The rising throughput of log-yards imposes new constraints on existing equipment and increases the complexity of delivering an optimal and uninterrupted supply of pulpwood to pulp mills. To find ways of addressing these problems by reducing log cycle times, this work uses a discrete-event mathematics model to simulate operations at a log-yard and study the impact of three different log-yard inventory strategies and two alternative machine systems for log transportation between main log-yard and buffer storage. The yard’s existing inventory strategy of last load in and first out limits access to older logs at the main storage site. By allocating space for 89,000 m³ and 99,000 m³ of pulpwood at the buffer storage it is possible to keep the log cycle time at the main storage to a maximum of 12 and 6 months. Additionally, the use of an alternative log transportation machine system comprising a material handler with a trailer increased the work time capacity utilization relative to the yard’s current machine system of two shuttle trucks and a material handler for transporting logs between the main and buffer storage areas. Compared to the currently-used last in first out inventory strategy and purposely emptying the main storage area once or twice per year did reduce the total work time of both machine systems by 14% and 30%. Consequently, the volume delivered from the buffer to the log-yard decreased on average by 17% and 37% when emptying the main storage area once and twice per year. Even with reduced work time when emptying the main storage area, both machine systems could fulfil given work load for transporting logs from the buffer storage to the main log-yard without interrupting operations of the log-yard.

中文翻译：

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使用模拟对原木场的纸浆木替代库存策略和机器系统进行比较

原木堆场吞吐量的不断增加对现有设备施加了新的限制，并增加了向制浆厂提供最佳且不间断的纸浆供应的复杂性。为了找到减少日志周期的方法来解决这些问题的方法，这项工作使用离散事件数学模型来模拟日志场的操作，并研究三种不同的日志场库存策略和两种替代机器系统对日志运输的影响在主日志库和缓冲区存储之间。船厂现有的最后进出先出库存策略限制了对主存储站点中较旧日志的访问。通过分配89,000 m ³和99,000 m ^3的空间在缓冲存储器中保存纸浆木材，可以将主存储器中的原木循环时间最多保持12个月和6个月。另外，与包括两个穿梭卡车的船坞的当前机器系统以及用于在主存储区和缓冲存储区之间运输原木的材料装卸机相比，使用包括具有拖车的材料装卸机的替代原木运输机械系统的使用增加了工作时间的容量利用率。与当前使用的后进先出库存策略相比，有意每年清空一次或两次主存储区确实使两个机器系统的总工作时间减少了14％和30％。因此，每年清空一次和两次主存储区时，从缓冲区传送到原木场的体积分别减少了17％和37％。