港口航道与海岸工程-外文翻译

港口航道与海岸工程-外文翻译内容摘要：

previous step, we used Year2020 AGV technical specs for the LiftAGVs. Now we increase the driving speeds according to latest standards: The new LiftAGVs can drive faster straight, faster in curves,and decelerate faster. This should cause shorter driving times per box, and hence increased QC productivity. The quay crane productivity increases significantly ag ain: with 4 to 5 bx/hr, as shown in Figure 10. The quay crane productivity increase is caused by the huge reduction in LiftAGV driving times per box. They only drive 5 minutes per box now, while this used to be minutes. The LiftAGVs generally arrive at the quay cranes earlier again,just like in Step 3, which causes an increase in waiting time to approach the quay crane transfer area, as shown in Figure 11. Note: average driving speed increased from 7 to km/hr. Step 5A: more opportunity moves The yard couldn‘t handle more moves in the original situation to make it beneficial to handle more than 10% of the containers with twinlift moves at the quay cranes. After Step 4, both the waterside and the landside RMG in the stack modules had 19% idle time. To make use of this spare time, we increased the twinlift percentage at the quay cranes. We assume most 20foot containers could be twinlifted when planned right. Because of this, and given the TEU factor of , the twinlift percentage is increased to 30%. Expected effects: The quay cranes can handle more containers per cycle (per move). If the container supply can be increased the productivity will go up. Maximum expected performance increase equals 18% (130%/110% boxes/cycle). The RMGs need to supply more containers faster. Their idle time will decrease and productivity will increase. Results The quay crane productivity is increased with some 3 bx/hr, or 10%,as shown in Figure 12. The quay crane performance increase is only possible because the RMGs were able to supply more containers to the interchange racks (and take more containers from them). The top graph in Figure 13 shows that each stack module was able to process one additional vessel job per hour: instead of . The increase in productive moves causes the time spent on productive moves to go up from 62% to 66%, as shown in the bottom graph, Figure 13. Idle percentage decreased from 19% to 16%. The remaining idle time shows there is still room for improvement. Step 5B: faster quay cranes (and NO increased twin percentage) The (19902020) dual trolley quay cranes in the original scenario and that have been used up to now, are relatively landside hoist has an average cycle time of 99 seconds. With modern cranes cycle times of 63 seconds should be possible. The kinematics of the cranes in the model have been adjusted in Step 5B to be able to make cycles of 63 seconds. Expected effects: The quay cranes can make more cycles per hour and hence productivity should increase. Waiting times for LiftAGVs at the quay cranes should decrease since the cranes need less time per move, and hence can serve the next LiftAGV sooner. Results The quay crane productivity increases by 5 to 7 bx/hr, or 20%,as shown in Figure 14. Other effects that were observed after this adjustment: • The quay crane status representing productive activity decreased from 90% to 65%. • The liftAGV waiting and interchange times at quay cranes decreased from 220 to 100 seconds per box processed. •The idle percentage of waterside RMGs decreased from 19% to 11%, and productivity increased from 62% to 73% (note: the differences do not even out because the landside RMG took over more unproductive work when the waterside productivity was increased) Step 6: all adjustments bined The final step is a parison between the start scenario and all adjustments described in the previous steps. We will see the overall impact on performance levels. Quay crane productivity has increased with bx/hr in the experiments with five vehicles per QC – or 68%! Remember that in Step 2, with the increased throughput, we already stated that QC productivity needed to go up to between 40 and 42 bx/hr and this goal has been achieved. The increased quay crane productivity is only possible with more efficient LiftAGVs and RMGs. Figure 16 shows that the LiftAGVs in the final scenario only need 7 minutes to plete one container move, while originally the AGVs needed 11 minutes. With the increased waterside productivities the stress on the yard has increased as well. The terminal throughput and according gate volume cause additional moves in the yard. The gate report shows that the RMGs are able to cope with this increased demand, because 460 truck moves have been handled and the truck service times are still acceptable, as shown in Figure 17. The increased demand on the yard is represented in the graph with RMG moves per stack module. In Step 6, the two RMGs in each stack module executed vessel boxes and gate boxes per hour, about 50% more than the original scenario. Meanwhile the number of housekeeping moves has been heavily reduced, as shown in Figure 18. This is not because there is less time, but because there is less need to do those moves. In the original scenario with dual RMGs, the RMGs often had to drop stackin containers as fast as possible to cope with lo。