Experimental Study on Passenger Movement Pattern Considering the Effect of Ship Heeling and Trim

船體傾斜狀態下船載人員運動特徵研究

Student thesis: Doctoral Thesis

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Author(s)

Detail(s)

Awarding Institution
Supervisors/Advisors
  • Siu Ming LO (Supervisor)
  • Shouxiang Lu (External person) (External Supervisor)
Award date31 Aug 2018

Abstract

As one of the most popular means for marine transportation and tourism, large passenger ship, especially the luxury cruise, gains far more attention from all walks of life over the past few years. Although the possibility for the occurrence of serious accidents is rather low, the consequences would be quite destructive. In such a catastrophe, an efficient evacuation might be the only promising means to minimize its consequence. While considering the particularities of evacuation in large passenger ships compared with the evacuation in buildings on land, the evacuation analysis for large passenger ships exhibits certain limitation in that the practical scenarios of rolling, pitching and listing have not been taken into account in model design.

To investigate the movement pattern of passengers considering the effect of ship heeling and trim, the experimental and theoretical studies on individual walking speed, individual spatiotemporal step characteristics, as well as single file moving characteristics, influenced by the heeling and trim angles were performed. The principle focus areas of this study are as follows:

(1) A ship corridor simulator with a size of 10.0m (L) ×1.8m (W) ×2.2m (H) was developed, which could simulate the ship corridor environment in heeling conditions, trim conditions and the combination of both by hydraulic device, so as to provide the ship heeling and trim environments for the experiments in this thesis.

(2) To investigate the individual walking speed influenced by the combined effect of ship heeling and trim, individual walking experiments were conducted in both fast and freely walking modes for female and male individual experimental subjects within the developed ship corridor simulator. When the heeling and/or trim angles are considered, average individual walking speed could be greatly attenuated, except that the average individual walking speed increases obviously under gravity effect during trim-down conditions as the trim-down slope increases from 0° to 10° when heeling angle α is 0°. So the maximum values for the average individual walking speed in this work could be achieved at the heeling angle α of 0°, with trim angle β ranging from -15° to -5°. The minimum values for the average individual walking speed could be obtained at the heeling angle α of 15°, with trim angle β of 20°. Compared to heeling angle, changing trim angle shows greater impact on average individual walking speed. When trim angle β>0°, the gradient of average individual walking speed along with the increasing heeling or trim angle is larger compared to that when trim angle β<0°. The average individual walking speed of female group is slower than that of male group, due to the difference in physical quality considering the gender factor. While the ratio of the individual walking speed of the female group to that of male group is not a constant, which could be affected by the difficulty of movement, such as walking with larger heeling or trim angles. In both freely and fast walking modes, the change of average individual walking speed versus the increasing heeling or trim angle presents similar tendency. It verifies the rationality of correlating fast walking speed and freely walking speed by using a coefficient in EXODUS, although the value of the coefficient used in EXODUS may need further study compared with the coefficient (78.6 ± 2.7%) obtained in this work. Furthermore, a prediction model for the individual walking speed reduction considering the combined effect of ship heeling and trim has been proposed. By providing the heeling and trim angles of an inclined condition, the individual walking speed reduction could be obtained, then with the individual walking speed in normal conditions, the individual walking speed in such an inclined condition could be calculated.

(3) To investigate the spatiotemporal step characteristics of individuals considering the effect of ship heeling and trim, individual walking experiments were conducted in both fast and freely walking modes for female and male individual experimental subjects within the developed ship corridor simulator. The distribution of the footprints and gait parameters are measured and analyzed. Individual experimental subjects tend to walk along the right side due to cultural factors. While the walking routes would be shifted with a larger heeling angle, meanwhile individuals tend to walk along the left side where a handrail is arranged when the trim-down angle exceeds 20° even though some of them did not use the handrail. Step length presents similar distribution to individual walking speed in different heeling and trim conditions, and it is positively linearly associated with individual walking speed, indicating that the increase in individual walking speed is directly related to the increase in the step length. However, there is no direct relationship between step width and individual walking speed, although walking with wider steps might weaken individual stability and increase fall risk during movement. Meanwhile, there is also a slight positive linear correlation between individual walking speed and step frequency. The increase of step frequency might lead to the increase in the individual walking speed. However, individuals could adopt quick and tiny steps in a much lower walking speed with larger step frequency to keep balance when the trim-down angle is too large.

(4) To investigate moving characteristics of single file passengers considering the effect of ship trim and heeling, single file walking experiments were conducted in fast walking mode for both female and male groups within the developed ship corridor simulator. Walking speed, density, distance headway and time headway are discussed, respectively. In normal conditions on land, pedestrian walking speed is mainly affected by the density. While during trim or heeling conditions, the density is no more the only factor that affects speed, since experimental subjects would change their walking gait and posture in trim or heeling conditions with larger angles which results in the attenuation of individual walking speed and group walking speed. Similar distributions of the group walking speed in single file movement could be observed compared with the individual walking speed in individual movement. The speed correlation coefficient between the adjacent experimental subjects would be higher for larger angles and lower speed, and experimental subjects are more likely to be influenced by the front neighbor rather than other experimental subjects in front. Moreover, both female and male experimental subjects need similar distance headway for walking in different trim or heeling conditions, and experimental subjects with lower individual walking speed need longer time headway to keep enough distance headway.

    Research areas

  • large passenger ship, ship evacuation, trim, heeling, individual walking speed, spatiotemporal step characteristics, single file moving characteristics