A simulation-based sizing approach for automated log yards

Abstract

Log yards store huge volumes of roundwood to provide raw material for the production process at sawmills. In order to achieve that, considerable transport efforts, usually done by wheel loaders and log stackers, are required. The automation of a log yard using automated storage components (ASCs) might be a promising way to simplify log yard processes and reduce costs. To address the related automated log yard configuration problem, a discrete event simulation model was developed in order to evaluate the alignment of various numbers and lengths of ASCs. We denote this model as a compact model as it is derived from a detailed one, in order to calculate a high number of eligible solutions. The approach was applied to a real-life case using data from an actual log yard of an Austrian sawmill. In order to test the model for various raw material distribution patterns and cost parameters, twelve scenarios were defined and compared. 6768 eligible combinations of ASC lengths were evaluated. The simulation model supports finding a configuration providing the required storage capacity at minimum cost for each scenario showing that the use of different ASC lengths is crucial. For the optimal solutions found never more than two different ASC lengths were used.