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| 1 | Mechanical Properties Prediction of the Mechanical Clinching Joints Based on Genetic Algorithm and BP Neural Network显示文摘For optimal design of mechanical clinching steel-aluminum joints, the back propagation(BP) neural network is used to research the mapping relationship between joining technique parameters including sheet thickness, sheet hardness, joint bottom diameter etc., and mechanical properties of shearing and peeling in order to investigate joining technology between various material plates in the steel-aluminum hybrid structure car body.Genetic algorithm(GA) is adopted to optimize the back-propagation neural network connection weights.The training and validating samples are made by the BTM? Tog-L-Loc system with different technologic parameters.The training samples' parameters and the corresponding joints' mechanical properties are supplied to the artificial neural network(ANN) for training.The validating samples' experimental data is used for checking up the prediction outputs.The calculation results show that GA can improve the model's prediction precision and generalization ability of BP neural network.The comparative analysis between the experimental data and the prediction outputs shows that ANN prediction models after training can effectively predict the mechanical properties of mechanical clinching joints and prove the feasibility and reliability of the intelligent neural networks system when used in the mechanical properties prediction of mechanical clinching joints.The prediction results can be used for a reference in the design of mechanical clinching steel-aluminum joints. | LONG Jiangqi LAN Fengchong CHEN Jiqing YU Ping | 2009 | Chinese Journal of Mechanical Engineering2009,22,1: | 22 |
| 2 | Experimental Study on Occupant's Thermal Responses under the Non-uniform Conditions in Vehicle Cabin during the Heating Period显示文摘The existing investigations on thermal comfort mostly focus on the thermal environment conditions, especially of the air-flow field and the temperature distributions in vehicle cabin. Less attention appears to direct to the thermal comfort or thermal sensation of occupants, even to the relationship between thermal conditions and thermal sensation. In this paper, a series of experiments were designed and conducted for understanding the non-uniform conditions and the occupant's thermal responses in vehicle cabin during the heating period. To accurately assess the transient temperature distribution in cabin in common daily condition, the air temperature at a number of positions is measured in a full size vehicle cabin under natural winter environment in South China by using a discrete thermocouples network. The occupant body is divided into nine segments, the skin temperature at each segment and the occupant's local thermal sensation at the head, body, upper limb and lower limb are monitored continuously. The skin temperature is observed by using a discrete thermocouples network, and the local thermal sensation is evaluated by using a seven-point thermal comfort survey questionnaire proposed by American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc(ASHRAE) Standard. The relationship between the skin temperature and the thermal sensation is discussed and regressed by statistics method. The results show that the interior air temperature is highly non-uniform over the vehicle cabin. The locations where the occupants sit have a significant effect on the occupant's thermal responses, including the skin temperature and the thermal sensation. The skin temperature and thermal sensation are quite different between body segments due to the effect of non-uniform conditions, clothing resistance, and the human thermal regulating system. A quantitative relationship between the thermal sensation and the skin temperature at each body segment of occupant in real life traffic is presented. The investigation result indicates that the skin temperature is a robust index to evaluate the thermal sensation. Applying the skin temperature to designing and controlling parameters of the heating, ventilation and air conditioning(HVAC) system may benefit the thermal comfort and reducing energy consumption. | ZHANG Wencan CHEN Jiqing LAN Fengchong | 2014 | Chinese Journal of Mechanical Engineering2014,27,2: | 8 |
