Hu J.,Northeastern University China |
Du L.-X.,Northeastern University China |
Wang J.-J.,Northeastern University China |
Sun Q.-Y.,WISDRI Engineering and Research Incorporation Ltd
Materials and Design | Year: 2014
For the purpose of developing Nb-V-Ti microalloyed, hot rolled, high strength automotive steel for usage in heavy-duty truck wheel-discs and wheel-rims, appropriate cooling processes were designed, and microstructures and comprehensive mechanical properties (tension, bending, hole-expansion, and Charpy impact) of the tested steels at two cooling schedules were studied. The results indicate that the steel consists of 90% 5. μm polygonal ferrite and 10% pearlite when subjected to a cooling rate of 13. °C/s and a coiling temperature of 650. °C. The yield strength, tensile strength, and hole-expansion ratio are 570. MPa, 615. MPa, and 95%, respectively, which meet the requirements of the wheel-disc application. The steel consists of 20% 3. μm polygonal ferrite and 80% bainite (granular bainite and a small amount of acicular ferrite) when subjected to a cooling rate of 30. °C/s and a coiling temperature of 430. °C. The yield strength, tensile strength, and hole-expansion ratio are 600. MPa, 655. MPa, and 66%, respectively, which meet the requirements of the wheel-rim application. Both the ferrite-pearlite steel and ferrite-bainite steel possess excellent bendability and Charpy impact property. The precipitation behavior and dislocation pattern are characterized and discussed. © 2013 Elsevier Ltd.
Ding W.,Wisdri Engineering and Research Incorporation Ltd
Advanced Materials Research | Year: 2012
Given that the traditional hot temper passing process cannot fulfill the demand of high strength steel on residual stress level and stable processability, leveler and temper passing process with dual servo valve (LTP-DSV) is developed to solve this technical problem. LTP-DSV process employs leveler to reduce residual stress level of high strength steel; uses dual servo valve variable gain rolling force control technology to improve performance stability of high strength steel; improves surface quality of high strength steel by means of temper passing. The residual stress level of products is substantially reduced on condition that the performance of high strength steel is ensured. The actual production data shows LTP-DS process is able to improve the performance and quality of high strength steel from all aspects. © (2012) Trans Tech Publications, Switzerland.
Liu G.,Shanxi University |
Li H.,WISDRI Engineering and Research Incorporation Ltd |
Feng X.,China University of Petroleum - Beijing |
Deng C.,China University of Petroleum - Beijing |
Chu K.H.,Shanxi University
Chemical Engineering Science | Year: 2013
For a hydrogen network with purification, it is postulated that different Purification Feed Flow Rates (PFFRs) will exert different effects on the hydrogen utility consumption. To optimize a hydrogen network with purification reuse, the effect of the PFFR on the hydrogen utility consumption should thus be analyzed systematically. However, no in-depth studies on this subject matter are available in the open literature. This work aims to bridge this research gap by establishing the relationship between the PFFR and the hydrogen utility consumption. According to the concepts of hydrogen surplus and pinch point, the characteristic of the pinch point is analyzed first, and it is found that the pinch point can only appear at the sink-tie-line which can intersect the source purity profile. Then, the quantitative relationship between the hydrogen utility adjustment and the hydrogen surplus is deduced, and a numerical method for identifying the pinch point and the minimum hydrogen utility consumption target is developed. Based on this, the quantitative relationship between the PFFR and the hydrogen surplus at each sink-tie-line is deduced. The upper bound of the PFFR can be identified from the hydrogen surplus variation diagram. The proposed numerical approach for targeting the hydrogen pinch problems and a systematic graphic method for identifying the limiting PFFR have the merit of being conceptually simple and easy to apply. Two cases are studied to illustrate the applicability of the proposed method. © 2012 Elsevier Ltd.
Fidan B.,University of Waterloo |
Gazi V.,Istanbul Kemerburgaz University |
Zhai S.,WISDRI Engineering and Research Incorporation Ltd. |
Cen N.,Ningbo Ulica Solar Science and Technology Company |
Karatas E.,Eti Makine Sanayi Ve Ticaret A. S.
IEEE Transactions on Industrial Electronics | Year: 2013
This paper presents a practical formation motion control scheme for robotic swarms based on single-view distance estimation, which is performed using a single nonsophisticated camera on each robot agent, and the prior information about the heights of the robots and other objects in the environment. Here, a nonsophisticated camera means one that has limited field of view and limited resolution. First, the vision mechanism is analyzed, and a single-view distance estimation scheme is designed. Then, a set of decentralized control laws, to be incorporated with distance estimation scheme, is introduced to move the robotic swarm in formation from an arbitrary initial position to an arbitrary final position without deforming the formation shape. The robots do not have any global positioning sensors, and they do not communicate with each other. The stability and performance of the overall system are analyzed mathematically. Later, practical issues are discussed regarding the proposed scheme, and the effects of delay and quantization in distance estimation are formally analyzed. Finally, we present experimental results demonstrating the performance of the proposed control scheme in real time. © 1982-2012 IEEE.
