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.

Fused deposition modeling (FDM) is the most versatile additive manufacturing technology owing to the low-cost materials that handle. However, FDM produce very rough parts which limit its use in molds and other industrial applications owing to stair-case effect. To obtain smoother surfaces, a post-processing phase may be introduced. In this research, a non-contact finishing process to FDM parts using hot air was developed. The hot air is directed locally at the stair-case in the surface till melting it which results after cooling to a smoother surface. An experimental setup was constructed to study the effects of different process parameters including air temperature, air flow rate and the moving velocity of air nozzle over parts surface. An improvement in the Roughness Average of a surfaces measured microscopic peaks and valleys (Ra) down to values of sub-micron was recorded from specimens with average surface roughness from7 to 8 μm.

Fused deposition modeling (FDM) is the most versatile additive manufacturing technology owing to the low-cost materials that handle. However, FDM produce very rough parts which limit its use in molds and other industrial applications owing to stair-case effect. To obtain smoother surfaces, a post-processing phase may be introduced. In this research, a non-contact finishing process to FDM parts using hot air was developed. The hot air is directed locally at the stair-case in the surface till melting it which results after cooling to a smoother surface. An experimental setup was constructed to study the effects of different process parameters including air temperature, air flow rate and the moving velocity of air nozzle over parts surface. An improvement in the Roughness Average of a surfaces measured microscopic peaks and valleys (Ra) down to values of sub-micron was recorded from specimens with average surface roughness from7 to 8 μm.

Fused deposition modeling (FDM) is the most versatile additive manufacturing technology owing to the low-cost materials that handle. However, FDM produce very rough parts which limit its use in molds and other industrial applications owing to stair-case effect. To obtain smoother surfaces, a post-processing phase may be introduced. In this research, a non-contact finishing process to FDM parts using hot air was developed. The hot air is directed locally at the stair-case in the surface till melting it which results after cooling to a smoother surface. An experimental setup was constructed to study the effects of different process parameters including air temperature, air flow rate and the moving velocity of air nozzle over parts surface. An improvement in the Roughness Average of a surfaces measured microscopic peaks and valleys (Ra) down to values of sub-micron was recorded from specimens with average surface roughness from7 to 8 μm.

Fused deposition modeling (FDM) is the most versatile additive manufacturing technology owing to the low-cost materials that handle. However, FDM produce very rough parts which limit its use in molds and other industrial applications owing to stair-case effect. To obtain smoother surfaces, a post-processing phase may be introduced. In this research, a non-contact finishing process to FDM parts using hot air was developed. The hot air is directed locally at the stair-case in the surface till melting it which results after cooling to a smoother surface. An experimental setup was constructed to study the effects of different process parameters including air temperature, air flow rate and the moving velocity of air nozzle over parts surface. An improvement in the Roughness Average of a surfaces measured microscopic peaks and valleys (Ra) down to values of sub-micron was recorded from specimens with average surface roughness from7 to 8 μm.

Fused deposition modeling (FDM) is the most versatile additive manufacturing technology owing to the low-cost materials that handle. However, FDM produce very rough parts which limit its use in molds and other industrial applications owing to stair-case effect. To obtain smoother surfaces, a post-processing phase may be introduced. In this research, a non-contact finishing process to FDM parts using hot air was developed. The hot air is directed locally at the stair-case in the surface till melting it which results after cooling to a smoother surface. An experimental setup was constructed to study the effects of different process parameters including air temperature, air flow rate and the moving velocity of air nozzle over parts surface. An improvement in the Roughness Average of a surfaces measured microscopic peaks and valleys (Ra) down to values of sub-micron was recorded from specimens with average surface roughness from7 to 8 μm.

Post-earthquake damages investigation in past and recent earthquakes has illustrated that the ground motion spatial variation plays an important role in the structural response of long span bridges. For the structural control of seismic-induced vibrations of cable-stayed bridges, it is extremely important to include the effects of the ground motion spatial variation in the analysis for design of an effective control system. The feasibility and efficiency of different vibration control strategies for the cable-stayed bridge under multiple support excitations have been examined to enhance a structure’s ability to withstand earthquake excitations. Comparison of the response due to non-uniform input ground motion with that due to uniform input demonstrates the importance of accounting for spatial variability of excitations. The performance of the optimized designed control systems for uniform input excitations gets worse dramatically over almost all of the evaluation criteria under multiple-support excitations.

Past and recent earthquakes events demonstrate that buildings with configuration irregularity are more vulnerable to earthquake damages. So it's essential to investigate the seismic response of these structures in active seismic zones to reduce the potential seismic damages. The configuration irregularities introduce major challenges in the seismic design of building structures. One such form of irregularity is the presence of re-entrant corners that causes stress concentration due to sudden changes in stiffness and torsion amplification in the buildings; hence causes early collapse. This, the conventional design codes have not recommendations for proper evaluation of these buildings yet. Thus, a constructive research into re-entrant corner irregularity problems is essentially needed greater than ever. The objective of this study is to grasp the seismic behavior of the buildings with irregular plan of L-shape floor plan through the evaluation of the configuration irregularity of reentrant corners effects on measured seismic response demands. The measured responses include inter-story drift; story shear force; overturning moment; torsion moment at the base and along the building height; top floor displacement; and torsional Irregularity Ratio. Three dimensional finite element model of nine stories moment resisting frame buildings as reference model is developed; six L-shaped models are formulated with gradual reduction in the plan of the reference model. The models are analyzed with ETABS using Equivalent Static Load (ESL) and Response Spectrum (RS) Methods. The results prove that buildings with severe irregularity are more vulnerable than those with regular configuration resulting from torsion behavior, and the additional shear force produced in the perpendicular direction to the earthquake input. Also, in the codal empirical equation for the calculation of fundamental period of vibration could not grasp significant higher vibration modes such as torsional vibration of irregular buildings that could significantly affect seismic demands.