| 3 | Control Algorithm of Electric Vehicle in Coasting Mode Based on Driving Feeling显示文摘Coasting in gear is a common driving mode for the conventional vehicle equipped with the internal combustion engine(ICE), and the assistant braking function of ICE is utilized to decelerate the vehicle in this mode. However, the electric vehicle(EV) does not have this feature in the coasting mode due to the relatively small inertia of the driving motor, so it will cause the driver cannot obtain the similar driving feeling to that of the conventional vehicle, and even a traffic accident may occur if the driver cannot immediately adapt to the changes. In this paper, the coasting control for EV is researched based on the driving feeling. A conventional vehicle equipped with continuously variable transmission(CVT) is taken as the reference vehicle, and the combined simulation model of EV is established based on AVL CRUISE and MATLAB/Simulink. The torque characteristic of the CVT output shaft is measured in coasting mode, and the data are smoothed and fitted to a polynomial curve. For the EV in coasting mode, if the state of charge(SOC) of the battery is below 95%, the polynomial curve is used as the control target for the torque characteristic of the driving motor, otherwise, the required torque is replaced by hydraulic braking torque to keep the same deceleration. The co-simulation of Matlab/Simulink/Stateflow and AVL CRUISE, as well as the hardware-in-loop experiment combined with d SPACE are carried out to verify the effectiveness and the real-time performance of the control algorithm. The results show that the EV with coasting braking control system has similar driving feeling to that of the reference vehicle, meanwhile, the battery SOC can be increased by 0.036% and 0.021% in the initial speed of 100 km/h and 50 km/h, respectively. The proposed control algorithm for EV is beneficial to improve the driving feeling in coasting mode, and it also makes the EV has the assistant braking function. | SUN Daxu LAN Fengchong ZHOU Yunjiao CHEN Jiqing | 2015 | Chinese Journal of Mechanical Engineering2015,28,3: | 5 |
| 4 | Effect of angiotensin converting enzyme inhibitor on the calcium transients and calcium handling proteins in ventricular myocytes from rats with heart failure显示文摘Background Chronic heart failure (CHF) is associated with calcium transients and calcium handling proteins. Angiotensin converting enzyme (ACE) inhibitor has been demonstrated to have beneficial effect on CHF. Yet studies addressed to the relationship between ACE inhibitor and calcium transients in CHF are rare. The aim of this study was to investigate the influence of ACE inhibitor (perindopril) on the contractility and calcium transients and calcium handling proteins in ventricular myocytes from rats with experimental heart failure.Methods Male Wistar rats were randomized to heart failure group treated with perindopril (CHF-T, 3 mg·kg -1 ·d -1 ), heart failure group without treatment (CHF-C) and sham-operated group (PS). Heart failure was induced by abdominal aortic constriction. All groups were further followed up for 12 weeks. Left ventricular myocytes were then isolated. Single cell shortening fraction and [Ca 2+ ]i were simultaneously measured by laser scanning confocal microscope under the field stimulation (1.0 Hz). Reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blot were performed to evaluate the changes of mRNA and protein of Na +-Ca 2+ exchanger (NCX1), sarcoplasmic reticulum Ca 2+ -ATPase (SERCA2) and phospholamban (PLB).Results The fraction of cell shortening (FS%) and [Ca 2+ ] imax (nmol/L) were significantly reduced in group CHF-C compared with group PS (FS%: 7.51±1.15 vs 13.21±1.49;[Ca 2+ ] imax :330.85±50.05 vs 498.16±14.07; both P <0.01), and restored at least partially in CHF-T group. In CHF-C group, the left ventricular mRNA of NCX1 and PLB were significantly upregulated in comparing with PS group (R NCX1/β-Actin : 0.51±0.12 vs 0.19±0.06, P <0.01; R PLB/β-Actin : 0.26±0.12 vs 0.20±0.08, P <0.05), while SERCA2 mRNA was downregulated (0.48±0.10 vs 0.80±0.11, P <0.01). The mRNA levels of NCX1 and SERCA2 in CHF-T group were between the CHF-C and PS group, and the differences of the latter two groups were significant (all P <0.05). In CHF-C and CHF-T groups, the protein expression of NCX1 were 1.141±0.047 and 1.074±0.081 times of that in PS group respectively (both P <0.05), and SERCA2 protein levels were 0.803±0.100 and 0.893±0.084 times of that in PS group respectively (both P <0.05). The protein expression of NCX1 and SERCA2 in the CHF-C and CHF-T groups is significantly different (both P <0.05).ConclusionACE inhibitor could improve cardiac function of failing heart through directly enhancing the contractility of single cardiomyocyte, and these effects are probably mediated by its roles in preventing the deleterious changes of calcium transients and calcium handling proteins in CHF. | WANGLi-chun MAHong HEJian-gui LIAOXin-xue CHENWen-fang LENGXiu-yu MALi MAIWei-yi TAOJun ZENGWu-tao LIUJun DONGYu-gang TANGAn-li FENGChong | 2005 | Chinese Medical Journal2005,,9: | 2 |
