Time filter

Source Type


Teng S.,Changchun University | Shi W.K.,Changchun University | Jun K.,Changchun University | Zhang Y.J.,NAC Automotive Research Institute | Liu T.F.,NAVECO Ltd.
Applied Mechanics and Materials | Year: 2014

Floor vibration model was established by FEM and the modal analysis was conducted, which were based on the condition that this experiment took the automobile floor as the research object and applied the basic theory of finite element analysis. Simultaneously the results of modal analysis were compared with the results of the experiment, verifying the accuracy of the model. This can be considered as a basis of providing reference for the optimization and improvement of light bus floor. © (2014) Trans Tech Publications, Switzerland. Source

Wang T.,Nanjing University of Science and Technology | Wang L.,Nanjing University of Science and Technology | Wang Y.,Nanjing University of Science and Technology | Zou X.,NAVECO Ltd. | Guo F.,NAVECO Ltd.
SAE Technical Papers | Year: 2015

The design of aluminum foam reinforced thin-walled tubes has garnered much interest recently due to the high energy absorption capacity of these tubes. As a new kind of engineering composite material, aluminum foam can hugely increase the crashworthiness capacity without sacrificing too much weight. In this paper, axisymmetric thin-walled hollow tubes with four different kinds of cross-sections (circular, square, hexagonal and octagonal) are studied to assess their performance for crashworthiness problems. It is found that the tube with square cross-section has the best crashworthiness performance under axial impact. To seek optimal designs of square aluminum foam reinforced thin-walled tubes, a surrogate modeling technique coupled with a multi-criteria particle swarm optimization algorithm has been developed, to maximize specific energy absorption (SEA) and minimize peak crash force (PCF). To improve the accuracy of the optimization process, meta-models of SEA and PCF were constructed using the response surface method and radial basis function method, respectively. Crash simulations carried out using LS-DYNA demonstrate that the optimal design has better crashworthiness characteristics than the baseline design. These results suggest that the proposed method can be of benefit in design optimization for other crashworthiness problems. Copyright © 2015 SAE International. Source

Ju Q.,Hohai University | Hao Z.-C.,Hohai University | Yu Z.-B.,Hohai University | Xu H.-Q.,China Institute of Water Resources and Hydropower Research | And 2 more authors.
Shuikexue Jinzhan/Advances in Water Science | Year: 2011

The performance of twenty-two General Circulation Models (GCMs) in simulating precipitation and temperature are evaluated and validated in the Yangtze River basin. Simulations of these GCMs were used in the IPCC Fourth Assessment Report (AR4). The Bjerknes Center for Climate Research (BCCR) Bergen Climate Model (BCM) 2.0, or BCCR_BCM2.0, and other six GCMs stand out from the twenty-two evaluated GCMs. Using an artificial neural network and climate change projections from the selected seven GCMs under A1B, A2 and B1 scenarios, the hydrological response to future climate change in the Yangtze River basin is studied. The projective on the subject is presented. The result shows that there could be a decreasing trend in the mean annual streamflow in the future. At the Yichang station, a dry year condition would be likely to become more common in a warmer world. The reduction of mean annual streamflow could reach as much as 520 m 3/s for dry years, while such a reduction would be 250 m 3/s for a normal year at the Datong station. The decrease in available water could be a big challenge to the practice of water allocation and management in the western and central routes of the South-to-North Diversion project. The mean monthly streamflow would be projected to be increasing during January to June, while, the opposite should be true during the second half of the year. At Yichang and Datong, the streamflow increases would be 29.6% and 13.8% during January to June and decreases could reach as much as -18.2% and -11% during the second half of the year, respectively. The variation of streamflow could be expected to be larger at Yichang than at Datong. During flooding seasons, there would be a decrease of -8.5% in Yichang streamflow, and a slight increase for other reasons. In contrast, the Datong streamflow would have a 2.3% increase during flooding seasons, and a slight decrease in non-flooding seasons. Source

Hao Z.-C.,Hohai University | Ju Q.,Hohai University | Wang L.,Technical University of Delft | Wang H.-M.,Hohai University | Jiang W.-J.,NAVECO Ltd.
Shuikexue Jinzhan/Advances in Water Science | Year: 2011

Predictions of extreme floods from 2010-2099 are made for the Huaihe River Basin using the projected future temperature and precipitation from 22 global climate models under A1B, A2 and B1 emission scenarios in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) and the Xin'anjiang monthly distributed hydrological model. The model is calibrated and validated with the satisfied results. The ensemble method is applied in the model prediction. The result shows that the A2 scenario would most likely result in a highest number of extreme flood events, and then followed by the A1B scenario and the B1 scenario, respectively. Under A1B, there would be an increased possibility of extreme flooding in the latter half of the 21st century; while for the A2 scenario, the extreme floods could be concentrated on the period 2035-2065 as well as after 2085. Under B1, the frequent extreme floods would most likely occur around 2070s. By integrating the diverse definitions of extreme events, we classify the extreme events into three groups based on the flood magnitudes. In the first magnitude group, the extreme flood events predicted under the A2 scenario would be the most with the largest average flood volume; while those under B1 would be the least with the minimum value of flood magnitude in the third group. There could be an increased occurrence of the extreme flood events in the first magnitude group among all three scenarios. The highest increase might be found under the A2 scenario and followed by A1B and B1. The proportion of extreme flood events in each of the three magnitude groups would also vary under different scenarios. The extreme flood events of the second magnitude group could be more frequently encountered under A1B and A2; while B1 could result in more third group extreme flooding. Nevertheless, there would only a small proportion of extreme flood events with the flood magnitude exceeding the great flood of 1954 in the first magnitude group. Source

Hao Z.,Hohai University | Ju Q.,Hohai University | Jiang W.,NAVECO Ltd. | Zhu C.,Hebei University of Engineering
The Scientific World Journal | Year: 2013

The Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC AR4) presents twenty-two global climate models (GCMs). In this paper, we evaluate the ability of 22 GCMs to reproduce temperature and precipitation over the Tibetan Plateau by comparing with ground observations for 1961 1900. The results suggest that all the GCMs underestimate surface air temperature and most models overestimate precipitation in most regions on the Tibetan Plateau. Only a few models (each 5 models for precipitation and temperature) appear roughly consistent with the observations in annual temperature and precipitation variations. Comparatively, GFCM21 and CGMR are able to better reproduce the observed annual temperature and precipitation variability over the Tibetan Plateau. Although the scenarios predicted by the GCMs vary greatly, all the models predict consistently increasing trends in temperature and precipitation in most regions in the Tibetan Plateau in the next 90 years. The results suggest that the temperature and precipitation will both increase in all three periods under different scenarios, with scenario A1 increasing the most and scenario A1B increasing the least. © 2013 Zhenchun Hao et al. Source

Discover hidden collaborations