Peng Y.,Nanjing University of Technology |
Wu C.,Beihang University |
Zheng Y.,Nanjing University of Technology |
Zheng Y.,Nanjing Municipal Design and Research Institute Co. |
Dong J.,Nanjing University of Technology
Materials | Year: 2017
Welded joints are prone to fatigue cracking with the existence of welding defects and bending stress. Fracture mechanics is a useful approach in which the fatigue life of the welded joint can be predicted. The key challenge of such predictions using fracture mechanics is how to accurately calculate the stress intensity factor (SIF). An empirical formula for calculating the SIF of welded joints under bending stress was developed by Baik, Yamada and Ishikawa based on the hybrid method. However, when calculating the SIF of a semi-elliptical crack, this study found that the accuracy of the Baik-Yamada formula was poor when comparing the benchmark results, experimental data and numerical results. The reasons for the reduced accuracy of the Baik-Yamada formula were identified and discussed in this paper. Furthermore, a new correction factor was developed and added to the Baik-Yamada formula by using theoretical analysis and numerical regression. Finally, the predictions using the modified Baik-Yamada formula were compared with the benchmark results, experimental data and numerical results. It was found that the accuracy of the modified Baik-Yamada formula was greatly improved. Therefore, it is proposed that this modified formula is used to conveniently and accurately calculate the SIF of semi-elliptical cracks in welded joints under bending stress. © 2017 by the authors.
Wang Z.,Nanjing Forestry University |
Jing Z.Q.,Nanjing Forestry University |
Kong Y.,Nanjing Municipal Design and Research Institute Co. |
Shen W.,Nanjing Municipal Design and Research Institute Co.
Applied Mechanics and Materials | Year: 2010
This study investigated the adsorption of congo red by activated carbon-attapulgite composite adsorbent (ACA) and zeolite-attapulgite composite adsorbent (ZA) from aqueous solution. All of these two adsorbents have mesopores and macropores structure different from general activated carbon adsorbent with micropores distribution through analysis of mercury porosimeter. The research focused on the effects of adsorption capacity in four aspects: contact time, solution pH, temperature and initial dye concentration. The results indicated that ACA had higher adsorption rate in the first 30 min contact time and ZA had higher removal percentage because of the difference on the pore size and total pore area. There was little difference on removal percentage of ACA and ZA when pH changing from 1 to 13 and the adsorption rate exceeded 94% in all kinds of pH condition. The removal efficiency of congo red on ACA and ZA increased from 92% to 95% with increase of temperature from 293K to323K. The reduction rate of congo red decreased with an increase in the initial congo red concentration for ACA and ZA.These results suggest that all of the two adsorbents is a potential low-cost adsorbent for the dye removal from industrial wastewater. © (2010) Trans Tech Publications.
Zheng W.,Nanjing Forestry University |
Jing Z.-Q.,Nanjing Forestry University |
Yu K.,Nanjing Municipal Design and Research Institute Co. |
Wei S.,Nanjing Municipal Design and Research Institute Co.
Key Engineering Materials | Year: 2011
The aim of this study was the assessment of reduction of chemical oxygen demand (COD) from micro-polluted water using activated carbon-attapulgite composite adsorbent prepared using activated carbon and natural attapulgite through compounding, granulation and calcination. The complete study was done in batch mode to investigate the effect of operating parameters. Adsorption of COD was found to be dependent on contact time, pH, temperature and initial COD concentration. Adsorption equilibrium attained within 80 minutes time. The optimum pH range for adsorption of organics was found to be 8. The sorption of organics decreased with rise of temperature because adsorption process was exothermic. The studied adsorption data fitted well to Langmuir adsorption model with the correlation coefficient 0.9947. The activated carbon-attapulgite composite adsorbent in this study shows very good promise for practical applicability on removal of COD from micro-polluted water.
Guan L.,Nanjing Municipal Design and Research Institute Co |
Jing Z.-Q.,Nanjing Forestry University |
Xiong S.-H.,Nanjing Municipal Design and Research Institute Co |
Wang A.-H.,Nanjing Municipal Design and Research Institute Co
Journal of Natural Disasters | Year: 2011
Blue-green algae event outbroken in Taihu Lake Basin impelled the overall upgrading and reconstruction of wastewater treatment plants in this basin. The main upgrading measures include enhanced biological treatment, advanced treatment and so on. Concrete measures should be selected according to the treatment requirements, present process and economic development level. The effluent water quality should be determined in consideration of water body pollution status and environment capacity. During the process of upgrading and reconstruction, more emphasis should be laid on the design and monitoring of influent wastewater quality and quantity. The project investment and running cost should be also controlled.
Li P.,Hohai University |
Yang T.,Nanjing Municipal Design and Research Institute Co. |
Liu H.-L.,Hohai University |
Wang Y.,Nanjing Municipal Design and Research Institute Co. |
Chen Y.-M.,Hohai University
Jiefangjun Ligong Daxue Xuebao/Journal of PLA University of Science and Technology (Natural Science Edition) | Year: 2011
Based on the foundation supporting project of the running double-track shield tunnels of Nanjing Metro Line 1, which was underlying Long-pan tunnels in Nanjing Railway Station Square, a series of design methods to resist the heave of the two existing shield tunnels were developed, including the pit reinforcement, artificial strip excavation and pile-sheet retaining. Furthermore, FLAC3D was employed to simulate the foundation support and the whole excavation process. The deformation regularity and influence factors of the shield tunnels were studied by comparing the numerical results with the filed data. It was concluded that the numerical method could simulate the real excavation process of the new tunnel. Under the condition of small deformation, the displacement of the shield tunnels was basically identical with that of the soil. Pile-sheet retaining method associated with pit reinforcement can effectively control the heave deformation of the metro tunnels during soft soil excavation. This study made a good example for the future similar engineering.
Hu F.,East China Jiaotong University |
He W.,Nanjing Municipal Design and Research Institute Co. |
Tang C.,East China Jiaotong University |
Zhong L.,East China Jiaotong University
Advanced Materials Research | Year: 2012
The purification efficiency of biological removal of iron and manganese was probed by pilot tests. In this experiment, the raw water were iron concentration of 0.96~5.56 mg/L, manganese concentration of 0.87~2.38 mg/L, dissolved oxygen of 2~4 mg/L, pH value neutral. In the condition of filter speed of 6 m/h, the average removal rate of iron and manganese reached 97.6% and 90.9% respectively, the effluent concentration of Fe2+ and Mn2+ were keep in below 0.1 mg/L. © (2012) Trans Tech Publications, Switzerland.
Guan Z.,Nanjing Municipal Design and Research Institute Co. |
Li Y.,Nanjing Municipal Design and Research Institute Co.
Wuhan Ligong Daxue Xuebao (Jiaotong Kexue Yu Gongcheng Ban)/Journal of Wuhan University of Technology (Transportation Science and Engineering) | Year: 2011
A rational interchange design of more traffic adaptability was put forward as the project of Dongchang Road interchange design. The volume of traffic and natural conditions were fully considered and the project characteristics, traffic analysis and comparison of different designs were analyzed carefully. The influence of the natural conditions and the volume of traffic on the interchange were pointed out in the design which satisfies the main traffic flow and traffic adaptability requirement. The design can also be used as reference for other projects.