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Peng Y.,Hunan University | Peng Y.,University of Strasbourg | Peng Y.,State Key Laboratory of Vehicle NVH and Safety Technology | Chen Y.,Hunan University | And 4 more authors.
Safety Science | Year: 2012

The objective was to assess head injury risks and kinematics of adult pedestrians and bicyclists in primary impact to the passenger cars and secondary impact to the ground using real world accident data and computer reconstructions of the accidents. For this purpose, a subsample of 402 pedestrians and 940 bicyclists from the GIDAS database, Germany, was used for the statistical analysis, from which 22 pedestrian and 18 bicyclist accidents were further selected for reconstruction. PC-Crash was used to calculate impact conditions, such as vehicle impact velocity, vehicle kinematic sequence, and thrown distance. These conditions were employed to identify the initial conditions in reconstruction in MADYMO program. A comparable analysis was conducted based on the results from accident analysis and computer reconstructions for the impact configurations and the resulting injury patterns of pedestrians and bicyclists in view of head injury risks. Differences in HIC, head-relative impact velocity, linear acceleration, maximum angular velocity and acceleration, contact force, thrown distance, Wrap Around Distance (WAD), and head contact time were evaluated. Injury risk curves were generated by using a logistic regression model for vehicle impact velocity. The results indicate that bicyclists suffered less severe injuries compared with severity of pedestrian injuries. In the selected samples, the AIS 2+ and AIS 3+ head injury risks for pedestrians are 50% probability at impact speed of 38.87. km/h and 54.39. km/h respectively, while for bicyclists at 53.66. km/h and 58.89. km/h respectively. The findings of high injury risks suggested that in the area with high frequency car-pedestrian accidents, the vehicle speed limit should be 40. km/h, while in the area with high frequency car-cyclist accidents the vehicle speed limit should be 50. km/h. © 2012 Elsevier Ltd.

Gao Z.,Jilin University | Gao Z.,State Key Laboratory of Vehicle NVH and Safety Technology | Zhao Y.,Jilin University
Procedia Engineering | Year: 2011

One of the critical logic deployment challenges faced by intelligent airbag system is whether the system can accurately determine the type of the occupant sitting in different postures. The main objective of this paper is the application of seat pressure sensors to predict the occupant classification, such as 5th percentile adult female and 50th percentile adult male and 95th percentile adult male. In the experiments, the occupants are recruited to sit in specified postures. During sitting, the pressure data of the occupants are measured. After that, T-S fuzzy model is introduced to investigate the highly nonlinear relationship between the pressure and the weight of the occupant. Finally, the system uses the weight information to determine the type of the occupant. Since the good validity and accuracy of the weight calculated by the T-S fuzzy model are shown in the experiments, the proposed algorithm can effectively identify the type of the occupant. © 2011 Published by Elsevier Ltd.

Hu P.,Dalian University of Technology | Hu P.,State Key Laboratory of Vehicle NVH and Safety Technology | Han X.,Dalian University of Technology | Li W.D.,Dalian University of Technology | And 3 more authors.
International Journal of Adhesion and Adhesives | Year: 2013

Adhesive bonding technique is widely studied and adopted in automotive industry in recent years, which leads to satisfactory joint mechanical properties and lightweight effects. In this study, the static mechanical performance of adhesively bonded joints after different temperature exposures was investigated through joint quasi-static shear-strength test. A response surface method using MATLAB programming was utilised to analyse the influences of exposure temperature and adhesive mechanical attributes on joint static strength. Visual inspection and scanning electron microscopy were later performed on the fracture surfaces to explain the failure mechanisms. Test results showed that long-term temperature exposure caused degradation in joint strength and failure displacement. It was found through response surface curve that comparing to higher temperature exposure, lower temperature causes greater and faster environmental degradation. Different types of fracture surfaces in the overlap zone were also detected through comparing adhesive joints under different environmental treatments. © 2012 Elsevier Ltd. All rights reserved.

Chen S.M.,Jilin University | Wang D.F.,Jilin University | Zan J.M.,State Key Laboratory of Vehicle NVH and Safety Technology
Mathematical Problems in Engineering | Year: 2011

In order to predict the interior noise of the automobile in the low and middle frequency band in the design and development stage, the hybrid FE-SEA model of an automobile was created using hybrid FE-SEA method. The modal density was calculated using analytical method and finite element method; the damping loss factors of the structural and acoustic cavity subsystems were also calculated with analytical method; the coupling loss factors between structure and structure, structure and acoustic cavity were both calculated. Four different kinds of excitations including road excitations, engine mount excitations, sound radiation excitations of the engine, and wind excitations are exerted on the body of automobile when the automobile is running on the road. All the excitations were calculated using virtual prototype technology, computational fluid dynamics (CFD), and experiments realized in the design and development stage. The interior noise of the automobile was predicted and verified at speed of 120km/h. The predicted and tested overall SPLs of the interior noise were 73.79 and 74.44dB(A) respectively. The comparison results also show that the prediction precision is satisfied, and the effectiveness and reliability of the hybrid FE-SEA model of the automobile is verified. © 2011 S. M. Chen et al.

Chen T.,State Key Laboratory of Vehicle NVH and Safety Technology | Peng Y.,Hunan University
Applied Mechanics and Materials | Year: 2014

In the concept design phase of new car development, the parametric simplified side impact model was established by implicit parametric technology. The design parameters of BIW were optimized based on simplified model, such as the shape of section and the thickness of parts. The side impact safety performance and lightweight requirements were set as restraints during optimizing. The case indicated that the intrusion and intrusive velocity of B-pillar were reduced more than 30% and the mass was reduced 5.6% by this method. © (2014) Trans Tech Publications, Switzerland.