| 5 | Crashworthiness research on S-shaped front rails made of steel–aluminum hybrid materials显示文摘 | Yunjiao Zhou Fengchong Lan Jiqing Chen | 2010 | Thin-Walled Structures2010,,2: | 1 |
| 6 | Numerical study on the influence of superstructure configuration on coach roll- over resistance performance 显示文摘 | Li Yi Lan Fengchong Chen Jiqing | 2012 | International Journal of Crashworthiness2012,17,6: | 1 |
| 7 | Investigation into Improvement for Anti-Rollover Propensity of SUV显示文摘Currently, many research from domestic and foreign on improving anti-rollover performance of vehicle mainly focus on the electronic control of auxiliary equipment, do not make full use of suspension layout to optimize anti-rollover performance of vehicle. This investigation into anti-rollover propensity improvement concentrates on the vehicle parameters greatly influencing on anti-rollover propensity of vehicle. A simulation based on fishhook procedure is used to perform design trials and evaluations aimed at ensuring an optimal balance between vehicle's design parameters and various engineering capacities, the anti-rollover propensity is optimized at the detailed design stage of a new SUV model. Firstly a four-DOF theoretical kinematic model is established, then a complete multi-body dynamics model built in ADAMS/car based on the whole vehicle parameters is correlated to the objective handing and stability test results of a mule car. Secondly, in fishhook test simulations, the Design of Experiments method is used to quantify the effect of the vehicle parameters on the anti-rollover performance. By means of the simulation, the roll center height of front suspension should be more than 30 mm, that of rear suspension less than 150 mm, and the HCG less than 620 mm for the SUV. The ratio of front to rear suspension roll stiffness should be ranged from 1.4 to 1.6 for the SUV. As a result, at the detailed design stage of product, the anti-rollover performance of vehicle can be improved by optimizing chassis and integrated vehicle parameters. | Fei Xiong Fengchong Lan Jiqing Chen Yuedong Yang | 2017 | Chinese Journal of Mechanical Engineering2017,30,3: | 0 |
| 8 | Uncertainty Optimization Design of a Vehicle Body Structure Considering Random Deviations显示文摘In vehicle body manufacturing,there are small differences between the actual value and design value of,for example,plate thickness and material characteristics.This is caused by the processing technology,environment and other uncertain factors.Therefore,the performance of the vehicle body processed according to the deterministic optimization solution fluctuates.The fluctuations may make structural performance fail to meet the design requirements.Thus,in this study,an optimization design is executed with 6σrobustness criteria and a Monte Carlo simulation single-loop optimization strategy based on the radial basis function neural network approximate model considering deviations in plate thickness,elastic modulus,and welding spot diameter,which is called the uncertainty optimization design method.As an example,considering the bending stiffness,torsion stiffness,and first-order frequency as constraints,the method is applied to the lightweight design of a car body structure,and the reliability of deterministic optimization design and uncertainty optimization design is compared.The results demonstrate that the uncertainty optimization design solution is effective and feasible without lowering the static stiffness and modal performance,and the weight is reduced. | Jianhua Zhou Fengchong Lan Jiqing Chen Fanjie Lai | 2018 | Automotive Innovation2018,1,4: | 0 |
| 9 | Vibration Characteristics of Framed SUV Cab Based on Coupled Transfer Path Analysis显示文摘The vibration transmission paths in a sport-utility vehicle with a frame structure were used to evaluate the coupled vibra-tion of each vibration transmission link.This method was based on the transmission path of an“engine-powertrain mount system-frame-vehicle body suspension-body-driver seat rail,”and the research objective was to improve the vibration char-acteristics of the cab.This coupled transfer path analysis combined analysis and experiment to establish the vehicle vibration transmission path model and a finite element simulation model.With this method,the vibration level of the driver’s seat rail was reduced and engineering practice was effectively used to improve the vibration characteristics of the cab.This method was applied to a framed SUV cabin. | Wei Yang Jiqing Chen Zongjian Liu Fengchong Lan | 2019 | Automotive Innovation2019,2,1: | 0 |