Flexible intermediate Bulk Container (FIBC) under Dynamic Load

摘要

The goal of this case study was to determine the effect of bulk materials on the durability of FIBC (Big Bags) under dynamic load conditions. Special attention was paid to the parameters defined in the test standards of the FIBC case study. The stress placed on the FIBC during a drop test is determined by the drop height, the gross weight and the bulk material behavior, To study the effect of the bulk material in more detail, the critical drop height at which the horizontally transmitted force reached the maximum allowable stress for the FIBC was determined for PP-granulate, PP-granulate with added weight, salt, glass spheres and water. Despite a similar angle of repose and particulate size, the vertical stress could be doubled for tests with salt in comparison to PP-granulate. Adding weight to the PP-granulate also impacted the stress on the FIBC. With added weight the vertical stress can be increased in comparison to PP-granulate. The results clearly show that the properties specified in the test standards are insufficient to fully describe the effect of substitute bulk materials on the structural integrity of the FIBC under dynamic loads. The static angle of repose does not illustrate the conditions under dynamic load for the tested bulk materials. The "harmfulness" of the bulk material on the basis of its impact on the structural integrity of the FIBC can vary greatly even for materials with the same angle of repose and particulate size. The level of stress applied is largely dependant on the flow behavior within the bulk material. A larger vertical load does not necessarily translate into a higher level of stress on the FIBC. The vertical load is the cause for the flow behavior. What portion of this load then acts on the FIBC-shell is dependent on events within the bulk material. The non-standard behavior of the tested bulk materials under dynamic load suggests that the key horizontal load during the FIBC drop test is not constant even if the test standards are met, unless the testing institutions utilize identical substitute bulk materials. The Clausthal University of Technology, Institute for Mining, has a BAM-approved testing standard for hazardous material bags and also carries out testing and advisory activities in addition to research.