成功在坚守目标中延续

<正>最高品质客户满意技术领导力在过去的四十年里,中国的生产总值保持着每八年增长一倍的速度向前推进。巨大的发展使中国一跃成为世界第二大经济体、世界最大的制造业国、世界最大的商品交易国、世界第二大消费者市场、世界第二大外国直接投资目的地。然而,2018年,中国的生产总值增长率"只有"6.6%,创下了近年来的最低,但我认为这正是经济增长平稳放缓的结果。相比以前的高增长率,"6.6%"确实略显偏     

成功,在坚守目标中延续

<正>在过去的四十年里,中国的生产总值保持着每八年增长一倍的速度向前推进。巨大的发展使中国一跃成为世界第二大经济体、世界最大的制造业国、世界最大的商品交易国、世界第二大消费者市场、世界第二大外国直接投资目的地。然而,2018年,中国的生产总值增长率"只有"6.6%,创下了近年来的最低,但我认为这正是经济增长平稳放缓的结果。相比以前的高增长率,"6.6%"确实略显偏低,但这其实已经是许多国家梦寐以求的数字,是德国今年设想增长率的     

Vehicle-Track Dynamics in the Mid-Frequency Range

During the last years railway companies have observed increasing problems with track damage like rail corrugation, deterioration of ballast or unround wheels. Since the origin of these damages is suspected in the mid-frequency dynamics, research activities in the frequency range from 50 up to 500 Hz have been initiated. The article demonstrates that in comparison to the low and high frequency range the knowledge about physical effects in the mid-frequency range is poor. Apart from a historical literature review on vehicle and track modelling, recently published methods and models are collated and problems in their mathematical treatise are mentioned. Regarding the vehicle, the paper shows the development starting with Klingel's massless wheelset model and ending with sophisticated elastic multibody system models. Concerning the track, different mathematical approaches in frequency and time domain are compared. In the mid-frequency range the pad, ballast and subsoil properties play an important role. Hence, the missing of experimentally validated models of these components is crucial. First attempts have been performed, which take into account the subsoil as layered half-space and the ballast as an assembly of viscoelastic rods. Besides the short time dynamics the article gives also an overview of the modelling of the wear phenomena mentioned above. An investigation of such long-term effects requires complex models of the entire vehicle-track system. The few wear models found in literature are discussed and first results are mentioned.     

成功,在坚守目标中延续

<正>在过去的40年里,中国的生产总值保持着每8年增长1倍的速度向前推进。巨大的发展使中国一跃成为世界第二大经济体、世界最大的制造业国、世界最大的商品交易国、世界第二大消费者市场、世界第二大外国直接投资目的地。然而,2018年,中国的生产总值增长率只有6.6%,创下了近年来的最低,但我认为这正是经济增长平稳放缓的结果。相比以前的高增长率,"6.6%"确实略显偏低,但这其实已经是许多国家梦寐以求的数字,是德国今年设想增长率的10倍。