Seismic vulnerability assessments of buildings after several earthquakes have confirmed that the pounding could be one of the key threats. The pounding among series of neighbouring building structures throughout earthquakes exerts repeated strikes on each other that could be a reason for structural damages ranging from light damage to even collapse. So, the main objectives are to provide constructive suggestions for code calibration through a numerical simulation for the estimation of the pounding risks on series of neighbouring buildings separated by minimum code-specified separation. A numerical simulation and FE analysis are developed to estimate the influence of pounding on the seismic response demands of adjacent buildings. The collision effects on 3-, 6- and 12-stories adjacent buildings are studied for different separation distances and alignment configurations and compared with a nominal model without pounding considerations. Based on the obtained results, it is concluded that the seriousness of the impact effects is influenced by the vibration characteristics of the adjacent buildings, the input excitation characteristics and whether the building is exposed to one- or two-sided impacts. There are additional loads caused by the pounding which leads to additional shear forces and acceleration at different story levels that do not appear in the no-pounding case.

Seismic vulnerability assessments of buildings after several earthquakes have confirmed that the pounding could be one of the key threats. The pounding among series of neighbouring building structures throughout earthquakes exerts repeated strikes on each other that could be a reason for structural damages ranging from light damage to even collapse. So, the main objectives are to provide constructive suggestions for code calibration through a numerical simulation for the estimation of the pounding risks on series of neighbouring buildings separated by minimum code-specified separation. A numerical simulation and FE analysis are developed to estimate the influence of pounding on the seismic response demands of adjacent buildings. The collision effects on 3-, 6- and 12-stories adjacent buildings are studied for different separation distances and alignment configurations and compared with a nominal model without pounding considerations. Based on the obtained results, it is concluded that the seriousness of the impact effects is influenced by the vibration characteristics of the adjacent buildings, the input excitation characteristics and whether the building is exposed to one- or two-sided impacts. There are additional loads caused by the pounding which leads to additional shear forces and acceleration at different story levels that do not appear in the no-pounding case.

In this study, a novel low-cost polishing process is applied on the surface of Fused Deposition Modeling (FDM) products. The developed polishing technique impinges a jet of hot air exit from a nozzle to FDM surfaces. The hot air locally melts the staircase on the surface and leaves it smoother by the effect of sintering phenomenon. Accordingly, the process introduces three main parameters: air jet temperature; air jet velocity; and nozzle translational velocity over the part surface. An experimental test rig was constructed to evaluate the polishing process and its parameters using surfaces with average pre-processed Ra values of 7.5 ∓ 0.5 μm. The process shows significant and reproducible improvements in surface roughness inherent with a glossy surface; whereas, an average reduction ratio up to 88% was reached which corresponds to Ra of 0.85 μm. It was found that there is an allowable range of nozzle translational velocity for every combination between jet velocity and jet temperature; otherwise, lower nozzle velocity than allowable causes overheating and surface deterioration. Furthermore, the study presents in-depth investigation to these deterioration phenomena appeared on the surface. As a result, this investigation demonstrated the possible defects in FDM part surfaces and also evaluated different process parameters. Moreover, it was observed that surface defects are reduced in the polished surfaces. For a concise conclusion, it was found that the condition of low jet velocity and high jet temperature gives the best polishing result over the allowable nozzle velocities.

In this study, a novel low-cost polishing process is applied on the surface of Fused Deposition Modeling (FDM) products. The developed polishing technique impinges a jet of hot air exit from a nozzle to FDM surfaces. The hot air locally melts the staircase on the surface and leaves it smoother by the effect of sintering phenomenon. Accordingly, the process introduces three main parameters: air jet temperature; air jet velocity; and nozzle translational velocity over the part surface. An experimental test rig was constructed to evaluate the polishing process and its parameters using surfaces with average pre-processed Ra values of 7.5 ∓ 0.5 μm. The process shows significant and reproducible improvements in surface roughness inherent with a glossy surface; whereas, an average reduction ratio up to 88% was reached which corresponds to Ra of 0.85 μm. It was found that there is an allowable range of nozzle translational velocity for every combination between jet velocity and jet temperature; otherwise, lower nozzle velocity than allowable causes overheating and surface deterioration. Furthermore, the study presents in-depth investigation to these deterioration phenomena appeared on the surface. As a result, this investigation demonstrated the possible defects in FDM part surfaces and also evaluated different process parameters. Moreover, it was observed that surface defects are reduced in the polished surfaces. For a concise conclusion, it was found that the condition of low jet velocity and high jet temperature gives the best polishing result over the allowable nozzle velocities.

In this study, a novel low-cost polishing process is applied on the surface of Fused Deposition Modeling (FDM) products. The developed polishing technique impinges a jet of hot air exit from a nozzle to FDM surfaces. The hot air locally melts the staircase on the surface and leaves it smoother by the effect of sintering phenomenon. Accordingly, the process introduces three main parameters: air jet temperature; air jet velocity; and nozzle translational velocity over the part surface. An experimental test rig was constructed to evaluate the polishing process and its parameters using surfaces with average pre-processed Ra values of 7.5 ∓ 0.5 μm. The process shows significant and reproducible improvements in surface roughness inherent with a glossy surface; whereas, an average reduction ratio up to 88% was reached which corresponds to Ra of 0.85 μm. It was found that there is an allowable range of nozzle translational velocity for every combination between jet velocity and jet temperature; otherwise, lower nozzle velocity than allowable causes overheating and surface deterioration. Furthermore, the study presents in-depth investigation to these deterioration phenomena appeared on the surface. As a result, this investigation demonstrated the possible defects in FDM part surfaces and also evaluated different process parameters. Moreover, it was observed that surface defects are reduced in the polished surfaces. For a concise conclusion, it was found that the condition of low jet velocity and high jet temperature gives the best polishing result over the allowable nozzle velocities.