Hu P.,Dalian University of Technology | Hu P.,State Key Laboratory of Vehicle NVH and Safety Technology | Han X.,Dalian University of Technology | Da Silva L.F.M.,University of Porto | And 2 more authors.
International Journal of Adhesion and Adhesives | Year: 2013

Structural adhesives are being widely adopted in aerospace and automobile industries. However, in many cases, hostile environments cause non-ignorable degradation in joints mechanical performance. In this work, a combined experimental-numerical approach was developed to characterise the effect of cyclic-temperature environment on adhesively bonded joints. The environmental degradation factor, Deg, was introduced into a cohesive zone model to evaluate the degradation process in the adhesive layer caused by the cyclic-temperature environment and the stress states in adhesive layer before and after temperature exposure treatment were investigated. Carefully designed experimental tests were carried out to validate the simulation results and help the numerical procedure to predict joint mechanical behaviour after environmental exposure. A response surface method was utilised to provide a better visualisation on the relationship between selected factors and response. Finally, the scanning electron microscopy was carried out to investigate the micro fracture mechanisms of adhesively bonded joints. © 2012 Elsevier Ltd. All rights reserved.

Du Y.,State Key Laboratory of Vehicle NVH and Safety Technology | Du Y.,Dalian University of Technology | Zhang J.,State Key Laboratory of Vehicle NVH and Safety Technology
Noise Control Engineering Journal | Year: 2012

As an effort to reduce energy consumption and hazardous emissions, lightweight design has become more and more important in new vehicle developments. In structural design, substituting conventional steel material with alternative low-density materials is one typical approach for weight reduction. However, the material and weight change often lead to variations in the dynamic characteristics of the structure such as its noise, vibration and harshness (NVH) performance. Based on a structural-acoustic coupled model of a rectangular cavity consisting of 1 or 2 flexible panels, this paper presents detailed parametric studies aiming at reducing the total weight of the structure and simultaneously improving the NVH performance. For the case of a single flexible panel subject to a point force excitation, it is found that substituting the heavier steel panel with a lighter aluminum panel may actually reduce the sound radiation inside the cavity, especially in the low frequency range. On the other hand, at higher frequencies, the radiated noise level seems to be roughly inversely proportional to the material density, making the lightweight design goal difficult to reach without sacrificing the NVH performance. For the case with dual flexible panels, it is shown that the two panels are generally weakly coupled through the acoustic cavity. Thus, their lightweight designs may be treated separately under a geometrically symmetrical load condition, or considered independent of the NVH criterion for the panel that is free of external excitation. However, for the latter case, within certain narrow frequency ranges where the modes from the two panels are sufficiently close and are also coupled well with the nearby acoustic mode, the cavity interior noise level may still be reduced significantly with a proper lightweight design of the panel. © 2012 Institute of Noise Control Engineering.

Gao Y.-K.,Tongji University | Feng H.-X.,Tongji University | Ma F.-W.,Zhejiang Geely Automobile Institute Co. | Yang L.,Changan Auto Global R and nter | Yang L.,State Key Laboratory of Vehicle NVH and Safety Technology
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2013

Modal frequencies and modal shapes of a BIW (body-in-white) reflect the inherent characteristics of an automotive body. They have an important influence on the interior noise. The car cavity also has modal frequencies and modal shapes. Acoustic modal test of a car cavity for a domestic SUV was performed with LMS data acquisition system. Firstly, the response points' signals were gained with a microphone array, and then the acoustic modal frequencies and modal shapes were extracted with PolyMAX method. The comparison between the acoustic modal frequencies and the test modal frequencies of the BIW showed that the first and the second acoustic modes of the car cavity are strongly coupled with the fourth and the tenth structural modes of the BIW. Finally, acoustic-structure coulpled resonance was verified through tests during the vehicle running. It was indicated that there are several ways to change the local modes of the automotive structure, such as, increasing the thickness of the key components, adding damping layer in the roof and floor, and strengthening the roof with ribs and so on; these actions can destroy the strong coupling between the modes of the BIW and the acoustic modes of the car cavity, decrease the lower frequency boom in the automotive.

Zhuang T.,Jiangsu University | Zuo Y.Y.,Jiangsu University | Zuo Y.Y.,State Key Laboratory of Vehicle NVH and Safety Technology
Applied Mechanics and Materials | Year: 2014

This experiment collected sound signals of four different cars driving at different speeds on highway and replayed the noise samples with playback software HEAD Audio Recorder. The subjective evaluation tests were carried out with paired comparison method. Evaluating models between subjective evaluation and objective psychoacoustic parameters were established with SPSS analysis software. © (2014) Trans Tech Publications, Switzerland.

Zhang H.,State Key Laboratory of Vehicle NVH and Safety Technology | Zhang H.,Chongqing University | Xu H.,Chongqing University | Liao C.,Chongqing University | Deng Z.,State Key Laboratory of Vehicle NVH and Safety Technology
Applied Mechanics and Materials | Year: 2012

Dynamic response is a key parameter for the engineering applications of MR damper. However, the response time has many different definitions, and which leads to a confusion of the measurement. Commonly, the response of MR damper in the new-designed status is focused, the instance after long-time use or standing-still has not been proposed. In this paper, the influence on the response time by the long-time standing-still is investigated, which shows that the response is largely lengthened. Next step, the measurement will be optimized, and the response of MR damper after long-time use will be in consideration. © (2012) Trans Tech Publications.

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