Huang K.,Wuhan University |
Wan J.W.,Wuhan University |
Chen C.X.,Wuhan University |
Mao D.F.,WISDRI Engineering and Research Incorporation Ltd |
Li Y.Q.,Chongqing Three Gorges University
Experimental Thermal and Fluid Science | Year: 2013
This paper experimentally investigated the effects of surface roughness on laminar flow in macro tubes (d=19 mm). Head drop experiments were conducted in six organic glass tubes with relative roughness (Δ/d) ranging from 1/118.75 to 1/6.66. Water head drop data were used to characterize the friction factor over a Reynolds number ranging from 300 to 25000. The experimental results for tubes with relative roughness (Δ/d< 5%) were in good agreement with Nikuradse' study. The friction factor could be well predicted by theoretical correlation fRe in laminar flow. Obvious deviation of the friction factor from the classical theory was observed for tubes with large relative roughness (Δ/d> 5%). The product of fRe was larger than 64 and increased with an increase in relative roughness. Earlier transition from laminar to turbulent flow was also confirmed. The critical Reynolds number linearly deceased as the relative roughness increased. © 2012 Elsevier Inc.
Liu G.,Xi'an Jiaotong University |
Li H.,WISDRI Engineering and Research Incorporation Ltd |
Feng X.,Xi'an Jiaotong University |
Deng C.,China University of Petroleum - Beijing
AIChE Journal | Year: 2013
The purification reuse/recycle is one effective resource conservation strategy. In this article, a novel conceptual method is proposed to identify the optimal purification feed flow rate (PFFR) and the corresponding maximum hydrogen utility savings (HUS) of the hydrogen network with purification reuse/recycle. In this method, the sources and sink-tie-lines are divided into three regions according to the purified product and purification feed. The quantitative relationship between the HUS and the PFFR is analyzed for the sink-tie-lines and sources of each region. With the quantitative relationship line between the HUS and the PFFR of each source plotted, the quantitative relationship diagram can be obtained and can be used to identify the pinch point and the HUS for a given PFFR. Furthermore, the optimal PFFR and the maximum HUS can be identified easily. Three cases are studied to illustrate the applicability of the proposed method. © 2012 American Institute of Chemical Engineers (AIChE).
Qin J.,WISDRI Engineering and Research Incorporation Ltd
Advances in Energy, Environment and Materials Science - Proceedings of the International Conference on Energy, Environment and Materials Science, EEMS 2015 | Year: 2016
The construction of population evacuation zones is the most important in the construction and its primary task is to select and determine where to construct the evacuation zones. In general, a population evacuation zone should be selected on the basis that it’s convenient to shelter and camouflage, easy to maneuver and denfence, and suitable for survival. How to select a population evacuation zone scientifically and appropriately is the primary problem to deal with. To address this issue, this essay lays special emphasis on the application of Analytic Hierarchy Process (AHP) in selecting a population evacuation zone with the theories of Science of Civil Air Defense. Besides, it takes Xinzhou District’s construction of population evacuation zone as a case to illustrate AHP’s practical application. © 2016 Taylor & Francis Group, London.
Chen X.-M.,Beijing Jiaotong University |
Liu Q.-X.,Beijing Jiaotong University |
Du G.,WISDRI Engineering and Research Incorporation Ltd
Jiaotong Yunshu Xitong Gongcheng Yu Xinxi/Journal of Transportation Systems Engineering and Information Technology | Year: 2011
Quantitative study on the travel costs of urban transit passengers has great significance for scientifically evaluating social benefits of public transportation system. Analysis of travel time values is one of the most important parts of traveler' s travel cost estimation. According to the stated preference (SP) survey data for Beijing residents, factors that influence public transport values of travel time are analyzed and a Logit-based model is used. An improved SP survey based model is proposed, in which traveler' s income is introduced as a variable. The parameters estimating the travel time values under the trip purposes of work/business and leisure are calibrated. Then the values of travel time under different conditions in Beijing are obtained (i.e. different trip purposes and with/without transferring). The results indicate that the travel time values for work are generally higher than those for leisure. The waiting time values are higher than transferring time values and in-vehicle time values under any circumstances, and the waiting time values are higher with transferring than those without transferring. ©2011 by Science Press.
Mu X.-F.,WISDRI Engineering and Research Incorporation Ltd
Wuhan Ligong Daxue Xuebao/Journal of Wuhan University of Technology | Year: 2010
Aiming at the deficiency of the local strength verification in the traditional design, the optimizing design of the lifting-hand is analyzed based on first-order optimizing arithmetic. At the same time, the analysis of the overall structure deformation of the full-hung tundish car is carried out by use of the finite element method. The results show that the overall strength of the lifting-hand and main frame meets the design requirements. Larger multiply stress of the lifting-hand exits in the leading arc part on the steel plate supported the tundish and the bottom of the steel plate supported the guide pulley. On the other hand, larger multiply stress of the main frame occurs in the leading arc parts which are used to connect the main frame with the driving wheels. Therefore, local strength of these positions should be adapted to strengthen during the course of the practical design.
Ding W.,WISDRI Engineering and Research Incorporation Ltd
Advanced Materials Research | Year: 2012
In order to enhancing strip flatness in temper mill, in this paper, stress state, micro structure characteristics of contact surface, energy characteristics, dislocation intensity were analyzed. Plastic deformation characteristics of metal during tempering process have been come to a conclusion. Two mechanisms, friction mechanism and elongation rate mechanism, are proposed for enhancing strip flatness during tempering process. On the basis of these mechanisms, strip flatness control strategies suitable for tempering of ordinary cold rolled products, cold rolled deep-draw products, hot rolled products and hot rolled high strength steel products are discussed, and proper equipment configuration is proposed.