Experimental study on the effectiveness of TLDs under wave loading     

Dong Sheng  Li Huajun  Lu Ming  Tomotsuka Takayama 《中国海洋大学学报(英文版)》2002,1(1):80-86

The objective of this study is to experimentally investigate the effectiveness of Tuned Liquid Dampers (TLDs) for suppressing the dynamic response of a platform structure subjected to wave loading and to explore the applicability of TLDs for suppressing the structural vibration of fixed offshore platforms. The experimental model is scaled according to a full size platform by matching its dynamic properties. Rectangular and circular TLDs of various sizes and water depths are examined.The experiments were performed in a 2-D wave flume. The effectiveness of TLDs is evaluated based on their response reduction. By observing the performance and the behavior of TLDs through laboratory experiments, the effects of a number of parameters including container shape, container size, number of dampers, frequency ratio, mass ratio, and incident wave characteristics are investigated.  相似文献   

基于GPS基线向量计算机场跑道真方位角     

朱晓江 《全球定位系统》2014,39(4):91-93

本文介绍了GPS相对静态定位测量结合站心地平直角坐标系计算跑道真方位角的方法,通过坐标方位角加上改正值计算真方位角的方法进行验证,结合工程实例对该方法进行验证。该方法计算过程简单,可靠性好,省时省力。  相似文献   

On the potential of Bartlett Lewis rectangular pulse models for simulating rainfall in Peninsular Malaysia     

Ibrahim Suliman Hanaish  Kamarulzaman Ibrahim  Abdul Aziz Jemain 《水文科学杂志》2013,58(8):1690-1703

Abstract

The applicability of two versions of the Bartlett Lewis rectangular pulse model, the original and the modified model, is discussed for describing the temporal and spatial variation of rainfall patterns observed at 15 raingauge stations in Peninsular Malaysia over the period 1971–2008; 17 different sets of moment combinations are fitted to these models based on the generalized method of moments approach. The common statistics included in all sets are the mean, variance, lag-1 autocorrelation and the probability of dry based on the hourly rainfall data. The analysis was carried out on hourly rainfall data from all 15 stations for all months of the year. Two stations, Petaling Jaya and Kemaman, located on the west and east coasts of the Peninsula, respectively, are considered for illustration of the results, taking the months of July and November, which correspond to the driest and wettest months, corresponding to the southwest monsoon (May–August) and northeast monsoon (November–February), respectively. The best moment combination found for the illustrative results is based on the common statistics, as well as the mean and variance based on 24-h aggregated rainfall data, the inclusion of which successfully improved the model performance; the errors were significantly reduced. It was also found that the performance of the fitted models based on the mean absolute deviate error varies according to the type of Bartlett Lewis model applied: errors are much smaller for the fitted model based on the modified model as compared to the original model. In addition, the fitted statistics: mean, lag-1 autocorrelation and probability of dry are quite well fitted for several aggregated time scales; however, the variances are underestimated in both models for all aggregated time scales, particularly in the case of the original model. The results of extreme value analysis indicate that the modified model failed to reproduce the annual hourly and daily rainfall extremes satisfactorily.