biodegradable Cardiovascular Stent. International Conference on Advanced Materials Mechanics & Manufacturing [Internet]. 2021 :42-48. Publisher's VersionAbstract
In recent years the development of health science to improve people’s lives and reduce the death rate from cardiovascular disease, researchers have invested in the solution of stents to treat cardiovascular disease. Usually a permanent implant (metal stent) is used to treat a temporary disease, effective on elastic recoil and negative remodeling, but promoting intimate proliferation. This is combated by an active stent, which nevertheless induces chronic inflammation and delayed healing (because of active drugs), with the risk of late thrombosis. The idea of resolution leads to the study of the behavior of temporary stent biodegradable and bioresorbable, once the healing process is completed. The purpose of this study is to reduce the disadvantages of metal stents, to do this; a biodegradable material (polylactic acid) is used. The fatigue behavior of a stent after its placement using geometric parameters selected from clinical cases (diastole and systole). A finite element numerical study in the field of biomaterial fatigue is proposed in order to investigate and understand the biodegradable behavior of the stent. The results of the numerical study show the predicted lifetime of the biodegradable fragrance.

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