Submerged arc welding（SAW）is one of the main welding processes with high deposition rate and high welding quality.This welding method is extensively used in welding large-diameter gas transmission pipelines and high...Submerged arc welding（SAW）is one of the main welding processes with high deposition rate and high welding quality.This welding method is extensively used in welding large-diameter gas transmission pipelines and high-pressure vessels.In welding of such structures,the selection process parameters has great influence on the weld bead geometry and consequently affects the weld quality.Based on Fuzzy logic and NSGA-II（Non-dominated Sorting Genetic Algorithm-II）algorithm,a new approach was proposed for weld bead geometry prediction and for process parameters optimization.First,different welding parameters including welding voltage,current and speed were set to perform SAW under different conditions on API X65 steel plates.Next,the designed Fuzzy model was used for predicting the weld bead geometry and modeling of the process.The obtained mean percentage error of penetration depth,weld bead width and height from the proposed Fuzzy model was 6.06%,6.40% and 5.82%,respectively.The process parameters were then optimized to achieve the desired values of convexity and penetration indexes simultaneously using NSGA-II algorithm.As a result,a set of optimum vectors（each vector contains current,voltage and speed within their selected experimental domains）was presented for desirable values of convexity and penetration indexes in the ranges of（0.106,0.168）and（0.354,0.561）respectively,which was more applicable in real conditions.展开更多
This work proposes a method to concurrently calibrate multiple acoustic speeds in different mediums with a photoacoustic（PA） and ultrasound（US） dual-modality imaging system. First, physical infrastructure informat...This work proposes a method to concurrently calibrate multiple acoustic speeds in different mediums with a photoacoustic（PA） and ultrasound（US） dual-modality imaging system. First, physical infrastructure information of the target is acquired through a US image. Then, we repeatedly build PA images around a special target to yield the best focused result by dynamically updating the acoustic speeds in a different medium of the target.With these correct acoustic propagation velocities in the according mediums, we can effectively optimize the PA image quality as the experiments proved, which might benefit future research in biomedical imaging science.展开更多
文摘Submerged arc welding（SAW）is one of the main welding processes with high deposition rate and high welding quality.This welding method is extensively used in welding large-diameter gas transmission pipelines and high-pressure vessels.In welding of such structures,the selection process parameters has great influence on the weld bead geometry and consequently affects the weld quality.Based on Fuzzy logic and NSGA-II（Non-dominated Sorting Genetic Algorithm-II）algorithm,a new approach was proposed for weld bead geometry prediction and for process parameters optimization.First,different welding parameters including welding voltage,current and speed were set to perform SAW under different conditions on API X65 steel plates.Next,the designed Fuzzy model was used for predicting the weld bead geometry and modeling of the process.The obtained mean percentage error of penetration depth,weld bead width and height from the proposed Fuzzy model was 6.06%,6.40% and 5.82%,respectively.The process parameters were then optimized to achieve the desired values of convexity and penetration indexes simultaneously using NSGA-II algorithm.As a result,a set of optimum vectors（each vector contains current,voltage and speed within their selected experimental domains）was presented for desirable values of convexity and penetration indexes in the ranges of（0.106,0.168）and（0.354,0.561）respectively,which was more applicable in real conditions.
基金supported by National Natural Science Foundation of China(No.61201425)the Natural Science Foundation of Jiangsu Province(No.BK20131280)the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘This work proposes a method to concurrently calibrate multiple acoustic speeds in different mediums with a photoacoustic（PA） and ultrasound（US） dual-modality imaging system. First, physical infrastructure information of the target is acquired through a US image. Then, we repeatedly build PA images around a special target to yield the best focused result by dynamically updating the acoustic speeds in a different medium of the target.With these correct acoustic propagation velocities in the according mediums, we can effectively optimize the PA image quality as the experiments proved, which might benefit future research in biomedical imaging science.