In this study, a novel low-cost polishing process is applied on the surface of Fused Deposition Modeling (FDM) products. The developed polishing technique impinges a jet of hot air exit from a nozzle to FDM surfaces. The hot air locally melts the staircase on the surface and leaves it smoother by the effect of sintering phenomenon. Accordingly, the process introduces three main parameters: air jet temperature; air jet velocity; and nozzle translational velocity over the part surface. An experimental test rig was constructed to evaluate the polishing process and its parameters using surfaces with average pre-processed Ra values of 7.5 ∓ 0.5 μm. The process shows significant and reproducible improvements in surface roughness inherent with a glossy surface; whereas, an average reduction ratio up to 88% was reached which corresponds to Ra of 0.85 μm. It was found that there is an allowable range of nozzle translational velocity for every combination between jet velocity and jet temperature; otherwise, lower nozzle velocity than allowable causes overheating and surface deterioration. Furthermore, the study presents in-depth investigation to these deterioration phenomena appeared on the surface. As a result, this investigation demonstrated the possible defects in FDM part surfaces and also evaluated different process parameters. Moreover, it was observed that surface defects are reduced in the polished surfaces. For a concise conclusion, it was found that the condition of low jet velocity and high jet temperature gives the best polishing result over the allowable nozzle velocities.

In this study, a novel low-cost polishing process is applied on the surface of Fused Deposition Modeling (FDM) products. The developed polishing technique impinges a jet of hot air exit from a nozzle to FDM surfaces. The hot air locally melts the staircase on the surface and leaves it smoother by the effect of sintering phenomenon. Accordingly, the process introduces three main parameters: air jet temperature; air jet velocity; and nozzle translational velocity over the part surface. An experimental test rig was constructed to evaluate the polishing process and its parameters using surfaces with average pre-processed Ra values of 7.5 ∓ 0.5 μm. The process shows significant and reproducible improvements in surface roughness inherent with a glossy surface; whereas, an average reduction ratio up to 88% was reached which corresponds to Ra of 0.85 μm. It was found that there is an allowable range of nozzle translational velocity for every combination between jet velocity and jet temperature; otherwise, lower nozzle velocity than allowable causes overheating and surface deterioration. Furthermore, the study presents in-depth investigation to these deterioration phenomena appeared on the surface. As a result, this investigation demonstrated the possible defects in FDM part surfaces and also evaluated different process parameters. Moreover, it was observed that surface defects are reduced in the polished surfaces. For a concise conclusion, it was found that the condition of low jet velocity and high jet temperature gives the best polishing result over the allowable nozzle velocities.

The present paper presents a heat transfer model to a new polishing process that smoothens the surface of products manufactured by fused deposition modeling (FDM) technology. FDM is one of the most common additive manufacturing techniques which, unfortunately, results in very rough surfaces when compared to similar technologies. This high roughness results from the stepped surface (stair like surface) caused by the technology nature of depositing several 2D layers to form the final 3D product. To smooth the surface, it is heated up till melting which trigger surface tension force to smooth the surface. To achieve surface melting, the surface is exposed to a localized hot air jet with certain temperature and velocity from a moving nozzle with appropriate translational velocity; this introduces three main process parameters: air jet temperature, air jet velocity and air nozzle translational velocity over the product surface. Two analytical heat transfer models were derived using different process parameters and proved to be in agreement with each other. Also, a part of the obtained experimental results verifies model results. Moreover, the effect of entrained air on the heated jet was considered in the model. It can be concluded that we have an analytical model fits the experimental one and represents the modeled process.

The present paper presents a heat transfer model to a new polishing process that smoothens the surface of products manufactured by fused deposition modeling (FDM) technology. FDM is one of the most common additive manufacturing techniques which, unfortunately, results in very rough surfaces when compared to similar technologies. This high roughness results from the stepped surface (stair like surface) caused by the technology nature of depositing several 2D layers to form the final 3D product. To smooth the surface, it is heated up till melting which trigger surface tension force to smooth the surface. To achieve surface melting, the surface is exposed to a localized hot air jet with certain temperature and velocity from a moving nozzle with appropriate translational velocity; this introduces three main process parameters: air jet temperature, air jet velocity and air nozzle translational velocity over the product surface. Two analytical heat transfer models were derived using different process parameters and proved to be in agreement with each other. Also, a part of the obtained experimental results verifies model results. Moreover, the effect of entrained air on the heated jet was considered in the model. It can be concluded that we have an analytical model fits the experimental one and represents the modeled process.

The present paper presents a heat transfer model to a new polishing process that smoothens the surface of products manufactured by fused deposition modeling (FDM) technology. FDM is one of the most common additive manufacturing techniques which, unfortunately, results in very rough surfaces when compared to similar technologies. This high roughness results from the stepped surface (stair like surface) caused by the technology nature of depositing several 2D layers to form the final 3D product. To smooth the surface, it is heated up till melting which trigger surface tension force to smooth the surface. To achieve surface melting, the surface is exposed to a localized hot air jet with certain temperature and velocity from a moving nozzle with appropriate translational velocity; this introduces three main process parameters: air jet temperature, air jet velocity and air nozzle translational velocity over the product surface. Two analytical heat transfer models were derived using different process parameters and proved to be in agreement with each other. Also, a part of the obtained experimental results verifies model results. Moreover, the effect of entrained air on the heated jet was considered in the model. It can be concluded that we have an analytical model fits the experimental one and represents the modeled process.